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 111583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 112583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1136471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 114dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1156471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1166471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1172ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 118ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 11981c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 120c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 12151c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 12207431506SAnshuman Khandual select ARCH_WANT_GENERAL_HUGETLB 1233876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 12447010c04SMuchun Song select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP if X86_64 12559612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 12638d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 127b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 12810916706SShile Zhang select BUILDTIME_TABLE_SORT 1296471b825SIngo Molnar select CLKEVT_I8253 1306471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1316471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1327cf8f44aSAlexander Potapenko # Word-size accesses may read uninitialized data past the trailing \0 1337cf8f44aSAlexander Potapenko # in strings and cause false KMSAN reports. 1347cf8f44aSAlexander Potapenko select DCACHE_WORD_ACCESS if !KMSAN 1353aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 13645471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 13745471cd9SLinus Torvalds select EDAC_SUPPORT 1386471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1396471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1406471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1416471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 14261dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1436471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 14427d6b4d1SThomas Gleixner select GENERIC_ENTRY 1456471b825SIngo Molnar select GENERIC_IOMAP 146c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1470fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 148ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1496471b825SIngo Molnar select GENERIC_IRQ_PROBE 150c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1516471b825SIngo Molnar select GENERIC_IRQ_SHOW 1526471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1532ae27137SSteven Price select GENERIC_PTDUMP 1546471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1556471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1567ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 157550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 15839656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 15917e5888eSHans de Goede select HARDIRQS_SW_RESEND 1607edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1616471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1626471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1636471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1646471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1656471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 166eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1676471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 168b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 169d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1700609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1711dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 172*4ca8cc8dSAlexander Potapenko select HAVE_ARCH_KMSAN if X86_64 1736471b825SIngo Molnar select HAVE_ARCH_KGDB 1749e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1759e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1761b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 177271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1786471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 179f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 180afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1816471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1826471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 183a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 184b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1857677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 186e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 187fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 188c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1892ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1906471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1916471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 19224a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER if X86_64 19324a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 1946471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 19503f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 1964ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 1976471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1989c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 199677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 20006aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 20102a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 202562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 203c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 204503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 20503f5781bSWang YanQing select HAVE_EBPF_JIT 20658340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2076630a8e5SChristoph Hellwig select HAVE_EISA 2085f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 20967a929e0SChristoph Hellwig select HAVE_FAST_GUP 210644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2116471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 2124a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2136471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2146b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2150067f129SK.Prasad select HAVE_HW_BREAKPOINT 2166471b825SIngo Molnar select HAVE_IOREMAP_PROT 217624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2186471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2194ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2206471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2216471b825SIngo Molnar select HAVE_KERNEL_GZIP 2226471b825SIngo Molnar select HAVE_KERNEL_LZ4 2236471b825SIngo Molnar select HAVE_KERNEL_LZMA 2246471b825SIngo Molnar select HAVE_KERNEL_LZO 2256471b825SIngo Molnar select HAVE_KERNEL_XZ 226fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2276471b825SIngo Molnar select HAVE_KPROBES 2286471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 229540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2306471b825SIngo Molnar select HAVE_KRETPROBES 231f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2326471b825SIngo Molnar select HAVE_KVM 2336471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2340102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 235ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2369f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 237be37c98dSKalesh Singh select HAVE_MOVE_PUD 23822102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 23942a0bb3fSPetr Mladek select HAVE_NMI 240489e355bSJosh Poimboeuf select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 24103f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2426471b825SIngo Molnar select HAVE_OPTPROBES 2436471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2446471b825SIngo Molnar select HAVE_PERF_EVENTS 245c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 24692e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 247eb01d42aSChristoph Hellwig select HAVE_PCI 248c5e63197SJiri Olsa select HAVE_PERF_REGS 249c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 250ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2511e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 25200998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2536471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 25403f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2553c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2567ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 257cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 258d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 25903f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 260e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 26103f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 26299cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 263d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2646471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2655f3da8c0SJosh Poimboeuf select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 2666471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2677c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2687ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 26905736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 270c0185808SThomas Gleixner select IRQ_FORCED_THREADING 2717ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2727ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 27386596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2742eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 275625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2766471b825SIngo Molnar select PERF_EVENTS 2773195ef59SPrarit Bhargava select RTC_LIB 278d6faca40SArnd Bergmann select RTC_MC146818_LIB 2796471b825SIngo Molnar select SPARSE_IRQ 28083fe27eaSPranith Kumar select SRCU 2816471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 28215f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2834aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2844510bffbSMark Rutland select TRACE_IRQFLAGS_NMI_SUPPORT 2856471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2863b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2876471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2880c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 28950468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 2909e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 2917d8330a5SBalbir Singh 292ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2933120e25eSJan Beulich def_bool y 2943120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 295ba7e4d13SIngo Molnar 29651b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 29751b26adaSLinus Torvalds string 29851b26adaSLinus Torvalds default "elf32-i386" if X86_32 29951b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 30051b26adaSLinus Torvalds 3018d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 3023c2362e6SHarvey Harrison def_bool y 3038d5fffb9SSam Ravnborg 3048d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 3053c2362e6SHarvey Harrison def_bool y 3068d5fffb9SSam Ravnborg 3078d5fffb9SSam Ravnborgconfig MMU 3083c2362e6SHarvey Harrison def_bool y 3098d5fffb9SSam Ravnborg 3109e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3119e08f57dSDaniel Cashman default 28 if 64BIT 3129e08f57dSDaniel Cashman default 8 3139e08f57dSDaniel Cashman 3149e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3159e08f57dSDaniel Cashman default 32 if 64BIT 3169e08f57dSDaniel Cashman default 16 3179e08f57dSDaniel Cashman 3189e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3199e08f57dSDaniel Cashman default 8 3209e08f57dSDaniel Cashman 3219e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3229e08f57dSDaniel Cashman default 16 3239e08f57dSDaniel Cashman 3248d5fffb9SSam Ravnborgconfig SBUS 3258d5fffb9SSam Ravnborg bool 3268d5fffb9SSam Ravnborg 3278d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3283120e25eSJan Beulich def_bool y 3293120e25eSJan Beulich depends on ISA_DMA_API 3308d5fffb9SSam Ravnborg 331d911c67eSAlexander Potapenkoconfig GENERIC_CSUM 332d911c67eSAlexander Potapenko bool 333d911c67eSAlexander Potapenko default y if KMSAN || KASAN 334d911c67eSAlexander Potapenko 3358d5fffb9SSam Ravnborgconfig GENERIC_BUG 3363c2362e6SHarvey Harrison def_bool y 3378d5fffb9SSam Ravnborg depends on BUG 338b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 339b93a531eSJan Beulich 340b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 341b93a531eSJan Beulich bool 3428d5fffb9SSam Ravnborg 3438d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3443120e25eSJan Beulich def_bool y 3453120e25eSJan Beulich depends on ISA_DMA_API 3468d5fffb9SSam Ravnborg 3471032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3481032c0baSSam Ravnborg def_bool y 3491032c0baSSam Ravnborg 3509a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3519a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3528d5fffb9SSam Ravnborg 353801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 354801e4062SJohannes Berg def_bool y 355801e4062SJohannes Berg 356d7109fe3SAndy Shevchenkoconfig ARCH_NR_GPIO 357d7109fe3SAndy Shevchenko int 358d7109fe3SAndy Shevchenko default 1024 if X86_64 359d7109fe3SAndy Shevchenko default 512 360d7109fe3SAndy Shevchenko 361f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 362f4cb5700SJohannes Berg def_bool y 363f4cb5700SJohannes Berg 3648d5fffb9SSam Ravnborgconfig AUDIT_ARCH 365e0fd24a3SJan Beulich def_bool y if X86_64 3668d5fffb9SSam Ravnborg 367d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 368d6f2d75aSAndrey Ryabinin hex 369d6f2d75aSAndrey Ryabinin depends on KASAN 370d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 371d6f2d75aSAndrey Ryabinin 37269575d38SShane Wangconfig HAVE_INTEL_TXT 37369575d38SShane Wang def_bool y 3746ea30386SKees Cook depends on INTEL_IOMMU && ACPI 37569575d38SShane Wang 3766b0c3d44SSam Ravnborgconfig X86_32_SMP 3776b0c3d44SSam Ravnborg def_bool y 3786b0c3d44SSam Ravnborg depends on X86_32 && SMP 3796b0c3d44SSam Ravnborg 3806b0c3d44SSam Ravnborgconfig X86_64_SMP 3816b0c3d44SSam Ravnborg def_bool y 3826b0c3d44SSam Ravnborg depends on X86_64 && SMP 3836b0c3d44SSam Ravnborg 3842b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3852b144498SSrikar Dronamraju def_bool y 3862b144498SSrikar Dronamraju 387d20642f0SRob Herringconfig FIX_EARLYCON_MEM 388d20642f0SRob Herring def_bool y 389d20642f0SRob Herring 39094d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 39194d49eb3SKirill A. Shutemov bool 39294d49eb3SKirill A. Shutemov 39398233368SKirill A. Shutemovconfig PGTABLE_LEVELS 39498233368SKirill A. Shutemov int 39577ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 39698233368SKirill A. Shutemov default 4 if X86_64 39798233368SKirill A. Shutemov default 3 if X86_PAE 39898233368SKirill A. Shutemov default 2 39998233368SKirill A. Shutemov 4002a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 4012a61f474SMasahiro Yamada bool 4021b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 4031b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 4042a61f474SMasahiro Yamada help 4052a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 4063fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 4073fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 4082a61f474SMasahiro Yamada 409506f1d07SSam Ravnborgmenu "Processor type and features" 410506f1d07SSam Ravnborg 411506f1d07SSam Ravnborgconfig SMP 412506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 413a7f7f624SMasahiro Yamada help 414506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4154a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4164a474157SRobert Graffham than one CPU, say Y. 417506f1d07SSam Ravnborg 4184a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 419506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 420506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4214a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 422506f1d07SSam Ravnborg will run faster if you say N here. 423506f1d07SSam Ravnborg 424506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 425506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 426506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 427506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 428506f1d07SSam Ravnborg 429506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 430506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 431506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 432506f1d07SSam Ravnborg 433cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4344f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 435506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 436506f1d07SSam Ravnborg 437506f1d07SSam Ravnborg If you don't know what to do here, say N. 438506f1d07SSam Ravnborg 4399def39beSJosh Triplettconfig X86_FEATURE_NAMES 4409def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4419def39beSJosh Triplett default y 442a7f7f624SMasahiro Yamada help 4439def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4449def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4459def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4469def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4479def39beSJosh Triplett 4489def39beSJosh Triplett If in doubt, say Y. 4499def39beSJosh Triplett 45006cd9a7dSYinghai Luconfig X86_X2APIC 45106cd9a7dSYinghai Lu bool "Support x2apic" 45219e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 453a7f7f624SMasahiro Yamada help 45406cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 45506cd9a7dSYinghai Lu 45606cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 45706cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 45806cd9a7dSYinghai Lu 45906cd9a7dSYinghai Lu If you don't know what to do here, say N. 46006cd9a7dSYinghai Lu 4616695c85bSYinghai Luconfig X86_MPPARSE 4624590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4637a527688SJan Beulich default y 4645ab74722SIngo Molnar depends on X86_LOCAL_APIC 465a7f7f624SMasahiro Yamada help 4666695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4676695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4686695c85bSYinghai Lu 469ddd70cf9SJun Nakajimaconfig GOLDFISH 470ddd70cf9SJun Nakajima def_bool y 471ddd70cf9SJun Nakajima depends on X86_GOLDFISH 472ddd70cf9SJun Nakajima 473e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 474e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4756fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 47659fe5a77SThomas Gleixner select KERNFS 477e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 47878e99b4aSFenghua Yu help 479e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4806fe07ce3SBabu Moger 4816fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4826fe07ce3SBabu Moger usage by the CPU. 4836fe07ce3SBabu Moger 4846fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4856fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4866fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4876fe07ce3SBabu Moger 4886fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4896fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4906fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 49178e99b4aSFenghua Yu 49278e99b4aSFenghua Yu Say N if unsure. 