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 796974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 80957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 81bece04b5SMarco Elver select ARCH_HAS_KCOV if X86_64 820c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 8310bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 840ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 85c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 8617596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 873010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 88eed9a328SYu Zhao select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 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 1113c516f89SSami Tolvanen select ARCH_SUPPORTS_CFI_CLANG if X86_64 1123c516f89SSami Tolvanen select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 113583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 114583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1156471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 116dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1176471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1186471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1192ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 120ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 12181c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 122c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 12351c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 12407431506SAnshuman Khandual select ARCH_WANT_GENERAL_HUGETLB 1253876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 12647010c04SMuchun Song select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP if X86_64 12759612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 12838d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 129b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 13010916706SShile Zhang select BUILDTIME_TABLE_SORT 1316471b825SIngo Molnar select CLKEVT_I8253 1326471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1336471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1347cf8f44aSAlexander Potapenko # Word-size accesses may read uninitialized data past the trailing \0 1357cf8f44aSAlexander Potapenko # in strings and cause false KMSAN reports. 1367cf8f44aSAlexander Potapenko select DCACHE_WORD_ACCESS if !KMSAN 1373aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 13845471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 13945471cd9SLinus Torvalds select EDAC_SUPPORT 1406471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1416471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1426471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1436471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 14461dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1456471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 14627d6b4d1SThomas Gleixner select GENERIC_ENTRY 1476471b825SIngo Molnar select GENERIC_IOMAP 148c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1490fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 150ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1516471b825SIngo Molnar select GENERIC_IRQ_PROBE 152c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1536471b825SIngo Molnar select GENERIC_IRQ_SHOW 1546471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1552ae27137SSteven Price select GENERIC_PTDUMP 1566471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1576471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1587ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 159550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 16039656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 16117e5888eSHans de Goede select HARDIRQS_SW_RESEND 1627edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1636471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1646471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1656471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1666471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1676471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 168eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1696471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 170b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 171d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1720609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1731dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1744ca8cc8dSAlexander Potapenko select HAVE_ARCH_KMSAN if X86_64 1756471b825SIngo Molnar select HAVE_ARCH_KGDB 1769e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1779e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1781b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 179271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1806471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 181f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 182afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1836471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1846471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 185a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 186b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1877677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 188e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 189fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 190c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1912ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1926471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1936471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 19424a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER if X86_64 19524a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 1966471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 19703f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 1984ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 1996471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 2009c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 201677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 20206aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 20302a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 204562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 205c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 206503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 20703f5781bSWang YanQing select HAVE_EBPF_JIT 20858340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2096630a8e5SChristoph Hellwig select HAVE_EISA 2105f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 21167a929e0SChristoph Hellwig select HAVE_FAST_GUP 212644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2136471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 2144a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2156471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2166b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2170067f129SK.Prasad select HAVE_HW_BREAKPOINT 2186471b825SIngo Molnar select HAVE_IOREMAP_PROT 219624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2206471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2214ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2226471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2236471b825SIngo Molnar select HAVE_KERNEL_GZIP 2246471b825SIngo Molnar select HAVE_KERNEL_LZ4 2256471b825SIngo Molnar select HAVE_KERNEL_LZMA 2266471b825SIngo Molnar select HAVE_KERNEL_LZO 2276471b825SIngo Molnar select HAVE_KERNEL_XZ 228fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2296471b825SIngo Molnar select HAVE_KPROBES 2306471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 231540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2326471b825SIngo Molnar select HAVE_KRETPROBES 233f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2346471b825SIngo Molnar select HAVE_KVM 2356471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2360102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 237ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2389f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 239be37c98dSKalesh Singh select HAVE_MOVE_PUD 24022102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 24142a0bb3fSPetr Mladek select HAVE_NMI 242489e355bSJosh Poimboeuf select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 24303f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2446471b825SIngo Molnar select HAVE_OPTPROBES 2456471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2466471b825SIngo Molnar select HAVE_PERF_EVENTS 247c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 24892e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 249eb01d42aSChristoph Hellwig select HAVE_PCI 250c5e63197SJiri Olsa select HAVE_PERF_REGS 251c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 252ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2531e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 25400998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2556471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 25603f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2573c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2587ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 259cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 260d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 26103f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 262e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 26303f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 26499cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 265d6761b8fSMathieu Desnoyers select HAVE_RSEQ 26609498135SMiguel Ojeda select HAVE_RUST if X86_64 2676471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2685f3da8c0SJosh Poimboeuf select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 2696471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2707c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2717ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 27205736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 273c0185808SThomas Gleixner select IRQ_FORCED_THREADING 2747ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2757ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 27686596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2772eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 278625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2796471b825SIngo Molnar select PERF_EVENTS 2803195ef59SPrarit Bhargava select RTC_LIB 281d6faca40SArnd Bergmann select RTC_MC146818_LIB 2826471b825SIngo Molnar select SPARSE_IRQ 28383fe27eaSPranith Kumar select SRCU 2846471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 28515f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2864aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2874510bffbSMark Rutland select TRACE_IRQFLAGS_NMI_SUPPORT 2886471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2893b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2906471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2910c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 29250468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 293*d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 294*d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_4B 2959e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 296ceea991aSJiri Olsa select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2977d8330a5SBalbir Singh 298ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2993120e25eSJan Beulich def_bool y 3003120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 301ba7e4d13SIngo Molnar 30251b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 30351b26adaSLinus Torvalds string 30451b26adaSLinus Torvalds default "elf32-i386" if X86_32 30551b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 30651b26adaSLinus Torvalds 3078d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 3083c2362e6SHarvey Harrison def_bool y 3098d5fffb9SSam Ravnborg 3108d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 3113c2362e6SHarvey Harrison def_bool y 3128d5fffb9SSam Ravnborg 3138d5fffb9SSam Ravnborgconfig MMU 3143c2362e6SHarvey Harrison def_bool y 3158d5fffb9SSam Ravnborg 3169e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3179e08f57dSDaniel Cashman default 28 if 64BIT 3189e08f57dSDaniel Cashman default 8 3199e08f57dSDaniel Cashman 3209e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3219e08f57dSDaniel Cashman default 32 if 64BIT 3229e08f57dSDaniel Cashman default 16 3239e08f57dSDaniel Cashman 3249e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3259e08f57dSDaniel Cashman default 8 3269e08f57dSDaniel Cashman 3279e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3289e08f57dSDaniel Cashman default 16 3299e08f57dSDaniel Cashman 3308d5fffb9SSam Ravnborgconfig SBUS 3318d5fffb9SSam Ravnborg bool 3328d5fffb9SSam Ravnborg 3338d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3343120e25eSJan Beulich def_bool y 3353120e25eSJan Beulich depends on ISA_DMA_API 3368d5fffb9SSam Ravnborg 337d911c67eSAlexander Potapenkoconfig GENERIC_CSUM 338d911c67eSAlexander Potapenko bool 339d911c67eSAlexander Potapenko default y if KMSAN || KASAN 340d911c67eSAlexander Potapenko 3418d5fffb9SSam Ravnborgconfig GENERIC_BUG 3423c2362e6SHarvey Harrison def_bool y 3438d5fffb9SSam Ravnborg depends on BUG 344b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 345b93a531eSJan Beulich 346b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 347b93a531eSJan Beulich bool 3488d5fffb9SSam Ravnborg 3498d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3503120e25eSJan Beulich def_bool y 3513120e25eSJan Beulich depends on ISA_DMA_API 3528d5fffb9SSam Ravnborg 3531032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3541032c0baSSam Ravnborg def_bool y 3551032c0baSSam Ravnborg 3569a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3579a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3588d5fffb9SSam Ravnborg 359801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 360801e4062SJohannes Berg def_bool y 361801e4062SJohannes Berg 362d7109fe3SAndy Shevchenkoconfig ARCH_NR_GPIO 363d7109fe3SAndy Shevchenko int 364d7109fe3SAndy Shevchenko default 1024 if X86_64 365d7109fe3SAndy Shevchenko default 512 366d7109fe3SAndy Shevchenko 367f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 368f4cb5700SJohannes Berg def_bool y 369f4cb5700SJohannes Berg 3708d5fffb9SSam Ravnborgconfig AUDIT_ARCH 371e0fd24a3SJan Beulich def_bool y if X86_64 3728d5fffb9SSam Ravnborg 373d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 374d6f2d75aSAndrey Ryabinin hex 375d6f2d75aSAndrey Ryabinin depends on KASAN 376d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 377d6f2d75aSAndrey Ryabinin 37869575d38SShane Wangconfig HAVE_INTEL_TXT 37969575d38SShane Wang def_bool y 3806ea30386SKees Cook depends on INTEL_IOMMU && ACPI 38169575d38SShane Wang 3826b0c3d44SSam Ravnborgconfig X86_32_SMP 3836b0c3d44SSam Ravnborg def_bool y 3846b0c3d44SSam Ravnborg depends on X86_32 && SMP 3856b0c3d44SSam Ravnborg 3866b0c3d44SSam Ravnborgconfig X86_64_SMP 3876b0c3d44SSam Ravnborg def_bool y 3886b0c3d44SSam Ravnborg depends on X86_64 && SMP 3896b0c3d44SSam Ravnborg 3902b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3912b144498SSrikar Dronamraju def_bool y 3922b144498SSrikar Dronamraju 393d20642f0SRob Herringconfig FIX_EARLYCON_MEM 394d20642f0SRob Herring def_bool y 395d20642f0SRob Herring 39694d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 39794d49eb3SKirill A. Shutemov bool 39894d49eb3SKirill A. Shutemov 39998233368SKirill A. Shutemovconfig PGTABLE_LEVELS 40098233368SKirill A. Shutemov int 40177ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 40298233368SKirill A. Shutemov default 4 if X86_64 40398233368SKirill A. Shutemov default 3 if X86_PAE 40498233368SKirill A. Shutemov default 2 40598233368SKirill A. Shutemov 4062a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 4072a61f474SMasahiro Yamada bool 4081b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 4091b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 4102a61f474SMasahiro Yamada help 4112a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 4123fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 4133fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 4142a61f474SMasahiro Yamada 415506f1d07SSam Ravnborgmenu "Processor type and features" 416506f1d07SSam Ravnborg 417506f1d07SSam Ravnborgconfig SMP 418506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 419a7f7f624SMasahiro Yamada help 420506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4214a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4224a474157SRobert Graffham than one CPU, say Y. 423506f1d07SSam Ravnborg 4244a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 425506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 426506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4274a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 428506f1d07SSam Ravnborg will run faster if you say N here. 429506f1d07SSam Ravnborg 430506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 431506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 432506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 433506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 434506f1d07SSam Ravnborg 435506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 436506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 437506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 438506f1d07SSam Ravnborg 439cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4404f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 441506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 442506f1d07SSam Ravnborg 443506f1d07SSam Ravnborg If you don't know what to do here, say N. 444506f1d07SSam Ravnborg 4459def39beSJosh Triplettconfig X86_FEATURE_NAMES 4469def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4479def39beSJosh Triplett default y 448a7f7f624SMasahiro Yamada help 4499def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4509def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4519def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4529def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4539def39beSJosh Triplett 4549def39beSJosh Triplett If in doubt, say Y. 4559def39beSJosh Triplett 45606cd9a7dSYinghai Luconfig X86_X2APIC 45706cd9a7dSYinghai Lu bool "Support x2apic" 45819e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 459a7f7f624SMasahiro Yamada help 46006cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 46106cd9a7dSYinghai Lu 46206cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 46306cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 46406cd9a7dSYinghai Lu 465b8d1d163SDaniel Sneddon Some Intel systems circa 2022 and later are locked into x2APIC mode 466b8d1d163SDaniel Sneddon and can not fall back to the legacy APIC modes if SGX or TDX are 467b8d1d163SDaniel Sneddon enabled in the BIOS. They will be unable to boot without enabling 468b8d1d163SDaniel Sneddon this option. 