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 72fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 73399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 7421266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 75b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 766471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 7772d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 78316d097cSDave Hansen select ARCH_HAS_FILTER_PGPROT 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 880aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 89ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 90d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 91d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 92ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 93ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 94ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 9525c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 96c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 977e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 9863703f37SKefeng Wang select ARCH_HAS_ZONE_DMA_SET if EXPERT 996471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 1006471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 10177fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 1025e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 1033599fe12SThomas Gleixner select ARCH_STACKWALK 1042c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 1056471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 1065d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 107d283d422SPasha Tatashin select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 1086471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 10914df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 110583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 111583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1126471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 113dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1146471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1156471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1162ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 117ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 11881c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 119c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 12051c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 1213876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 12259612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 12338d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 124b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 12510916706SShile Zhang select BUILDTIME_TABLE_SORT 1266471b825SIngo Molnar select CLKEVT_I8253 1276471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1286471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1296471b825SIngo Molnar select DCACHE_WORD_ACCESS 1303aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 13145471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 13245471cd9SLinus Torvalds select EDAC_SUPPORT 1336471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1346471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1356471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1366471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 13761dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1386471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 13927d6b4d1SThomas Gleixner select GENERIC_ENTRY 1406471b825SIngo Molnar select GENERIC_IOMAP 141c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1420fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 143ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1446471b825SIngo Molnar select GENERIC_IRQ_PROBE 145c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1466471b825SIngo Molnar select GENERIC_IRQ_SHOW 1476471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1482ae27137SSteven Price select GENERIC_PTDUMP 1496471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1506471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1517ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 152550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 15339656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 15417e5888eSHans de Goede select HARDIRQS_SW_RESEND 1557edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1566471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1576471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1586471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1596471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1606471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 1616471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 162b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 163d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1640609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1651dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1666471b825SIngo Molnar select HAVE_ARCH_KGDB 1679e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1689e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1691b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 170271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1716471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 172f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 173afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1746471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1756471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 176a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 177b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1787677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 179e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 180fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 181c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1822ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1836471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1846471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1856471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 186d1f250e2SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 1876471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 1886dafca97SSami Tolvanen select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 1894ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 1906471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1919c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 192677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 19306aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 19402a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 195562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 196c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 197503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 19803f5781bSWang YanQing select HAVE_EBPF_JIT 19958340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2006630a8e5SChristoph Hellwig select HAVE_EISA 2015f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 20267a929e0SChristoph Hellwig select HAVE_FAST_GUP 203644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2046471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 2054a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2066471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2076b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2080067f129SK.Prasad select HAVE_HW_BREAKPOINT 2096471b825SIngo Molnar select HAVE_IOREMAP_PROT 210624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2116471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2126471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2136471b825SIngo Molnar select HAVE_KERNEL_GZIP 2146471b825SIngo Molnar select HAVE_KERNEL_LZ4 2156471b825SIngo Molnar select HAVE_KERNEL_LZMA 2166471b825SIngo Molnar select HAVE_KERNEL_LZO 2176471b825SIngo Molnar select HAVE_KERNEL_XZ 218fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2196471b825SIngo Molnar select HAVE_KPROBES 2206471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 221540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2226471b825SIngo Molnar select HAVE_KRETPROBES 2236471b825SIngo Molnar select HAVE_KVM 2246471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2250102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 226ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2279f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 228be37c98dSKalesh Singh select HAVE_MOVE_PUD 22942a0bb3fSPetr Mladek select HAVE_NMI 2306471b825SIngo Molnar select HAVE_OPTPROBES 2316471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2326471b825SIngo Molnar select HAVE_PERF_EVENTS 233c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 23492e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 235eb01d42aSChristoph Hellwig select HAVE_PCI 236c5e63197SJiri Olsa select HAVE_PERF_REGS 237c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 238ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 23900998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2406471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 2416415b38bSJiri Slaby select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 2423c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2437ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 244cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 245d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 246c763ea26SIngo Molnar select HAVE_STACK_VALIDATION if X86_64 247e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 2481e7e4788SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 2496ef869e0SMichal Hocko select HAVE_PREEMPT_DYNAMIC 250d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2516471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2526471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2537c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2547ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 25505736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 256c0185808SThomas Gleixner select IRQ_FORCED_THREADING 2577ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2587ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 25986596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2602eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 261625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2626471b825SIngo Molnar select PERF_EVENTS 2633195ef59SPrarit Bhargava select RTC_LIB 264d6faca40SArnd Bergmann select RTC_MC146818_LIB 2656471b825SIngo Molnar select SPARSE_IRQ 26683fe27eaSPranith Kumar select SRCU 2671e7e4788SJosh Poimboeuf select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 2686471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 26915f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2704aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2716471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2726471b825SIngo Molnar select VIRT_TO_BUS 2733b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2746471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2750c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 27650468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 2779e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 2787d8330a5SBalbir Singh 279ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2803120e25eSJan Beulich def_bool y 2813120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 282ba7e4d13SIngo Molnar 28351b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 28451b26adaSLinus Torvalds string 28551b26adaSLinus Torvalds default "elf32-i386" if X86_32 28651b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 28751b26adaSLinus Torvalds 2888d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2893c2362e6SHarvey Harrison def_bool y 2908d5fffb9SSam Ravnborg 2918d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2923c2362e6SHarvey Harrison def_bool y 2938d5fffb9SSam Ravnborg 2948d5fffb9SSam Ravnborgconfig MMU 2953c2362e6SHarvey Harrison def_bool y 2968d5fffb9SSam Ravnborg 2979e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 2989e08f57dSDaniel Cashman default 28 if 64BIT 2999e08f57dSDaniel Cashman default 8 3009e08f57dSDaniel Cashman 3019e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3029e08f57dSDaniel Cashman default 32 if 64BIT 3039e08f57dSDaniel Cashman default 16 3049e08f57dSDaniel Cashman 3059e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3069e08f57dSDaniel Cashman default 8 3079e08f57dSDaniel Cashman 3089e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3099e08f57dSDaniel Cashman default 16 3109e08f57dSDaniel Cashman 3118d5fffb9SSam Ravnborgconfig SBUS 3128d5fffb9SSam Ravnborg bool 3138d5fffb9SSam Ravnborg 3148d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3153120e25eSJan Beulich def_bool y 3163120e25eSJan Beulich depends on ISA_DMA_API 3178d5fffb9SSam Ravnborg 3188d5fffb9SSam Ravnborgconfig GENERIC_BUG 3193c2362e6SHarvey Harrison def_bool y 3208d5fffb9SSam Ravnborg depends on BUG 321b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 322b93a531eSJan Beulich 323b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 324b93a531eSJan Beulich bool 3258d5fffb9SSam Ravnborg 3268d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3273120e25eSJan Beulich def_bool y 3283120e25eSJan Beulich depends on ISA_DMA_API 3298d5fffb9SSam Ravnborg 3301032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3311032c0baSSam Ravnborg def_bool y 3321032c0baSSam Ravnborg 3339a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3349a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3358d5fffb9SSam Ravnborg 336316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT 337316d097cSDave Hansen def_bool y 338316d097cSDave Hansen 339801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 340801e4062SJohannes Berg def_bool y 341801e4062SJohannes Berg 342d7109fe3SAndy Shevchenkoconfig ARCH_NR_GPIO 343d7109fe3SAndy Shevchenko int 344d7109fe3SAndy Shevchenko default 1024 if X86_64 345d7109fe3SAndy Shevchenko default 512 346d7109fe3SAndy Shevchenko 347f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 348f4cb5700SJohannes Berg def_bool y 349f4cb5700SJohannes Berg 35053313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB 35153313b2cSSteve Capper def_bool y 35253313b2cSSteve Capper 3538d5fffb9SSam Ravnborgconfig AUDIT_ARCH 354e0fd24a3SJan Beulich def_bool y if X86_64 3558d5fffb9SSam Ravnborg 356d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 357d6f2d75aSAndrey Ryabinin hex 358d6f2d75aSAndrey Ryabinin depends on KASAN 359d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 360d6f2d75aSAndrey Ryabinin 36169575d38SShane Wangconfig HAVE_INTEL_TXT 36269575d38SShane Wang def_bool y 3636ea30386SKees Cook depends on INTEL_IOMMU && ACPI 36469575d38SShane Wang 3656b0c3d44SSam Ravnborgconfig X86_32_SMP 3666b0c3d44SSam Ravnborg def_bool y 3676b0c3d44SSam Ravnborg depends on X86_32 && SMP 3686b0c3d44SSam Ravnborg 3696b0c3d44SSam Ravnborgconfig X86_64_SMP 3706b0c3d44SSam Ravnborg def_bool y 3716b0c3d44SSam Ravnborg depends on X86_64 && SMP 3726b0c3d44SSam Ravnborg 3732b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3742b144498SSrikar Dronamraju def_bool y 3752b144498SSrikar Dronamraju 376d20642f0SRob Herringconfig FIX_EARLYCON_MEM 377d20642f0SRob Herring def_bool y 378d20642f0SRob Herring 37994d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 38094d49eb3SKirill A. Shutemov bool 38194d49eb3SKirill A. Shutemov 38298233368SKirill A. Shutemovconfig PGTABLE_LEVELS 38398233368SKirill A. Shutemov int 38477ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 38598233368SKirill A. Shutemov default 4 if X86_64 38698233368SKirill A. Shutemov default 3 if X86_PAE 38798233368SKirill A. Shutemov default 2 38898233368SKirill A. Shutemov 3892a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3902a61f474SMasahiro Yamada bool 3912a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3922a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3932a61f474SMasahiro Yamada help 3942a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3953fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 3963fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 3972a61f474SMasahiro Yamada 398506f1d07SSam Ravnborgmenu "Processor type and features" 399506f1d07SSam Ravnborg 400506f1d07SSam Ravnborgconfig SMP 401506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 402a7f7f624SMasahiro Yamada help 403506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4044a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4054a474157SRobert Graffham than one CPU, say Y. 406506f1d07SSam Ravnborg 4074a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 408506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 409506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4104a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 411506f1d07SSam Ravnborg will run faster if you say N here. 412506f1d07SSam Ravnborg 413506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 414506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 415506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 416506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 417506f1d07SSam Ravnborg 418506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 419506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 420506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 421506f1d07SSam Ravnborg 422cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4234f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 424506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 425506f1d07SSam Ravnborg 426506f1d07SSam Ravnborg If you don't know what to do here, say N. 427506f1d07SSam Ravnborg 4289def39beSJosh Triplettconfig X86_FEATURE_NAMES 4299def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4309def39beSJosh Triplett default y 431a7f7f624SMasahiro Yamada help 4329def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4339def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4349def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4359def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4369def39beSJosh Triplett 4379def39beSJosh Triplett If in doubt, say Y. 4389def39beSJosh Triplett 43906cd9a7dSYinghai Luconfig X86_X2APIC 44006cd9a7dSYinghai Lu bool "Support x2apic" 44119e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 442a7f7f624SMasahiro Yamada help 44306cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 44406cd9a7dSYinghai Lu 44506cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 44606cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 44706cd9a7dSYinghai Lu 44806cd9a7dSYinghai Lu If you don't know what to do here, say N. 44906cd9a7dSYinghai Lu 4506695c85bSYinghai Luconfig X86_MPPARSE 4514590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4527a527688SJan Beulich default y 4535ab74722SIngo Molnar depends on X86_LOCAL_APIC 454a7f7f624SMasahiro Yamada help 4556695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4566695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4576695c85bSYinghai Lu 458ddd70cf9SJun Nakajimaconfig GOLDFISH 459ddd70cf9SJun Nakajima def_bool y 460ddd70cf9SJun Nakajima depends on X86_GOLDFISH 461ddd70cf9SJun Nakajima 46276b04384SDavid Woodhouseconfig RETPOLINE 46376b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 46476b04384SDavid Woodhouse default y 46576b04384SDavid Woodhouse help 46676b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 46776b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 46876b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 46976b04384SDavid Woodhouse support for full protection. The kernel may run slower. 