49378e99b4aSFenghua Yu 4948425091fSRavikiran G Thirumalaiif X86_32 495a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 496a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 497a0d0bb4dSRandy Dunlap depends on SMP 498a7f7f624SMasahiro Yamada help 499e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 500a0d0bb4dSRandy Dunlap 501c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 502c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 503c5c606d9SRavikiran G Thirumalai default y 504a7f7f624SMasahiro Yamada help 50506ac8346SIngo Molnar If you disable this option then the kernel will only support 50606ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 50706ac8346SIngo Molnar systems out there.) 50806ac8346SIngo Molnar 5098425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5108425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 511cb7b8023SBen Hutchings Goldfish (Android emulator) 5128425091fSRavikiran G Thirumalai AMD Elan 5138425091fSRavikiran G Thirumalai RDC R-321x SoC 5148425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 51583125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5163f4110a4SThomas Gleixner Moorestown MID devices 51706ac8346SIngo Molnar 51806ac8346SIngo Molnar If you have one of these systems, or if you want to build a 51906ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 520758cd94aSJuerg Haefligerendif # X86_32 52106ac8346SIngo Molnar 5228425091fSRavikiran G Thirumalaiif X86_64 5238425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5248425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5258425091fSRavikiran G Thirumalai default y 526a7f7f624SMasahiro Yamada help 5278425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5288425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5298425091fSRavikiran G Thirumalai systems out there.) 5308425091fSRavikiran G Thirumalai 5318425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5328425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 53344b111b5SSteffen Persvold Numascale NumaChip 5348425091fSRavikiran G Thirumalai ScaleMP vSMP 5358425091fSRavikiran G Thirumalai SGI Ultraviolet 5368425091fSRavikiran G Thirumalai 5378425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5388425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 539758cd94aSJuerg Haefligerendif # X86_64 540c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 541c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 54244b111b5SSteffen Persvoldconfig X86_NUMACHIP 54344b111b5SSteffen Persvold bool "Numascale NumaChip" 54444b111b5SSteffen Persvold depends on X86_64 54544b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 54644b111b5SSteffen Persvold depends on NUMA 54744b111b5SSteffen Persvold depends on SMP 54844b111b5SSteffen Persvold depends on X86_X2APIC 549f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 550a7f7f624SMasahiro Yamada help 55144b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 55244b111b5SSteffen Persvold enable more than ~168 cores. 55344b111b5SSteffen Persvold If you don't have one of these, you should say N here. 55403b48632SNick Piggin 5556a48565eSIngo Molnarconfig X86_VSMP 556c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5576276a074SBorislav Petkov select HYPERVISOR_GUEST 5586a48565eSIngo Molnar select PARAVIRT 5596a48565eSIngo Molnar depends on X86_64 && PCI 560c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 561ead91d4bSShai Fultheim depends on SMP 562a7f7f624SMasahiro Yamada help 5636a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5646a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5656a48565eSIngo Molnar if you have one of these machines. 5666a48565eSIngo Molnar 567c5c606d9SRavikiran G Thirumalaiconfig X86_UV 568c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 569c5c606d9SRavikiran G Thirumalai depends on X86_64 570c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 57154c28d29SJack Steiner depends on NUMA 5721ecb4ae5SAndrew Morton depends on EFI 573c2209ea5SIngo Molnar depends on KEXEC_CORE 5749d6c26e7SSuresh Siddha depends on X86_X2APIC 5751222e564SIngo Molnar depends on PCI 576a7f7f624SMasahiro Yamada help 577c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 578c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 579c5c606d9SRavikiran G Thirumalai 580c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 581c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 582506f1d07SSam Ravnborg 583ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 584ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 585cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 586a7f7f624SMasahiro Yamada help 587ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 588ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 589ddd70cf9SJun Nakajima Goldfish emulator say N here. 590ddd70cf9SJun Nakajima 591c751e17bSThomas Gleixnerconfig X86_INTEL_CE 592c751e17bSThomas Gleixner bool "CE4100 TV platform" 593c751e17bSThomas Gleixner depends on PCI 594c751e17bSThomas Gleixner depends on PCI_GODIRECT 5956084a6e2SJiang Liu depends on X86_IO_APIC 596c751e17bSThomas Gleixner depends on X86_32 597c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 59837bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 599da6b737bSSebastian Andrzej Siewior select OF 600da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 601a7f7f624SMasahiro Yamada help 602c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 603c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 604c751e17bSThomas Gleixner boxes and media devices. 605c751e17bSThomas Gleixner 6064cb9b00fSDavid Cohenconfig X86_INTEL_MID 60743605ef1SAlan Cox bool "Intel MID platform support" 60843605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 609edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6101ea7c673SAlan Cox depends on PCI 6113fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6121ea7c673SAlan Cox depends on X86_IO_APIC 6134cb9b00fSDavid Cohen select I2C 6147c9c3a1eSAlan Cox select DW_APB_TIMER 61554b34aa0SMika Westerberg select INTEL_SCU_PCI 616a7f7f624SMasahiro Yamada help 6174cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6184cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6194cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6201ea7c673SAlan Cox 6214cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6224cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 62343605ef1SAlan Cox 6248bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6258bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6268bbc2a13SBryan O'Donoghue depends on X86_32 6278bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6288bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6298bbc2a13SBryan O'Donoghue depends on X86_TSC 6308bbc2a13SBryan O'Donoghue depends on PCI 6318bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6328bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6338bbc2a13SBryan O'Donoghue select IOSF_MBI 6348bbc2a13SBryan O'Donoghue select INTEL_IMR 6359ab6eb51SAndy Shevchenko select COMMON_CLK 636a7f7f624SMasahiro Yamada help 6378bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6388bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6398bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6408bbc2a13SBryan O'Donoghue 6413d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6423d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6435962dd22SSinan Kaya depends on X86 && ACPI && PCI 6443d48aab1SMika Westerberg select COMMON_CLK 6450f531431SMathias Nyman select PINCTRL 646eebb3e8dSAndy Shevchenko select IOSF_MBI 647a7f7f624SMasahiro Yamada help 6483d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6493d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6500f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6510f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6523d48aab1SMika Westerberg 65392082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 65492082a88SKen Xue bool "AMD ACPI2Platform devices support" 65592082a88SKen Xue depends on ACPI 65692082a88SKen Xue select COMMON_CLK 65792082a88SKen Xue select PINCTRL 658a7f7f624SMasahiro Yamada help 65992082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 66092082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 66192082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 66292082a88SKen Xue implemented under PINCTRL subsystem. 66392082a88SKen Xue 664ced3ce76SDavid E. Boxconfig IOSF_MBI 665ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 666ced3ce76SDavid E. Box depends on PCI 667a7f7f624SMasahiro Yamada help 668ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 669ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 670ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 671ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 672ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 673ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 674ced3ce76SDavid E. Box This list is not meant to be exclusive. 675ced3ce76SDavid E. Box - BayTrail 676ced3ce76SDavid E. Box - Braswell 677ced3ce76SDavid E. Box - Quark 678ced3ce76SDavid E. Box 679ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 680ced3ce76SDavid E. Box 681ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 682ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 683ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 684a7f7f624SMasahiro Yamada help 685ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 686ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 687ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 688ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 689ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 690ed2226bdSDavid E. Box device they want to access. 691ed2226bdSDavid E. Box 692ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 693ed2226bdSDavid E. Box 694c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 695c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 696506f1d07SSam Ravnborg depends on X86_32 697c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 698c5c606d9SRavikiran G Thirumalai select M486 699c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 700a7f7f624SMasahiro Yamada help 701c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 702c5c606d9SRavikiran G Thirumalai as R-8610-(G). 703c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 704c5c606d9SRavikiran G Thirumalai 705e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7069c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7079c398017SIngo Molnar depends on X86_32 && SMP 708c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 709a7f7f624SMasahiro Yamada help 710b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 711b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 712b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 713b5660ba7SH. Peter Anvin one and will fallback to default. 714d49c4288SYinghai Lu 715c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 716d49c4288SYinghai Lu 717d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7186fc108a0SJan Beulich def_bool y 719d949f36fSLinus Torvalds # MCE code calls memory_failure(): 720d949f36fSLinus Torvalds depends on X86_MCE 721d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 722d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 723d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 724d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 725d949f36fSLinus Torvalds 72683125a3aSAlessandro Rubiniconfig STA2X11 72783125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 72883125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 72983125a3aSAlessandro Rubini select SWIOTLB 73083125a3aSAlessandro Rubini select MFD_STA2X11 7310145071bSLinus Walleij select GPIOLIB 732a7f7f624SMasahiro Yamada help 73383125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 73483125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 73583125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 73683125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 73783125a3aSAlessandro Rubini standard PC machines. 73883125a3aSAlessandro Rubini 73982148d1dSShérabconfig X86_32_IRIS 74082148d1dSShérab tristate "Eurobraille/Iris poweroff module" 74182148d1dSShérab depends on X86_32 742a7f7f624SMasahiro Yamada help 74382148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 74482148d1dSShérab to shut themselves down properly. A special I/O sequence is 74582148d1dSShérab needed to do so, which is what this module does at 74682148d1dSShérab kernel shutdown. 74782148d1dSShérab 74882148d1dSShérab This is only for Iris machines from EuroBraille. 74982148d1dSShérab 75082148d1dSShérab If unused, say N. 75182148d1dSShérab 752ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7533c2362e6SHarvey Harrison def_bool y 7543c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 755a87d0914SKen Chen depends on X86 756a7f7f624SMasahiro Yamada help 757506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 758506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 759506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 760506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 761506f1d07SSam Ravnborg 762506f1d07SSam Ravnborg If in doubt, say "Y". 763506f1d07SSam Ravnborg 7646276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7656276a074SBorislav Petkov bool "Linux guest support" 766a7f7f624SMasahiro Yamada help 7676276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7686276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7696276a074SBorislav Petkov setup. 770506f1d07SSam Ravnborg 7716276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7726276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 773506f1d07SSam Ravnborg 7746276a074SBorislav Petkovif HYPERVISOR_GUEST 775506f1d07SSam Ravnborg 776e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 777e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 778a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 779a7f7f624SMasahiro Yamada help 780e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 781e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 782e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 783e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 784e61bd94aSEduardo Pereira Habkost 785c00a280aSJuergen Grossconfig PARAVIRT_XXL 786c00a280aSJuergen Gross bool 787c00a280aSJuergen Gross 7886276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7896276a074SBorislav Petkov bool "paravirt-ops debugging" 7906276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 791a7f7f624SMasahiro Yamada help 7926276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7936276a074SBorislav Petkov a paravirt_op is missing when it is called. 