469b8d1d163SDaniel Sneddon 47006cd9a7dSYinghai Lu If you don't know what to do here, say N. 47106cd9a7dSYinghai Lu 4726695c85bSYinghai Luconfig X86_MPPARSE 4734590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4747a527688SJan Beulich default y 4755ab74722SIngo Molnar depends on X86_LOCAL_APIC 476a7f7f624SMasahiro Yamada help 4776695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4786695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4796695c85bSYinghai Lu 480ddd70cf9SJun Nakajimaconfig GOLDFISH 481ddd70cf9SJun Nakajima def_bool y 482ddd70cf9SJun Nakajima depends on X86_GOLDFISH 483ddd70cf9SJun Nakajima 484e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 485e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4866fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48759fe5a77SThomas Gleixner select KERNFS 488e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48978e99b4aSFenghua Yu help 490e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4916fe07ce3SBabu Moger 4926fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4936fe07ce3SBabu Moger usage by the CPU. 4946fe07ce3SBabu Moger 4956fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4966fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4976fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4986fe07ce3SBabu Moger 4996fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 5006fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 5016fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 50278e99b4aSFenghua Yu 50378e99b4aSFenghua Yu Say N if unsure. 50478e99b4aSFenghua Yu 5058425091fSRavikiran G Thirumalaiif X86_32 506a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 507a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 508a0d0bb4dSRandy Dunlap depends on SMP 509a7f7f624SMasahiro Yamada help 510e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 511a0d0bb4dSRandy Dunlap 512c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 513c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 514c5c606d9SRavikiran G Thirumalai default y 515a7f7f624SMasahiro Yamada help 51606ac8346SIngo Molnar If you disable this option then the kernel will only support 51706ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51806ac8346SIngo Molnar systems out there.) 51906ac8346SIngo Molnar 5208425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5218425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 522cb7b8023SBen Hutchings Goldfish (Android emulator) 5238425091fSRavikiran G Thirumalai AMD Elan 5248425091fSRavikiran G Thirumalai RDC R-321x SoC 5258425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 52683125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5273f4110a4SThomas Gleixner Moorestown MID devices 52806ac8346SIngo Molnar 52906ac8346SIngo Molnar If you have one of these systems, or if you want to build a 53006ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 531758cd94aSJuerg Haefligerendif # X86_32 53206ac8346SIngo Molnar 5338425091fSRavikiran G Thirumalaiif X86_64 5348425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5358425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5368425091fSRavikiran G Thirumalai default y 537a7f7f624SMasahiro Yamada help 5388425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5398425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5408425091fSRavikiran G Thirumalai systems out there.) 5418425091fSRavikiran G Thirumalai 5428425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5438425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 54444b111b5SSteffen Persvold Numascale NumaChip 5458425091fSRavikiran G Thirumalai ScaleMP vSMP 5468425091fSRavikiran G Thirumalai SGI Ultraviolet 5478425091fSRavikiran G Thirumalai 5488425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5498425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 550758cd94aSJuerg Haefligerendif # X86_64 551c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 552c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 55344b111b5SSteffen Persvoldconfig X86_NUMACHIP 55444b111b5SSteffen Persvold bool "Numascale NumaChip" 55544b111b5SSteffen Persvold depends on X86_64 55644b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55744b111b5SSteffen Persvold depends on NUMA 55844b111b5SSteffen Persvold depends on SMP 55944b111b5SSteffen Persvold depends on X86_X2APIC 560f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 561a7f7f624SMasahiro Yamada help 56244b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 56344b111b5SSteffen Persvold enable more than ~168 cores. 56444b111b5SSteffen Persvold If you don't have one of these, you should say N here. 56503b48632SNick Piggin 5666a48565eSIngo Molnarconfig X86_VSMP 567c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5686276a074SBorislav Petkov select HYPERVISOR_GUEST 5696a48565eSIngo Molnar select PARAVIRT 5706a48565eSIngo Molnar depends on X86_64 && PCI 571c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 572ead91d4bSShai Fultheim depends on SMP 573a7f7f624SMasahiro Yamada help 5746a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5756a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5766a48565eSIngo Molnar if you have one of these machines. 5776a48565eSIngo Molnar 578c5c606d9SRavikiran G Thirumalaiconfig X86_UV 579c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 580c5c606d9SRavikiran G Thirumalai depends on X86_64 581c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 58254c28d29SJack Steiner depends on NUMA 5831ecb4ae5SAndrew Morton depends on EFI 584c2209ea5SIngo Molnar depends on KEXEC_CORE 5859d6c26e7SSuresh Siddha depends on X86_X2APIC 5861222e564SIngo Molnar depends on PCI 587a7f7f624SMasahiro Yamada help 588c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 589c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 590c5c606d9SRavikiran G Thirumalai 591c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 592c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 593506f1d07SSam Ravnborg 594ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 595ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 596cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 597a7f7f624SMasahiro Yamada help 598ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 599ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 600ddd70cf9SJun Nakajima Goldfish emulator say N here. 601ddd70cf9SJun Nakajima 602c751e17bSThomas Gleixnerconfig X86_INTEL_CE 603c751e17bSThomas Gleixner bool "CE4100 TV platform" 604c751e17bSThomas Gleixner depends on PCI 605c751e17bSThomas Gleixner depends on PCI_GODIRECT 6066084a6e2SJiang Liu depends on X86_IO_APIC 607c751e17bSThomas Gleixner depends on X86_32 608c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60937bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 610da6b737bSSebastian Andrzej Siewior select OF 611da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 612a7f7f624SMasahiro Yamada help 613c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 614c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 615c751e17bSThomas Gleixner boxes and media devices. 616c751e17bSThomas Gleixner 6174cb9b00fSDavid Cohenconfig X86_INTEL_MID 61843605ef1SAlan Cox bool "Intel MID platform support" 61943605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 620edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6211ea7c673SAlan Cox depends on PCI 6223fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6231ea7c673SAlan Cox depends on X86_IO_APIC 6244cb9b00fSDavid Cohen select I2C 6257c9c3a1eSAlan Cox select DW_APB_TIMER 62654b34aa0SMika Westerberg select INTEL_SCU_PCI 627a7f7f624SMasahiro Yamada help 6284cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6294cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6304cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6311ea7c673SAlan Cox 6324cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6334cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 63443605ef1SAlan Cox 6358bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6368bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6378bbc2a13SBryan O'Donoghue depends on X86_32 6388bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6398bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6408bbc2a13SBryan O'Donoghue depends on X86_TSC 6418bbc2a13SBryan O'Donoghue depends on PCI 6428bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6438bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6448bbc2a13SBryan O'Donoghue select IOSF_MBI 6458bbc2a13SBryan O'Donoghue select INTEL_IMR 6469ab6eb51SAndy Shevchenko select COMMON_CLK 647a7f7f624SMasahiro Yamada help 6488bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6498bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6508bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6518bbc2a13SBryan O'Donoghue 6523d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6533d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6545962dd22SSinan Kaya depends on X86 && ACPI && PCI 6553d48aab1SMika Westerberg select COMMON_CLK 6560f531431SMathias Nyman select PINCTRL 657eebb3e8dSAndy Shevchenko select IOSF_MBI 658a7f7f624SMasahiro Yamada help 6593d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6603d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6610f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6620f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6633d48aab1SMika Westerberg 66492082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 66592082a88SKen Xue bool "AMD ACPI2Platform devices support" 66692082a88SKen Xue depends on ACPI 66792082a88SKen Xue select COMMON_CLK 66892082a88SKen Xue select PINCTRL 669a7f7f624SMasahiro Yamada help 67092082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 67192082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 67292082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 67392082a88SKen Xue implemented under PINCTRL subsystem. 67492082a88SKen Xue 675ced3ce76SDavid E. Boxconfig IOSF_MBI 676ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 677ced3ce76SDavid E. Box depends on PCI 678a7f7f624SMasahiro Yamada help 679ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 680ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 681ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 682ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 683ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 684ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 685ced3ce76SDavid E. Box This list is not meant to be exclusive. 686ced3ce76SDavid E. Box - BayTrail 687ced3ce76SDavid E. Box - Braswell 688ced3ce76SDavid E. Box - Quark 689ced3ce76SDavid E. Box 690ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 691ced3ce76SDavid E. Box 692ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 693ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 694ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 695a7f7f624SMasahiro Yamada help 696ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 697ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 698ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 699ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 700ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 701ed2226bdSDavid E. Box device they want to access. 702ed2226bdSDavid E. Box 703ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 704ed2226bdSDavid E. Box 705c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 706c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 707506f1d07SSam Ravnborg depends on X86_32 708c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 709c5c606d9SRavikiran G Thirumalai select M486 710c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 711a7f7f624SMasahiro Yamada help 712c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 713c5c606d9SRavikiran G Thirumalai as R-8610-(G). 714c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 715c5c606d9SRavikiran G Thirumalai 716e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7179c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7189c398017SIngo Molnar depends on X86_32 && SMP 719c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 720a7f7f624SMasahiro Yamada help 721b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 722b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 723b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 724b5660ba7SH. Peter Anvin one and will fallback to default. 725d49c4288SYinghai Lu 726c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 727d49c4288SYinghai Lu 728d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7296fc108a0SJan Beulich def_bool y 730d949f36fSLinus Torvalds # MCE code calls memory_failure(): 731d949f36fSLinus Torvalds depends on X86_MCE 732d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 733d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 734d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 735d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 736d949f36fSLinus Torvalds 73783125a3aSAlessandro Rubiniconfig STA2X11 73883125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73983125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 74083125a3aSAlessandro Rubini select SWIOTLB 74183125a3aSAlessandro Rubini select MFD_STA2X11 7420145071bSLinus Walleij select GPIOLIB 743a7f7f624SMasahiro Yamada help 74483125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 74583125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 74683125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74783125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74883125a3aSAlessandro Rubini standard PC machines. 74983125a3aSAlessandro Rubini 75082148d1dSShérabconfig X86_32_IRIS 75182148d1dSShérab tristate "Eurobraille/Iris poweroff module" 75282148d1dSShérab depends on X86_32 753a7f7f624SMasahiro Yamada help 75482148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 75582148d1dSShérab to shut themselves down properly. A special I/O sequence is 75682148d1dSShérab needed to do so, which is what this module does at 75782148d1dSShérab kernel shutdown. 75882148d1dSShérab 75982148d1dSShérab This is only for Iris machines from EuroBraille. 76082148d1dSShérab 76182148d1dSShérab If unused, say N. 76282148d1dSShérab 763ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7643c2362e6SHarvey Harrison def_bool y 7653c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 766a87d0914SKen Chen depends on X86 767a7f7f624SMasahiro Yamada help 768506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 769506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 770506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 771506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 772506f1d07SSam Ravnborg 773506f1d07SSam Ravnborg If in doubt, say "Y". 774506f1d07SSam Ravnborg 7756276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7766276a074SBorislav Petkov bool "Linux guest support" 777a7f7f624SMasahiro Yamada help 7786276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7796276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7806276a074SBorislav Petkov setup. 781506f1d07SSam Ravnborg 7826276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7836276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 784506f1d07SSam Ravnborg 7856276a074SBorislav Petkovif HYPERVISOR_GUEST 786506f1d07SSam Ravnborg 787e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 788e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 789a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 790a7f7f624SMasahiro Yamada help 791e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 792e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 793e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 794e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 795e61bd94aSEduardo Pereira Habkost 796c00a280aSJuergen Grossconfig PARAVIRT_XXL 797c00a280aSJuergen Gross bool 798c00a280aSJuergen Gross 7996276a074SBorislav Petkovconfig PARAVIRT_DEBUG 8006276a074SBorislav Petkov bool "paravirt-ops debugging" 8016276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 802a7f7f624SMasahiro Yamada help 8036276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 8046276a074SBorislav Petkov a paravirt_op is missing when it is called. 