47076b04384SDavid Woodhouse 471e463a09aSPeter Zijlstraconfig CC_HAS_SLS 472e463a09aSPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 473e463a09aSPeter Zijlstra 474e463a09aSPeter Zijlstraconfig SLS 475e463a09aSPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 476e463a09aSPeter Zijlstra depends on CC_HAS_SLS && X86_64 477e463a09aSPeter Zijlstra default n 478e463a09aSPeter Zijlstra help 479e463a09aSPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 480e463a09aSPeter Zijlstra against straight line speculation. The kernel image might be slightly 481e463a09aSPeter Zijlstra larger. 482e463a09aSPeter Zijlstra 483e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 484e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4856fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48659fe5a77SThomas Gleixner select KERNFS 487e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48878e99b4aSFenghua Yu help 489e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4906fe07ce3SBabu Moger 4916fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4926fe07ce3SBabu Moger usage by the CPU. 4936fe07ce3SBabu Moger 4946fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4956fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4966fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4976fe07ce3SBabu Moger 4986fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4996fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 5006fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 50178e99b4aSFenghua Yu 50278e99b4aSFenghua Yu Say N if unsure. 50378e99b4aSFenghua Yu 5048425091fSRavikiran G Thirumalaiif X86_32 505a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 506a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 507a0d0bb4dSRandy Dunlap depends on SMP 508a7f7f624SMasahiro Yamada help 509e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 510a0d0bb4dSRandy Dunlap 511c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 512c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 513c5c606d9SRavikiran G Thirumalai default y 514a7f7f624SMasahiro Yamada help 51506ac8346SIngo Molnar If you disable this option then the kernel will only support 51606ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51706ac8346SIngo Molnar systems out there.) 51806ac8346SIngo Molnar 5198425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5208425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 521cb7b8023SBen Hutchings Goldfish (Android emulator) 5228425091fSRavikiran G Thirumalai AMD Elan 5238425091fSRavikiran G Thirumalai RDC R-321x SoC 5248425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 52583125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5263f4110a4SThomas Gleixner Moorestown MID devices 52706ac8346SIngo Molnar 52806ac8346SIngo Molnar If you have one of these systems, or if you want to build a 52906ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5308425091fSRavikiran G Thirumalaiendif 53106ac8346SIngo Molnar 5328425091fSRavikiran G Thirumalaiif X86_64 5338425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5348425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5358425091fSRavikiran G Thirumalai default y 536a7f7f624SMasahiro Yamada help 5378425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5388425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5398425091fSRavikiran G Thirumalai systems out there.) 5408425091fSRavikiran G Thirumalai 5418425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5428425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 54344b111b5SSteffen Persvold Numascale NumaChip 5448425091fSRavikiran G Thirumalai ScaleMP vSMP 5458425091fSRavikiran G Thirumalai SGI Ultraviolet 5468425091fSRavikiran G Thirumalai 5478425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5488425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5498425091fSRavikiran G Thirumalaiendif 550c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 551c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 55244b111b5SSteffen Persvoldconfig X86_NUMACHIP 55344b111b5SSteffen Persvold bool "Numascale NumaChip" 55444b111b5SSteffen Persvold depends on X86_64 55544b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55644b111b5SSteffen Persvold depends on NUMA 55744b111b5SSteffen Persvold depends on SMP 55844b111b5SSteffen Persvold depends on X86_X2APIC 559f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 560a7f7f624SMasahiro Yamada help 56144b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 56244b111b5SSteffen Persvold enable more than ~168 cores. 56344b111b5SSteffen Persvold If you don't have one of these, you should say N here. 56403b48632SNick Piggin 5656a48565eSIngo Molnarconfig X86_VSMP 566c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5676276a074SBorislav Petkov select HYPERVISOR_GUEST 5686a48565eSIngo Molnar select PARAVIRT 5696a48565eSIngo Molnar depends on X86_64 && PCI 570c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 571ead91d4bSShai Fultheim depends on SMP 572a7f7f624SMasahiro Yamada help 5736a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5746a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5756a48565eSIngo Molnar if you have one of these machines. 5766a48565eSIngo Molnar 577c5c606d9SRavikiran G Thirumalaiconfig X86_UV 578c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 579c5c606d9SRavikiran G Thirumalai depends on X86_64 580c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 58154c28d29SJack Steiner depends on NUMA 5821ecb4ae5SAndrew Morton depends on EFI 583c2209ea5SIngo Molnar depends on KEXEC_CORE 5849d6c26e7SSuresh Siddha depends on X86_X2APIC 5851222e564SIngo Molnar depends on PCI 586a7f7f624SMasahiro Yamada help 587c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 588c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 589c5c606d9SRavikiran G Thirumalai 590c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 591c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 592506f1d07SSam Ravnborg 593ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 594ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 595cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 596a7f7f624SMasahiro Yamada help 597ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 598ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 599ddd70cf9SJun Nakajima Goldfish emulator say N here. 600ddd70cf9SJun Nakajima 601c751e17bSThomas Gleixnerconfig X86_INTEL_CE 602c751e17bSThomas Gleixner bool "CE4100 TV platform" 603c751e17bSThomas Gleixner depends on PCI 604c751e17bSThomas Gleixner depends on PCI_GODIRECT 6056084a6e2SJiang Liu depends on X86_IO_APIC 606c751e17bSThomas Gleixner depends on X86_32 607c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60837bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 609da6b737bSSebastian Andrzej Siewior select OF 610da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 611a7f7f624SMasahiro Yamada help 612c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 613c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 614c751e17bSThomas Gleixner boxes and media devices. 615c751e17bSThomas Gleixner 6164cb9b00fSDavid Cohenconfig X86_INTEL_MID 61743605ef1SAlan Cox bool "Intel MID platform support" 61843605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 619edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6201ea7c673SAlan Cox depends on PCI 6213fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6221ea7c673SAlan Cox depends on X86_IO_APIC 6234cb9b00fSDavid Cohen select I2C 6247c9c3a1eSAlan Cox select DW_APB_TIMER 62554b34aa0SMika Westerberg select INTEL_SCU_PCI 626a7f7f624SMasahiro Yamada help 6274cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6284cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6294cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6301ea7c673SAlan Cox 6314cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6324cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 63343605ef1SAlan Cox 6348bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6358bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6368bbc2a13SBryan O'Donoghue depends on X86_32 6378bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6388bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6398bbc2a13SBryan O'Donoghue depends on X86_TSC 6408bbc2a13SBryan O'Donoghue depends on PCI 6418bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6428bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6438bbc2a13SBryan O'Donoghue select IOSF_MBI 6448bbc2a13SBryan O'Donoghue select INTEL_IMR 6459ab6eb51SAndy Shevchenko select COMMON_CLK 646a7f7f624SMasahiro Yamada help 6478bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6488bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6498bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6508bbc2a13SBryan O'Donoghue 6513d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6523d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6535962dd22SSinan Kaya depends on X86 && ACPI && PCI 6543d48aab1SMika Westerberg select COMMON_CLK 6550f531431SMathias Nyman select PINCTRL 656eebb3e8dSAndy Shevchenko select IOSF_MBI 657a7f7f624SMasahiro Yamada help 6583d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6593d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6600f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6610f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6623d48aab1SMika Westerberg 66392082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 66492082a88SKen Xue bool "AMD ACPI2Platform devices support" 66592082a88SKen Xue depends on ACPI 66692082a88SKen Xue select COMMON_CLK 66792082a88SKen Xue select PINCTRL 668a7f7f624SMasahiro Yamada help 66992082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 67092082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 67192082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 67292082a88SKen Xue implemented under PINCTRL subsystem. 67392082a88SKen Xue 674ced3ce76SDavid E. Boxconfig IOSF_MBI 675ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 676ced3ce76SDavid E. Box depends on PCI 677a7f7f624SMasahiro Yamada help 678ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 679ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 680ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 681ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 682ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 683ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 684ced3ce76SDavid E. Box This list is not meant to be exclusive. 685ced3ce76SDavid E. Box - BayTrail 686ced3ce76SDavid E. Box - Braswell 687ced3ce76SDavid E. Box - Quark 688ced3ce76SDavid E. Box 689ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 690ced3ce76SDavid E. Box 691ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 692ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 693ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 694a7f7f624SMasahiro Yamada help 695ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 696ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 697ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 698ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 699ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 700ed2226bdSDavid E. Box device they want to access. 701ed2226bdSDavid E. Box 702ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 703ed2226bdSDavid E. Box 704c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 705c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 706506f1d07SSam Ravnborg depends on X86_32 707c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 708c5c606d9SRavikiran G Thirumalai select M486 709c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 710a7f7f624SMasahiro Yamada help 711c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 712c5c606d9SRavikiran G Thirumalai as R-8610-(G). 713c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 714c5c606d9SRavikiran G Thirumalai 715e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7169c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7179c398017SIngo Molnar depends on X86_32 && SMP 718c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 719a7f7f624SMasahiro Yamada help 720b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 721b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 722b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 723b5660ba7SH. Peter Anvin one and will fallback to default. 724d49c4288SYinghai Lu 725c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 726d49c4288SYinghai Lu 727d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7286fc108a0SJan Beulich def_bool y 729d949f36fSLinus Torvalds # MCE code calls memory_failure(): 730d949f36fSLinus Torvalds depends on X86_MCE 731d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 732d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 733d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 734d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 735d949f36fSLinus Torvalds 73683125a3aSAlessandro Rubiniconfig STA2X11 73783125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73883125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 73983125a3aSAlessandro Rubini select SWIOTLB 74083125a3aSAlessandro Rubini select MFD_STA2X11 7410145071bSLinus Walleij select GPIOLIB 742a7f7f624SMasahiro Yamada help 74383125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 74483125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 74583125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74683125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74783125a3aSAlessandro Rubini standard PC machines. 74883125a3aSAlessandro Rubini 74982148d1dSShérabconfig X86_32_IRIS 75082148d1dSShérab tristate "Eurobraille/Iris poweroff module" 75182148d1dSShérab depends on X86_32 752a7f7f624SMasahiro Yamada help 75382148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 75482148d1dSShérab to shut themselves down properly. A special I/O sequence is 75582148d1dSShérab needed to do so, which is what this module does at 75682148d1dSShérab kernel shutdown. 75782148d1dSShérab 75882148d1dSShérab This is only for Iris machines from EuroBraille. 75982148d1dSShérab 76082148d1dSShérab If unused, say N. 76182148d1dSShérab 762ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7633c2362e6SHarvey Harrison def_bool y 7643c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 765a87d0914SKen Chen depends on X86 766a7f7f624SMasahiro Yamada help 767506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 768506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 769506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 770506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 771506f1d07SSam Ravnborg 772506f1d07SSam Ravnborg If in doubt, say "Y". 