7946276a074SBorislav Petkov 795b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 796b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 7976ea30386SKees Cook depends on PARAVIRT && SMP 798a7f7f624SMasahiro Yamada help 799b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 800b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 801b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 802b4ecc126SJeremy Fitzhardinge 8034c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8044c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 805b4ecc126SJeremy Fitzhardinge 8064c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 807b4ecc126SJeremy Fitzhardinge 808ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 809ecca2502SZhao Yakui def_bool n 810ecca2502SZhao Yakui 8116276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8126276a074SBorislav Petkov 8136276a074SBorislav Petkovconfig KVM_GUEST 8146276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8156276a074SBorislav Petkov depends on PARAVIRT 8166276a074SBorislav Petkov select PARAVIRT_CLOCK 817a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 818b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8196276a074SBorislav Petkov default y 820a7f7f624SMasahiro Yamada help 8216276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8226276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8236276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8246276a074SBorislav Petkov underlying device model, the host provides the guest with 8256276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8266276a074SBorislav Petkov 827a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 828a1c4423bSMarcelo Tosatti def_bool n 829a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 830a1c4423bSMarcelo Tosatti help 831a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 832a1c4423bSMarcelo Tosatti 8337733607fSMaran Wilsonconfig PVH 8347733607fSMaran Wilson bool "Support for running PVH guests" 835a7f7f624SMasahiro Yamada help 8367733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8377733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8387733607fSMaran Wilson 8396276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8406276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8416276a074SBorislav Petkov depends on PARAVIRT 842a7f7f624SMasahiro Yamada help 8436276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8446276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8456276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8466276a074SBorislav Petkov that, there can be a small performance impact. 8476276a074SBorislav Petkov 8486276a074SBorislav Petkov If in doubt, say N here. 8496276a074SBorislav Petkov 8507af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8517af192c9SGerd Hoffmann bool 8527af192c9SGerd Hoffmann 8534a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8544a362601SJan Kiszka bool "Jailhouse non-root cell support" 855abde587bSArnd Bergmann depends on X86_64 && PCI 85687e65d05SJan Kiszka select X86_PM_TIMER 857a7f7f624SMasahiro Yamada help 8584a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8594a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8604a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8614a362601SJan Kiszka 862ec7972c9SZhao Yakuiconfig ACRN_GUEST 863ec7972c9SZhao Yakui bool "ACRN Guest support" 864ec7972c9SZhao Yakui depends on X86_64 865498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 866ec7972c9SZhao Yakui help 867ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 868ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 869ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 870ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 871ec7972c9SZhao Yakui found in https://projectacrn.org/. 872ec7972c9SZhao Yakui 87359bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST 87459bd54a8SKuppuswamy Sathyanarayanan bool "Intel TDX (Trust Domain Extensions) - Guest Support" 87559bd54a8SKuppuswamy Sathyanarayanan depends on X86_64 && CPU_SUP_INTEL 87659bd54a8SKuppuswamy Sathyanarayanan depends on X86_X2APIC 87741394e33SKirill A. Shutemov select ARCH_HAS_CC_PLATFORM 878968b4931SKirill A. Shutemov select X86_MEM_ENCRYPT 87977a512e3SSean Christopherson select X86_MCE 88059bd54a8SKuppuswamy Sathyanarayanan help 88159bd54a8SKuppuswamy Sathyanarayanan Support running as a guest under Intel TDX. Without this support, 88259bd54a8SKuppuswamy Sathyanarayanan the guest kernel can not boot or run under TDX. 88359bd54a8SKuppuswamy Sathyanarayanan TDX includes memory encryption and integrity capabilities 88459bd54a8SKuppuswamy Sathyanarayanan which protect the confidentiality and integrity of guest 88559bd54a8SKuppuswamy Sathyanarayanan memory contents and CPU state. TDX guests are protected from 88659bd54a8SKuppuswamy Sathyanarayanan some attacks from the VMM. 88759bd54a8SKuppuswamy Sathyanarayanan 8886276a074SBorislav Petkovendif # HYPERVISOR_GUEST 88997349135SJeremy Fitzhardinge 890506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 891506f1d07SSam Ravnborg 892506f1d07SSam Ravnborgconfig HPET_TIMER 8933c2362e6SHarvey Harrison def_bool X86_64 894506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 895a7f7f624SMasahiro Yamada help 896506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 897506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 898506f1d07SSam Ravnborg present. 899506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 900506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 901506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 9024e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9034e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 904506f1d07SSam Ravnborg 905506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 906506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 907506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 908506f1d07SSam Ravnborg 909506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 910506f1d07SSam Ravnborg 911506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9123c2362e6SHarvey Harrison def_bool y 9133228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 914506f1d07SSam Ravnborg 9156a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 916506f1d07SSam Ravnborg# The code disables itself when not needed. 9177ae9392cSThomas Petazzoniconfig DMI 9187ae9392cSThomas Petazzoni default y 919cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9206a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 921a7f7f624SMasahiro Yamada help 9227ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9237ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9247ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9257ae9392cSThomas Petazzoni BIOS code. 9267ae9392cSThomas Petazzoni 927506f1d07SSam Ravnborgconfig GART_IOMMU 92838901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9292f9237d4SChristoph Hellwig select DMA_OPS 930a4ce5a48SChristoph Hellwig select IOMMU_HELPER 931506f1d07SSam Ravnborg select SWIOTLB 93223ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 933a7f7f624SMasahiro Yamada help 934ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 935ced3c42cSIngo Molnar GART based hardware IOMMUs. 936ced3c42cSIngo Molnar 937ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 938ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 939ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 940ced3c42cSIngo Molnar 941ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 942ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 943ced3c42cSIngo Molnar 944ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 945ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 946ced3c42cSIngo Molnar 32-bit limited device. 947ced3c42cSIngo Molnar 948ced3c42cSIngo Molnar If unsure, say Y. 949506f1d07SSam Ravnborg 9508b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT 9518b766b0fSMichal Suchanek bool 9528b766b0fSMichal Suchanek help 9538b766b0fSMichal Suchanek If true, at least one selected framebuffer driver can take advantage 9548b766b0fSMichal Suchanek of VESA video modes set at an early boot stage via the vga= parameter. 9558b766b0fSMichal Suchanek 9561184dc2fSMike Travisconfig MAXSMP 957ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9586ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 95936f5101aSMike Travis select CPUMASK_OFFSTACK 960a7f7f624SMasahiro Yamada help 961ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9621184dc2fSMike Travis If unsure, say N. 963506f1d07SSam Ravnborg 964aec6487eSIngo Molnar# 965aec6487eSIngo Molnar# The maximum number of CPUs supported: 966aec6487eSIngo Molnar# 967aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 968aec6487eSIngo Molnar# and which can be configured interactively in the 969aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 970aec6487eSIngo Molnar# 971aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 972aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 973aec6487eSIngo Molnar# 974aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 975aec6487eSIngo Molnar# interactive configuration. ) 976aec6487eSIngo Molnar# 977a0d0bb4dSRandy Dunlap 978aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 979a0d0bb4dSRandy Dunlap int 980aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 981a0d0bb4dSRandy Dunlap default 1 if !SMP 982a0d0bb4dSRandy Dunlap default 2 983a0d0bb4dSRandy Dunlap 984aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 985a0d0bb4dSRandy Dunlap int 986a0d0bb4dSRandy Dunlap depends on X86_32 987aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 988aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 989a0d0bb4dSRandy Dunlap default 1 if !SMP 990a0d0bb4dSRandy Dunlap 991aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 992a0d0bb4dSRandy Dunlap int 993a0d0bb4dSRandy Dunlap depends on X86_64 9941edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9951edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 996a0d0bb4dSRandy Dunlap default 1 if !SMP 997aec6487eSIngo Molnar 998aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 999aec6487eSIngo Molnar int 1000aec6487eSIngo Molnar depends on X86_32 1001aec6487eSIngo Molnar default 32 if X86_BIGSMP 1002aec6487eSIngo Molnar default 8 if SMP 1003aec6487eSIngo Molnar default 1 if !SMP 1004aec6487eSIngo Molnar 1005aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1006aec6487eSIngo Molnar int 1007aec6487eSIngo Molnar depends on X86_64 1008a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1009a0d0bb4dSRandy Dunlap default 64 if SMP 1010aec6487eSIngo Molnar default 1 if !SMP 1011a0d0bb4dSRandy Dunlap 1012506f1d07SSam Ravnborgconfig NR_CPUS 101336f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1014aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1015aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1016a7f7f624SMasahiro Yamada help 1017506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1018bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1019cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1020506f1d07SSam Ravnborg minimum value which makes sense is 2. 1021506f1d07SSam Ravnborg 1022aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1023aec6487eSIngo Molnar to the kernel image. 1024506f1d07SSam Ravnborg 102566558b73STim Chenconfig SCHED_CLUSTER 102666558b73STim Chen bool "Cluster scheduler support" 102766558b73STim Chen depends on SMP 102866558b73STim Chen default y 102966558b73STim Chen help 103066558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 103166558b73STim Chen making when dealing with machines that have clusters of CPUs. 103266558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 103366558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 103466558b73STim Chen busses. 103566558b73STim Chen 1036506f1d07SSam Ravnborgconfig SCHED_SMT 1037dbe73364SThomas Gleixner def_bool y if SMP 1038506f1d07SSam Ravnborg 1039506f1d07SSam Ravnborgconfig SCHED_MC 10403c2362e6SHarvey Harrison def_bool y 10413c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1042c8e56d20SBorislav Petkov depends on SMP 1043a7f7f624SMasahiro Yamada help 1044506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1045506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1046506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1047506f1d07SSam Ravnborg 1048de966cf4STim Chenconfig SCHED_MC_PRIO 1049de966cf4STim Chen bool "CPU core priorities scheduler support" 10500a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10510a21fc12SIngo Molnar select X86_INTEL_PSTATE 10520a21fc12SIngo Molnar select CPU_FREQ 1053de966cf4STim Chen default y 1054a7f7f624SMasahiro Yamada help 1055de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1056de966cf4STim Chen core ordering determined at manufacturing time, which allows 1057de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1058de966cf4STim Chen single threaded workloads) than others. 1059de966cf4STim Chen 1060de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1061de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1062de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1063de966cf4STim Chen overall system performance can be achieved. 1064de966cf4STim Chen 1065de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1066de966cf4STim Chen 1067de966cf4STim Chen If unsure say Y here. 10685e76b2abSTim Chen 106930b8b006SThomas Gleixnerconfig UP_LATE_INIT 107030b8b006SThomas Gleixner def_bool y 1071ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 107230b8b006SThomas Gleixner 1073506f1d07SSam Ravnborgconfig X86_UP_APIC 107450849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 107550849eefSJan Beulich default PCI_MSI 107638a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1077a7f7f624SMasahiro Yamada help 1078506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1079506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1080506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1081506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1082506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1083506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1084506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1085506f1d07SSam Ravnborg lockups. 1086506f1d07SSam Ravnborg 1087506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1088506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1089506f1d07SSam Ravnborg depends on X86_UP_APIC 1090a7f7f624SMasahiro Yamada help 1091506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1092506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1093506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1094506f1d07SSam Ravnborg 1095506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1096506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1097506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1098506f1d07SSam Ravnborg 1099506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 11003c2362e6SHarvey Harrison def_bool y 11010dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1102b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 110352f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1104506f1d07SSam Ravnborg 1105506f1d07SSam Ravnborgconfig X86_IO_APIC 1106b1da1e71SJan Beulich def_bool y 1107b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1108506f1d07SSam Ravnborg 110941b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 111041b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 111141b9eb26SStefan Assmann depends on X86_IO_APIC 1112a7f7f624SMasahiro Yamada help 111341b9eb26SStefan Assmann This option enables a workaround that fixes a source of 111441b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 111541b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 111641b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 111741b9eb26SStefan Assmann 111841b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 111941b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 112041b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 112141b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 112241b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 112341b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 112441b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 112541b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 112641b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 112741b9eb26SStefan Assmann down (vital) interrupt lines. 112841b9eb26SStefan Assmann 112941b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 113041b9eb26SStefan Assmann increased on these systems. 113141b9eb26SStefan Assmann 1132506f1d07SSam Ravnborgconfig X86_MCE 1133bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1134648ed940SChen, Gong select GENERIC_ALLOCATOR 1135e57dbaf7SBorislav Petkov default y 1136a7f7f624SMasahiro Yamada help 1137bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1138bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1139506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1140bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11414efc0670SAndi Kleen 11425de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11435de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11445de97c9fSTony Luck depends on X86_MCE 1145a7f7f624SMasahiro Yamada help 11465de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11475de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11485de97c9fSTony Luck rasdaemon solution. 11495de97c9fSTony Luck 1150506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11513c2362e6SHarvey Harrison def_bool y 11523c2362e6SHarvey Harrison prompt "Intel MCE features" 1153c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1154a7f7f624SMasahiro Yamada help 1155506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1156506f1d07SSam Ravnborg the thermal monitor. 1157506f1d07SSam Ravnborg 1158506f1d07SSam Ravnborgconfig X86_MCE_AMD 11593c2362e6SHarvey Harrison def_bool y 11603c2362e6SHarvey Harrison prompt "AMD MCE features" 1161f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1162a7f7f624SMasahiro Yamada help 1163506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1164506f1d07SSam Ravnborg the DRAM Error Threshold. 