8056276a074SBorislav Petkov 806b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 807b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8086ea30386SKees Cook depends on PARAVIRT && SMP 809a7f7f624SMasahiro Yamada help 810b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 811b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 812b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 813b4ecc126SJeremy Fitzhardinge 8144c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8154c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 816b4ecc126SJeremy Fitzhardinge 8174c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 818b4ecc126SJeremy Fitzhardinge 819ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 820ecca2502SZhao Yakui def_bool n 821ecca2502SZhao Yakui 8226276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8236276a074SBorislav Petkov 8246276a074SBorislav Petkovconfig KVM_GUEST 8256276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8266276a074SBorislav Petkov depends on PARAVIRT 8276276a074SBorislav Petkov select PARAVIRT_CLOCK 828a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 829b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8306276a074SBorislav Petkov default y 831a7f7f624SMasahiro Yamada help 8326276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8336276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8346276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8356276a074SBorislav Petkov underlying device model, the host provides the guest with 8366276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8376276a074SBorislav Petkov 838a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 839a1c4423bSMarcelo Tosatti def_bool n 840a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 841a1c4423bSMarcelo Tosatti help 842a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 843a1c4423bSMarcelo Tosatti 8447733607fSMaran Wilsonconfig PVH 8457733607fSMaran Wilson bool "Support for running PVH guests" 846a7f7f624SMasahiro Yamada help 8477733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8487733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8497733607fSMaran Wilson 8506276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8516276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8526276a074SBorislav Petkov depends on PARAVIRT 853a7f7f624SMasahiro Yamada help 8546276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8556276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8566276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8576276a074SBorislav Petkov that, there can be a small performance impact. 8586276a074SBorislav Petkov 8596276a074SBorislav Petkov If in doubt, say N here. 8606276a074SBorislav Petkov 8617af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8627af192c9SGerd Hoffmann bool 8637af192c9SGerd Hoffmann 8644a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8654a362601SJan Kiszka bool "Jailhouse non-root cell support" 866abde587bSArnd Bergmann depends on X86_64 && PCI 86787e65d05SJan Kiszka select X86_PM_TIMER 868a7f7f624SMasahiro Yamada help 8694a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8704a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8714a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8724a362601SJan Kiszka 873ec7972c9SZhao Yakuiconfig ACRN_GUEST 874ec7972c9SZhao Yakui bool "ACRN Guest support" 875ec7972c9SZhao Yakui depends on X86_64 876498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 877ec7972c9SZhao Yakui help 878ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 879ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 880ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 881ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 882ec7972c9SZhao Yakui found in https://projectacrn.org/. 883ec7972c9SZhao Yakui 88459bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST 88559bd54a8SKuppuswamy Sathyanarayanan bool "Intel TDX (Trust Domain Extensions) - Guest Support" 88659bd54a8SKuppuswamy Sathyanarayanan depends on X86_64 && CPU_SUP_INTEL 88759bd54a8SKuppuswamy Sathyanarayanan depends on X86_X2APIC 88841394e33SKirill A. Shutemov select ARCH_HAS_CC_PLATFORM 889968b4931SKirill A. Shutemov select X86_MEM_ENCRYPT 89077a512e3SSean Christopherson select X86_MCE 89159bd54a8SKuppuswamy Sathyanarayanan help 89259bd54a8SKuppuswamy Sathyanarayanan Support running as a guest under Intel TDX. Without this support, 89359bd54a8SKuppuswamy Sathyanarayanan the guest kernel can not boot or run under TDX. 89459bd54a8SKuppuswamy Sathyanarayanan TDX includes memory encryption and integrity capabilities 89559bd54a8SKuppuswamy Sathyanarayanan which protect the confidentiality and integrity of guest 89659bd54a8SKuppuswamy Sathyanarayanan memory contents and CPU state. TDX guests are protected from 89759bd54a8SKuppuswamy Sathyanarayanan some attacks from the VMM. 89859bd54a8SKuppuswamy Sathyanarayanan 8996276a074SBorislav Petkovendif # HYPERVISOR_GUEST 90097349135SJeremy Fitzhardinge 901506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 902506f1d07SSam Ravnborg 903506f1d07SSam Ravnborgconfig HPET_TIMER 9043c2362e6SHarvey Harrison def_bool X86_64 905506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 906a7f7f624SMasahiro Yamada help 907506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 908506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 909506f1d07SSam Ravnborg present. 910506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 911506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 912506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 9134e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9144e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 915506f1d07SSam Ravnborg 916506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 917506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 918506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 919506f1d07SSam Ravnborg 920506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 921506f1d07SSam Ravnborg 922506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9233c2362e6SHarvey Harrison def_bool y 9243228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 925506f1d07SSam Ravnborg 9266a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 927506f1d07SSam Ravnborg# The code disables itself when not needed. 9287ae9392cSThomas Petazzoniconfig DMI 9297ae9392cSThomas Petazzoni default y 930cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9316a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 932a7f7f624SMasahiro Yamada help 9337ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9347ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9357ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9367ae9392cSThomas Petazzoni BIOS code. 9377ae9392cSThomas Petazzoni 938506f1d07SSam Ravnborgconfig GART_IOMMU 93938901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9402f9237d4SChristoph Hellwig select DMA_OPS 941a4ce5a48SChristoph Hellwig select IOMMU_HELPER 942506f1d07SSam Ravnborg select SWIOTLB 94323ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 944a7f7f624SMasahiro Yamada help 945ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 946ced3c42cSIngo Molnar GART based hardware IOMMUs. 947ced3c42cSIngo Molnar 948ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 949ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 950ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 951ced3c42cSIngo Molnar 952ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 953ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 954ced3c42cSIngo Molnar 955ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 956ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 957ced3c42cSIngo Molnar 32-bit limited device. 958ced3c42cSIngo Molnar 959ced3c42cSIngo Molnar If unsure, say Y. 960506f1d07SSam Ravnborg 9618b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT 9628b766b0fSMichal Suchanek bool 9638b766b0fSMichal Suchanek help 9648b766b0fSMichal Suchanek If true, at least one selected framebuffer driver can take advantage 9658b766b0fSMichal Suchanek of VESA video modes set at an early boot stage via the vga= parameter. 9668b766b0fSMichal Suchanek 9671184dc2fSMike Travisconfig MAXSMP 968ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9696ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 97036f5101aSMike Travis select CPUMASK_OFFSTACK 971a7f7f624SMasahiro Yamada help 972ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9731184dc2fSMike Travis If unsure, say N. 974506f1d07SSam Ravnborg 975aec6487eSIngo Molnar# 976aec6487eSIngo Molnar# The maximum number of CPUs supported: 977aec6487eSIngo Molnar# 978aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 979aec6487eSIngo Molnar# and which can be configured interactively in the 980aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 981aec6487eSIngo Molnar# 982aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 983aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 984aec6487eSIngo Molnar# 985aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 986aec6487eSIngo Molnar# interactive configuration. ) 987aec6487eSIngo Molnar# 988a0d0bb4dSRandy Dunlap 989aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 990a0d0bb4dSRandy Dunlap int 991aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 992a0d0bb4dSRandy Dunlap default 1 if !SMP 993a0d0bb4dSRandy Dunlap default 2 994a0d0bb4dSRandy Dunlap 995aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 996a0d0bb4dSRandy Dunlap int 997a0d0bb4dSRandy Dunlap depends on X86_32 998aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 999aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 1000a0d0bb4dSRandy Dunlap default 1 if !SMP 1001a0d0bb4dSRandy Dunlap 1002aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 1003a0d0bb4dSRandy Dunlap int 1004a0d0bb4dSRandy Dunlap depends on X86_64 10051edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 10061edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 1007a0d0bb4dSRandy Dunlap default 1 if !SMP 1008aec6487eSIngo Molnar 1009aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1010aec6487eSIngo Molnar int 1011aec6487eSIngo Molnar depends on X86_32 1012aec6487eSIngo Molnar default 32 if X86_BIGSMP 1013aec6487eSIngo Molnar default 8 if SMP 1014aec6487eSIngo Molnar default 1 if !SMP 1015aec6487eSIngo Molnar 1016aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1017aec6487eSIngo Molnar int 1018aec6487eSIngo Molnar depends on X86_64 1019a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1020a0d0bb4dSRandy Dunlap default 64 if SMP 1021aec6487eSIngo Molnar default 1 if !SMP 1022a0d0bb4dSRandy Dunlap 1023506f1d07SSam Ravnborgconfig NR_CPUS 102436f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1025aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1026aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1027a7f7f624SMasahiro Yamada help 1028506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1029bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1030cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1031506f1d07SSam Ravnborg minimum value which makes sense is 2. 1032506f1d07SSam Ravnborg 1033aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1034aec6487eSIngo Molnar to the kernel image. 1035506f1d07SSam Ravnborg 103666558b73STim Chenconfig SCHED_CLUSTER 103766558b73STim Chen bool "Cluster scheduler support" 103866558b73STim Chen depends on SMP 103966558b73STim Chen default y 104066558b73STim Chen help 104166558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 104266558b73STim Chen making when dealing with machines that have clusters of CPUs. 104366558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 104466558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 104566558b73STim Chen busses. 104666558b73STim Chen 1047506f1d07SSam Ravnborgconfig SCHED_SMT 1048dbe73364SThomas Gleixner def_bool y if SMP 1049506f1d07SSam Ravnborg 1050506f1d07SSam Ravnborgconfig SCHED_MC 10513c2362e6SHarvey Harrison def_bool y 10523c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1053c8e56d20SBorislav Petkov depends on SMP 1054a7f7f624SMasahiro Yamada help 1055506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1056506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1057506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1058506f1d07SSam Ravnborg 1059de966cf4STim Chenconfig SCHED_MC_PRIO 1060de966cf4STim Chen bool "CPU core priorities scheduler support" 10610a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10620a21fc12SIngo Molnar select X86_INTEL_PSTATE 10630a21fc12SIngo Molnar select CPU_FREQ 1064de966cf4STim Chen default y 1065a7f7f624SMasahiro Yamada help 1066de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1067de966cf4STim Chen core ordering determined at manufacturing time, which allows 1068de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1069de966cf4STim Chen single threaded workloads) than others. 1070de966cf4STim Chen 1071de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1072de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1073de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1074de966cf4STim Chen overall system performance can be achieved. 1075de966cf4STim Chen 1076de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1077de966cf4STim Chen 1078de966cf4STim Chen If unsure say Y here. 10795e76b2abSTim Chen 108030b8b006SThomas Gleixnerconfig UP_LATE_INIT 108130b8b006SThomas Gleixner def_bool y 1082ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 108330b8b006SThomas Gleixner 1084506f1d07SSam Ravnborgconfig X86_UP_APIC 108550849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 108650849eefSJan Beulich default PCI_MSI 108738a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1088a7f7f624SMasahiro Yamada help 1089506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1090506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1091506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1092506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1093506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1094506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1095506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1096506f1d07SSam Ravnborg lockups. 1097506f1d07SSam Ravnborg 1098506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1099506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1100506f1d07SSam Ravnborg depends on X86_UP_APIC 1101a7f7f624SMasahiro Yamada help 1102506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1103506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1104506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1105506f1d07SSam Ravnborg 1106506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1107506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1108506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1109506f1d07SSam Ravnborg 1110506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 11113c2362e6SHarvey Harrison def_bool y 11120dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1113b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 111452f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1115506f1d07SSam Ravnborg 1116506f1d07SSam Ravnborgconfig X86_IO_APIC 1117b1da1e71SJan Beulich def_bool y 1118b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1119506f1d07SSam Ravnborg 112041b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 112141b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 112241b9eb26SStefan Assmann depends on X86_IO_APIC 1123a7f7f624SMasahiro Yamada help 112441b9eb26SStefan Assmann This option enables a workaround that fixes a source of 112541b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 112641b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 112741b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 112841b9eb26SStefan Assmann 112941b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 113041b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 113141b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 113241b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 113341b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 113441b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 113541b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 113641b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 113741b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 113841b9eb26SStefan Assmann down (vital) interrupt lines. 113941b9eb26SStefan Assmann 114041b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 114141b9eb26SStefan Assmann increased on these systems. 114241b9eb26SStefan Assmann 1143506f1d07SSam Ravnborgconfig X86_MCE 1144bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1145648ed940SChen, Gong select GENERIC_ALLOCATOR 1146e57dbaf7SBorislav Petkov default y 1147a7f7f624SMasahiro Yamada help 1148bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1149bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1150506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1151bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11524efc0670SAndi Kleen 11535de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11545de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11555de97c9fSTony Luck depends on X86_MCE 1156a7f7f624SMasahiro Yamada help 11575de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11585de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11595de97c9fSTony Luck rasdaemon solution. 11605de97c9fSTony Luck 1161506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11623c2362e6SHarvey Harrison def_bool y 11633c2362e6SHarvey Harrison prompt "Intel MCE features" 1164c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1165a7f7f624SMasahiro Yamada help 1166506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1167506f1d07SSam Ravnborg the thermal monitor. 