773506f1d07SSam Ravnborg 7746276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7756276a074SBorislav Petkov bool "Linux guest support" 776a7f7f624SMasahiro Yamada help 7776276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7786276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7796276a074SBorislav Petkov setup. 780506f1d07SSam Ravnborg 7816276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7826276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 783506f1d07SSam Ravnborg 7846276a074SBorislav Petkovif HYPERVISOR_GUEST 785506f1d07SSam Ravnborg 786e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 787e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 788a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 789a7f7f624SMasahiro Yamada help 790e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 791e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 792e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 793e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 794e61bd94aSEduardo Pereira Habkost 795c00a280aSJuergen Grossconfig PARAVIRT_XXL 796c00a280aSJuergen Gross bool 797c00a280aSJuergen Gross 7986276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7996276a074SBorislav Petkov bool "paravirt-ops debugging" 8006276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 801a7f7f624SMasahiro Yamada help 8026276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 8036276a074SBorislav Petkov a paravirt_op is missing when it is called. 8046276a074SBorislav Petkov 805b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 806b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8076ea30386SKees Cook depends on PARAVIRT && SMP 808a7f7f624SMasahiro Yamada help 809b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 810b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 811b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 812b4ecc126SJeremy Fitzhardinge 8134c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8144c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 815b4ecc126SJeremy Fitzhardinge 8164c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 817b4ecc126SJeremy Fitzhardinge 818ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 819ecca2502SZhao Yakui def_bool n 820ecca2502SZhao Yakui 8216276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8226276a074SBorislav Petkov 8236276a074SBorislav Petkovconfig KVM_GUEST 8246276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8256276a074SBorislav Petkov depends on PARAVIRT 8266276a074SBorislav Petkov select PARAVIRT_CLOCK 827a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 828b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8296276a074SBorislav Petkov default y 830a7f7f624SMasahiro Yamada help 8316276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8326276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8336276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8346276a074SBorislav Petkov underlying device model, the host provides the guest with 8356276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8366276a074SBorislav Petkov 837a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 838a1c4423bSMarcelo Tosatti def_bool n 839a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 840a1c4423bSMarcelo Tosatti help 841a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 842a1c4423bSMarcelo Tosatti 8437733607fSMaran Wilsonconfig PVH 8447733607fSMaran Wilson bool "Support for running PVH guests" 845a7f7f624SMasahiro Yamada help 8467733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8477733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8487733607fSMaran Wilson 8496276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8506276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8516276a074SBorislav Petkov depends on PARAVIRT 852a7f7f624SMasahiro Yamada help 8536276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8546276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8556276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8566276a074SBorislav Petkov that, there can be a small performance impact. 8576276a074SBorislav Petkov 8586276a074SBorislav Petkov If in doubt, say N here. 8596276a074SBorislav Petkov 8607af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8617af192c9SGerd Hoffmann bool 8627af192c9SGerd Hoffmann 8634a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8644a362601SJan Kiszka bool "Jailhouse non-root cell support" 865abde587bSArnd Bergmann depends on X86_64 && PCI 86687e65d05SJan Kiszka select X86_PM_TIMER 867a7f7f624SMasahiro Yamada help 8684a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8694a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8704a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8714a362601SJan Kiszka 872ec7972c9SZhao Yakuiconfig ACRN_GUEST 873ec7972c9SZhao Yakui bool "ACRN Guest support" 874ec7972c9SZhao Yakui depends on X86_64 875498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 876ec7972c9SZhao Yakui help 877ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 878ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 879ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 880ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 881ec7972c9SZhao Yakui found in https://projectacrn.org/. 882ec7972c9SZhao Yakui 8836276a074SBorislav Petkovendif #HYPERVISOR_GUEST 88497349135SJeremy Fitzhardinge 885506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 886506f1d07SSam Ravnborg 887506f1d07SSam Ravnborgconfig HPET_TIMER 8883c2362e6SHarvey Harrison def_bool X86_64 889506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 890a7f7f624SMasahiro Yamada help 891506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 892506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 893506f1d07SSam Ravnborg present. 894506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 895506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 896506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8974e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 8984e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 899506f1d07SSam Ravnborg 900506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 901506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 902506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 903506f1d07SSam Ravnborg 904506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 905506f1d07SSam Ravnborg 906506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9073c2362e6SHarvey Harrison def_bool y 9083228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 909506f1d07SSam Ravnborg 9106a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 911506f1d07SSam Ravnborg# The code disables itself when not needed. 9127ae9392cSThomas Petazzoniconfig DMI 9137ae9392cSThomas Petazzoni default y 914cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9156a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 916a7f7f624SMasahiro Yamada help 9177ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9187ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9197ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9207ae9392cSThomas Petazzoni BIOS code. 9217ae9392cSThomas Petazzoni 922506f1d07SSam Ravnborgconfig GART_IOMMU 92338901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9242f9237d4SChristoph Hellwig select DMA_OPS 925a4ce5a48SChristoph Hellwig select IOMMU_HELPER 926506f1d07SSam Ravnborg select SWIOTLB 92723ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 928a7f7f624SMasahiro Yamada help 929ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 930ced3c42cSIngo Molnar GART based hardware IOMMUs. 931ced3c42cSIngo Molnar 932ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 933ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 934ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 935ced3c42cSIngo Molnar 936ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 937ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 938ced3c42cSIngo Molnar 939ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 940ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 941ced3c42cSIngo Molnar 32-bit limited device. 942ced3c42cSIngo Molnar 943ced3c42cSIngo Molnar If unsure, say Y. 944506f1d07SSam Ravnborg 9451184dc2fSMike Travisconfig MAXSMP 946ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9476ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 94836f5101aSMike Travis select CPUMASK_OFFSTACK 949a7f7f624SMasahiro Yamada help 950ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9511184dc2fSMike Travis If unsure, say N. 952506f1d07SSam Ravnborg 953aec6487eSIngo Molnar# 954aec6487eSIngo Molnar# The maximum number of CPUs supported: 955aec6487eSIngo Molnar# 956aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 957aec6487eSIngo Molnar# and which can be configured interactively in the 958aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 959aec6487eSIngo Molnar# 960aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 961aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 962aec6487eSIngo Molnar# 963aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 964aec6487eSIngo Molnar# interactive configuration. ) 965aec6487eSIngo Molnar# 966a0d0bb4dSRandy Dunlap 967aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 968a0d0bb4dSRandy Dunlap int 969aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 970a0d0bb4dSRandy Dunlap default 1 if !SMP 971a0d0bb4dSRandy Dunlap default 2 972a0d0bb4dSRandy Dunlap 973aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 974a0d0bb4dSRandy Dunlap int 975a0d0bb4dSRandy Dunlap depends on X86_32 976aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 977aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 978a0d0bb4dSRandy Dunlap default 1 if !SMP 979a0d0bb4dSRandy Dunlap 980aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 981a0d0bb4dSRandy Dunlap int 982a0d0bb4dSRandy Dunlap depends on X86_64 9831edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9841edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 985a0d0bb4dSRandy Dunlap default 1 if !SMP 986aec6487eSIngo Molnar 987aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 988aec6487eSIngo Molnar int 989aec6487eSIngo Molnar depends on X86_32 990aec6487eSIngo Molnar default 32 if X86_BIGSMP 991aec6487eSIngo Molnar default 8 if SMP 992aec6487eSIngo Molnar default 1 if !SMP 993aec6487eSIngo Molnar 994aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 995aec6487eSIngo Molnar int 996aec6487eSIngo Molnar depends on X86_64 997a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 998a0d0bb4dSRandy Dunlap default 64 if SMP 999aec6487eSIngo Molnar default 1 if !SMP 1000a0d0bb4dSRandy Dunlap 1001506f1d07SSam Ravnborgconfig NR_CPUS 100236f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1003aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1004aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1005a7f7f624SMasahiro Yamada help 1006506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1007bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1008cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1009506f1d07SSam Ravnborg minimum value which makes sense is 2. 1010506f1d07SSam Ravnborg 1011aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1012aec6487eSIngo Molnar to the kernel image. 1013506f1d07SSam Ravnborg 101466558b73STim Chenconfig SCHED_CLUSTER 101566558b73STim Chen bool "Cluster scheduler support" 101666558b73STim Chen depends on SMP 101766558b73STim Chen default y 101866558b73STim Chen help 101966558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 102066558b73STim Chen making when dealing with machines that have clusters of CPUs. 102166558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 102266558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 102366558b73STim Chen busses. 102466558b73STim Chen 1025506f1d07SSam Ravnborgconfig SCHED_SMT 1026dbe73364SThomas Gleixner def_bool y if SMP 1027506f1d07SSam Ravnborg 1028506f1d07SSam Ravnborgconfig SCHED_MC 10293c2362e6SHarvey Harrison def_bool y 10303c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1031c8e56d20SBorislav Petkov depends on SMP 1032a7f7f624SMasahiro Yamada help 1033506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1034506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1035506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1036506f1d07SSam Ravnborg 1037de966cf4STim Chenconfig SCHED_MC_PRIO 1038de966cf4STim Chen bool "CPU core priorities scheduler support" 10390a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10400a21fc12SIngo Molnar select X86_INTEL_PSTATE 10410a21fc12SIngo Molnar select CPU_FREQ 1042de966cf4STim Chen default y 1043a7f7f624SMasahiro Yamada help 1044de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1045de966cf4STim Chen core ordering determined at manufacturing time, which allows 1046de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1047de966cf4STim Chen single threaded workloads) than others. 1048de966cf4STim Chen 1049de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1050de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1051de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1052de966cf4STim Chen overall system performance can be achieved. 1053de966cf4STim Chen 1054de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1055de966cf4STim Chen 1056de966cf4STim Chen If unsure say Y here. 10575e76b2abSTim Chen 105830b8b006SThomas Gleixnerconfig UP_LATE_INIT 105930b8b006SThomas Gleixner def_bool y 1060ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 106130b8b006SThomas Gleixner 1062506f1d07SSam Ravnborgconfig X86_UP_APIC 106350849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 106450849eefSJan Beulich default PCI_MSI 106538a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1066a7f7f624SMasahiro Yamada help 1067506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1068506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1069506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1070506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1071506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1072506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1073506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1074506f1d07SSam Ravnborg lockups. 1075506f1d07SSam Ravnborg 1076506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1077506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1078506f1d07SSam Ravnborg depends on X86_UP_APIC 1079a7f7f624SMasahiro Yamada help 1080506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1081506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1082506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1083506f1d07SSam Ravnborg 1084506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1085506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1086506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1087506f1d07SSam Ravnborg 1088506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10893c2362e6SHarvey Harrison def_bool y 10900dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1091b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 109252f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1093506f1d07SSam Ravnborg 1094506f1d07SSam Ravnborgconfig X86_IO_APIC 1095b1da1e71SJan Beulich def_bool y 1096b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1097506f1d07SSam Ravnborg 109841b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 109941b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 110041b9eb26SStefan Assmann depends on X86_IO_APIC 1101a7f7f624SMasahiro Yamada help 110241b9eb26SStefan Assmann This option enables a workaround that fixes a source of 110341b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 110441b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 110541b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 110641b9eb26SStefan Assmann 110741b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 110841b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 110941b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 111041b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 111141b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 111241b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 111341b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 111441b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 111541b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 111641b9eb26SStefan Assmann down (vital) interrupt lines. 111741b9eb26SStefan Assmann 111841b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 111941b9eb26SStefan Assmann increased on these systems. 112041b9eb26SStefan Assmann 1121506f1d07SSam Ravnborgconfig X86_MCE 1122bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1123648ed940SChen, Gong select GENERIC_ALLOCATOR 1124e57dbaf7SBorislav Petkov default y 1125a7f7f624SMasahiro Yamada help 1126bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1127bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1128506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1129bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11304efc0670SAndi Kleen 11315de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11325de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11335de97c9fSTony Luck depends on X86_MCE 1134a7f7f624SMasahiro Yamada help 11355de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11365de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11375de97c9fSTony Luck rasdaemon solution. 