1165506f1d07SSam Ravnborg 11664efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11676fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1168c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1169a7f7f624SMasahiro Yamada help 11704efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11715065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11724efc0670SAndi Kleen line. 11734efc0670SAndi Kleen 1174b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1175b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11766fc108a0SJan Beulich def_bool y 1177b2762686SAndi Kleen 1178ea149b36SAndi Kleenconfig X86_MCE_INJECT 1179bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1180ea149b36SAndi Kleen tristate "Machine check injector support" 1181a7f7f624SMasahiro Yamada help 1182ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1183ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1184ea149b36SAndi Kleen QA it is safe to say n. 1185ea149b36SAndi Kleen 118607dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1187e633c65aSKan Liang 11885aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11891e642812SIngo Molnar bool "Legacy VM86 support" 1190506f1d07SSam Ravnborg depends on X86_32 1191a7f7f624SMasahiro Yamada help 11925aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11935aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11945aef51c3SAndy Lutomirski 11955aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11965aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11975aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11985aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11995aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12001e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12011e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12021e642812SIngo Molnar mode might be faster than emulation and you might want to 12031e642812SIngo Molnar enable this option. 12045aef51c3SAndy Lutomirski 12051e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12061e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12071e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12081e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12095aef51c3SAndy Lutomirski 12101e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12111e642812SIngo Molnar and slows down exception handling a tiny bit. 12125aef51c3SAndy Lutomirski 12131e642812SIngo Molnar If unsure, say N here. 12145aef51c3SAndy Lutomirski 12155aef51c3SAndy Lutomirskiconfig VM86 12165aef51c3SAndy Lutomirski bool 12175aef51c3SAndy Lutomirski default X86_LEGACY_VM86 121834273f41SH. Peter Anvin 121934273f41SH. Peter Anvinconfig X86_16BIT 122034273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 122134273f41SH. Peter Anvin default y 1222a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1223a7f7f624SMasahiro Yamada help 122434273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 122534273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 122634273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 122734273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 122834273f41SH. Peter Anvin 122934273f41SH. Peter Anvinconfig X86_ESPFIX32 123034273f41SH. Peter Anvin def_bool y 123134273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1232506f1d07SSam Ravnborg 1233197725deSH. Peter Anvinconfig X86_ESPFIX64 1234197725deSH. Peter Anvin def_bool y 123534273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1236506f1d07SSam Ravnborg 12371ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12381ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12391ad83c85SAndy Lutomirski default y 12401ad83c85SAndy Lutomirski depends on X86_64 1241a7f7f624SMasahiro Yamada help 12421ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12431ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12441ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12451ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12461ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12471ad83c85SAndy Lutomirski 0xffffffffff600?00. 12481ad83c85SAndy Lutomirski 12491ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12501ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12511ad83c85SAndy Lutomirski 12521ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12531ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12541ad83c85SAndy Lutomirski 1255111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1256111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1257a24ca997SThomas Gleixner default y 1258a7f7f624SMasahiro Yamada help 1259111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1260111e7b15SThomas Gleixner for legacy applications. 1261111e7b15SThomas Gleixner 1262c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1263c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1264c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1265c8137aceSThomas Gleixner capabilities and permission from potentially active security 1266c8137aceSThomas Gleixner modules. 1267c8137aceSThomas Gleixner 1268c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1269c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1270a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1271a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1272c8137aceSThomas Gleixner 1273506f1d07SSam Ravnborgconfig TOSHIBA 1274506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1275506f1d07SSam Ravnborg depends on X86_32 1276a7f7f624SMasahiro Yamada help 1277506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1278506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1279506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1280506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1281506f1d07SSam Ravnborg 1282506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1283506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1284506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1285506f1d07SSam Ravnborg 1286506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1287506f1d07SSam Ravnborg Say N otherwise. 1288506f1d07SSam Ravnborg 1289506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12909ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12919ba16087SJan Beulich depends on X86_32 1292a7f7f624SMasahiro Yamada help 1293506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1294506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1295506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1296506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1297506f1d07SSam Ravnborg system. 1298506f1d07SSam Ravnborg 1299506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13005e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1301506f1d07SSam Ravnborg 1302506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1303506f1d07SSam Ravnborg enable this option even if you don't need it. 1304506f1d07SSam Ravnborg Say N otherwise. 1305506f1d07SSam Ravnborg 1306506f1d07SSam Ravnborgconfig MICROCODE 13079a2bc335SBorislav Petkov bool "CPU microcode loading support" 13089a2bc335SBorislav Petkov default y 130980030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1310a7f7f624SMasahiro Yamada help 1311506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13125f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13135f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13145f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13155f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13165f9c01aaSBorislav Petkov the Linux kernel. 1317506f1d07SSam Ravnborg 13185f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1319cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13205f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13215f9c01aaSBorislav Petkov initrd for microcode blobs. 1322506f1d07SSam Ravnborg 1323c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1324c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1325c508c46eSBenjamin Gilbert config option. 1326506f1d07SSam Ravnborg 13278d86f390SPeter Orubaconfig MICROCODE_INTEL 1328e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13299c55d99eSBorislav Petkov depends on CPU_SUP_INTEL && MICROCODE 13308d86f390SPeter Oruba default MICROCODE 1331a7f7f624SMasahiro Yamada help 13328d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13338d86f390SPeter Oruba processors. 13348d86f390SPeter Oruba 1335b8989db9SAlan For the current Intel microcode data package go to 1336b8989db9SAlan <https://downloadcenter.intel.com> and search for 1337b8989db9SAlan 'Linux Processor Microcode Data File'. 13388d86f390SPeter Oruba 133980cc9f10SPeter Orubaconfig MICROCODE_AMD 1340e43f6e67SBorislav Petkov bool "AMD microcode loading support" 13419c55d99eSBorislav Petkov depends on CPU_SUP_AMD && MICROCODE 1342a7f7f624SMasahiro Yamada help 134380cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 134480cc9f10SPeter Oruba processors will be enabled. 134580cc9f10SPeter Oruba 1346a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING 1347a77a94f8SBorislav Petkov bool "Late microcode loading (DANGEROUS)" 1348c02f48e0SBorislav Petkov default n 1349506f1d07SSam Ravnborg depends on MICROCODE 1350a7f7f624SMasahiro Yamada help 1351a77a94f8SBorislav Petkov Loading microcode late, when the system is up and executing instructions 1352a77a94f8SBorislav Petkov is a tricky business and should be avoided if possible. Just the sequence 1353a77a94f8SBorislav Petkov of synchronizing all cores and SMT threads is one fragile dance which does 1354a77a94f8SBorislav Petkov not guarantee that cores might not softlock after the loading. Therefore, 1355a77a94f8SBorislav Petkov use this at your own risk. Late loading taints the kernel too. 1356506f1d07SSam Ravnborg 1357506f1d07SSam Ravnborgconfig X86_MSR 1358506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1359a7f7f624SMasahiro Yamada help 1360506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1361506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1362506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1363506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1364506f1d07SSam Ravnborg systems. 1365506f1d07SSam Ravnborg 1366506f1d07SSam Ravnborgconfig X86_CPUID 1367506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1368a7f7f624SMasahiro Yamada help 1369506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1370506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1371506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1372506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1373506f1d07SSam Ravnborg 1374506f1d07SSam Ravnborgchoice 1375506f1d07SSam Ravnborg prompt "High Memory Support" 13766fc108a0SJan Beulich default HIGHMEM4G 1377506f1d07SSam Ravnborg depends on X86_32 1378506f1d07SSam Ravnborg 1379506f1d07SSam Ravnborgconfig NOHIGHMEM 1380506f1d07SSam Ravnborg bool "off" 1381a7f7f624SMasahiro Yamada help 1382506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1383506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1384506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1385506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1386506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1387506f1d07SSam Ravnborg "high memory". 1388506f1d07SSam Ravnborg 1389506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1390506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1391506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1392506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1393506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1394506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1395506f1d07SSam Ravnborg possible. 1396506f1d07SSam Ravnborg 1397506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1398506f1d07SSam Ravnborg answer "4GB" here. 1399506f1d07SSam Ravnborg 1400506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1401506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1402506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1403506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1404506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1405506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1406506f1d07SSam Ravnborg 1407506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1408506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1409506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1410506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1411506f1d07SSam Ravnborg kernel at boot time.) 1412506f1d07SSam Ravnborg 1413506f1d07SSam Ravnborg If unsure, say "off". 1414506f1d07SSam Ravnborg 1415506f1d07SSam Ravnborgconfig HIGHMEM4G 1416506f1d07SSam Ravnborg bool "4GB" 1417a7f7f624SMasahiro Yamada help 1418506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1419506f1d07SSam Ravnborg gigabytes of physical RAM. 1420506f1d07SSam Ravnborg 1421506f1d07SSam Ravnborgconfig HIGHMEM64G 1422506f1d07SSam Ravnborg bool "64GB" 1423225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1424506f1d07SSam Ravnborg select X86_PAE 1425a7f7f624SMasahiro Yamada help 1426506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1427506f1d07SSam Ravnborg gigabytes of physical RAM. 1428506f1d07SSam Ravnborg 1429506f1d07SSam Ravnborgendchoice 1430506f1d07SSam Ravnborg 1431506f1d07SSam Ravnborgchoice 14326a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1433506f1d07SSam Ravnborg default VMSPLIT_3G 1434506f1d07SSam Ravnborg depends on X86_32 1435a7f7f624SMasahiro Yamada help 1436506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1437506f1d07SSam Ravnborg 1438506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1439506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1440506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1441506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1442506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1443506f1d07SSam Ravnborg available to user programs, making the address space there 1444506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1445506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1446506f1d07SSam Ravnborg kernel modules. 1447506f1d07SSam Ravnborg 1448506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1449506f1d07SSam Ravnborg option alone! 1450506f1d07SSam Ravnborg 1451506f1d07SSam Ravnborg config VMSPLIT_3G 1452506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1453506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1454506f1d07SSam Ravnborg depends on !X86_PAE 1455506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1456506f1d07SSam Ravnborg config VMSPLIT_2G 1457506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1458506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1459506f1d07SSam Ravnborg depends on !X86_PAE 1460506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1461506f1d07SSam Ravnborg config VMSPLIT_1G 1462506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1463506f1d07SSam Ravnborgendchoice 1464506f1d07SSam Ravnborg 1465506f1d07SSam Ravnborgconfig PAGE_OFFSET 1466506f1d07SSam Ravnborg hex 1467506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1468506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1469506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1470506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1471506f1d07SSam Ravnborg default 0xC0000000 1472506f1d07SSam Ravnborg depends on X86_32 1473506f1d07SSam Ravnborg 1474506f1d07SSam Ravnborgconfig HIGHMEM 14753c2362e6SHarvey Harrison def_bool y 1476506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1477506f1d07SSam Ravnborg 1478506f1d07SSam Ravnborgconfig X86_PAE 14799ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1480506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1481d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14829d99c712SChristian Melki select SWIOTLB 1483a7f7f624SMasahiro Yamada help 1484506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1485506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1486506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1487506f1d07SSam Ravnborg consumes more pagetable space per process. 1488506f1d07SSam Ravnborg 148977ef56e4SKirill A. Shutemovconfig X86_5LEVEL 149077ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 149118ec1eafSKirill A. Shutemov default y 1492eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1493162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 149477ef56e4SKirill A. Shutemov depends on X86_64 1495a7f7f624SMasahiro Yamada help 149677ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 149777ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 149877ef56e4SKirill A. Shutemov physical address space. 149977ef56e4SKirill A. Shutemov 150077ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 150177ef56e4SKirill A. Shutemov 15026657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15036657fca0SKirill A. Shutemov support 4- or 5-level paging. 150477ef56e4SKirill A. Shutemov 1505cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 150677ef56e4SKirill A. Shutemov information. 150777ef56e4SKirill A. Shutemov 150877ef56e4SKirill A. Shutemov Say N if unsure. 150977ef56e4SKirill A. Shutemov 151010971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1511e5008abeSLuis R. Rodriguez def_bool y 15122e1da13fSVlastimil Babka depends on X86_64 1513a7f7f624SMasahiro Yamada help 151410971ab2SIngo Molnar Certain kernel features effectively disable kernel 151510971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 151610971ab2SIngo Molnar supports them), so don't confuse the user by printing 151710971ab2SIngo Molnar that we have them enabled. 