1168506f1d07SSam Ravnborg 1169506f1d07SSam Ravnborgconfig X86_MCE_AMD 11703c2362e6SHarvey Harrison def_bool y 11713c2362e6SHarvey Harrison prompt "AMD MCE features" 1172f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1173a7f7f624SMasahiro Yamada help 1174506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1175506f1d07SSam Ravnborg the DRAM Error Threshold. 1176506f1d07SSam Ravnborg 11774efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11786fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1179c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1180a7f7f624SMasahiro Yamada help 11814efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11825065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11834efc0670SAndi Kleen line. 11844efc0670SAndi Kleen 1185b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1186b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11876fc108a0SJan Beulich def_bool y 1188b2762686SAndi Kleen 1189ea149b36SAndi Kleenconfig X86_MCE_INJECT 1190bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1191ea149b36SAndi Kleen tristate "Machine check injector support" 1192a7f7f624SMasahiro Yamada help 1193ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1194ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1195ea149b36SAndi Kleen QA it is safe to say n. 1196ea149b36SAndi Kleen 119707dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1198e633c65aSKan Liang 11995aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 12001e642812SIngo Molnar bool "Legacy VM86 support" 1201506f1d07SSam Ravnborg depends on X86_32 1202a7f7f624SMasahiro Yamada help 12035aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 12045aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 12055aef51c3SAndy Lutomirski 12065aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 12075aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 12085aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 12095aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 12105aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12111e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12121e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12131e642812SIngo Molnar mode might be faster than emulation and you might want to 12141e642812SIngo Molnar enable this option. 12155aef51c3SAndy Lutomirski 12161e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12171e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12181e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12191e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12205aef51c3SAndy Lutomirski 12211e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12221e642812SIngo Molnar and slows down exception handling a tiny bit. 12235aef51c3SAndy Lutomirski 12241e642812SIngo Molnar If unsure, say N here. 12255aef51c3SAndy Lutomirski 12265aef51c3SAndy Lutomirskiconfig VM86 12275aef51c3SAndy Lutomirski bool 12285aef51c3SAndy Lutomirski default X86_LEGACY_VM86 122934273f41SH. Peter Anvin 123034273f41SH. Peter Anvinconfig X86_16BIT 123134273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 123234273f41SH. Peter Anvin default y 1233a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1234a7f7f624SMasahiro Yamada help 123534273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 123634273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 123734273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 123834273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 123934273f41SH. Peter Anvin 124034273f41SH. Peter Anvinconfig X86_ESPFIX32 124134273f41SH. Peter Anvin def_bool y 124234273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1243506f1d07SSam Ravnborg 1244197725deSH. Peter Anvinconfig X86_ESPFIX64 1245197725deSH. Peter Anvin def_bool y 124634273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1247506f1d07SSam Ravnborg 12481ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12491ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12501ad83c85SAndy Lutomirski default y 12511ad83c85SAndy Lutomirski depends on X86_64 1252a7f7f624SMasahiro Yamada help 12531ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12541ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12551ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12561ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12571ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12581ad83c85SAndy Lutomirski 0xffffffffff600?00. 12591ad83c85SAndy Lutomirski 12601ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12611ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12621ad83c85SAndy Lutomirski 12631ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12641ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12651ad83c85SAndy Lutomirski 1266111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1267111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1268a24ca997SThomas Gleixner default y 1269a7f7f624SMasahiro Yamada help 1270111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1271111e7b15SThomas Gleixner for legacy applications. 1272111e7b15SThomas Gleixner 1273c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1274c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1275c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1276c8137aceSThomas Gleixner capabilities and permission from potentially active security 1277c8137aceSThomas Gleixner modules. 1278c8137aceSThomas Gleixner 1279c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1280c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1281a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1282a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1283c8137aceSThomas Gleixner 1284506f1d07SSam Ravnborgconfig TOSHIBA 1285506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1286506f1d07SSam Ravnborg depends on X86_32 1287a7f7f624SMasahiro Yamada help 1288506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1289506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1290506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1291506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1292506f1d07SSam Ravnborg 1293506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1294506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1295506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1296506f1d07SSam Ravnborg 1297506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1298506f1d07SSam Ravnborg Say N otherwise. 1299506f1d07SSam Ravnborg 1300506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 13019ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 13029ba16087SJan Beulich depends on X86_32 1303a7f7f624SMasahiro Yamada help 1304506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1305506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1306506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1307506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1308506f1d07SSam Ravnborg system. 1309506f1d07SSam Ravnborg 1310506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13115e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1312506f1d07SSam Ravnborg 1313506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1314506f1d07SSam Ravnborg enable this option even if you don't need it. 1315506f1d07SSam Ravnborg Say N otherwise. 1316506f1d07SSam Ravnborg 1317506f1d07SSam Ravnborgconfig MICROCODE 13189a2bc335SBorislav Petkov bool "CPU microcode loading support" 13199a2bc335SBorislav Petkov default y 132080030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1321a7f7f624SMasahiro Yamada help 1322506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13235f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13245f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13255f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13265f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13275f9c01aaSBorislav Petkov the Linux kernel. 1328506f1d07SSam Ravnborg 13295f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1330cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13315f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13325f9c01aaSBorislav Petkov initrd for microcode blobs. 1333506f1d07SSam Ravnborg 1334c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1335c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1336c508c46eSBenjamin Gilbert config option. 1337506f1d07SSam Ravnborg 13388d86f390SPeter Orubaconfig MICROCODE_INTEL 1339e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13409c55d99eSBorislav Petkov depends on CPU_SUP_INTEL && MICROCODE 13418d86f390SPeter Oruba default MICROCODE 1342a7f7f624SMasahiro Yamada help 13438d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13448d86f390SPeter Oruba processors. 13458d86f390SPeter Oruba 1346b8989db9SAlan For the current Intel microcode data package go to 1347b8989db9SAlan <https://downloadcenter.intel.com> and search for 1348b8989db9SAlan 'Linux Processor Microcode Data File'. 13498d86f390SPeter Oruba 135080cc9f10SPeter Orubaconfig MICROCODE_AMD 1351e43f6e67SBorislav Petkov bool "AMD microcode loading support" 13529c55d99eSBorislav Petkov depends on CPU_SUP_AMD && MICROCODE 1353a7f7f624SMasahiro Yamada help 135480cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 135580cc9f10SPeter Oruba processors will be enabled. 135680cc9f10SPeter Oruba 1357a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING 1358a77a94f8SBorislav Petkov bool "Late microcode loading (DANGEROUS)" 1359c02f48e0SBorislav Petkov default n 1360506f1d07SSam Ravnborg depends on MICROCODE 1361a7f7f624SMasahiro Yamada help 1362a77a94f8SBorislav Petkov Loading microcode late, when the system is up and executing instructions 1363a77a94f8SBorislav Petkov is a tricky business and should be avoided if possible. Just the sequence 1364a77a94f8SBorislav Petkov of synchronizing all cores and SMT threads is one fragile dance which does 1365a77a94f8SBorislav Petkov not guarantee that cores might not softlock after the loading. Therefore, 1366a77a94f8SBorislav Petkov use this at your own risk. Late loading taints the kernel too. 1367506f1d07SSam Ravnborg 1368506f1d07SSam Ravnborgconfig X86_MSR 1369506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1370a7f7f624SMasahiro Yamada help 1371506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1372506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1373506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1374506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1375506f1d07SSam Ravnborg systems. 1376506f1d07SSam Ravnborg 1377506f1d07SSam Ravnborgconfig X86_CPUID 1378506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1379a7f7f624SMasahiro Yamada help 1380506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1381506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1382506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1383506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1384506f1d07SSam Ravnborg 1385506f1d07SSam Ravnborgchoice 1386506f1d07SSam Ravnborg prompt "High Memory Support" 13876fc108a0SJan Beulich default HIGHMEM4G 1388506f1d07SSam Ravnborg depends on X86_32 1389506f1d07SSam Ravnborg 1390506f1d07SSam Ravnborgconfig NOHIGHMEM 1391506f1d07SSam Ravnborg bool "off" 1392a7f7f624SMasahiro Yamada help 1393506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1394506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1395506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1396506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1397506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1398506f1d07SSam Ravnborg "high memory". 1399506f1d07SSam Ravnborg 1400506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1401506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1402506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1403506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1404506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1405506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1406506f1d07SSam Ravnborg possible. 1407506f1d07SSam Ravnborg 1408506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1409506f1d07SSam Ravnborg answer "4GB" here. 1410506f1d07SSam Ravnborg 1411506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1412506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1413506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1414506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1415506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1416506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1417506f1d07SSam Ravnborg 1418506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1419506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1420506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1421506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1422506f1d07SSam Ravnborg kernel at boot time.) 1423506f1d07SSam Ravnborg 1424506f1d07SSam Ravnborg If unsure, say "off". 1425506f1d07SSam Ravnborg 1426506f1d07SSam Ravnborgconfig HIGHMEM4G 1427506f1d07SSam Ravnborg bool "4GB" 1428a7f7f624SMasahiro Yamada help 1429506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1430506f1d07SSam Ravnborg gigabytes of physical RAM. 1431506f1d07SSam Ravnborg 1432506f1d07SSam Ravnborgconfig HIGHMEM64G 1433506f1d07SSam Ravnborg bool "64GB" 1434225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1435506f1d07SSam Ravnborg select X86_PAE 1436a7f7f624SMasahiro Yamada help 1437506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1438506f1d07SSam Ravnborg gigabytes of physical RAM. 1439506f1d07SSam Ravnborg 1440506f1d07SSam Ravnborgendchoice 1441506f1d07SSam Ravnborg 1442506f1d07SSam Ravnborgchoice 14436a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1444506f1d07SSam Ravnborg default VMSPLIT_3G 1445506f1d07SSam Ravnborg depends on X86_32 1446a7f7f624SMasahiro Yamada help 1447506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1448506f1d07SSam Ravnborg 1449506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1450506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1451506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1452506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1453506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1454506f1d07SSam Ravnborg available to user programs, making the address space there 1455506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1456506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1457506f1d07SSam Ravnborg kernel modules. 1458506f1d07SSam Ravnborg 1459506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1460506f1d07SSam Ravnborg option alone! 1461506f1d07SSam Ravnborg 1462506f1d07SSam Ravnborg config VMSPLIT_3G 1463506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1464506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1465506f1d07SSam Ravnborg depends on !X86_PAE 1466506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1467506f1d07SSam Ravnborg config VMSPLIT_2G 1468506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1469506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1470506f1d07SSam Ravnborg depends on !X86_PAE 1471506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1472506f1d07SSam Ravnborg config VMSPLIT_1G 1473506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1474506f1d07SSam Ravnborgendchoice 1475506f1d07SSam Ravnborg 1476506f1d07SSam Ravnborgconfig PAGE_OFFSET 1477506f1d07SSam Ravnborg hex 1478506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1479506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1480506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1481506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1482506f1d07SSam Ravnborg default 0xC0000000 1483506f1d07SSam Ravnborg depends on X86_32 1484506f1d07SSam Ravnborg 1485506f1d07SSam Ravnborgconfig HIGHMEM 14863c2362e6SHarvey Harrison def_bool y 1487506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1488506f1d07SSam Ravnborg 1489506f1d07SSam Ravnborgconfig X86_PAE 14909ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1491506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1492d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14939d99c712SChristian Melki select SWIOTLB 1494a7f7f624SMasahiro Yamada help 1495506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1496506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1497506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1498506f1d07SSam Ravnborg consumes more pagetable space per process. 1499506f1d07SSam Ravnborg 150077ef56e4SKirill A. Shutemovconfig X86_5LEVEL 150177ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 150218ec1eafSKirill A. Shutemov default y 1503eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1504162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 150577ef56e4SKirill A. Shutemov depends on X86_64 1506a7f7f624SMasahiro Yamada help 150777ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 150877ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 150977ef56e4SKirill A. Shutemov physical address space. 151077ef56e4SKirill A. Shutemov 151177ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 151277ef56e4SKirill A. Shutemov 15136657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15146657fca0SKirill A. Shutemov support 4- or 5-level paging. 151577ef56e4SKirill A. Shutemov 1516cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 151777ef56e4SKirill A. Shutemov information. 151877ef56e4SKirill A. Shutemov 151977ef56e4SKirill A. Shutemov Say N if unsure. 