11385de97c9fSTony Luck 1139506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11403c2362e6SHarvey Harrison def_bool y 11413c2362e6SHarvey Harrison prompt "Intel MCE features" 1142c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1143a7f7f624SMasahiro Yamada help 1144506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1145506f1d07SSam Ravnborg the thermal monitor. 1146506f1d07SSam Ravnborg 1147506f1d07SSam Ravnborgconfig X86_MCE_AMD 11483c2362e6SHarvey Harrison def_bool y 11493c2362e6SHarvey Harrison prompt "AMD MCE features" 1150f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1151a7f7f624SMasahiro Yamada help 1152506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1153506f1d07SSam Ravnborg the DRAM Error Threshold. 1154506f1d07SSam Ravnborg 11554efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11566fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1157c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1158a7f7f624SMasahiro Yamada help 11594efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11605065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11614efc0670SAndi Kleen line. 11624efc0670SAndi Kleen 1163b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1164b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11656fc108a0SJan Beulich def_bool y 1166b2762686SAndi Kleen 1167ea149b36SAndi Kleenconfig X86_MCE_INJECT 1168bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1169ea149b36SAndi Kleen tristate "Machine check injector support" 1170a7f7f624SMasahiro Yamada help 1171ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1172ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1173ea149b36SAndi Kleen QA it is safe to say n. 1174ea149b36SAndi Kleen 117507dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1176e633c65aSKan Liang 11775aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11781e642812SIngo Molnar bool "Legacy VM86 support" 1179506f1d07SSam Ravnborg depends on X86_32 1180a7f7f624SMasahiro Yamada help 11815aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11825aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11835aef51c3SAndy Lutomirski 11845aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11855aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11865aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11875aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11885aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 11891e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 11901e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 11911e642812SIngo Molnar mode might be faster than emulation and you might want to 11921e642812SIngo Molnar enable this option. 11935aef51c3SAndy Lutomirski 11941e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 11951e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 11961e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 11971e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 11985aef51c3SAndy Lutomirski 11991e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12001e642812SIngo Molnar and slows down exception handling a tiny bit. 12015aef51c3SAndy Lutomirski 12021e642812SIngo Molnar If unsure, say N here. 12035aef51c3SAndy Lutomirski 12045aef51c3SAndy Lutomirskiconfig VM86 12055aef51c3SAndy Lutomirski bool 12065aef51c3SAndy Lutomirski default X86_LEGACY_VM86 120734273f41SH. Peter Anvin 120834273f41SH. Peter Anvinconfig X86_16BIT 120934273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 121034273f41SH. Peter Anvin default y 1211a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1212a7f7f624SMasahiro Yamada help 121334273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 121434273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 121534273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 121634273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 121734273f41SH. Peter Anvin 121834273f41SH. Peter Anvinconfig X86_ESPFIX32 121934273f41SH. Peter Anvin def_bool y 122034273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1221506f1d07SSam Ravnborg 1222197725deSH. Peter Anvinconfig X86_ESPFIX64 1223197725deSH. Peter Anvin def_bool y 122434273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1225506f1d07SSam Ravnborg 12261ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12271ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12281ad83c85SAndy Lutomirski default y 12291ad83c85SAndy Lutomirski depends on X86_64 1230a7f7f624SMasahiro Yamada help 12311ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12321ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12331ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12341ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12351ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12361ad83c85SAndy Lutomirski 0xffffffffff600?00. 12371ad83c85SAndy Lutomirski 12381ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12391ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12401ad83c85SAndy Lutomirski 12411ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12421ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12431ad83c85SAndy Lutomirski 1244111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1245111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1246a24ca997SThomas Gleixner default y 1247a7f7f624SMasahiro Yamada help 1248111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1249111e7b15SThomas Gleixner for legacy applications. 1250111e7b15SThomas Gleixner 1251c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1252c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1253c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1254c8137aceSThomas Gleixner capabilities and permission from potentially active security 1255c8137aceSThomas Gleixner modules. 1256c8137aceSThomas Gleixner 1257c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1258c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1259a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1260a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1261c8137aceSThomas Gleixner 1262506f1d07SSam Ravnborgconfig TOSHIBA 1263506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1264506f1d07SSam Ravnborg depends on X86_32 1265a7f7f624SMasahiro Yamada help 1266506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1267506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1268506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1269506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1270506f1d07SSam Ravnborg 1271506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1272506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1273506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1274506f1d07SSam Ravnborg 1275506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1276506f1d07SSam Ravnborg Say N otherwise. 1277506f1d07SSam Ravnborg 1278506f1d07SSam Ravnborgconfig I8K 1279039ae585SPali Rohár tristate "Dell i8k legacy laptop support" 1280ef775a0eSRandy Dunlap depends on HWMON 1281ef775a0eSRandy Dunlap depends on PROC_FS 1282039ae585SPali Rohár select SENSORS_DELL_SMM 1283a7f7f624SMasahiro Yamada help 1284039ae585SPali Rohár This option enables legacy /proc/i8k userspace interface in hwmon 1285039ae585SPali Rohár dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1286039ae585SPali Rohár temperature and allows controlling fan speeds of Dell laptops via 1287039ae585SPali Rohár System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1288039ae585SPali Rohár it reports also power and hotkey status. For fan speed control is 1289039ae585SPali Rohár needed userspace package i8kutils. 1290506f1d07SSam Ravnborg 1291039ae585SPali Rohár Say Y if you intend to run this kernel on old Dell laptops or want to 1292039ae585SPali Rohár use userspace package i8kutils. 1293506f1d07SSam Ravnborg Say N otherwise. 1294506f1d07SSam Ravnborg 1295506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12969ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12979ba16087SJan Beulich depends on X86_32 1298a7f7f624SMasahiro Yamada help 1299506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1300506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1301506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1302506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1303506f1d07SSam Ravnborg system. 1304506f1d07SSam Ravnborg 1305506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13065e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1307506f1d07SSam Ravnborg 1308506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1309506f1d07SSam Ravnborg enable this option even if you don't need it. 1310506f1d07SSam Ravnborg Say N otherwise. 1311506f1d07SSam Ravnborg 1312506f1d07SSam Ravnborgconfig MICROCODE 13139a2bc335SBorislav Petkov bool "CPU microcode loading support" 13149a2bc335SBorislav Petkov default y 131580030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1316a7f7f624SMasahiro Yamada help 1317506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13185f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13195f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13205f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13215f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13225f9c01aaSBorislav Petkov the Linux kernel. 1323506f1d07SSam Ravnborg 13245f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1325cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13265f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13275f9c01aaSBorislav Petkov initrd for microcode blobs. 1328506f1d07SSam Ravnborg 1329c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1330c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1331c508c46eSBenjamin Gilbert config option. 1332506f1d07SSam Ravnborg 13338d86f390SPeter Orubaconfig MICROCODE_INTEL 1334e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13358d86f390SPeter Oruba depends on MICROCODE 13368d86f390SPeter Oruba default MICROCODE 1337a7f7f624SMasahiro Yamada help 13388d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13398d86f390SPeter Oruba processors. 13408d86f390SPeter Oruba 1341b8989db9SAlan For the current Intel microcode data package go to 1342b8989db9SAlan <https://downloadcenter.intel.com> and search for 1343b8989db9SAlan 'Linux Processor Microcode Data File'. 13448d86f390SPeter Oruba 134580cc9f10SPeter Orubaconfig MICROCODE_AMD 1346e43f6e67SBorislav Petkov bool "AMD microcode loading support" 134780cc9f10SPeter Oruba depends on MICROCODE 1348a7f7f624SMasahiro Yamada help 134980cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 135080cc9f10SPeter Oruba processors will be enabled. 135180cc9f10SPeter Oruba 1352506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1353c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1354c02f48e0SBorislav Petkov default n 1355506f1d07SSam Ravnborg depends on MICROCODE 1356a7f7f624SMasahiro Yamada help 1357c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1358c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1359c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1360c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1361c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1362cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1363506f1d07SSam Ravnborg 1364506f1d07SSam Ravnborgconfig X86_MSR 1365506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1366a7f7f624SMasahiro Yamada help 1367506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1368506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1369506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1370506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1371506f1d07SSam Ravnborg systems. 1372506f1d07SSam Ravnborg 1373506f1d07SSam Ravnborgconfig X86_CPUID 1374506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1375a7f7f624SMasahiro Yamada help 1376506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1377506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1378506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1379506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1380506f1d07SSam Ravnborg 1381506f1d07SSam Ravnborgchoice 1382506f1d07SSam Ravnborg prompt "High Memory Support" 13836fc108a0SJan Beulich default HIGHMEM4G 1384506f1d07SSam Ravnborg depends on X86_32 1385506f1d07SSam Ravnborg 1386506f1d07SSam Ravnborgconfig NOHIGHMEM 1387506f1d07SSam Ravnborg bool "off" 1388a7f7f624SMasahiro Yamada help 1389506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1390506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1391506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1392506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1393506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1394506f1d07SSam Ravnborg "high memory". 1395506f1d07SSam Ravnborg 1396506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1397506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1398506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1399506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1400506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1401506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1402506f1d07SSam Ravnborg possible. 1403506f1d07SSam Ravnborg 1404506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1405506f1d07SSam Ravnborg answer "4GB" here. 1406506f1d07SSam Ravnborg 1407506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1408506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1409506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1410506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1411506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1412506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1413506f1d07SSam Ravnborg 1414506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1415506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1416506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1417506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1418506f1d07SSam Ravnborg kernel at boot time.) 1419506f1d07SSam Ravnborg 1420506f1d07SSam Ravnborg If unsure, say "off". 1421506f1d07SSam Ravnborg 1422506f1d07SSam Ravnborgconfig HIGHMEM4G 1423506f1d07SSam Ravnborg bool "4GB" 1424a7f7f624SMasahiro Yamada help 1425506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1426506f1d07SSam Ravnborg gigabytes of physical RAM. 1427506f1d07SSam Ravnborg 1428506f1d07SSam Ravnborgconfig HIGHMEM64G 1429506f1d07SSam Ravnborg bool "64GB" 1430225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1431506f1d07SSam Ravnborg select X86_PAE 1432a7f7f624SMasahiro Yamada help 1433506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1434506f1d07SSam Ravnborg gigabytes of physical RAM. 1435506f1d07SSam Ravnborg 1436506f1d07SSam Ravnborgendchoice 1437506f1d07SSam Ravnborg 1438506f1d07SSam Ravnborgchoice 14396a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1440506f1d07SSam Ravnborg default VMSPLIT_3G 1441506f1d07SSam Ravnborg depends on X86_32 1442a7f7f624SMasahiro Yamada help 1443506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1444506f1d07SSam Ravnborg 1445506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1446506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1447506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1448506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1449506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1450506f1d07SSam Ravnborg available to user programs, making the address space there 1451506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1452506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1453506f1d07SSam Ravnborg kernel modules. 1454506f1d07SSam Ravnborg 1455506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1456506f1d07SSam Ravnborg option alone! 1457506f1d07SSam Ravnborg 1458506f1d07SSam Ravnborg config VMSPLIT_3G 1459506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1460506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1461506f1d07SSam Ravnborg depends on !X86_PAE 1462506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1463506f1d07SSam Ravnborg config VMSPLIT_2G 1464506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1465506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1466506f1d07SSam Ravnborg depends on !X86_PAE 1467506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1468506f1d07SSam Ravnborg config VMSPLIT_1G 1469506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1470506f1d07SSam Ravnborgendchoice 1471506f1d07SSam Ravnborg 1472506f1d07SSam Ravnborgconfig PAGE_OFFSET 1473506f1d07SSam Ravnborg hex 1474506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1475506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1476506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1477506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1478506f1d07SSam Ravnborg default 0xC0000000 1479506f1d07SSam Ravnborg depends on X86_32 1480506f1d07SSam Ravnborg 1481506f1d07SSam Ravnborgconfig HIGHMEM 14823c2362e6SHarvey Harrison def_bool y 1483506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1484506f1d07SSam Ravnborg 1485506f1d07SSam Ravnborgconfig X86_PAE 14869ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1487506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1488d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14899d99c712SChristian Melki select SWIOTLB 1490a7f7f624SMasahiro Yamada help 1491506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1492506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1493506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1494506f1d07SSam Ravnborg consumes more pagetable space per process. 