15189e899816SNick Piggin 15195c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15205c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15215c280cf6SThomas Gleixner depends on DEBUG_FS 1522a7f7f624SMasahiro Yamada help 1523b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1524a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15255c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15265c280cf6SThomas Gleixner 152720f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 152820f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 152920f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 153020f07a04SKirill A. Shutemov def_bool n 153120f07a04SKirill A. Shutemov 15327744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15337744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15347744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 153582fef0adSDavid Rientjes select DMA_COHERENT_POOL 1536ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1537597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1538aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 153920f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 1540a7f7f624SMasahiro Yamada help 15417744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15427744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15437744ccdbSTom Lendacky Encryption (SME). 15447744ccdbSTom Lendacky 15457744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15467744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15477744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1548a7f7f624SMasahiro Yamada help 15497744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15507744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15517744ccdbSTom Lendacky 15527744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15537744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15547744ccdbSTom Lendacky 15557744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15567744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15577744ccdbSTom Lendacky 1558506f1d07SSam Ravnborg# Common NUMA Features 1559506f1d07SSam Ravnborgconfig NUMA 1560e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1561506f1d07SSam Ravnborg depends on SMP 1562b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1563b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15647ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1565a7f7f624SMasahiro Yamada help 1566e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1567fd51b2d7SKOSAKI Motohiro 1568506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1569506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1570506f1d07SSam Ravnborg NUMA awareness to the kernel. 1571506f1d07SSam Ravnborg 1572c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1573fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1574fd51b2d7SKOSAKI Motohiro 1575b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15767cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1577fd51b2d7SKOSAKI Motohiro 1578fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1579506f1d07SSam Ravnborg 1580eec1d4faSHans Rosenfeldconfig AMD_NUMA 15813c2362e6SHarvey Harrison def_bool y 15823c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15835da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1584a7f7f624SMasahiro Yamada help 1585eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1586eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1587eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1588eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1589eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1590506f1d07SSam Ravnborg 1591506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15923c2362e6SHarvey Harrison def_bool y 15933c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1594506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1595506f1d07SSam Ravnborg select ACPI_NUMA 1596a7f7f624SMasahiro Yamada help 1597506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1598506f1d07SSam Ravnborg 1599506f1d07SSam Ravnborgconfig NUMA_EMU 1600506f1d07SSam Ravnborg bool "NUMA emulation" 16011b7e03efSTejun Heo depends on NUMA 1602a7f7f624SMasahiro Yamada help 1603506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1604506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1605506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1606506f1d07SSam Ravnborg 1607506f1d07SSam Ravnborgconfig NODES_SHIFT 1608d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 160951591e31SDavid Rientjes range 1 10 161051591e31SDavid Rientjes default "10" if MAXSMP 1611506f1d07SSam Ravnborg default "6" if X86_64 1612506f1d07SSam Ravnborg default "3" 1613a9ee6cf5SMike Rapoport depends on NUMA 1614a7f7f624SMasahiro Yamada help 16151184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1616692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1617506f1d07SSam Ravnborg 1618506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1619506f1d07SSam Ravnborg def_bool y 16203b16651fSTejun Heo depends on X86_32 && !NUMA 1621506f1d07SSam Ravnborg 1622506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1623506f1d07SSam Ravnborg def_bool y 16246ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1625506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1626506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1627506f1d07SSam Ravnborg 16283b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16296ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16303b16651fSTejun Heo 1631506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1632506f1d07SSam Ravnborg def_bool y 16334eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1634506f1d07SSam Ravnborg 1635506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1636a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16375c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1638a0842b70SToshi Kani help 1639a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1640cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1641a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1642506f1d07SSam Ravnborg 16433b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16443b16651fSTejun Heo def_bool y 16453b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16463b16651fSTejun Heo 1647a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1648a29815a3SAvi Kivity hex 1649a29815a3SAvi Kivity default 0 if X86_32 1650a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1651a29815a3SAvi Kivity 16527a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16537a67832cSDan Williams bool 16547a67832cSDan Williams 1655ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16567a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16579f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16589f53f9faSDan Williams depends on BLK_DEV 16597a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16607b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16619f53f9faSDan Williams select LIBNVDIMM 1662ec776ef6SChristoph Hellwig help 1663ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1664ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1665ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1666ec776ef6SChristoph Hellwig they can be used for persistent storage. 1667ec776ef6SChristoph Hellwig 1668ec776ef6SChristoph Hellwig Say Y if unsure. 1669ec776ef6SChristoph Hellwig 1670506f1d07SSam Ravnborgconfig HIGHPTE 1671506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16726fc108a0SJan Beulich depends on HIGHMEM 1673a7f7f624SMasahiro Yamada help 1674506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1675506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1676506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1677506f1d07SSam Ravnborg entries in high memory. 1678506f1d07SSam Ravnborg 16799f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16809f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1681a7f7f624SMasahiro Yamada help 16829f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16839f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16849f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16859f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16869f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16879f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16889f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16898c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16909f077871SJeremy Fitzhardinge 16919f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16929f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16939f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16949f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16959f077871SJeremy Fitzhardinge 16969f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16979f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16989f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16999f077871SJeremy Fitzhardinge memory. 17009f077871SJeremy Fitzhardinge 1701c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1702c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1703c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1704c885df50SJeremy Fitzhardinge default y 1705a7f7f624SMasahiro Yamada help 1706c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1707c885df50SJeremy Fitzhardinge on or off. 1708c885df50SJeremy Fitzhardinge 1709506f1d07SSam Ravnborgconfig MATH_EMULATION 1710506f1d07SSam Ravnborg bool 1711a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 171287d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1713a7f7f624SMasahiro Yamada help 1714506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1715506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1716506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1717506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1718506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1719506f1d07SSam Ravnborg coprocessor or this emulation. 1720506f1d07SSam Ravnborg 1721506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1722506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1723506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1724506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1725506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1726506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1727506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1728506f1d07SSam Ravnborg intend to use this kernel on different machines. 1729506f1d07SSam Ravnborg 1730506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1731506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1732506f1d07SSam Ravnborg 1733506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1734506f1d07SSam Ravnborg kernel, it won't hurt. 1735506f1d07SSam Ravnborg 1736506f1d07SSam Ravnborgconfig MTRR 17376fc108a0SJan Beulich def_bool y 17386a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1739a7f7f624SMasahiro Yamada help 1740506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1741506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1742506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1743506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1744506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1745506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1746506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1747506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1748506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1749506f1d07SSam Ravnborg 1750506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1751506f1d07SSam Ravnborg control registers on other processors can be easily supported 1752506f1d07SSam Ravnborg as well: 1753506f1d07SSam Ravnborg 1754506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1755506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1756506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1757506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1758506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1759506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1760506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1761506f1d07SSam Ravnborg 1762506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1763506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1764506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1765506f1d07SSam Ravnborg 1766506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1767506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1768506f1d07SSam Ravnborg 1769cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1770506f1d07SSam Ravnborg 177195ffa243SYinghai Luconfig MTRR_SANITIZER 17722ffb3501SYinghai Lu def_bool y 177395ffa243SYinghai Lu prompt "MTRR cleanup support" 177495ffa243SYinghai Lu depends on MTRR 1775a7f7f624SMasahiro Yamada help 1776aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1777aba3728cSThomas Gleixner add writeback entries. 177895ffa243SYinghai Lu 1779aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1780692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1781aba3728cSThomas Gleixner mtrr_chunk_size. 178295ffa243SYinghai Lu 17832ffb3501SYinghai Lu If unsure, say Y. 178495ffa243SYinghai Lu 178595ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1786f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1787f5098d62SYinghai Lu range 0 1 1788f5098d62SYinghai Lu default "0" 178995ffa243SYinghai Lu depends on MTRR_SANITIZER 1790a7f7f624SMasahiro Yamada help 1791f5098d62SYinghai Lu Enable mtrr cleanup default value 179295ffa243SYinghai Lu 179312031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 179412031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 179512031a62SYinghai Lu range 0 7 179612031a62SYinghai Lu default "1" 179712031a62SYinghai Lu depends on MTRR_SANITIZER 1798a7f7f624SMasahiro Yamada help 179912031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1800aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 180112031a62SYinghai Lu 18022e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18036fc108a0SJan Beulich def_bool y 18046a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18052a8a2719SIngo Molnar depends on MTRR 1806a7f7f624SMasahiro Yamada help 18072e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1808042b78e4SVenki Pallipadi 18092e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18102e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18112e5d9c85Svenkatesh.pallipadi@intel.com 18122e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1813042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18142e5d9c85Svenkatesh.pallipadi@intel.com 18152e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18162e5d9c85Svenkatesh.pallipadi@intel.com 181746cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 181846cf98cdSVenkatesh Pallipadi def_bool y 181946cf98cdSVenkatesh Pallipadi depends on X86_PAT 182046cf98cdSVenkatesh Pallipadi 1821b971880fSBabu Mogerconfig X86_UMIP 1822796ebc81SRicardo Neri def_bool y 1823b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1824a7f7f624SMasahiro Yamada help 1825b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1826b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1827b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1828b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1829b971880fSBabu Moger information about the hardware state. 1830796ebc81SRicardo Neri 1831796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1832796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1833796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1834796ebc81SRicardo Neri results are dummy. 1835aa35f896SRicardo Neri 1836156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1837156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1838156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1839156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1840262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1841262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1842156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1843262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1844156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1845156ff4a5SPeter Zijlstra 1846156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1847156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 1848156ff4a5SPeter Zijlstra bool 184903f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1850f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1851f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 185203f16cd0SJosh Poimboeuf select OBJTOOL 1853156ff4a5SPeter Zijlstra help 1854156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1855156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1856156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1857156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1858156ff4a5SPeter Zijlstra code with them to make this happen. 1859156ff4a5SPeter Zijlstra 1860ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18614cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1862ed53a0d9SPeter Zijlstra 1863ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1864ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1865ed53a0d9SPeter Zijlstra kernel image. 1866ed53a0d9SPeter Zijlstra 186735e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 186838f3e775SBabu Moger prompt "Memory Protection Keys" 186935e97790SDave Hansen def_bool y 1870284244a9SDave Hansen # Note: only available in 64-bit mode 187138f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 187252c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 187352c8e601SIngo Molnar select ARCH_HAS_PKEYS 1874a7f7f624SMasahiro Yamada help 1875284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1876284244a9SDave Hansen page-based protections, but without requiring modification of the 1877284244a9SDave Hansen page tables when an application changes protection domains. 