152077ef56e4SKirill A. Shutemov 152110971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1522e5008abeSLuis R. Rodriguez def_bool y 15232e1da13fSVlastimil Babka depends on X86_64 1524a7f7f624SMasahiro Yamada help 152510971ab2SIngo Molnar Certain kernel features effectively disable kernel 152610971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 152710971ab2SIngo Molnar supports them), so don't confuse the user by printing 152810971ab2SIngo Molnar that we have them enabled. 15299e899816SNick Piggin 15305c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15315c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15325c280cf6SThomas Gleixner depends on DEBUG_FS 1533a7f7f624SMasahiro Yamada help 1534b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1535a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15365c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15375c280cf6SThomas Gleixner 153820f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 153920f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 154020f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 154120f07a04SKirill A. Shutemov def_bool n 154220f07a04SKirill A. Shutemov 15437744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15447744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15457744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 154682fef0adSDavid Rientjes select DMA_COHERENT_POOL 1547ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1548597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1549aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 155020f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 1551a7f7f624SMasahiro Yamada help 15527744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15537744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15547744ccdbSTom Lendacky Encryption (SME). 15557744ccdbSTom Lendacky 15567744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15577744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15587744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1559a7f7f624SMasahiro Yamada help 15607744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15617744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15627744ccdbSTom Lendacky 15637744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15647744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15657744ccdbSTom Lendacky 15667744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15677744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15687744ccdbSTom Lendacky 1569506f1d07SSam Ravnborg# Common NUMA Features 1570506f1d07SSam Ravnborgconfig NUMA 1571e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1572506f1d07SSam Ravnborg depends on SMP 1573b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1574b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15757ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1576a7f7f624SMasahiro Yamada help 1577e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1578fd51b2d7SKOSAKI Motohiro 1579506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1580506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1581506f1d07SSam Ravnborg NUMA awareness to the kernel. 1582506f1d07SSam Ravnborg 1583c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1584fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1585fd51b2d7SKOSAKI Motohiro 1586b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15877cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1588fd51b2d7SKOSAKI Motohiro 1589fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1590506f1d07SSam Ravnborg 1591eec1d4faSHans Rosenfeldconfig AMD_NUMA 15923c2362e6SHarvey Harrison def_bool y 15933c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15945da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1595a7f7f624SMasahiro Yamada help 1596eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1597eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1598eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1599eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1600eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1601506f1d07SSam Ravnborg 1602506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 16033c2362e6SHarvey Harrison def_bool y 16043c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1605506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1606506f1d07SSam Ravnborg select ACPI_NUMA 1607a7f7f624SMasahiro Yamada help 1608506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1609506f1d07SSam Ravnborg 1610506f1d07SSam Ravnborgconfig NUMA_EMU 1611506f1d07SSam Ravnborg bool "NUMA emulation" 16121b7e03efSTejun Heo depends on NUMA 1613a7f7f624SMasahiro Yamada help 1614506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1615506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1616506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1617506f1d07SSam Ravnborg 1618506f1d07SSam Ravnborgconfig NODES_SHIFT 1619d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 162051591e31SDavid Rientjes range 1 10 162151591e31SDavid Rientjes default "10" if MAXSMP 1622506f1d07SSam Ravnborg default "6" if X86_64 1623506f1d07SSam Ravnborg default "3" 1624a9ee6cf5SMike Rapoport depends on NUMA 1625a7f7f624SMasahiro Yamada help 16261184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1627692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1628506f1d07SSam Ravnborg 1629506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1630506f1d07SSam Ravnborg def_bool y 16313b16651fSTejun Heo depends on X86_32 && !NUMA 1632506f1d07SSam Ravnborg 1633506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1634506f1d07SSam Ravnborg def_bool y 16356ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1636506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1637506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1638506f1d07SSam Ravnborg 16393b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16406ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16413b16651fSTejun Heo 1642506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1643506f1d07SSam Ravnborg def_bool y 16444eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1645506f1d07SSam Ravnborg 1646506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1647a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16485c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1649a0842b70SToshi Kani help 1650a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1651cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1652a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1653506f1d07SSam Ravnborg 16543b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16553b16651fSTejun Heo def_bool y 16563b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16573b16651fSTejun Heo 1658a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1659a29815a3SAvi Kivity hex 1660a29815a3SAvi Kivity default 0 if X86_32 1661a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1662a29815a3SAvi Kivity 16637a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16647a67832cSDan Williams bool 16657a67832cSDan Williams 1666ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16677a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16689f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16699f53f9faSDan Williams depends on BLK_DEV 16707a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16717b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16729f53f9faSDan Williams select LIBNVDIMM 1673ec776ef6SChristoph Hellwig help 1674ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1675ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1676ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1677ec776ef6SChristoph Hellwig they can be used for persistent storage. 1678ec776ef6SChristoph Hellwig 1679ec776ef6SChristoph Hellwig Say Y if unsure. 1680ec776ef6SChristoph Hellwig 1681506f1d07SSam Ravnborgconfig HIGHPTE 1682506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16836fc108a0SJan Beulich depends on HIGHMEM 1684a7f7f624SMasahiro Yamada help 1685506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1686506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1687506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1688506f1d07SSam Ravnborg entries in high memory. 1689506f1d07SSam Ravnborg 16909f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16919f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1692a7f7f624SMasahiro Yamada help 16939f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16949f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16959f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16969f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16979f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16989f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16999f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 17008c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 17019f077871SJeremy Fitzhardinge 17029f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 17039f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 17049f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 17059f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 17069f077871SJeremy Fitzhardinge 17079f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 17089f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 17099f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 17109f077871SJeremy Fitzhardinge memory. 17119f077871SJeremy Fitzhardinge 1712c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1713c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1714c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1715c885df50SJeremy Fitzhardinge default y 1716a7f7f624SMasahiro Yamada help 1717c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1718c885df50SJeremy Fitzhardinge on or off. 1719c885df50SJeremy Fitzhardinge 1720506f1d07SSam Ravnborgconfig MATH_EMULATION 1721506f1d07SSam Ravnborg bool 1722a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 172387d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1724a7f7f624SMasahiro Yamada help 1725506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1726506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1727506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1728506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1729506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1730506f1d07SSam Ravnborg coprocessor or this emulation. 1731506f1d07SSam Ravnborg 1732506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1733506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1734506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1735506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1736506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1737506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1738506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1739506f1d07SSam Ravnborg intend to use this kernel on different machines. 1740506f1d07SSam Ravnborg 1741506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1742506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1743506f1d07SSam Ravnborg 1744506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1745506f1d07SSam Ravnborg kernel, it won't hurt. 1746506f1d07SSam Ravnborg 1747506f1d07SSam Ravnborgconfig MTRR 17486fc108a0SJan Beulich def_bool y 17496a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1750a7f7f624SMasahiro Yamada help 1751506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1752506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1753506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1754506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1755506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1756506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1757506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1758506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1759506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1760506f1d07SSam Ravnborg 1761506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1762506f1d07SSam Ravnborg control registers on other processors can be easily supported 1763506f1d07SSam Ravnborg as well: 1764506f1d07SSam Ravnborg 1765506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1766506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1767506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1768506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1769506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1770506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1771506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1772506f1d07SSam Ravnborg 1773506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1774506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1775506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1776506f1d07SSam Ravnborg 1777506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1778506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1779506f1d07SSam Ravnborg 1780cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1781506f1d07SSam Ravnborg 178295ffa243SYinghai Luconfig MTRR_SANITIZER 17832ffb3501SYinghai Lu def_bool y 178495ffa243SYinghai Lu prompt "MTRR cleanup support" 178595ffa243SYinghai Lu depends on MTRR 1786a7f7f624SMasahiro Yamada help 1787aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1788aba3728cSThomas Gleixner add writeback entries. 178995ffa243SYinghai Lu 1790aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1791692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1792aba3728cSThomas Gleixner mtrr_chunk_size. 179395ffa243SYinghai Lu 17942ffb3501SYinghai Lu If unsure, say Y. 179595ffa243SYinghai Lu 179695ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1797f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1798f5098d62SYinghai Lu range 0 1 1799f5098d62SYinghai Lu default "0" 180095ffa243SYinghai Lu depends on MTRR_SANITIZER 1801a7f7f624SMasahiro Yamada help 1802f5098d62SYinghai Lu Enable mtrr cleanup default value 180395ffa243SYinghai Lu 180412031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 180512031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 180612031a62SYinghai Lu range 0 7 180712031a62SYinghai Lu default "1" 180812031a62SYinghai Lu depends on MTRR_SANITIZER 1809a7f7f624SMasahiro Yamada help 181012031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1811aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 181212031a62SYinghai Lu 18132e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18146fc108a0SJan Beulich def_bool y 18156a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18162a8a2719SIngo Molnar depends on MTRR 1817a7f7f624SMasahiro Yamada help 18182e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1819042b78e4SVenki Pallipadi 18202e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18212e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18222e5d9c85Svenkatesh.pallipadi@intel.com 18232e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1824042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18252e5d9c85Svenkatesh.pallipadi@intel.com 18262e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18272e5d9c85Svenkatesh.pallipadi@intel.com 182846cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 182946cf98cdSVenkatesh Pallipadi def_bool y 183046cf98cdSVenkatesh Pallipadi depends on X86_PAT 183146cf98cdSVenkatesh Pallipadi 1832b971880fSBabu Mogerconfig X86_UMIP 1833796ebc81SRicardo Neri def_bool y 1834b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1835a7f7f624SMasahiro Yamada help 1836b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1837b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1838b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1839b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1840b971880fSBabu Moger information about the hardware state. 1841796ebc81SRicardo Neri 1842796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1843796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1844796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1845796ebc81SRicardo Neri results are dummy. 1846aa35f896SRicardo Neri 1847156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1848156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1849156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1850156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1851262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1852262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1853156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1854262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1855156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1856156ff4a5SPeter Zijlstra 1857156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1858156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 1859156ff4a5SPeter Zijlstra bool 186003f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1861f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1862f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 186303f16cd0SJosh Poimboeuf select OBJTOOL 1864156ff4a5SPeter Zijlstra help 1865156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1866156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1867156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1868156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1869156ff4a5SPeter Zijlstra code with them to make this happen. 1870156ff4a5SPeter Zijlstra 1871ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18724cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1873ed53a0d9SPeter Zijlstra 1874ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1875ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1876ed53a0d9SPeter Zijlstra kernel image. 