1495506f1d07SSam Ravnborg 149677ef56e4SKirill A. Shutemovconfig X86_5LEVEL 149777ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 149818ec1eafSKirill A. Shutemov default y 1499eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1500162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 150177ef56e4SKirill A. Shutemov depends on X86_64 1502a7f7f624SMasahiro Yamada help 150377ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 150477ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 150577ef56e4SKirill A. Shutemov physical address space. 150677ef56e4SKirill A. Shutemov 150777ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 150877ef56e4SKirill A. Shutemov 15096657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15106657fca0SKirill A. Shutemov support 4- or 5-level paging. 151177ef56e4SKirill A. Shutemov 1512cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 151377ef56e4SKirill A. Shutemov information. 151477ef56e4SKirill A. Shutemov 151577ef56e4SKirill A. Shutemov Say N if unsure. 151677ef56e4SKirill A. Shutemov 151710971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1518e5008abeSLuis R. Rodriguez def_bool y 15192e1da13fSVlastimil Babka depends on X86_64 1520a7f7f624SMasahiro Yamada help 152110971ab2SIngo Molnar Certain kernel features effectively disable kernel 152210971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 152310971ab2SIngo Molnar supports them), so don't confuse the user by printing 152410971ab2SIngo Molnar that we have them enabled. 15259e899816SNick Piggin 15265c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15275c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15285c280cf6SThomas Gleixner depends on DEBUG_FS 1529a7f7f624SMasahiro Yamada help 1530b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1531a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15325c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15335c280cf6SThomas Gleixner 153420f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 153520f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 153620f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 153720f07a04SKirill A. Shutemov select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 153820f07a04SKirill A. Shutemov def_bool n 153920f07a04SKirill A. Shutemov 15407744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15417744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15427744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 154382fef0adSDavid Rientjes select DMA_COHERENT_POOL 1544ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1545597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1546aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 154720f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 1548a7f7f624SMasahiro Yamada help 15497744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15507744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15517744ccdbSTom Lendacky Encryption (SME). 15527744ccdbSTom Lendacky 15537744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15547744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15557744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1556a7f7f624SMasahiro Yamada help 15577744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15587744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15597744ccdbSTom Lendacky 15607744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15617744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15627744ccdbSTom Lendacky 15637744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15647744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15657744ccdbSTom Lendacky 1566506f1d07SSam Ravnborg# Common NUMA Features 1567506f1d07SSam Ravnborgconfig NUMA 1568e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1569506f1d07SSam Ravnborg depends on SMP 1570b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1571b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15727ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1573a7f7f624SMasahiro Yamada help 1574e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1575fd51b2d7SKOSAKI Motohiro 1576506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1577506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1578506f1d07SSam Ravnborg NUMA awareness to the kernel. 1579506f1d07SSam Ravnborg 1580c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1581fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1582fd51b2d7SKOSAKI Motohiro 1583b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15847cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1585fd51b2d7SKOSAKI Motohiro 1586fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1587506f1d07SSam Ravnborg 1588eec1d4faSHans Rosenfeldconfig AMD_NUMA 15893c2362e6SHarvey Harrison def_bool y 15903c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15915da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1592a7f7f624SMasahiro Yamada help 1593eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1594eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1595eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1596eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1597eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1598506f1d07SSam Ravnborg 1599506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 16003c2362e6SHarvey Harrison def_bool y 16013c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1602506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1603506f1d07SSam Ravnborg select ACPI_NUMA 1604a7f7f624SMasahiro Yamada help 1605506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1606506f1d07SSam Ravnborg 1607506f1d07SSam Ravnborgconfig NUMA_EMU 1608506f1d07SSam Ravnborg bool "NUMA emulation" 16091b7e03efSTejun Heo depends on NUMA 1610a7f7f624SMasahiro Yamada help 1611506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1612506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1613506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1614506f1d07SSam Ravnborg 1615506f1d07SSam Ravnborgconfig NODES_SHIFT 1616d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 161751591e31SDavid Rientjes range 1 10 161851591e31SDavid Rientjes default "10" if MAXSMP 1619506f1d07SSam Ravnborg default "6" if X86_64 1620506f1d07SSam Ravnborg default "3" 1621a9ee6cf5SMike Rapoport depends on NUMA 1622a7f7f624SMasahiro Yamada help 16231184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1624692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1625506f1d07SSam Ravnborg 1626506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1627506f1d07SSam Ravnborg def_bool y 16283b16651fSTejun Heo depends on X86_32 && !NUMA 1629506f1d07SSam Ravnborg 1630506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1631506f1d07SSam Ravnborg def_bool y 16326ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1633506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1634506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1635506f1d07SSam Ravnborg 16363b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16376ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16383b16651fSTejun Heo 1639506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1640506f1d07SSam Ravnborg def_bool y 1641b263295dSChristoph Lameter depends on ARCH_SPARSEMEM_ENABLE 1642506f1d07SSam Ravnborg 1643506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1644a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16455c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1646a0842b70SToshi Kani help 1647a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1648cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1649a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1650506f1d07SSam Ravnborg 16513b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16523b16651fSTejun Heo def_bool y 16533b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16543b16651fSTejun Heo 1655a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1656a29815a3SAvi Kivity hex 1657a29815a3SAvi Kivity default 0 if X86_32 1658a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1659a29815a3SAvi Kivity 16607a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16617a67832cSDan Williams bool 16627a67832cSDan Williams 1663ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16647a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16659f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16669f53f9faSDan Williams depends on BLK_DEV 16677a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16687b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16699f53f9faSDan Williams select LIBNVDIMM 1670ec776ef6SChristoph Hellwig help 1671ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1672ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1673ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1674ec776ef6SChristoph Hellwig they can be used for persistent storage. 1675ec776ef6SChristoph Hellwig 1676ec776ef6SChristoph Hellwig Say Y if unsure. 1677ec776ef6SChristoph Hellwig 1678506f1d07SSam Ravnborgconfig HIGHPTE 1679506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16806fc108a0SJan Beulich depends on HIGHMEM 1681a7f7f624SMasahiro Yamada help 1682506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1683506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1684506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1685506f1d07SSam Ravnborg entries in high memory. 1686506f1d07SSam Ravnborg 16879f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16889f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1689a7f7f624SMasahiro Yamada help 16909f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16919f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16929f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16939f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16949f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16959f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16969f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16978c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16989f077871SJeremy Fitzhardinge 16999f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 17009f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 17019f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 17029f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 17039f077871SJeremy Fitzhardinge 17049f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 17059f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 17069f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 17079f077871SJeremy Fitzhardinge memory. 17089f077871SJeremy Fitzhardinge 1709c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1710c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1711c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1712c885df50SJeremy Fitzhardinge default y 1713a7f7f624SMasahiro Yamada help 1714c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1715c885df50SJeremy Fitzhardinge on or off. 1716c885df50SJeremy Fitzhardinge 1717506f1d07SSam Ravnborgconfig MATH_EMULATION 1718506f1d07SSam Ravnborg bool 1719a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 172087d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1721a7f7f624SMasahiro Yamada help 1722506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1723506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1724506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1725506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1726506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1727506f1d07SSam Ravnborg coprocessor or this emulation. 1728506f1d07SSam Ravnborg 1729506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1730506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1731506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1732506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1733506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1734506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1735506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1736506f1d07SSam Ravnborg intend to use this kernel on different machines. 1737506f1d07SSam Ravnborg 1738506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1739506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1740506f1d07SSam Ravnborg 1741506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1742506f1d07SSam Ravnborg kernel, it won't hurt. 1743506f1d07SSam Ravnborg 1744506f1d07SSam Ravnborgconfig MTRR 17456fc108a0SJan Beulich def_bool y 17466a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1747a7f7f624SMasahiro Yamada help 1748506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1749506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1750506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1751506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1752506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1753506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1754506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1755506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1756506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1757506f1d07SSam Ravnborg 1758506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1759506f1d07SSam Ravnborg control registers on other processors can be easily supported 1760506f1d07SSam Ravnborg as well: 1761506f1d07SSam Ravnborg 1762506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1763506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1764506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1765506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1766506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1767506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1768506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1769506f1d07SSam Ravnborg 1770506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1771506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1772506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1773506f1d07SSam Ravnborg 1774506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1775506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1776506f1d07SSam Ravnborg 1777cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1778506f1d07SSam Ravnborg 177995ffa243SYinghai Luconfig MTRR_SANITIZER 17802ffb3501SYinghai Lu def_bool y 178195ffa243SYinghai Lu prompt "MTRR cleanup support" 178295ffa243SYinghai Lu depends on MTRR 1783a7f7f624SMasahiro Yamada help 1784aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1785aba3728cSThomas Gleixner add writeback entries. 178695ffa243SYinghai Lu 1787aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1788692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1789aba3728cSThomas Gleixner mtrr_chunk_size. 179095ffa243SYinghai Lu 17912ffb3501SYinghai Lu If unsure, say Y. 179295ffa243SYinghai Lu 179395ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1794f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1795f5098d62SYinghai Lu range 0 1 1796f5098d62SYinghai Lu default "0" 179795ffa243SYinghai Lu depends on MTRR_SANITIZER 1798a7f7f624SMasahiro Yamada help 1799f5098d62SYinghai Lu Enable mtrr cleanup default value 180095ffa243SYinghai Lu 180112031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 180212031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 180312031a62SYinghai Lu range 0 7 180412031a62SYinghai Lu default "1" 180512031a62SYinghai Lu depends on MTRR_SANITIZER 1806a7f7f624SMasahiro Yamada help 180712031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1808aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 180912031a62SYinghai Lu 18102e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18116fc108a0SJan Beulich def_bool y 18126a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18132a8a2719SIngo Molnar depends on MTRR 1814a7f7f624SMasahiro Yamada help 18152e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1816042b78e4SVenki Pallipadi 18172e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18182e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18192e5d9c85Svenkatesh.pallipadi@intel.com 18202e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1821042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18222e5d9c85Svenkatesh.pallipadi@intel.com 18232e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18242e5d9c85Svenkatesh.pallipadi@intel.com 182546cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 182646cf98cdSVenkatesh Pallipadi def_bool y 182746cf98cdSVenkatesh Pallipadi depends on X86_PAT 182846cf98cdSVenkatesh Pallipadi 1829628c6246SH. Peter Anvinconfig ARCH_RANDOM 1830628c6246SH. Peter Anvin def_bool y 1831628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1832a7f7f624SMasahiro Yamada help 1833628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1834628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1835628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1836628c6246SH. Peter Anvin secure hardware random number generator. 