1878284244a9SDave Hansen 18791eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1880284244a9SDave Hansen 1881284244a9SDave Hansen If unsure, say y. 188235e97790SDave Hansen 1883db616173SMichal Hockochoice 1884db616173SMichal Hocko prompt "TSX enable mode" 1885db616173SMichal Hocko depends on CPU_SUP_INTEL 1886db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1887db616173SMichal Hocko help 1888db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1889db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1890db616173SMichal Hocko can lead to a noticeable performance boost. 1891db616173SMichal Hocko 1892db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1893db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1894db616173SMichal Hocko will be more of those attacks discovered in the future. 1895db616173SMichal Hocko 1896db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1897db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1898db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1899db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1900db616173SMichal Hocko for the particular machine. 1901db616173SMichal Hocko 1902db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1903db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1904db616173SMichal Hocko details. 1905db616173SMichal Hocko 1906db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1907db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1908db616173SMichal Hocko relevant. 1909db616173SMichal Hocko 1910db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1911db616173SMichal Hocko bool "off" 1912db616173SMichal Hocko help 1913db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1914db616173SMichal Hocko 1915db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1916db616173SMichal Hocko bool "on" 1917db616173SMichal Hocko help 1918db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1919db616173SMichal Hocko line parameter. 1920db616173SMichal Hocko 1921db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1922db616173SMichal Hocko bool "auto" 1923db616173SMichal Hocko help 1924db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1925db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1926db616173SMichal Hockoendchoice 1927db616173SMichal Hocko 1928e7e05452SSean Christophersonconfig X86_SGX 1929e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1930e7e05452SSean Christopherson depends on X86_64 && CPU_SUP_INTEL 1931e7e05452SSean Christopherson depends on CRYPTO=y 1932e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1933e7e05452SSean Christopherson select SRCU 1934e7e05452SSean Christopherson select MMU_NOTIFIER 1935901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 193640e0e784STony Luck select XARRAY_MULTI 1937e7e05452SSean Christopherson help 1938e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1939e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1940e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1941e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1942e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1943e7e05452SSean Christopherson hardware. 1944e7e05452SSean Christopherson 1945e7e05452SSean Christopherson If unsure, say N. 1946e7e05452SSean Christopherson 1947506f1d07SSam Ravnborgconfig EFI 19489ba16087SJan Beulich bool "EFI runtime service support" 19495b83683fSHuang, Ying depends on ACPI 1950f6ce5002SSergey Vlasov select UCS2_STRING 1951022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19521ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1953a7f7f624SMasahiro Yamada help 19548b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1955506f1d07SSam Ravnborg available (such as the EFI variable services). 1956506f1d07SSam Ravnborg 19578b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19588b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19598b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19608b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19618b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19628b2cb7a8SHuang, Ying platforms. 1963506f1d07SSam Ravnborg 1964291f3632SMatt Flemingconfig EFI_STUB 1965291f3632SMatt Fleming bool "EFI stub support" 1966c6dbd3e5SPeter Zijlstra depends on EFI 19678f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19687b2a583aSMatt Fleming select RELOCATABLE 1969a7f7f624SMasahiro Yamada help 1970291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1971291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1972291f3632SMatt Fleming 19734f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19740c759662SMatt Fleming 19757d453eeeSMatt Flemingconfig EFI_MIXED 19767d453eeeSMatt Fleming bool "EFI mixed-mode support" 19777d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1978a7f7f624SMasahiro Yamada help 19797d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19807d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19817d453eeeSMatt Fleming mode. 19827d453eeeSMatt Fleming 19837d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19847d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19857d453eeeSMatt Fleming the EFI handover protocol must be used. 19867d453eeeSMatt Fleming 19877d453eeeSMatt Fleming If unsure, say N. 19887d453eeeSMatt Fleming 19898636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 1990506f1d07SSam Ravnborg 1991506f1d07SSam Ravnborgconfig KEXEC 1992506f1d07SSam Ravnborg bool "kexec system call" 19932965faa5SDave Young select KEXEC_CORE 1994a7f7f624SMasahiro Yamada help 1995506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 1996506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 1997506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 1998506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 1999506f1d07SSam Ravnborg 2000506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2001506f1d07SSam Ravnborg 2002506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2003506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2004bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2005bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2006bf220695SGeert Uytterhoeven made. 2007506f1d07SSam Ravnborg 200874ca317cSVivek Goyalconfig KEXEC_FILE 200974ca317cSVivek Goyal bool "kexec file based system call" 20102965faa5SDave Young select KEXEC_CORE 2011b69a2afdSJonathan McDowell select HAVE_IMA_KEXEC if IMA 201274ca317cSVivek Goyal depends on X86_64 201374ca317cSVivek Goyal depends on CRYPTO=y 201474ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2015a7f7f624SMasahiro Yamada help 201674ca317cSVivek Goyal This is new version of kexec system call. This system call is 201774ca317cSVivek Goyal file based and takes file descriptors as system call argument 201874ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 201974ca317cSVivek Goyal accepted by previous system call. 202074ca317cSVivek Goyal 2021b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2022b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2023b799a09fSAKASHI Takahiro 202499d5cadfSJiri Bohacconfig KEXEC_SIG 20258e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 202674ca317cSVivek Goyal depends on KEXEC_FILE 2027a7f7f624SMasahiro Yamada help 202899d5cadfSJiri Bohac 202999d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 203099d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 203199d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 203299d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 203399d5cadfSJiri Bohac 203499d5cadfSJiri Bohac In addition to this option, you need to enable signature 203599d5cadfSJiri Bohac verification for the corresponding kernel image type being 203699d5cadfSJiri Bohac loaded in order for this to work. 203799d5cadfSJiri Bohac 203899d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 203999d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 204099d5cadfSJiri Bohac depends on KEXEC_SIG 2041a7f7f624SMasahiro Yamada help 20428e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2043d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20448e7d8381SVivek Goyal 20458e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20468e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 204799d5cadfSJiri Bohac depends on KEXEC_SIG 20488e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20498e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2050a7f7f624SMasahiro Yamada help 20518e7d8381SVivek Goyal Enable bzImage signature verification support. 20528e7d8381SVivek Goyal 2053506f1d07SSam Ravnborgconfig CRASH_DUMP 205404b69447SPavel Machek bool "kernel crash dumps" 2055506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2056a7f7f624SMasahiro Yamada help 2057506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2058506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2059506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2060506f1d07SSam Ravnborg a specially reserved region and then later executed after 2061506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2062506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2063506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2064506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2065330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2066506f1d07SSam Ravnborg 20673ab83521SHuang Yingconfig KEXEC_JUMP 20686ea30386SKees Cook bool "kexec jump" 2069fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2070a7f7f624SMasahiro Yamada help 207189081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 207289081d17SHuang Ying code in physical address mode via KEXEC 20733ab83521SHuang Ying 2074506f1d07SSam Ravnborgconfig PHYSICAL_START 20756a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2076ceefccc9SH. Peter Anvin default "0x1000000" 2077a7f7f624SMasahiro Yamada help 2078506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2079506f1d07SSam Ravnborg 2080506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2081506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2082506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2083506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2084506f1d07SSam Ravnborg address. 2085506f1d07SSam Ravnborg 2086506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2087506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2088506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2089506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2090506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2091506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2092506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2093506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2094506f1d07SSam Ravnborg 2095ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2096ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2097ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2098ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2099ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2100ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2101ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2102330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2103ceefccc9SH. Peter Anvin for more details about crash dumps. 2104506f1d07SSam Ravnborg 2105506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2106506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2107506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2108506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2109506f1d07SSam Ravnborg is present because there are users out there who continue to use 2110506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2111506f1d07SSam Ravnborg line. 2112506f1d07SSam Ravnborg 2113506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2114506f1d07SSam Ravnborg 2115506f1d07SSam Ravnborgconfig RELOCATABLE 211626717808SH. Peter Anvin bool "Build a relocatable kernel" 211726717808SH. Peter Anvin default y 2118a7f7f624SMasahiro Yamada help 2119506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2120506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2121506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2122506f1d07SSam Ravnborg but are discarded at runtime. 2123506f1d07SSam Ravnborg 2124506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2125506f1d07SSam Ravnborg must live at a different physical address than the primary 2126506f1d07SSam Ravnborg kernel. 2127506f1d07SSam Ravnborg 2128506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2129506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21308ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2131506f1d07SSam Ravnborg 21328ab3820fSKees Cookconfig RANDOMIZE_BASE 2133e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21348ab3820fSKees Cook depends on RELOCATABLE 21356807c846SIngo Molnar default y 2136a7f7f624SMasahiro Yamada help 2137e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2138e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2139e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2140e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2141e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2142e8581e3dSBaoquan He code internals. 2143e8581e3dSBaoquan He 2144ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2145ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2146ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2147ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2148ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2149ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2150ed9f007eSKees Cook 2151ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2152ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2153ed9f007eSKees Cook 512MB (8 bits of entropy). 21548ab3820fSKees Cook 2155a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2156e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2157e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2158ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2159ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2160ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2161ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2162ed9f007eSKees Cook theoretically possible, but the implementations are further 2163ed9f007eSKees Cook limited due to memory layouts. 2164e8581e3dSBaoquan He 21656807c846SIngo Molnar If unsure, say Y. 2166da2b6fb9SKees Cook 21678ab3820fSKees Cook# Relocation on x86 needs some additional build support 2168845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2169845adf72SH. Peter Anvin def_bool y 21708ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2171845adf72SH. Peter Anvin 2172506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2173a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21748ab3820fSKees Cook default "0x200000" 2175a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2176a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2177a7f7f624SMasahiro Yamada help 2178506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2179506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2180506f1d07SSam Ravnborg address which meets above alignment restriction. 2181506f1d07SSam Ravnborg 2182506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2183506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2184506f1d07SSam Ravnborg address aligned to above value and run from there. 2185506f1d07SSam Ravnborg 2186506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2187506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2188506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2189506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2190506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2191506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2192506f1d07SSam Ravnborg above alignment restrictions. 2193506f1d07SSam Ravnborg 2194a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2195a0215061SKees Cook this value must be a multiple of 0x200000. 2196a0215061SKees Cook 2197506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2198506f1d07SSam Ravnborg 2199eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2200eedb92abSKirill A. Shutemov bool 2201a7f7f624SMasahiro Yamada help 2202eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2203eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2204eedb92abSKirill A. Shutemov 22050483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22060483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22070483e1faSThomas Garnier depends on X86_64 22080483e1faSThomas Garnier depends on RANDOMIZE_BASE 2209eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22100483e1faSThomas Garnier default RANDOMIZE_BASE 2211a7f7f624SMasahiro Yamada help 22120483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22130483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22140483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22150483e1faSThomas Garnier 22160483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22170483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22180483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22190483e1faSThomas Garnier addresses for each memory section. 