1877ed53a0d9SPeter Zijlstra 187835e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 187938f3e775SBabu Moger prompt "Memory Protection Keys" 188035e97790SDave Hansen def_bool y 1881284244a9SDave Hansen # Note: only available in 64-bit mode 188238f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 188352c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 188452c8e601SIngo Molnar select ARCH_HAS_PKEYS 1885a7f7f624SMasahiro Yamada help 1886284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1887284244a9SDave Hansen page-based protections, but without requiring modification of the 1888284244a9SDave Hansen page tables when an application changes protection domains. 1889284244a9SDave Hansen 18901eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1891284244a9SDave Hansen 1892284244a9SDave Hansen If unsure, say y. 189335e97790SDave Hansen 1894db616173SMichal Hockochoice 1895db616173SMichal Hocko prompt "TSX enable mode" 1896db616173SMichal Hocko depends on CPU_SUP_INTEL 1897db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1898db616173SMichal Hocko help 1899db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1900db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1901db616173SMichal Hocko can lead to a noticeable performance boost. 1902db616173SMichal Hocko 1903db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1904db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1905db616173SMichal Hocko will be more of those attacks discovered in the future. 1906db616173SMichal Hocko 1907db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1908db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1909db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1910db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1911db616173SMichal Hocko for the particular machine. 1912db616173SMichal Hocko 1913db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1914db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1915db616173SMichal Hocko details. 1916db616173SMichal Hocko 1917db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1918db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1919db616173SMichal Hocko relevant. 1920db616173SMichal Hocko 1921db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1922db616173SMichal Hocko bool "off" 1923db616173SMichal Hocko help 1924db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1925db616173SMichal Hocko 1926db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1927db616173SMichal Hocko bool "on" 1928db616173SMichal Hocko help 1929db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1930db616173SMichal Hocko line parameter. 1931db616173SMichal Hocko 1932db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1933db616173SMichal Hocko bool "auto" 1934db616173SMichal Hocko help 1935db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1936db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1937db616173SMichal Hockoendchoice 1938db616173SMichal Hocko 1939e7e05452SSean Christophersonconfig X86_SGX 1940e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1941b8d1d163SDaniel Sneddon depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1942e7e05452SSean Christopherson depends on CRYPTO=y 1943e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1944e7e05452SSean Christopherson select SRCU 1945e7e05452SSean Christopherson select MMU_NOTIFIER 1946901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 194740e0e784STony Luck select XARRAY_MULTI 1948e7e05452SSean Christopherson help 1949e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1950e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1951e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1952e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1953e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1954e7e05452SSean Christopherson hardware. 1955e7e05452SSean Christopherson 1956e7e05452SSean Christopherson If unsure, say N. 1957e7e05452SSean Christopherson 1958506f1d07SSam Ravnborgconfig EFI 19599ba16087SJan Beulich bool "EFI runtime service support" 19605b83683fSHuang, Ying depends on ACPI 1961f6ce5002SSergey Vlasov select UCS2_STRING 1962022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19631ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1964a7f7f624SMasahiro Yamada help 19658b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1966506f1d07SSam Ravnborg available (such as the EFI variable services). 1967506f1d07SSam Ravnborg 19688b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19698b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19708b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19718b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19728b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19738b2cb7a8SHuang, Ying platforms. 1974506f1d07SSam Ravnborg 1975291f3632SMatt Flemingconfig EFI_STUB 1976291f3632SMatt Fleming bool "EFI stub support" 1977c6dbd3e5SPeter Zijlstra depends on EFI 19788f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19797b2a583aSMatt Fleming select RELOCATABLE 1980a7f7f624SMasahiro Yamada help 1981291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1982291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1983291f3632SMatt Fleming 19844f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19850c759662SMatt Fleming 19867d453eeeSMatt Flemingconfig EFI_MIXED 19877d453eeeSMatt Fleming bool "EFI mixed-mode support" 19887d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1989a7f7f624SMasahiro Yamada help 19907d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19917d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19927d453eeeSMatt Fleming mode. 19937d453eeeSMatt Fleming 19947d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19957d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19967d453eeeSMatt Fleming the EFI handover protocol must be used. 19977d453eeeSMatt Fleming 19987d453eeeSMatt Fleming If unsure, say N. 19997d453eeeSMatt Fleming 20008636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2001506f1d07SSam Ravnborg 2002506f1d07SSam Ravnborgconfig KEXEC 2003506f1d07SSam Ravnborg bool "kexec system call" 20042965faa5SDave Young select KEXEC_CORE 2005a7f7f624SMasahiro Yamada help 2006506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2007506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2008506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2009506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2010506f1d07SSam Ravnborg 2011506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2012506f1d07SSam Ravnborg 2013506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2014506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2015bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2016bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2017bf220695SGeert Uytterhoeven made. 2018506f1d07SSam Ravnborg 201974ca317cSVivek Goyalconfig KEXEC_FILE 202074ca317cSVivek Goyal bool "kexec file based system call" 20212965faa5SDave Young select KEXEC_CORE 2022b69a2afdSJonathan McDowell select HAVE_IMA_KEXEC if IMA 202374ca317cSVivek Goyal depends on X86_64 202474ca317cSVivek Goyal depends on CRYPTO=y 202574ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2026a7f7f624SMasahiro Yamada help 202774ca317cSVivek Goyal This is new version of kexec system call. This system call is 202874ca317cSVivek Goyal file based and takes file descriptors as system call argument 202974ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 203074ca317cSVivek Goyal accepted by previous system call. 203174ca317cSVivek Goyal 2032b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2033b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2034b799a09fSAKASHI Takahiro 203599d5cadfSJiri Bohacconfig KEXEC_SIG 20368e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 203774ca317cSVivek Goyal depends on KEXEC_FILE 2038a7f7f624SMasahiro Yamada help 203999d5cadfSJiri Bohac 204099d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 204199d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 204299d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 204399d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 204499d5cadfSJiri Bohac 204599d5cadfSJiri Bohac In addition to this option, you need to enable signature 204699d5cadfSJiri Bohac verification for the corresponding kernel image type being 204799d5cadfSJiri Bohac loaded in order for this to work. 204899d5cadfSJiri Bohac 204999d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 205099d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 205199d5cadfSJiri Bohac depends on KEXEC_SIG 2052a7f7f624SMasahiro Yamada help 20538e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2054d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20558e7d8381SVivek Goyal 20568e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20578e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 205899d5cadfSJiri Bohac depends on KEXEC_SIG 20598e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20608e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2061a7f7f624SMasahiro Yamada help 20628e7d8381SVivek Goyal Enable bzImage signature verification support. 20638e7d8381SVivek Goyal 2064506f1d07SSam Ravnborgconfig CRASH_DUMP 206504b69447SPavel Machek bool "kernel crash dumps" 2066506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2067a7f7f624SMasahiro Yamada help 2068506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2069506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2070506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2071506f1d07SSam Ravnborg a specially reserved region and then later executed after 2072506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2073506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2074506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2075506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2076330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2077506f1d07SSam Ravnborg 20783ab83521SHuang Yingconfig KEXEC_JUMP 20796ea30386SKees Cook bool "kexec jump" 2080fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2081a7f7f624SMasahiro Yamada help 208289081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 208389081d17SHuang Ying code in physical address mode via KEXEC 20843ab83521SHuang Ying 2085506f1d07SSam Ravnborgconfig PHYSICAL_START 20866a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2087ceefccc9SH. Peter Anvin default "0x1000000" 2088a7f7f624SMasahiro Yamada help 2089506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2090506f1d07SSam Ravnborg 2091506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2092506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2093506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2094506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2095506f1d07SSam Ravnborg address. 2096506f1d07SSam Ravnborg 2097506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2098506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2099506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2100506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2101506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2102506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2103506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2104506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2105506f1d07SSam Ravnborg 2106ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2107ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2108ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2109ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2110ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2111ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2112ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2113330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2114ceefccc9SH. Peter Anvin for more details about crash dumps. 2115506f1d07SSam Ravnborg 2116506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2117506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2118506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2119506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2120506f1d07SSam Ravnborg is present because there are users out there who continue to use 2121506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2122506f1d07SSam Ravnborg line. 2123506f1d07SSam Ravnborg 2124506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2125506f1d07SSam Ravnborg 2126506f1d07SSam Ravnborgconfig RELOCATABLE 212726717808SH. Peter Anvin bool "Build a relocatable kernel" 212826717808SH. Peter Anvin default y 2129a7f7f624SMasahiro Yamada help 2130506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2131506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2132506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2133506f1d07SSam Ravnborg but are discarded at runtime. 2134506f1d07SSam Ravnborg 2135506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2136506f1d07SSam Ravnborg must live at a different physical address than the primary 2137506f1d07SSam Ravnborg kernel. 2138506f1d07SSam Ravnborg 2139506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2140506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21418ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2142506f1d07SSam Ravnborg 21438ab3820fSKees Cookconfig RANDOMIZE_BASE 2144e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21458ab3820fSKees Cook depends on RELOCATABLE 21466807c846SIngo Molnar default y 2147a7f7f624SMasahiro Yamada help 2148e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2149e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2150e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2151e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2152e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2153e8581e3dSBaoquan He code internals. 2154e8581e3dSBaoquan He 2155ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2156ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2157ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2158ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2159ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2160ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2161ed9f007eSKees Cook 2162ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2163ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2164ed9f007eSKees Cook 512MB (8 bits of entropy). 21658ab3820fSKees Cook 2166a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2167e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2168e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2169ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2170ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2171ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2172ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2173ed9f007eSKees Cook theoretically possible, but the implementations are further 2174ed9f007eSKees Cook limited due to memory layouts. 2175e8581e3dSBaoquan He 21766807c846SIngo Molnar If unsure, say Y. 2177da2b6fb9SKees Cook 21788ab3820fSKees Cook# Relocation on x86 needs some additional build support 2179845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2180845adf72SH. Peter Anvin def_bool y 21818ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2182845adf72SH. Peter Anvin 2183506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2184a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21858ab3820fSKees Cook default "0x200000" 2186a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2187a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2188a7f7f624SMasahiro Yamada help 2189506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2190506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2191506f1d07SSam Ravnborg address which meets above alignment restriction. 2192506f1d07SSam Ravnborg 2193506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2194506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2195506f1d07SSam Ravnborg address aligned to above value and run from there. 2196506f1d07SSam Ravnborg 2197506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2198506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2199506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2200506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2201506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2202506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2203506f1d07SSam Ravnborg above alignment restrictions. 2204506f1d07SSam Ravnborg 2205a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2206a0215061SKees Cook this value must be a multiple of 0x200000. 2207a0215061SKees Cook 2208506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2209506f1d07SSam Ravnborg 2210eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2211eedb92abSKirill A. Shutemov bool 2212a7f7f624SMasahiro Yamada help 2213eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2214eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2215eedb92abSKirill A. Shutemov 22160483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22170483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22180483e1faSThomas Garnier depends on X86_64 22190483e1faSThomas Garnier depends on RANDOMIZE_BASE 2220eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22210483e1faSThomas Garnier default RANDOMIZE_BASE 2222a7f7f624SMasahiro Yamada help 22230483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22240483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22250483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22260483e1faSThomas Garnier 22270483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22280483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22290483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22300483e1faSThomas Garnier addresses for each memory section. 