1837628c6246SH. Peter Anvin 183851ae4a2dSH. Peter Anvinconfig X86_SMAP 183951ae4a2dSH. Peter Anvin def_bool y 184051ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 1841a7f7f624SMasahiro Yamada help 184251ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 184351ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 184451ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 184551ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 184651ae4a2dSH. Peter Anvin 184751ae4a2dSH. Peter Anvin If unsure, say Y. 184851ae4a2dSH. Peter Anvin 1849b971880fSBabu Mogerconfig X86_UMIP 1850796ebc81SRicardo Neri def_bool y 1851b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1852a7f7f624SMasahiro Yamada help 1853b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1854b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1855b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1856b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1857b971880fSBabu Moger information about the hardware state. 1858796ebc81SRicardo Neri 1859796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1860796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1861796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1862796ebc81SRicardo Neri results are dummy. 1863aa35f896SRicardo Neri 1864*156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1865*156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1866*156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1867*156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1868*156ff4a5SPeter Zijlstra # fentry check to work around https://reviews.llvm.org/D111108 1869*156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1870*156ff4a5SPeter Zijlstra (CC_IS_CLANG && $(success,echo "void a(void) {}" | $(CC) -Werror $(CLANG_FLAGS) -fcf-protection=branch -mfentry -pg -x c - -c -o /dev/null))) && \ 1871*156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1872*156ff4a5SPeter Zijlstra 1873*156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1874*156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 1875*156ff4a5SPeter Zijlstra bool 1876*156ff4a5SPeter Zijlstra depends on X86_64 && CC_HAS_IBT 1877*156ff4a5SPeter Zijlstra help 1878*156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1879*156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1880*156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1881*156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1882*156ff4a5SPeter Zijlstra code with them to make this happen. 1883*156ff4a5SPeter Zijlstra 188435e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 188538f3e775SBabu Moger prompt "Memory Protection Keys" 188635e97790SDave Hansen def_bool y 1887284244a9SDave Hansen # Note: only available in 64-bit mode 188838f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 188952c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 189052c8e601SIngo Molnar select ARCH_HAS_PKEYS 1891a7f7f624SMasahiro Yamada help 1892284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1893284244a9SDave Hansen page-based protections, but without requiring modification of the 1894284244a9SDave Hansen page tables when an application changes protection domains. 1895284244a9SDave Hansen 18961eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1897284244a9SDave Hansen 1898284244a9SDave Hansen If unsure, say y. 189935e97790SDave Hansen 1900db616173SMichal Hockochoice 1901db616173SMichal Hocko prompt "TSX enable mode" 1902db616173SMichal Hocko depends on CPU_SUP_INTEL 1903db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1904db616173SMichal Hocko help 1905db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1906db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1907db616173SMichal Hocko can lead to a noticeable performance boost. 1908db616173SMichal Hocko 1909db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1910db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1911db616173SMichal Hocko will be more of those attacks discovered in the future. 1912db616173SMichal Hocko 1913db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1914db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1915db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1916db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1917db616173SMichal Hocko for the particular machine. 1918db616173SMichal Hocko 1919db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1920db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1921db616173SMichal Hocko details. 1922db616173SMichal Hocko 1923db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1924db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1925db616173SMichal Hocko relevant. 1926db616173SMichal Hocko 1927db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1928db616173SMichal Hocko bool "off" 1929db616173SMichal Hocko help 1930db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1931db616173SMichal Hocko 1932db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1933db616173SMichal Hocko bool "on" 1934db616173SMichal Hocko help 1935db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1936db616173SMichal Hocko line parameter. 1937db616173SMichal Hocko 1938db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1939db616173SMichal Hocko bool "auto" 1940db616173SMichal Hocko help 1941db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1942db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1943db616173SMichal Hockoendchoice 1944db616173SMichal Hocko 1945e7e05452SSean Christophersonconfig X86_SGX 1946e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1947e7e05452SSean Christopherson depends on X86_64 && CPU_SUP_INTEL 1948e7e05452SSean Christopherson depends on CRYPTO=y 1949e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1950e7e05452SSean Christopherson select SRCU 1951e7e05452SSean Christopherson select MMU_NOTIFIER 1952901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 195340e0e784STony Luck select XARRAY_MULTI 1954e7e05452SSean Christopherson help 1955e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1956e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1957e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1958e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1959e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1960e7e05452SSean Christopherson hardware. 1961e7e05452SSean Christopherson 1962e7e05452SSean Christopherson If unsure, say N. 1963e7e05452SSean Christopherson 1964506f1d07SSam Ravnborgconfig EFI 19659ba16087SJan Beulich bool "EFI runtime service support" 19665b83683fSHuang, Ying depends on ACPI 1967f6ce5002SSergey Vlasov select UCS2_STRING 1968022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19691ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1970a7f7f624SMasahiro Yamada help 19718b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1972506f1d07SSam Ravnborg available (such as the EFI variable services). 1973506f1d07SSam Ravnborg 19748b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19758b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19768b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19778b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19788b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19798b2cb7a8SHuang, Ying platforms. 1980506f1d07SSam Ravnborg 1981291f3632SMatt Flemingconfig EFI_STUB 1982291f3632SMatt Fleming bool "EFI stub support" 1983c6dbd3e5SPeter Zijlstra depends on EFI 19848f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19857b2a583aSMatt Fleming select RELOCATABLE 1986a7f7f624SMasahiro Yamada help 1987291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1988291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1989291f3632SMatt Fleming 19904f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19910c759662SMatt Fleming 19927d453eeeSMatt Flemingconfig EFI_MIXED 19937d453eeeSMatt Fleming bool "EFI mixed-mode support" 19947d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1995a7f7f624SMasahiro Yamada help 19967d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19977d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19987d453eeeSMatt Fleming mode. 19997d453eeeSMatt Fleming 20007d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 20017d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 20027d453eeeSMatt Fleming the EFI handover protocol must be used. 20037d453eeeSMatt Fleming 20047d453eeeSMatt Fleming If unsure, say N. 20057d453eeeSMatt Fleming 20068636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2007506f1d07SSam Ravnborg 2008506f1d07SSam Ravnborgconfig KEXEC 2009506f1d07SSam Ravnborg bool "kexec system call" 20102965faa5SDave Young select KEXEC_CORE 2011a7f7f624SMasahiro Yamada help 2012506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2013506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2014506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2015506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2016506f1d07SSam Ravnborg 2017506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2018506f1d07SSam Ravnborg 2019506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2020506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2021bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2022bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2023bf220695SGeert Uytterhoeven made. 2024506f1d07SSam Ravnborg 202574ca317cSVivek Goyalconfig KEXEC_FILE 202674ca317cSVivek Goyal bool "kexec file based system call" 20272965faa5SDave Young select KEXEC_CORE 202874ca317cSVivek Goyal select BUILD_BIN2C 202974ca317cSVivek Goyal depends on X86_64 203074ca317cSVivek Goyal depends on CRYPTO=y 203174ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2032a7f7f624SMasahiro Yamada help 203374ca317cSVivek Goyal This is new version of kexec system call. This system call is 203474ca317cSVivek Goyal file based and takes file descriptors as system call argument 203574ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 203674ca317cSVivek Goyal accepted by previous system call. 203774ca317cSVivek Goyal 2038b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2039b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2040b799a09fSAKASHI Takahiro 204199d5cadfSJiri Bohacconfig KEXEC_SIG 20428e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 204374ca317cSVivek Goyal depends on KEXEC_FILE 2044a7f7f624SMasahiro Yamada help 204599d5cadfSJiri Bohac 204699d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 204799d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 204899d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 204999d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 205099d5cadfSJiri Bohac 205199d5cadfSJiri Bohac In addition to this option, you need to enable signature 205299d5cadfSJiri Bohac verification for the corresponding kernel image type being 205399d5cadfSJiri Bohac loaded in order for this to work. 205499d5cadfSJiri Bohac 205599d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 205699d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 205799d5cadfSJiri Bohac depends on KEXEC_SIG 2058a7f7f624SMasahiro Yamada help 20598e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2060d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20618e7d8381SVivek Goyal 20628e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20638e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 206499d5cadfSJiri Bohac depends on KEXEC_SIG 20658e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20668e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2067a7f7f624SMasahiro Yamada help 20688e7d8381SVivek Goyal Enable bzImage signature verification support. 20698e7d8381SVivek Goyal 2070506f1d07SSam Ravnborgconfig CRASH_DUMP 207104b69447SPavel Machek bool "kernel crash dumps" 2072506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2073a7f7f624SMasahiro Yamada help 2074506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2075506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2076506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2077506f1d07SSam Ravnborg a specially reserved region and then later executed after 2078506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2079506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2080506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2081506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2082330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2083506f1d07SSam Ravnborg 20843ab83521SHuang Yingconfig KEXEC_JUMP 20856ea30386SKees Cook bool "kexec jump" 2086fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2087a7f7f624SMasahiro Yamada help 208889081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 208989081d17SHuang Ying code in physical address mode via KEXEC 20903ab83521SHuang Ying 2091506f1d07SSam Ravnborgconfig PHYSICAL_START 20926a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2093ceefccc9SH. Peter Anvin default "0x1000000" 2094a7f7f624SMasahiro Yamada help 2095506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2096506f1d07SSam Ravnborg 2097506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2098506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2099506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2100506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2101506f1d07SSam Ravnborg address. 2102506f1d07SSam Ravnborg 2103506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2104506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2105506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2106506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2107506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2108506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2109506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2110506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2111506f1d07SSam Ravnborg 2112ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2113ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2114ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2115ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2116ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2117ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2118ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2119330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2120ceefccc9SH. Peter Anvin for more details about crash dumps. 2121506f1d07SSam Ravnborg 2122506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2123506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2124506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2125506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2126506f1d07SSam Ravnborg is present because there are users out there who continue to use 2127506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2128506f1d07SSam Ravnborg line. 2129506f1d07SSam Ravnborg 2130506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2131506f1d07SSam Ravnborg 2132506f1d07SSam Ravnborgconfig RELOCATABLE 213326717808SH. Peter Anvin bool "Build a relocatable kernel" 213426717808SH. Peter Anvin default y 2135a7f7f624SMasahiro Yamada help 2136506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2137506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2138506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2139506f1d07SSam Ravnborg but are discarded at runtime. 2140506f1d07SSam Ravnborg 2141506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2142506f1d07SSam Ravnborg must live at a different physical address than the primary 2143506f1d07SSam Ravnborg kernel. 2144506f1d07SSam Ravnborg 2145506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2146506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21478ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2148506f1d07SSam Ravnborg 21498ab3820fSKees Cookconfig RANDOMIZE_BASE 2150e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21518ab3820fSKees Cook depends on RELOCATABLE 21526807c846SIngo Molnar default y 2153a7f7f624SMasahiro Yamada help 2154e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2155e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2156e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2157e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2158e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2159e8581e3dSBaoquan He code internals. 2160e8581e3dSBaoquan He 2161ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2162ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2163ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2164ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2165ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2166ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2167ed9f007eSKees Cook 2168ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2169ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2170ed9f007eSKees Cook 512MB (8 bits of entropy). 21718ab3820fSKees Cook 2172a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2173e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2174e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2175ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2176ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2177ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2178ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2179ed9f007eSKees Cook theoretically possible, but the implementations are further 2180ed9f007eSKees Cook limited due to memory layouts. 