22200483e1faSThomas Garnier 22216807c846SIngo Molnar If unsure, say Y. 22220483e1faSThomas Garnier 222390397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 222490397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 222590397a41SThomas Garnier depends on RANDOMIZE_MEMORY 222690397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 222790397a41SThomas Garnier default "0x0" 222890397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 222990397a41SThomas Garnier range 0x0 0x40 2230a7f7f624SMasahiro Yamada help 223190397a41SThomas Garnier Define the padding in terabytes added to the existing physical 223290397a41SThomas Garnier memory size during kernel memory randomization. It is useful 223390397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 223490397a41SThomas Garnier address randomization. 223590397a41SThomas Garnier 223690397a41SThomas Garnier If unsure, leave at the default value. 223790397a41SThomas Garnier 2238506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2239bebd024eSThomas Gleixner def_bool y 224040b31360SStephen Rothwell depends on SMP 2241506f1d07SSam Ravnborg 224280aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 224380aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22442c922cd0SKees Cook depends on HOTPLUG_CPU 2245a7f7f624SMasahiro Yamada help 224680aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 224780aa1dffSFenghua Yu 224880aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 224980aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 225080aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 225180aa1dffSFenghua Yu 225280aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 225380aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 225480aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 225580aa1dffSFenghua Yu 225680aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 225780aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 225880aa1dffSFenghua Yu 225980aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 226080aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 226180aa1dffSFenghua Yu be other CPU0 dependencies. 226280aa1dffSFenghua Yu 226380aa1dffSFenghua Yu Please make sure the dependencies are under your control before 226480aa1dffSFenghua Yu you enable this feature. 226580aa1dffSFenghua Yu 226680aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 226780aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 226880aa1dffSFenghua Yu parameter cpu0_hotplug. 226980aa1dffSFenghua Yu 2270a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2271a71c8bc5SFenghua Yu def_bool n 2272a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22732c922cd0SKees Cook depends on HOTPLUG_CPU 2274a7f7f624SMasahiro Yamada help 2275a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2276a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2277a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2278a71c8bc5SFenghua Yu 2279a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2280a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2281a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2282a71c8bc5SFenghua Yu 2283a71c8bc5SFenghua Yu If unsure, say N. 2284a71c8bc5SFenghua Yu 2285506f1d07SSam Ravnborgconfig COMPAT_VDSO 2286b0b49f26SAndy Lutomirski def_bool n 2287b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2288953fee1dSIngo Molnar depends on COMPAT_32 2289a7f7f624SMasahiro Yamada help 2290b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2291b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2292b0b49f26SAndy Lutomirski indicated in its segment table. 2293e84446deSRandy Dunlap 2294b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2295b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2296b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2297b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2298b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2299506f1d07SSam Ravnborg 2300b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2301b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2302b0b49f26SAndy Lutomirski 2303b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2304b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2305b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2306b0b49f26SAndy Lutomirski 2307b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2308b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2309506f1d07SSam Ravnborg 23103dc33bd3SKees Cookchoice 23113dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23123dc33bd3SKees Cook depends on X86_64 2313625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23143dc33bd3SKees Cook help 23153dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23163dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23173dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23183dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23193dc33bd3SKees Cook 23203dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2321bf00745eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2322bf00745eSAndy Lutomirski is deprecated and can only be enabled using the kernel command 2323bf00745eSAndy Lutomirski line. 23243dc33bd3SKees Cook 23253dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23263dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23273dc33bd3SKees Cook to improve security. 23283dc33bd3SKees Cook 2329bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23303dc33bd3SKees Cook 2331bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2332bd49e16eSAndy Lutomirski bool "Emulate execution only" 2333bd49e16eSAndy Lutomirski help 2334bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2335bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2336bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2337bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2338bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2339bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2340bd49e16eSAndy Lutomirski buffer. 23413dc33bd3SKees Cook 23423dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23433dc33bd3SKees Cook bool "None" 23443dc33bd3SKees Cook help 23453dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23463dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23473dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23483dc33bd3SKees Cook will be reported to dmesg, so that either old or 23493dc33bd3SKees Cook malicious userspace programs can be identified. 23503dc33bd3SKees Cook 23513dc33bd3SKees Cookendchoice 23523dc33bd3SKees Cook 2353516cbf37STim Birdconfig CMDLINE_BOOL 2354516cbf37STim Bird bool "Built-in kernel command line" 2355a7f7f624SMasahiro Yamada help 2356516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2357516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2358516cbf37STim Bird necessary or convenient to provide some or all of the 2359516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2360516cbf37STim Bird to not rely on the boot loader to provide them.) 2361516cbf37STim Bird 2362516cbf37STim Bird To compile command line arguments into the kernel, 2363516cbf37STim Bird set this option to 'Y', then fill in the 236469711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2365516cbf37STim Bird 2366516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2367516cbf37STim Bird should leave this option set to 'N'. 2368516cbf37STim Bird 2369516cbf37STim Birdconfig CMDLINE 2370516cbf37STim Bird string "Built-in kernel command string" 2371516cbf37STim Bird depends on CMDLINE_BOOL 2372516cbf37STim Bird default "" 2373a7f7f624SMasahiro Yamada help 2374516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2375516cbf37STim Bird image and used at boot time. If the boot loader provides a 2376516cbf37STim Bird command line at boot time, it is appended to this string to 2377516cbf37STim Bird form the full kernel command line, when the system boots. 2378516cbf37STim Bird 2379516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2380516cbf37STim Bird change this behavior. 2381516cbf37STim Bird 2382516cbf37STim Bird In most cases, the command line (whether built-in or provided 2383516cbf37STim Bird by the boot loader) should specify the device for the root 2384516cbf37STim Bird file system. 2385516cbf37STim Bird 2386516cbf37STim Birdconfig CMDLINE_OVERRIDE 2387516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2388645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2389a7f7f624SMasahiro Yamada help 2390516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2391516cbf37STim Bird command line, and use ONLY the built-in command line. 2392516cbf37STim Bird 2393516cbf37STim Bird This is used to work around broken boot loaders. This should 2394516cbf37STim Bird be set to 'N' under normal conditions. 2395516cbf37STim Bird 2396a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2397a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2398a5b9e5a2SAndy Lutomirski default y 2399a7f7f624SMasahiro Yamada help 2400a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2401a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2402a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2403a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2404a5b9e5a2SAndy Lutomirski threading libraries. 2405a5b9e5a2SAndy Lutomirski 2406a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2407a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2408a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2409a5b9e5a2SAndy Lutomirski 2410a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2411a5b9e5a2SAndy Lutomirski 24123aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 24133aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 24143aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 24153aac3ebeSThomas Gleixner help 24163aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 24173aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 24183aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 24193aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 24203aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 24213aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 24223aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 24233aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 24243aac3ebeSThomas Gleixner never get a signal delivered. 24253aac3ebeSThomas Gleixner 24263aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24273aac3ebeSThomas Gleixner 2428b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2429b700e7f0SSeth Jennings 2430506f1d07SSam Ravnborgendmenu 2431506f1d07SSam Ravnborg 2432f43b9876SPeter Zijlstraconfig CC_HAS_SLS 2433f43b9876SPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 2434f43b9876SPeter Zijlstra 2435f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK 2436f43b9876SPeter Zijlstra def_bool $(cc-option,-mfunction-return=thunk-extern) 2437f43b9876SPeter Zijlstra 2438f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS 2439f43b9876SPeter Zijlstra bool "Mitigations for speculative execution vulnerabilities" 2440f43b9876SPeter Zijlstra default y 2441f43b9876SPeter Zijlstra help 2442f43b9876SPeter Zijlstra Say Y here to enable options which enable mitigations for 2443f43b9876SPeter Zijlstra speculative execution hardware vulnerabilities. 2444f43b9876SPeter Zijlstra 2445f43b9876SPeter Zijlstra If you say N, all mitigations will be disabled. You really 2446f43b9876SPeter Zijlstra should know what you are doing to say so. 2447f43b9876SPeter Zijlstra 2448f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS 2449f43b9876SPeter Zijlstra 2450f43b9876SPeter Zijlstraconfig PAGE_TABLE_ISOLATION 2451f43b9876SPeter Zijlstra bool "Remove the kernel mapping in user mode" 2452f43b9876SPeter Zijlstra default y 2453f43b9876SPeter Zijlstra depends on (X86_64 || X86_PAE) 2454f43b9876SPeter Zijlstra help 2455f43b9876SPeter Zijlstra This feature reduces the number of hardware side channels by 2456f43b9876SPeter Zijlstra ensuring that the majority of kernel addresses are not mapped 2457f43b9876SPeter Zijlstra into userspace. 2458f43b9876SPeter Zijlstra 2459f43b9876SPeter Zijlstra See Documentation/x86/pti.rst for more details. 2460f43b9876SPeter Zijlstra 2461f43b9876SPeter Zijlstraconfig RETPOLINE 2462f43b9876SPeter Zijlstra bool "Avoid speculative indirect branches in kernel" 2463f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2464f43b9876SPeter Zijlstra default y 2465f43b9876SPeter Zijlstra help 2466f43b9876SPeter Zijlstra Compile kernel with the retpoline compiler options to guard against 2467f43b9876SPeter Zijlstra kernel-to-user data leaks by avoiding speculative indirect 2468f43b9876SPeter Zijlstra branches. Requires a compiler with -mindirect-branch=thunk-extern 2469f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2470f43b9876SPeter Zijlstra 2471f43b9876SPeter Zijlstraconfig RETHUNK 2472f43b9876SPeter Zijlstra bool "Enable return-thunks" 2473f43b9876SPeter Zijlstra depends on RETPOLINE && CC_HAS_RETURN_THUNK 2474f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2475b648ab48SBen Hutchings default y if X86_64 2476f43b9876SPeter Zijlstra help 2477f43b9876SPeter Zijlstra Compile the kernel with the return-thunks compiler option to guard 2478f43b9876SPeter Zijlstra against kernel-to-user data leaks by avoiding return speculation. 2479f43b9876SPeter Zijlstra Requires a compiler with -mfunction-return=thunk-extern 2480f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2481f43b9876SPeter Zijlstra 2482f43b9876SPeter Zijlstraconfig CPU_UNRET_ENTRY 2483f43b9876SPeter Zijlstra bool "Enable UNRET on kernel entry" 2484b648ab48SBen Hutchings depends on CPU_SUP_AMD && RETHUNK && X86_64 2485f43b9876SPeter Zijlstra default y 2486f43b9876SPeter Zijlstra help 2487f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=unret mitigation. 2488f43b9876SPeter Zijlstra 2489f43b9876SPeter Zijlstraconfig CPU_IBPB_ENTRY 2490f43b9876SPeter Zijlstra bool "Enable IBPB on kernel entry" 2491b648ab48SBen Hutchings depends on CPU_SUP_AMD && X86_64 2492f43b9876SPeter Zijlstra default y 2493f43b9876SPeter Zijlstra help 2494f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=ibpb mitigation. 2495f43b9876SPeter Zijlstra 2496f43b9876SPeter Zijlstraconfig CPU_IBRS_ENTRY 2497f43b9876SPeter Zijlstra bool "Enable IBRS on kernel entry" 2498b648ab48SBen Hutchings depends on CPU_SUP_INTEL && X86_64 2499f43b9876SPeter Zijlstra default y 2500f43b9876SPeter Zijlstra help 2501f43b9876SPeter Zijlstra Compile the kernel with support for the spectre_v2=ibrs mitigation. 2502f43b9876SPeter Zijlstra This mitigates both spectre_v2 and retbleed at great cost to 2503f43b9876SPeter Zijlstra performance. 2504f43b9876SPeter Zijlstra 2505f43b9876SPeter Zijlstraconfig SLS 2506f43b9876SPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 2507f43b9876SPeter Zijlstra depends on CC_HAS_SLS && X86_64 2508f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2509f43b9876SPeter Zijlstra default n 2510f43b9876SPeter Zijlstra help 2511f43b9876SPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 2512f43b9876SPeter Zijlstra against straight line speculation. The kernel image might be slightly 2513f43b9876SPeter Zijlstra larger. 2514f43b9876SPeter Zijlstra 2515f43b9876SPeter Zijlstraendif 2516f43b9876SPeter Zijlstra 25173072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 25183072e413SMichal Hocko def_bool y 25195c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 25203072e413SMichal Hocko 2521f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2522f91ef222SOscar Salvador def_bool y 2523f91ef222SOscar Salvador 2524da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2525e279b6c1SSam Ravnborg 2526e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 25273c2362e6SHarvey Harrison def_bool y 252844556530SZhimin Gu depends on HIBERNATION 2529e279b6c1SSam Ravnborg 2530e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2531e279b6c1SSam Ravnborg 2532e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2533e279b6c1SSam Ravnborg 2534a6b68076SAndi Kleenconfig X86_APM_BOOT 25356fc108a0SJan Beulich def_bool y 2536282e5aabSPaul Bolle depends on APM 2537a6b68076SAndi Kleen 2538e279b6c1SSam Ravnborgmenuconfig APM 2539e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2540efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2541a7f7f624SMasahiro Yamada help 2542e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2543e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2544e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2545e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2546e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2547e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2548e279b6c1SSam Ravnborg 2549e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2550e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2551e279b6c1SSam Ravnborg 2552e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2553e279b6c1SSam Ravnborg machines with more than one CPU. 2554e279b6c1SSam Ravnborg 2555e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2556151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 25572dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2558e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2559e279b6c1SSam Ravnborg 2560e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2561e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2562e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2563e279b6c1SSam Ravnborg 2564e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2565e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2566e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2567e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2568e279b6c1SSam Ravnborg 2569e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2570e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2571e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2572e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2573e279b6c1SSam Ravnborg APM in your BIOS). 