22310483e1faSThomas Garnier 22326807c846SIngo Molnar If unsure, say Y. 22330483e1faSThomas Garnier 223490397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 223590397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 223690397a41SThomas Garnier depends on RANDOMIZE_MEMORY 223790397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 223890397a41SThomas Garnier default "0x0" 223990397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 224090397a41SThomas Garnier range 0x0 0x40 2241a7f7f624SMasahiro Yamada help 224290397a41SThomas Garnier Define the padding in terabytes added to the existing physical 224390397a41SThomas Garnier memory size during kernel memory randomization. It is useful 224490397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 224590397a41SThomas Garnier address randomization. 224690397a41SThomas Garnier 224790397a41SThomas Garnier If unsure, leave at the default value. 224890397a41SThomas Garnier 2249506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2250bebd024eSThomas Gleixner def_bool y 225140b31360SStephen Rothwell depends on SMP 2252506f1d07SSam Ravnborg 225380aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 225480aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22552c922cd0SKees Cook depends on HOTPLUG_CPU 2256a7f7f624SMasahiro Yamada help 225780aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 225880aa1dffSFenghua Yu 225980aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 226080aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 226180aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 226280aa1dffSFenghua Yu 226380aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 226480aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 226580aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 226680aa1dffSFenghua Yu 226780aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 226880aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 226980aa1dffSFenghua Yu 227080aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 227180aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 227280aa1dffSFenghua Yu be other CPU0 dependencies. 227380aa1dffSFenghua Yu 227480aa1dffSFenghua Yu Please make sure the dependencies are under your control before 227580aa1dffSFenghua Yu you enable this feature. 227680aa1dffSFenghua Yu 227780aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 227880aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 227980aa1dffSFenghua Yu parameter cpu0_hotplug. 228080aa1dffSFenghua Yu 2281a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2282a71c8bc5SFenghua Yu def_bool n 2283a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22842c922cd0SKees Cook depends on HOTPLUG_CPU 2285a7f7f624SMasahiro Yamada help 2286a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2287a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2288a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2289a71c8bc5SFenghua Yu 2290a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2291a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2292a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2293a71c8bc5SFenghua Yu 2294a71c8bc5SFenghua Yu If unsure, say N. 2295a71c8bc5SFenghua Yu 2296506f1d07SSam Ravnborgconfig COMPAT_VDSO 2297b0b49f26SAndy Lutomirski def_bool n 2298b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2299953fee1dSIngo Molnar depends on COMPAT_32 2300a7f7f624SMasahiro Yamada help 2301b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2302b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2303b0b49f26SAndy Lutomirski indicated in its segment table. 2304e84446deSRandy Dunlap 2305b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2306b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2307b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2308b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2309b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2310506f1d07SSam Ravnborg 2311b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2312b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2313b0b49f26SAndy Lutomirski 2314b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2315b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2316b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2317b0b49f26SAndy Lutomirski 2318b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2319b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2320506f1d07SSam Ravnborg 23213dc33bd3SKees Cookchoice 23223dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23233dc33bd3SKees Cook depends on X86_64 2324625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23253dc33bd3SKees Cook help 23263dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23273dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23283dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23293dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23303dc33bd3SKees Cook 23313dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2332bf00745eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2333bf00745eSAndy Lutomirski is deprecated and can only be enabled using the kernel command 2334bf00745eSAndy Lutomirski line. 23353dc33bd3SKees Cook 23363dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23373dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23383dc33bd3SKees Cook to improve security. 23393dc33bd3SKees Cook 2340bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23413dc33bd3SKees Cook 2342bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2343bd49e16eSAndy Lutomirski bool "Emulate execution only" 2344bd49e16eSAndy Lutomirski help 2345bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2346bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2347bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2348bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2349bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2350bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2351bd49e16eSAndy Lutomirski buffer. 23523dc33bd3SKees Cook 23533dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23543dc33bd3SKees Cook bool "None" 23553dc33bd3SKees Cook help 23563dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23573dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23583dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23593dc33bd3SKees Cook will be reported to dmesg, so that either old or 23603dc33bd3SKees Cook malicious userspace programs can be identified. 23613dc33bd3SKees Cook 23623dc33bd3SKees Cookendchoice 23633dc33bd3SKees Cook 2364516cbf37STim Birdconfig CMDLINE_BOOL 2365516cbf37STim Bird bool "Built-in kernel command line" 2366a7f7f624SMasahiro Yamada help 2367516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2368516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2369516cbf37STim Bird necessary or convenient to provide some or all of the 2370516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2371516cbf37STim Bird to not rely on the boot loader to provide them.) 2372516cbf37STim Bird 2373516cbf37STim Bird To compile command line arguments into the kernel, 2374516cbf37STim Bird set this option to 'Y', then fill in the 237569711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2376516cbf37STim Bird 2377516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2378516cbf37STim Bird should leave this option set to 'N'. 2379516cbf37STim Bird 2380516cbf37STim Birdconfig CMDLINE 2381516cbf37STim Bird string "Built-in kernel command string" 2382516cbf37STim Bird depends on CMDLINE_BOOL 2383516cbf37STim Bird default "" 2384a7f7f624SMasahiro Yamada help 2385516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2386516cbf37STim Bird image and used at boot time. If the boot loader provides a 2387516cbf37STim Bird command line at boot time, it is appended to this string to 2388516cbf37STim Bird form the full kernel command line, when the system boots. 2389516cbf37STim Bird 2390516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2391516cbf37STim Bird change this behavior. 2392516cbf37STim Bird 2393516cbf37STim Bird In most cases, the command line (whether built-in or provided 2394516cbf37STim Bird by the boot loader) should specify the device for the root 2395516cbf37STim Bird file system. 2396516cbf37STim Bird 2397516cbf37STim Birdconfig CMDLINE_OVERRIDE 2398516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2399645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2400a7f7f624SMasahiro Yamada help 2401516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2402516cbf37STim Bird command line, and use ONLY the built-in command line. 2403516cbf37STim Bird 2404516cbf37STim Bird This is used to work around broken boot loaders. This should 2405516cbf37STim Bird be set to 'N' under normal conditions. 2406516cbf37STim Bird 2407a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2408a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2409a5b9e5a2SAndy Lutomirski default y 2410a7f7f624SMasahiro Yamada help 2411a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2412a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2413a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2414a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2415a5b9e5a2SAndy Lutomirski threading libraries. 2416a5b9e5a2SAndy Lutomirski 2417a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2418a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2419a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2420a5b9e5a2SAndy Lutomirski 2421a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2422a5b9e5a2SAndy Lutomirski 24233aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 24243aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 24253aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 24263aac3ebeSThomas Gleixner help 24273aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 24283aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 24293aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 24303aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 24313aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 24323aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 24333aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 24343aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 24353aac3ebeSThomas Gleixner never get a signal delivered. 24363aac3ebeSThomas Gleixner 24373aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24383aac3ebeSThomas Gleixner 2439b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2440b700e7f0SSeth Jennings 2441506f1d07SSam Ravnborgendmenu 2442506f1d07SSam Ravnborg 2443f43b9876SPeter Zijlstraconfig CC_HAS_SLS 2444f43b9876SPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 2445f43b9876SPeter Zijlstra 2446f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK 2447f43b9876SPeter Zijlstra def_bool $(cc-option,-mfunction-return=thunk-extern) 2448f43b9876SPeter Zijlstra 2449f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS 2450f43b9876SPeter Zijlstra bool "Mitigations for speculative execution vulnerabilities" 2451f43b9876SPeter Zijlstra default y 2452f43b9876SPeter Zijlstra help 2453f43b9876SPeter Zijlstra Say Y here to enable options which enable mitigations for 2454f43b9876SPeter Zijlstra speculative execution hardware vulnerabilities. 2455f43b9876SPeter Zijlstra 2456f43b9876SPeter Zijlstra If you say N, all mitigations will be disabled. You really 2457f43b9876SPeter Zijlstra should know what you are doing to say so. 2458f43b9876SPeter Zijlstra 2459f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS 2460f43b9876SPeter Zijlstra 2461f43b9876SPeter Zijlstraconfig PAGE_TABLE_ISOLATION 2462f43b9876SPeter Zijlstra bool "Remove the kernel mapping in user mode" 2463f43b9876SPeter Zijlstra default y 2464f43b9876SPeter Zijlstra depends on (X86_64 || X86_PAE) 2465f43b9876SPeter Zijlstra help 2466f43b9876SPeter Zijlstra This feature reduces the number of hardware side channels by 2467f43b9876SPeter Zijlstra ensuring that the majority of kernel addresses are not mapped 2468f43b9876SPeter Zijlstra into userspace. 2469f43b9876SPeter Zijlstra 2470f43b9876SPeter Zijlstra See Documentation/x86/pti.rst for more details. 2471f43b9876SPeter Zijlstra 2472f43b9876SPeter Zijlstraconfig RETPOLINE 2473f43b9876SPeter Zijlstra bool "Avoid speculative indirect branches in kernel" 2474f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2475f43b9876SPeter Zijlstra default y 2476f43b9876SPeter Zijlstra help 2477f43b9876SPeter Zijlstra Compile kernel with the retpoline compiler options to guard against 2478f43b9876SPeter Zijlstra kernel-to-user data leaks by avoiding speculative indirect 2479f43b9876SPeter Zijlstra branches. Requires a compiler with -mindirect-branch=thunk-extern 2480f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2481f43b9876SPeter Zijlstra 2482f43b9876SPeter Zijlstraconfig RETHUNK 2483f43b9876SPeter Zijlstra bool "Enable return-thunks" 2484f43b9876SPeter Zijlstra depends on RETPOLINE && CC_HAS_RETURN_THUNK 2485f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2486b648ab48SBen Hutchings default y if X86_64 2487f43b9876SPeter Zijlstra help 2488f43b9876SPeter Zijlstra Compile the kernel with the return-thunks compiler option to guard 2489f43b9876SPeter Zijlstra against kernel-to-user data leaks by avoiding return speculation. 2490f43b9876SPeter Zijlstra Requires a compiler with -mfunction-return=thunk-extern 2491f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2492f43b9876SPeter Zijlstra 2493f43b9876SPeter Zijlstraconfig CPU_UNRET_ENTRY 2494f43b9876SPeter Zijlstra bool "Enable UNRET on kernel entry" 2495b648ab48SBen Hutchings depends on CPU_SUP_AMD && RETHUNK && X86_64 2496f43b9876SPeter Zijlstra default y 2497f43b9876SPeter Zijlstra help 2498f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=unret mitigation. 2499f43b9876SPeter Zijlstra 2500f43b9876SPeter Zijlstraconfig CPU_IBPB_ENTRY 2501f43b9876SPeter Zijlstra bool "Enable IBPB on kernel entry" 2502b648ab48SBen Hutchings depends on CPU_SUP_AMD && X86_64 2503f43b9876SPeter Zijlstra default y 2504f43b9876SPeter Zijlstra help 2505f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=ibpb mitigation. 2506f43b9876SPeter Zijlstra 2507f43b9876SPeter Zijlstraconfig CPU_IBRS_ENTRY 2508f43b9876SPeter Zijlstra bool "Enable IBRS on kernel entry" 2509b648ab48SBen Hutchings depends on CPU_SUP_INTEL && X86_64 2510f43b9876SPeter Zijlstra default y 2511f43b9876SPeter Zijlstra help 2512f43b9876SPeter Zijlstra Compile the kernel with support for the spectre_v2=ibrs mitigation. 2513f43b9876SPeter Zijlstra This mitigates both spectre_v2 and retbleed at great cost to 2514f43b9876SPeter Zijlstra performance. 2515f43b9876SPeter Zijlstra 2516f43b9876SPeter Zijlstraconfig SLS 2517f43b9876SPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 2518f43b9876SPeter Zijlstra depends on CC_HAS_SLS && X86_64 2519f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2520f43b9876SPeter Zijlstra default n 2521f43b9876SPeter Zijlstra help 2522f43b9876SPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 2523f43b9876SPeter Zijlstra against straight line speculation. The kernel image might be slightly 2524f43b9876SPeter Zijlstra larger. 2525f43b9876SPeter Zijlstra 2526f43b9876SPeter Zijlstraendif 2527f43b9876SPeter Zijlstra 25283072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 25293072e413SMichal Hocko def_bool y 25305c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 25313072e413SMichal Hocko 2532f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2533f91ef222SOscar Salvador def_bool y 2534f91ef222SOscar Salvador 2535da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2536e279b6c1SSam Ravnborg 2537e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 25383c2362e6SHarvey Harrison def_bool y 253944556530SZhimin Gu depends on HIBERNATION 2540e279b6c1SSam Ravnborg 2541e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2542e279b6c1SSam Ravnborg 2543e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2544e279b6c1SSam Ravnborg 2545a6b68076SAndi Kleenconfig X86_APM_BOOT 25466fc108a0SJan Beulich def_bool y 2547282e5aabSPaul Bolle depends on APM 2548a6b68076SAndi Kleen 2549e279b6c1SSam Ravnborgmenuconfig APM 2550e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2551efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2552a7f7f624SMasahiro Yamada help 2553e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2554e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2555e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2556e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2557e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2558e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2559e279b6c1SSam Ravnborg 2560e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2561e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2562e279b6c1SSam Ravnborg 2563e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2564e279b6c1SSam Ravnborg machines with more than one CPU. 2565e279b6c1SSam Ravnborg 2566e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2567151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 25682dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2569e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2570e279b6c1SSam Ravnborg 2571e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2572e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2573e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2574e279b6c1SSam Ravnborg 2575e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2576e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2577e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2578e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2579e279b6c1SSam Ravnborg 2580e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2581e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2582e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2583e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2584e279b6c1SSam Ravnborg APM in your BIOS). 