2181e8581e3dSBaoquan He 21826807c846SIngo Molnar If unsure, say Y. 2183da2b6fb9SKees Cook 21848ab3820fSKees Cook# Relocation on x86 needs some additional build support 2185845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2186845adf72SH. Peter Anvin def_bool y 21878ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2188845adf72SH. Peter Anvin 2189506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2190a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21918ab3820fSKees Cook default "0x200000" 2192a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2193a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2194a7f7f624SMasahiro Yamada help 2195506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2196506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2197506f1d07SSam Ravnborg address which meets above alignment restriction. 2198506f1d07SSam Ravnborg 2199506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2200506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2201506f1d07SSam Ravnborg address aligned to above value and run from there. 2202506f1d07SSam Ravnborg 2203506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2204506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2205506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2206506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2207506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2208506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2209506f1d07SSam Ravnborg above alignment restrictions. 2210506f1d07SSam Ravnborg 2211a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2212a0215061SKees Cook this value must be a multiple of 0x200000. 2213a0215061SKees Cook 2214506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2215506f1d07SSam Ravnborg 2216eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2217eedb92abSKirill A. Shutemov bool 2218a7f7f624SMasahiro Yamada help 2219eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2220eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2221eedb92abSKirill A. Shutemov 22220483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22230483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22240483e1faSThomas Garnier depends on X86_64 22250483e1faSThomas Garnier depends on RANDOMIZE_BASE 2226eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22270483e1faSThomas Garnier default RANDOMIZE_BASE 2228a7f7f624SMasahiro Yamada help 22290483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22300483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22310483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22320483e1faSThomas Garnier 22330483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22340483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22350483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22360483e1faSThomas Garnier addresses for each memory section. 22370483e1faSThomas Garnier 22386807c846SIngo Molnar If unsure, say Y. 22390483e1faSThomas Garnier 224090397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 224190397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 224290397a41SThomas Garnier depends on RANDOMIZE_MEMORY 224390397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 224490397a41SThomas Garnier default "0x0" 224590397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 224690397a41SThomas Garnier range 0x0 0x40 2247a7f7f624SMasahiro Yamada help 224890397a41SThomas Garnier Define the padding in terabytes added to the existing physical 224990397a41SThomas Garnier memory size during kernel memory randomization. It is useful 225090397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 225190397a41SThomas Garnier address randomization. 225290397a41SThomas Garnier 225390397a41SThomas Garnier If unsure, leave at the default value. 225490397a41SThomas Garnier 2255506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2256bebd024eSThomas Gleixner def_bool y 225740b31360SStephen Rothwell depends on SMP 2258506f1d07SSam Ravnborg 225980aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 226080aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22612c922cd0SKees Cook depends on HOTPLUG_CPU 2262a7f7f624SMasahiro Yamada help 226380aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 226480aa1dffSFenghua Yu 226580aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 226680aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 226780aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 226880aa1dffSFenghua Yu 226980aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 227080aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 227180aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 227280aa1dffSFenghua Yu 227380aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 227480aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 227580aa1dffSFenghua Yu 227680aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 227780aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 227880aa1dffSFenghua Yu be other CPU0 dependencies. 227980aa1dffSFenghua Yu 228080aa1dffSFenghua Yu Please make sure the dependencies are under your control before 228180aa1dffSFenghua Yu you enable this feature. 228280aa1dffSFenghua Yu 228380aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 228480aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 228580aa1dffSFenghua Yu parameter cpu0_hotplug. 228680aa1dffSFenghua Yu 2287a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2288a71c8bc5SFenghua Yu def_bool n 2289a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22902c922cd0SKees Cook depends on HOTPLUG_CPU 2291a7f7f624SMasahiro Yamada help 2292a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2293a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2294a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2295a71c8bc5SFenghua Yu 2296a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2297a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2298a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2299a71c8bc5SFenghua Yu 2300a71c8bc5SFenghua Yu If unsure, say N. 2301a71c8bc5SFenghua Yu 2302506f1d07SSam Ravnborgconfig COMPAT_VDSO 2303b0b49f26SAndy Lutomirski def_bool n 2304b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2305953fee1dSIngo Molnar depends on COMPAT_32 2306a7f7f624SMasahiro Yamada help 2307b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2308b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2309b0b49f26SAndy Lutomirski indicated in its segment table. 2310e84446deSRandy Dunlap 2311b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2312b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2313b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2314b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2315b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2316506f1d07SSam Ravnborg 2317b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2318b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2319b0b49f26SAndy Lutomirski 2320b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2321b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2322b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2323b0b49f26SAndy Lutomirski 2324b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2325b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2326506f1d07SSam Ravnborg 23273dc33bd3SKees Cookchoice 23283dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23293dc33bd3SKees Cook depends on X86_64 2330625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23313dc33bd3SKees Cook help 23323dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23333dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23343dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23353dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23363dc33bd3SKees Cook 23373dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2338bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23393dc33bd3SKees Cook 23403dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23413dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23423dc33bd3SKees Cook to improve security. 23433dc33bd3SKees Cook 2344bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23453dc33bd3SKees Cook 23463dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2347bd49e16eSAndy Lutomirski bool "Full emulation" 23483dc33bd3SKees Cook help 2349bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2350bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2351bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2352bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2353bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2354bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2355bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2356bd49e16eSAndy Lutomirski 2357bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2358bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2359bd49e16eSAndy Lutomirski 2360bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2361bd49e16eSAndy Lutomirski bool "Emulate execution only" 2362bd49e16eSAndy Lutomirski help 2363bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2364bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2365bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2366bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2367bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2368bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2369bd49e16eSAndy Lutomirski buffer. 23703dc33bd3SKees Cook 23713dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23723dc33bd3SKees Cook bool "None" 23733dc33bd3SKees Cook help 23743dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23753dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23763dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23773dc33bd3SKees Cook will be reported to dmesg, so that either old or 23783dc33bd3SKees Cook malicious userspace programs can be identified. 23793dc33bd3SKees Cook 23803dc33bd3SKees Cookendchoice 23813dc33bd3SKees Cook 2382516cbf37STim Birdconfig CMDLINE_BOOL 2383516cbf37STim Bird bool "Built-in kernel command line" 2384a7f7f624SMasahiro Yamada help 2385516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2386516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2387516cbf37STim Bird necessary or convenient to provide some or all of the 2388516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2389516cbf37STim Bird to not rely on the boot loader to provide them.) 2390516cbf37STim Bird 2391516cbf37STim Bird To compile command line arguments into the kernel, 2392516cbf37STim Bird set this option to 'Y', then fill in the 239369711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2394516cbf37STim Bird 2395516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2396516cbf37STim Bird should leave this option set to 'N'. 2397516cbf37STim Bird 2398516cbf37STim Birdconfig CMDLINE 2399516cbf37STim Bird string "Built-in kernel command string" 2400516cbf37STim Bird depends on CMDLINE_BOOL 2401516cbf37STim Bird default "" 2402a7f7f624SMasahiro Yamada help 2403516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2404516cbf37STim Bird image and used at boot time. If the boot loader provides a 2405516cbf37STim Bird command line at boot time, it is appended to this string to 2406516cbf37STim Bird form the full kernel command line, when the system boots. 2407516cbf37STim Bird 2408516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2409516cbf37STim Bird change this behavior. 2410516cbf37STim Bird 2411516cbf37STim Bird In most cases, the command line (whether built-in or provided 2412516cbf37STim Bird by the boot loader) should specify the device for the root 2413516cbf37STim Bird file system. 2414516cbf37STim Bird 2415516cbf37STim Birdconfig CMDLINE_OVERRIDE 2416516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2417645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2418a7f7f624SMasahiro Yamada help 2419516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2420516cbf37STim Bird command line, and use ONLY the built-in command line. 2421516cbf37STim Bird 2422516cbf37STim Bird This is used to work around broken boot loaders. This should 2423516cbf37STim Bird be set to 'N' under normal conditions. 2424516cbf37STim Bird 2425a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2426a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2427a5b9e5a2SAndy Lutomirski default y 2428a7f7f624SMasahiro Yamada help 2429a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2430a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2431a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2432a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2433a5b9e5a2SAndy Lutomirski threading libraries. 2434a5b9e5a2SAndy Lutomirski 2435a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2436a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2437a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2438a5b9e5a2SAndy Lutomirski 2439a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2440a5b9e5a2SAndy Lutomirski 24413aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 24423aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 24433aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 24443aac3ebeSThomas Gleixner help 24453aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 24463aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 24473aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 24483aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 24493aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 24503aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 24513aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 24523aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 24533aac3ebeSThomas Gleixner never get a signal delivered. 24543aac3ebeSThomas Gleixner 24553aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24563aac3ebeSThomas Gleixner 2457b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2458b700e7f0SSeth Jennings 2459506f1d07SSam Ravnborgendmenu 2460506f1d07SSam Ravnborg 24613072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24623072e413SMichal Hocko def_bool y 24635c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 24643072e413SMichal Hocko 2465f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2466f91ef222SOscar Salvador def_bool y 2467f91ef222SOscar Salvador 2468da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2469e279b6c1SSam Ravnborg 2470e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 24713c2362e6SHarvey Harrison def_bool y 247244556530SZhimin Gu depends on HIBERNATION 2473e279b6c1SSam Ravnborg 2474e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2475e279b6c1SSam Ravnborg 2476e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2477e279b6c1SSam Ravnborg 2478a6b68076SAndi Kleenconfig X86_APM_BOOT 24796fc108a0SJan Beulich def_bool y 2480282e5aabSPaul Bolle depends on APM 2481a6b68076SAndi Kleen 2482e279b6c1SSam Ravnborgmenuconfig APM 2483e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2484efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2485a7f7f624SMasahiro Yamada help 2486e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2487e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2488e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2489e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2490e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2491e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2492e279b6c1SSam Ravnborg 2493e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2494e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2495e279b6c1SSam Ravnborg 2496e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2497e279b6c1SSam Ravnborg machines with more than one CPU. 2498e279b6c1SSam Ravnborg 2499e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2500151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 25012dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2502e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2503e279b6c1SSam Ravnborg 2504e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2505e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2506e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2507e279b6c1SSam Ravnborg 2508e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2509e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2510e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2511e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2512e279b6c1SSam Ravnborg 2513e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2514e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2515e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2516e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2517e279b6c1SSam Ravnborg APM in your BIOS). 2518e279b6c1SSam Ravnborg 2519e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2520e279b6c1SSam Ravnborg "weird" problems: 2521e279b6c1SSam Ravnborg 2522e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2523e279b6c1SSam Ravnborg enabled. 