2574e279b6c1SSam Ravnborg 2575e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2576e279b6c1SSam Ravnborg "weird" problems: 2577e279b6c1SSam Ravnborg 2578e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2579e279b6c1SSam Ravnborg enabled. 2580e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2581e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2582e279b6c1SSam Ravnborg the "no387" option to the kernel 2583e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2584e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2585e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2586e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2587e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2588e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2589e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2590e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2591e279b6c1SSam Ravnborg 11) exchange RAM chips 2592e279b6c1SSam Ravnborg 12) exchange the motherboard. 2593e279b6c1SSam Ravnborg 2594e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2595e279b6c1SSam Ravnborg module will be called apm. 2596e279b6c1SSam Ravnborg 2597e279b6c1SSam Ravnborgif APM 2598e279b6c1SSam Ravnborg 2599e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2600e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2601a7f7f624SMasahiro Yamada help 2602e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2603e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2604e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2605e279b6c1SSam Ravnborg 2606e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2607e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2608a7f7f624SMasahiro Yamada help 2609e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2610e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2611e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2612e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2613e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2614e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2615e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2616e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2617e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2618e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2619e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2620e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2621e279b6c1SSam Ravnborg this feature. 2622e279b6c1SSam Ravnborg 2623e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2624dd8af076SLen Brown depends on CPU_IDLE 2625e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2626a7f7f624SMasahiro Yamada help 2627e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2628e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2629e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2630e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2631e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2632e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2633e279b6c1SSam Ravnborg this option does nothing.) 2634e279b6c1SSam Ravnborg 2635e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2636e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2637a7f7f624SMasahiro Yamada help 2638e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2639e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2640e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2641e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2642e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2643e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2644e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2645e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2646e279b6c1SSam Ravnborg especially if you are using gpm. 2647e279b6c1SSam Ravnborg 2648e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2649e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2650a7f7f624SMasahiro Yamada help 2651e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2652e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2653e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2654e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2655e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2656e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2657e279b6c1SSam Ravnborg 2658e279b6c1SSam Ravnborgendif # APM 2659e279b6c1SSam Ravnborg 2660bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2661e279b6c1SSam Ravnborg 2662e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2663e279b6c1SSam Ravnborg 266427471fdbSAndy Henroidsource "drivers/idle/Kconfig" 266527471fdbSAndy Henroid 2666e279b6c1SSam Ravnborgendmenu 2667e279b6c1SSam Ravnborg 2668e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2669e279b6c1SSam Ravnborg 2670e279b6c1SSam Ravnborgchoice 2671e279b6c1SSam Ravnborg prompt "PCI access mode" 2672efefa6f6SIngo Molnar depends on X86_32 && PCI 2673e279b6c1SSam Ravnborg default PCI_GOANY 2674a7f7f624SMasahiro Yamada help 2675e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2676e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2677e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2678e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2679e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2680e279b6c1SSam Ravnborg 2681e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2682e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2683e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2684e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2685e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2686e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2687e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2688e279b6c1SSam Ravnborg 2689e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2690e279b6c1SSam Ravnborg bool "BIOS" 2691e279b6c1SSam Ravnborg 2692e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2693e279b6c1SSam Ravnborg bool "MMConfig" 2694e279b6c1SSam Ravnborg 2695e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2696e279b6c1SSam Ravnborg bool "Direct" 2697e279b6c1SSam Ravnborg 26983ef0e1f8SAndres Salomonconfig PCI_GOOLPC 269976fb6570SDaniel Drake bool "OLPC XO-1" 27003ef0e1f8SAndres Salomon depends on OLPC 27013ef0e1f8SAndres Salomon 27022bdd1b03SAndres Salomonconfig PCI_GOANY 27032bdd1b03SAndres Salomon bool "Any" 27042bdd1b03SAndres Salomon 2705e279b6c1SSam Ravnborgendchoice 2706e279b6c1SSam Ravnborg 2707e279b6c1SSam Ravnborgconfig PCI_BIOS 27083c2362e6SHarvey Harrison def_bool y 2709efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2710e279b6c1SSam Ravnborg 2711e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2712e279b6c1SSam Ravnborgconfig PCI_DIRECT 27133c2362e6SHarvey Harrison def_bool y 27140aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2715e279b6c1SSam Ravnborg 2716e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2717b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2718b45c9f36SJan Kiszka default y 27194590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2720b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2721e279b6c1SSam Ravnborg 27223ef0e1f8SAndres Salomonconfig PCI_OLPC 27232bdd1b03SAndres Salomon def_bool y 27242bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 27253ef0e1f8SAndres Salomon 2726b5401a96SAlex Nixonconfig PCI_XEN 2727b5401a96SAlex Nixon def_bool y 2728b5401a96SAlex Nixon depends on PCI && XEN 2729b5401a96SAlex Nixon 27308364e1f8SJan Kiszkaconfig MMCONF_FAM10H 27318364e1f8SJan Kiszka def_bool y 27328364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2733e279b6c1SSam Ravnborg 27343f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 27356a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 27366ea30386SKees Cook depends on PCI 27373f6ea84aSIra W. Snyder help 27383f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 27393f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 27403f6ea84aSIra W. Snyder not have ACPI. 27413f6ea84aSIra W. Snyder 274264a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 274364a5fed6SBjorn Helgaas is known to be incomplete. 274464a5fed6SBjorn Helgaas 274564a5fed6SBjorn Helgaas You should say N unless you know you need this. 274664a5fed6SBjorn Helgaas 27473a495511SWilliam Breathitt Grayconfig ISA_BUS 274817a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 27493a495511SWilliam Breathitt Gray help 275017a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 275117a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 275217a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 275317a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 275417a2a129SWilliam Breathitt Gray not have an ISA bus. 27553a495511SWilliam Breathitt Gray 27563a495511SWilliam Breathitt Gray If unsure, say N. 27573a495511SWilliam Breathitt Gray 27581c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2759e279b6c1SSam Ravnborgconfig ISA_DMA_API 27601c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 27611c00f016SDavid Rientjes default y 27621c00f016SDavid Rientjes help 27631c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 27641c00f016SDavid Rientjes If unsure, say Y. 2765e279b6c1SSam Ravnborg 276651e68d05SLinus Torvaldsif X86_32 276751e68d05SLinus Torvalds 2768e279b6c1SSam Ravnborgconfig ISA 2769e279b6c1SSam Ravnborg bool "ISA support" 2770a7f7f624SMasahiro Yamada help 2771e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2772e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2773e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2774e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2775e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2776e279b6c1SSam Ravnborg 2777e279b6c1SSam Ravnborgconfig SCx200 2778e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2779a7f7f624SMasahiro Yamada help 2780e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2781e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2782e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2783e279b6c1SSam Ravnborg for other scx200_* drivers. 2784e279b6c1SSam Ravnborg 2785e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2786e279b6c1SSam Ravnborg 2787e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2788e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2789592913ecSJohn Stultz depends on SCx200 2790e279b6c1SSam Ravnborg default y 2791a7f7f624SMasahiro Yamada help 2792e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2793e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2794e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2795e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2796e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2797e279b6c1SSam Ravnborg 27983ef0e1f8SAndres Salomonconfig OLPC 27993ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 280054008979SThomas Gleixner depends on !X86_PAE 28013c554946SAndres Salomon select GPIOLIB 2802dc3119e7SThomas Gleixner select OF 280345bb1674SDaniel Drake select OF_PROMTREE 2804b4e51854SGrant Likely select IRQ_DOMAIN 28050c3d931bSLubomir Rintel select OLPC_EC 2806a7f7f624SMasahiro Yamada help 28073ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 28083ef0e1f8SAndres Salomon XO hardware. 28093ef0e1f8SAndres Salomon 2810a3128588SDaniel Drakeconfig OLPC_XO1_PM 2811a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2812fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2813a7f7f624SMasahiro Yamada help 281497c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2815bf1ebf00SDaniel Drake 2816cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2817cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2818cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2819a7f7f624SMasahiro Yamada help 2820cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2821cfee9597SDaniel Drake programmable wakeup source. 2822cfee9597SDaniel Drake 28237feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 28247feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 282592e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2826ed8e47feSRandy Dunlap depends on INPUT=y 2827d8d01a63SDaniel Drake select POWER_SUPPLY 2828a7f7f624SMasahiro Yamada help 28297feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 28307bc74b3dSDaniel Drake - EC-driven system wakeups 28317feda8e9SDaniel Drake - Power button 28327bc74b3dSDaniel Drake - Ebook switch 28332cf2baeaSDaniel Drake - Lid switch 2834e1040ac6SDaniel Drake - AC adapter status updates 2835e1040ac6SDaniel Drake - Battery status updates 28367feda8e9SDaniel Drake 2837a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2838a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2839d8d01a63SDaniel Drake depends on OLPC && ACPI 2840d8d01a63SDaniel Drake select POWER_SUPPLY 2841a7f7f624SMasahiro Yamada help 2842a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2843a0f30f59SDaniel Drake - EC-driven system wakeups 2844a0f30f59SDaniel Drake - AC adapter status updates 2845a0f30f59SDaniel Drake - Battery status updates 2846e279b6c1SSam Ravnborg 2847d4f3e350SEd Wildgooseconfig ALIX 2848d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2849d4f3e350SEd Wildgoose select GPIOLIB 2850a7f7f624SMasahiro Yamada help 2851d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2852d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2853d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2854d4f3e350SEd Wildgoose get added here. 2855d4f3e350SEd Wildgoose 2856d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2857d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2858d4f3e350SEd Wildgoose 2859d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2860d4f3e350SEd Wildgoose 2861da4e3302SPhilip Prindevilleconfig NET5501 2862da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2863da4e3302SPhilip Prindeville select GPIOLIB 2864a7f7f624SMasahiro Yamada help 2865da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2866da4e3302SPhilip Prindeville 28673197059aSPhilip A. Prindevilleconfig GEOS 28683197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28693197059aSPhilip A. Prindeville select GPIOLIB 28703197059aSPhilip A. Prindeville depends on DMI 2871a7f7f624SMasahiro Yamada help 28723197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28733197059aSPhilip A. Prindeville 28747d029125SVivien Didelotconfig TS5500 28757d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28767d029125SVivien Didelot depends on MELAN 28777d029125SVivien Didelot select CHECK_SIGNATURE 28787d029125SVivien Didelot select NEW_LEDS 28797d029125SVivien Didelot select LEDS_CLASS 2880a7f7f624SMasahiro Yamada help 28817d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28827d029125SVivien Didelot 2883e279b6c1SSam Ravnborgendif # X86_32 2884e279b6c1SSam Ravnborg 288523ac4ae8SAndreas Herrmannconfig AMD_NB 2886e279b6c1SSam Ravnborg def_bool y 28870e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2888e279b6c1SSam Ravnborg 2889e279b6c1SSam Ravnborgendmenu 2890e279b6c1SSam Ravnborg 28911572497cSChristoph Hellwigmenu "Binary Emulations" 2892e279b6c1SSam Ravnborg 2893e279b6c1SSam Ravnborgconfig IA32_EMULATION 2894e279b6c1SSam Ravnborg bool "IA32 Emulation" 2895e279b6c1SSam Ravnborg depends on X86_64 289639f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2897d1603990SRandy Dunlap select BINFMT_ELF 289839f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2899a7f7f624SMasahiro Yamada help 29005fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 29015fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 29025fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2903e279b6c1SSam Ravnborg 290483a44a4fSMasahiro Yamadaconfig X86_X32_ABI 29056ea30386SKees Cook bool "x32 ABI for 64-bit mode" 29069b54050bSBrian Gerst depends on X86_64 2907aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 2908aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 2909aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 2910aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 2911aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2912a7f7f624SMasahiro Yamada help 29135fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 29145fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 29155fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 29165fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 29175fd92e65SH. J. Lu 2918953fee1dSIngo Molnarconfig COMPAT_32 2919953fee1dSIngo Molnar def_bool y 2920953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2921953fee1dSIngo Molnar select HAVE_UID16 2922953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2923953fee1dSIngo Molnar 2924e279b6c1SSam Ravnborgconfig COMPAT 29253c2362e6SHarvey Harrison def_bool y 292683a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 2927e279b6c1SSam Ravnborg 2928e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 29293120e25eSJan Beulich def_bool y 2930a9251280SLinus Torvalds depends on COMPAT 2931ee009e4aSDavid Howells 2932e279b6c1SSam Ravnborgendmenu 2933e279b6c1SSam Ravnborg 2934e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2935e5beae16SKeith Packard def_bool y 2936e5beae16SKeith Packard depends on X86_32 2937e5beae16SKeith Packard 2938edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 29395e8ebd84SJason A. Donenfeld 29405e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2941