2585e279b6c1SSam Ravnborg 2586e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2587e279b6c1SSam Ravnborg "weird" problems: 2588e279b6c1SSam Ravnborg 2589e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2590e279b6c1SSam Ravnborg enabled. 25917987448fSStephen Kitt 2) pass the "idle=poll" option to the kernel 2592e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2593e279b6c1SSam Ravnborg the "no387" option to the kernel 2594e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2595e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2596e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2597e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2598e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2599e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2600e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2601e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2602e279b6c1SSam Ravnborg 11) exchange RAM chips 2603e279b6c1SSam Ravnborg 12) exchange the motherboard. 2604e279b6c1SSam Ravnborg 2605e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2606e279b6c1SSam Ravnborg module will be called apm. 2607e279b6c1SSam Ravnborg 2608e279b6c1SSam Ravnborgif APM 2609e279b6c1SSam Ravnborg 2610e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2611e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2612a7f7f624SMasahiro Yamada help 2613e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2614e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2615e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2616e279b6c1SSam Ravnborg 2617e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2618e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2619a7f7f624SMasahiro Yamada help 2620e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2621e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2622e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2623e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2624e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2625e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2626e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2627e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2628e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2629e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2630e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2631e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2632e279b6c1SSam Ravnborg this feature. 2633e279b6c1SSam Ravnborg 2634e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2635dd8af076SLen Brown depends on CPU_IDLE 2636e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2637a7f7f624SMasahiro Yamada help 2638e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2639e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2640e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2641e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2642e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2643e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2644e279b6c1SSam Ravnborg this option does nothing.) 2645e279b6c1SSam Ravnborg 2646e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2647e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2648a7f7f624SMasahiro Yamada help 2649e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2650e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2651e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2652e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2653e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2654e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2655e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2656e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2657e279b6c1SSam Ravnborg especially if you are using gpm. 2658e279b6c1SSam Ravnborg 2659e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2660e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2661a7f7f624SMasahiro Yamada help 2662e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2663e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2664e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2665e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2666e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2667e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2668e279b6c1SSam Ravnborg 2669e279b6c1SSam Ravnborgendif # APM 2670e279b6c1SSam Ravnborg 2671bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2672e279b6c1SSam Ravnborg 2673e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2674e279b6c1SSam Ravnborg 267527471fdbSAndy Henroidsource "drivers/idle/Kconfig" 267627471fdbSAndy Henroid 2677e279b6c1SSam Ravnborgendmenu 2678e279b6c1SSam Ravnborg 2679e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2680e279b6c1SSam Ravnborg 2681e279b6c1SSam Ravnborgchoice 2682e279b6c1SSam Ravnborg prompt "PCI access mode" 2683efefa6f6SIngo Molnar depends on X86_32 && PCI 2684e279b6c1SSam Ravnborg default PCI_GOANY 2685a7f7f624SMasahiro Yamada help 2686e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2687e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2688e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2689e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2690e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2691e279b6c1SSam Ravnborg 2692e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2693e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2694e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2695e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2696e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2697e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2698e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2699e279b6c1SSam Ravnborg 2700e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2701e279b6c1SSam Ravnborg bool "BIOS" 2702e279b6c1SSam Ravnborg 2703e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2704e279b6c1SSam Ravnborg bool "MMConfig" 2705e279b6c1SSam Ravnborg 2706e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2707e279b6c1SSam Ravnborg bool "Direct" 2708e279b6c1SSam Ravnborg 27093ef0e1f8SAndres Salomonconfig PCI_GOOLPC 271076fb6570SDaniel Drake bool "OLPC XO-1" 27113ef0e1f8SAndres Salomon depends on OLPC 27123ef0e1f8SAndres Salomon 27132bdd1b03SAndres Salomonconfig PCI_GOANY 27142bdd1b03SAndres Salomon bool "Any" 27152bdd1b03SAndres Salomon 2716e279b6c1SSam Ravnborgendchoice 2717e279b6c1SSam Ravnborg 2718e279b6c1SSam Ravnborgconfig PCI_BIOS 27193c2362e6SHarvey Harrison def_bool y 2720efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2721e279b6c1SSam Ravnborg 2722e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2723e279b6c1SSam Ravnborgconfig PCI_DIRECT 27243c2362e6SHarvey Harrison def_bool y 27250aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2726e279b6c1SSam Ravnborg 2727e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2728b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2729b45c9f36SJan Kiszka default y 27304590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2731b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2732e279b6c1SSam Ravnborg 27333ef0e1f8SAndres Salomonconfig PCI_OLPC 27342bdd1b03SAndres Salomon def_bool y 27352bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 27363ef0e1f8SAndres Salomon 2737b5401a96SAlex Nixonconfig PCI_XEN 2738b5401a96SAlex Nixon def_bool y 2739b5401a96SAlex Nixon depends on PCI && XEN 2740b5401a96SAlex Nixon 27418364e1f8SJan Kiszkaconfig MMCONF_FAM10H 27428364e1f8SJan Kiszka def_bool y 27438364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2744e279b6c1SSam Ravnborg 27453f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 27466a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 27476ea30386SKees Cook depends on PCI 27483f6ea84aSIra W. Snyder help 27493f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 27503f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 27513f6ea84aSIra W. Snyder not have ACPI. 27523f6ea84aSIra W. Snyder 275364a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 275464a5fed6SBjorn Helgaas is known to be incomplete. 275564a5fed6SBjorn Helgaas 275664a5fed6SBjorn Helgaas You should say N unless you know you need this. 275764a5fed6SBjorn Helgaas 27583a495511SWilliam Breathitt Grayconfig ISA_BUS 275917a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 27603a495511SWilliam Breathitt Gray help 276117a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 276217a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 276317a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 276417a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 276517a2a129SWilliam Breathitt Gray not have an ISA bus. 27663a495511SWilliam Breathitt Gray 27673a495511SWilliam Breathitt Gray If unsure, say N. 27683a495511SWilliam Breathitt Gray 27691c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2770e279b6c1SSam Ravnborgconfig ISA_DMA_API 27711c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 27721c00f016SDavid Rientjes default y 27731c00f016SDavid Rientjes help 27741c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 27751c00f016SDavid Rientjes If unsure, say Y. 2776e279b6c1SSam Ravnborg 277751e68d05SLinus Torvaldsif X86_32 277851e68d05SLinus Torvalds 2779e279b6c1SSam Ravnborgconfig ISA 2780e279b6c1SSam Ravnborg bool "ISA support" 2781a7f7f624SMasahiro Yamada help 2782e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2783e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2784e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2785e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2786e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2787e279b6c1SSam Ravnborg 2788e279b6c1SSam Ravnborgconfig SCx200 2789e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2790a7f7f624SMasahiro Yamada help 2791e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2792e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2793e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2794e279b6c1SSam Ravnborg for other scx200_* drivers. 2795e279b6c1SSam Ravnborg 2796e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2797e279b6c1SSam Ravnborg 2798e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2799e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2800592913ecSJohn Stultz depends on SCx200 2801e279b6c1SSam Ravnborg default y 2802a7f7f624SMasahiro Yamada help 2803e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2804e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2805e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2806e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2807e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2808e279b6c1SSam Ravnborg 28093ef0e1f8SAndres Salomonconfig OLPC 28103ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 281154008979SThomas Gleixner depends on !X86_PAE 28123c554946SAndres Salomon select GPIOLIB 2813dc3119e7SThomas Gleixner select OF 281445bb1674SDaniel Drake select OF_PROMTREE 2815b4e51854SGrant Likely select IRQ_DOMAIN 28160c3d931bSLubomir Rintel select OLPC_EC 2817a7f7f624SMasahiro Yamada help 28183ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 28193ef0e1f8SAndres Salomon XO hardware. 28203ef0e1f8SAndres Salomon 2821a3128588SDaniel Drakeconfig OLPC_XO1_PM 2822a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2823fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2824a7f7f624SMasahiro Yamada help 282597c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2826bf1ebf00SDaniel Drake 2827cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2828cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2829cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2830a7f7f624SMasahiro Yamada help 2831cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2832cfee9597SDaniel Drake programmable wakeup source. 2833cfee9597SDaniel Drake 28347feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 28357feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 283692e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2837ed8e47feSRandy Dunlap depends on INPUT=y 2838d8d01a63SDaniel Drake select POWER_SUPPLY 2839a7f7f624SMasahiro Yamada help 28407feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 28417bc74b3dSDaniel Drake - EC-driven system wakeups 28427feda8e9SDaniel Drake - Power button 28437bc74b3dSDaniel Drake - Ebook switch 28442cf2baeaSDaniel Drake - Lid switch 2845e1040ac6SDaniel Drake - AC adapter status updates 2846e1040ac6SDaniel Drake - Battery status updates 28477feda8e9SDaniel Drake 2848a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2849a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2850d8d01a63SDaniel Drake depends on OLPC && ACPI 2851d8d01a63SDaniel Drake select POWER_SUPPLY 2852a7f7f624SMasahiro Yamada help 2853a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2854a0f30f59SDaniel Drake - EC-driven system wakeups 2855a0f30f59SDaniel Drake - AC adapter status updates 2856a0f30f59SDaniel Drake - Battery status updates 2857e279b6c1SSam Ravnborg 2858d4f3e350SEd Wildgooseconfig ALIX 2859d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2860d4f3e350SEd Wildgoose select GPIOLIB 2861a7f7f624SMasahiro Yamada help 2862d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2863d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2864d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2865d4f3e350SEd Wildgoose get added here. 2866d4f3e350SEd Wildgoose 2867d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2868d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2869d4f3e350SEd Wildgoose 2870d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2871d4f3e350SEd Wildgoose 2872da4e3302SPhilip Prindevilleconfig NET5501 2873da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2874da4e3302SPhilip Prindeville select GPIOLIB 2875a7f7f624SMasahiro Yamada help 2876da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2877da4e3302SPhilip Prindeville 28783197059aSPhilip A. Prindevilleconfig GEOS 28793197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28803197059aSPhilip A. Prindeville select GPIOLIB 28813197059aSPhilip A. Prindeville depends on DMI 2882a7f7f624SMasahiro Yamada help 28833197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28843197059aSPhilip A. Prindeville 28857d029125SVivien Didelotconfig TS5500 28867d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28877d029125SVivien Didelot depends on MELAN 28887d029125SVivien Didelot select CHECK_SIGNATURE 28897d029125SVivien Didelot select NEW_LEDS 28907d029125SVivien Didelot select LEDS_CLASS 2891a7f7f624SMasahiro Yamada help 28927d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28937d029125SVivien Didelot 2894e279b6c1SSam Ravnborgendif # X86_32 2895e279b6c1SSam Ravnborg 289623ac4ae8SAndreas Herrmannconfig AMD_NB 2897e279b6c1SSam Ravnborg def_bool y 28980e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2899e279b6c1SSam Ravnborg 2900e279b6c1SSam Ravnborgendmenu 2901e279b6c1SSam Ravnborg 29021572497cSChristoph Hellwigmenu "Binary Emulations" 2903e279b6c1SSam Ravnborg 2904e279b6c1SSam Ravnborgconfig IA32_EMULATION 2905e279b6c1SSam Ravnborg bool "IA32 Emulation" 2906e279b6c1SSam Ravnborg depends on X86_64 290739f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2908d1603990SRandy Dunlap select BINFMT_ELF 290939f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2910a7f7f624SMasahiro Yamada help 29115fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 29125fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 29135fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2914e279b6c1SSam Ravnborg 291583a44a4fSMasahiro Yamadaconfig X86_X32_ABI 29166ea30386SKees Cook bool "x32 ABI for 64-bit mode" 29179b54050bSBrian Gerst depends on X86_64 2918aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 2919aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 2920aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 2921aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 2922aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2923a7f7f624SMasahiro Yamada help 29245fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 29255fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 29265fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 29275fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 29285fd92e65SH. J. Lu 2929953fee1dSIngo Molnarconfig COMPAT_32 2930953fee1dSIngo Molnar def_bool y 2931953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2932953fee1dSIngo Molnar select HAVE_UID16 2933953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2934953fee1dSIngo Molnar 2935e279b6c1SSam Ravnborgconfig COMPAT 29363c2362e6SHarvey Harrison def_bool y 293783a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 2938e279b6c1SSam Ravnborg 2939e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 29403120e25eSJan Beulich def_bool y 2941a9251280SLinus Torvalds depends on COMPAT 2942ee009e4aSDavid Howells 2943e279b6c1SSam Ravnborgendmenu 2944e279b6c1SSam Ravnborg 2945e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2946e5beae16SKeith Packard def_bool y 2947e5beae16SKeith Packard depends on X86_32 2948e5beae16SKeith Packard 2949edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 29505e8ebd84SJason A. Donenfeld 29515e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2952