2524e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2525e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2526e279b6c1SSam Ravnborg the "no387" option to the kernel 2527e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2528e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2529e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2530e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2531e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2532e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2533e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2534e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2535e279b6c1SSam Ravnborg 11) exchange RAM chips 2536e279b6c1SSam Ravnborg 12) exchange the motherboard. 2537e279b6c1SSam Ravnborg 2538e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2539e279b6c1SSam Ravnborg module will be called apm. 2540e279b6c1SSam Ravnborg 2541e279b6c1SSam Ravnborgif APM 2542e279b6c1SSam Ravnborg 2543e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2544e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2545a7f7f624SMasahiro Yamada help 2546e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2547e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2548e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2549e279b6c1SSam Ravnborg 2550e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2551e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2552a7f7f624SMasahiro Yamada help 2553e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2554e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2555e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2556e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2557e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2558e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2559e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2560e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2561e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2562e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2563e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2564e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2565e279b6c1SSam Ravnborg this feature. 2566e279b6c1SSam Ravnborg 2567e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2568dd8af076SLen Brown depends on CPU_IDLE 2569e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2570a7f7f624SMasahiro Yamada help 2571e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2572e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2573e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2574e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2575e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2576e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2577e279b6c1SSam Ravnborg this option does nothing.) 2578e279b6c1SSam Ravnborg 2579e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2580e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2581a7f7f624SMasahiro Yamada help 2582e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2583e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2584e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2585e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2586e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2587e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2588e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2589e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2590e279b6c1SSam Ravnborg especially if you are using gpm. 2591e279b6c1SSam Ravnborg 2592e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2593e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2594a7f7f624SMasahiro Yamada help 2595e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2596e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2597e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2598e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2599e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2600e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2601e279b6c1SSam Ravnborg 2602e279b6c1SSam Ravnborgendif # APM 2603e279b6c1SSam Ravnborg 2604bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2605e279b6c1SSam Ravnborg 2606e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2607e279b6c1SSam Ravnborg 260827471fdbSAndy Henroidsource "drivers/idle/Kconfig" 260927471fdbSAndy Henroid 2610e279b6c1SSam Ravnborgendmenu 2611e279b6c1SSam Ravnborg 2612e279b6c1SSam Ravnborg 2613e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2614e279b6c1SSam Ravnborg 2615e279b6c1SSam Ravnborgchoice 2616e279b6c1SSam Ravnborg prompt "PCI access mode" 2617efefa6f6SIngo Molnar depends on X86_32 && PCI 2618e279b6c1SSam Ravnborg default PCI_GOANY 2619a7f7f624SMasahiro Yamada help 2620e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2621e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2622e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2623e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2624e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2625e279b6c1SSam Ravnborg 2626e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2627e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2628e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2629e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2630e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2631e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2632e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2633e279b6c1SSam Ravnborg 2634e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2635e279b6c1SSam Ravnborg bool "BIOS" 2636e279b6c1SSam Ravnborg 2637e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2638e279b6c1SSam Ravnborg bool "MMConfig" 2639e279b6c1SSam Ravnborg 2640e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2641e279b6c1SSam Ravnborg bool "Direct" 2642e279b6c1SSam Ravnborg 26433ef0e1f8SAndres Salomonconfig PCI_GOOLPC 264476fb6570SDaniel Drake bool "OLPC XO-1" 26453ef0e1f8SAndres Salomon depends on OLPC 26463ef0e1f8SAndres Salomon 26472bdd1b03SAndres Salomonconfig PCI_GOANY 26482bdd1b03SAndres Salomon bool "Any" 26492bdd1b03SAndres Salomon 2650e279b6c1SSam Ravnborgendchoice 2651e279b6c1SSam Ravnborg 2652e279b6c1SSam Ravnborgconfig PCI_BIOS 26533c2362e6SHarvey Harrison def_bool y 2654efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2655e279b6c1SSam Ravnborg 2656e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2657e279b6c1SSam Ravnborgconfig PCI_DIRECT 26583c2362e6SHarvey Harrison def_bool y 26590aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2660e279b6c1SSam Ravnborg 2661e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2662b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2663b45c9f36SJan Kiszka default y 26644590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2665b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2666e279b6c1SSam Ravnborg 26673ef0e1f8SAndres Salomonconfig PCI_OLPC 26682bdd1b03SAndres Salomon def_bool y 26692bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 26703ef0e1f8SAndres Salomon 2671b5401a96SAlex Nixonconfig PCI_XEN 2672b5401a96SAlex Nixon def_bool y 2673b5401a96SAlex Nixon depends on PCI && XEN 2674b5401a96SAlex Nixon 26758364e1f8SJan Kiszkaconfig MMCONF_FAM10H 26768364e1f8SJan Kiszka def_bool y 26778364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2678e279b6c1SSam Ravnborg 26793f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 26806a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 26816ea30386SKees Cook depends on PCI 26823f6ea84aSIra W. Snyder help 26833f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 26843f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 26853f6ea84aSIra W. Snyder not have ACPI. 26863f6ea84aSIra W. Snyder 268764a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 268864a5fed6SBjorn Helgaas is known to be incomplete. 268964a5fed6SBjorn Helgaas 269064a5fed6SBjorn Helgaas You should say N unless you know you need this. 269164a5fed6SBjorn Helgaas 26923a495511SWilliam Breathitt Grayconfig ISA_BUS 269317a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 26943a495511SWilliam Breathitt Gray help 269517a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 269617a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 269717a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 269817a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 269917a2a129SWilliam Breathitt Gray not have an ISA bus. 27003a495511SWilliam Breathitt Gray 27013a495511SWilliam Breathitt Gray If unsure, say N. 27023a495511SWilliam Breathitt Gray 27031c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2704e279b6c1SSam Ravnborgconfig ISA_DMA_API 27051c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 27061c00f016SDavid Rientjes default y 27071c00f016SDavid Rientjes help 27081c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 27091c00f016SDavid Rientjes If unsure, say Y. 2710e279b6c1SSam Ravnborg 271151e68d05SLinus Torvaldsif X86_32 271251e68d05SLinus Torvalds 2713e279b6c1SSam Ravnborgconfig ISA 2714e279b6c1SSam Ravnborg bool "ISA support" 2715a7f7f624SMasahiro Yamada help 2716e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2717e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2718e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2719e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2720e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2721e279b6c1SSam Ravnborg 2722e279b6c1SSam Ravnborgconfig SCx200 2723e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2724a7f7f624SMasahiro Yamada help 2725e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2726e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2727e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2728e279b6c1SSam Ravnborg for other scx200_* drivers. 2729e279b6c1SSam Ravnborg 2730e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2731e279b6c1SSam Ravnborg 2732e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2733e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2734592913ecSJohn Stultz depends on SCx200 2735e279b6c1SSam Ravnborg default y 2736a7f7f624SMasahiro Yamada help 2737e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2738e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2739e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2740e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2741e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2742e279b6c1SSam Ravnborg 27433ef0e1f8SAndres Salomonconfig OLPC 27443ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 274554008979SThomas Gleixner depends on !X86_PAE 27463c554946SAndres Salomon select GPIOLIB 2747dc3119e7SThomas Gleixner select OF 274845bb1674SDaniel Drake select OF_PROMTREE 2749b4e51854SGrant Likely select IRQ_DOMAIN 27500c3d931bSLubomir Rintel select OLPC_EC 2751a7f7f624SMasahiro Yamada help 27523ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27533ef0e1f8SAndres Salomon XO hardware. 27543ef0e1f8SAndres Salomon 2755a3128588SDaniel Drakeconfig OLPC_XO1_PM 2756a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2757fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2758a7f7f624SMasahiro Yamada help 275997c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2760bf1ebf00SDaniel Drake 2761cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2762cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2763cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2764a7f7f624SMasahiro Yamada help 2765cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2766cfee9597SDaniel Drake programmable wakeup source. 2767cfee9597SDaniel Drake 27687feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 27697feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 277092e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2771ed8e47feSRandy Dunlap depends on INPUT=y 2772d8d01a63SDaniel Drake select POWER_SUPPLY 2773a7f7f624SMasahiro Yamada help 27747feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 27757bc74b3dSDaniel Drake - EC-driven system wakeups 27767feda8e9SDaniel Drake - Power button 27777bc74b3dSDaniel Drake - Ebook switch 27782cf2baeaSDaniel Drake - Lid switch 2779e1040ac6SDaniel Drake - AC adapter status updates 2780e1040ac6SDaniel Drake - Battery status updates 27817feda8e9SDaniel Drake 2782a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2783a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2784d8d01a63SDaniel Drake depends on OLPC && ACPI 2785d8d01a63SDaniel Drake select POWER_SUPPLY 2786a7f7f624SMasahiro Yamada help 2787a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2788a0f30f59SDaniel Drake - EC-driven system wakeups 2789a0f30f59SDaniel Drake - AC adapter status updates 2790a0f30f59SDaniel Drake - Battery status updates 2791e279b6c1SSam Ravnborg 2792d4f3e350SEd Wildgooseconfig ALIX 2793d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2794d4f3e350SEd Wildgoose select GPIOLIB 2795a7f7f624SMasahiro Yamada help 2796d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2797d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2798d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2799d4f3e350SEd Wildgoose get added here. 2800d4f3e350SEd Wildgoose 2801d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2802d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2803d4f3e350SEd Wildgoose 2804d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2805d4f3e350SEd Wildgoose 2806da4e3302SPhilip Prindevilleconfig NET5501 2807da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2808da4e3302SPhilip Prindeville select GPIOLIB 2809a7f7f624SMasahiro Yamada help 2810da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2811da4e3302SPhilip Prindeville 28123197059aSPhilip A. Prindevilleconfig GEOS 28133197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28143197059aSPhilip A. Prindeville select GPIOLIB 28153197059aSPhilip A. Prindeville depends on DMI 2816a7f7f624SMasahiro Yamada help 28173197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28183197059aSPhilip A. Prindeville 28197d029125SVivien Didelotconfig TS5500 28207d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28217d029125SVivien Didelot depends on MELAN 28227d029125SVivien Didelot select CHECK_SIGNATURE 28237d029125SVivien Didelot select NEW_LEDS 28247d029125SVivien Didelot select LEDS_CLASS 2825a7f7f624SMasahiro Yamada help 28267d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28277d029125SVivien Didelot 2828e279b6c1SSam Ravnborgendif # X86_32 2829e279b6c1SSam Ravnborg 283023ac4ae8SAndreas Herrmannconfig AMD_NB 2831e279b6c1SSam Ravnborg def_bool y 28320e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2833e279b6c1SSam Ravnborg 2834e279b6c1SSam Ravnborgendmenu 2835e279b6c1SSam Ravnborg 2836e279b6c1SSam Ravnborg 28371572497cSChristoph Hellwigmenu "Binary Emulations" 2838e279b6c1SSam Ravnborg 2839e279b6c1SSam Ravnborgconfig IA32_EMULATION 2840e279b6c1SSam Ravnborg bool "IA32 Emulation" 2841e279b6c1SSam Ravnborg depends on X86_64 284239f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2843d1603990SRandy Dunlap select BINFMT_ELF 284439f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2845a7f7f624SMasahiro Yamada help 28465fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 28475fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 28485fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2849e279b6c1SSam Ravnborg 2850e279b6c1SSam Ravnborgconfig IA32_AOUT 2851e279b6c1SSam Ravnborg tristate "IA32 a.out support" 28526b213e1bSDavid Woodhouse depends on IA32_EMULATION 2853eac61655SBorislav Petkov depends on BROKEN 2854a7f7f624SMasahiro Yamada help 2855e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2856e279b6c1SSam Ravnborg 28570bf62763SH. Peter Anvinconfig X86_X32 28586ea30386SKees Cook bool "x32 ABI for 64-bit mode" 28599b54050bSBrian Gerst depends on X86_64 2860a7f7f624SMasahiro Yamada help 28615fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 28625fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 28635fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 28645fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 28655fd92e65SH. J. Lu 28665fd92e65SH. J. Lu You will need a recent binutils (2.22 or later) with 28675fd92e65SH. J. Lu elf32_x86_64 support enabled to compile a kernel with this 28685fd92e65SH. J. Lu option set. 28695fd92e65SH. J. Lu 2870953fee1dSIngo Molnarconfig COMPAT_32 2871953fee1dSIngo Molnar def_bool y 2872953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2873953fee1dSIngo Molnar select HAVE_UID16 2874953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2875953fee1dSIngo Molnar 2876e279b6c1SSam Ravnborgconfig COMPAT 28773c2362e6SHarvey Harrison def_bool y 28780bf62763SH. Peter Anvin depends on IA32_EMULATION || X86_X32 2879e279b6c1SSam Ravnborg 28803120e25eSJan Beulichif COMPAT 2881e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 28823120e25eSJan Beulich def_bool y 2883e279b6c1SSam Ravnborg 2884e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 28853c2362e6SHarvey Harrison def_bool y 28863120e25eSJan Beulich depends on SYSVIPC 28873120e25eSJan Beulichendif 2888ee009e4aSDavid Howells 2889e279b6c1SSam Ravnborgendmenu 2890e279b6c1SSam Ravnborg 2891e279b6c1SSam Ravnborg 2892e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2893e5beae16SKeith Packard def_bool y 2894e5beae16SKeith Packard depends on X86_32 2895e5beae16SKeith Packard 2896edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 28975e8ebd84SJason A. Donenfeld 28985e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2899