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 351032c0baSSam Ravnborg 36518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 37518049d9SSteven Rostedt (VMware) def_bool y 38518049d9SSteven Rostedt (VMware) depends on X86_32 39518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 40518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 41518049d9SSteven Rostedt (VMware) help 42518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 43518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 44518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 45518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 46518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 47d94e0685SIngo Molnar# 48d94e0685SIngo Molnar# Arch settings 49d94e0685SIngo Molnar# 50d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 51d94e0685SIngo Molnar# ported to 32-bit as well. ) 52d94e0685SIngo Molnar# 538d5fffb9SSam Ravnborgconfig X86 543c2362e6SHarvey Harrison def_bool y 55c763ea26SIngo Molnar # 56c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 57c763ea26SIngo Molnar # 586471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 596e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 60942fa985SYury Norov select ARCH_32BIT_OFF_T if X86_32 612a21ad57SThomas Gleixner select ARCH_CLOCKSOURCE_INIT 6291dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 64399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 6521266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 66b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 676471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 6872d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 69316d097cSDave Hansen select ARCH_HAS_FILTER_PGPROT 706974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 71957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 720f1441b4SPeter Zijlstra select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 730c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 7410bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 750ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 76c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 7717596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 783010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 790aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 80ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 81d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 82d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 83ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 84ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 85ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 8625c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 87c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 887e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 896471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 906471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 9177fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 925e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 933599fe12SThomas Gleixner select ARCH_STACKWALK 942c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 956471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 965d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 976471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 9814df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 996471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 1006471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1016471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1022ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 103ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 10481c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 105c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 1063876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 10759612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 10838d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 10910916706SShile Zhang select BUILDTIME_TABLE_SORT 1106471b825SIngo Molnar select CLKEVT_I8253 1116471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1126471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1136471b825SIngo Molnar select DCACHE_WORD_ACCESS 11445471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 11545471cd9SLinus Torvalds select EDAC_SUPPORT 1166471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1176471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1186471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1196471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 12061dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1216471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 12227d6b4d1SThomas Gleixner select GENERIC_ENTRY 1236471b825SIngo Molnar select GENERIC_FIND_FIRST_BIT 1246471b825SIngo Molnar select GENERIC_IOMAP 125c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1260fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 127ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1286471b825SIngo Molnar select GENERIC_IRQ_PROBE 129c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1306471b825SIngo Molnar select GENERIC_IRQ_SHOW 1316471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1322ae27137SSteven Price select GENERIC_PTDUMP 1336471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1346471b825SIngo Molnar select GENERIC_STRNCPY_FROM_USER 1356471b825SIngo Molnar select GENERIC_STRNLEN_USER 1366471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1377ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 138550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 13939656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 14017e5888eSHans de Goede select HARDIRQS_SW_RESEND 1417edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1426471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1436471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1446471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1456471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1466471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 1476471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 148b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 149d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1500609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1516471b825SIngo Molnar select HAVE_ARCH_KGDB 1529e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1539e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1541b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 155271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1566471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 157f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 158afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1596471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1606471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 161a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 162b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 163e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 164c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1652ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1666471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1676471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1686471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 169d1f250e2SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 1706471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 1716471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1729c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 173677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 17406aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 17502a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 176562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 17703f5781bSWang YanQing select HAVE_EBPF_JIT 17858340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 1796630a8e5SChristoph Hellwig select HAVE_EISA 1805f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 18167a929e0SChristoph Hellwig select HAVE_FAST_GUP 182644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 1836471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 1846471b825SIngo Molnar select HAVE_FUNCTION_GRAPH_TRACER 1856471b825SIngo Molnar select HAVE_FUNCTION_TRACER 1866b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 1870067f129SK.Prasad select HAVE_HW_BREAKPOINT 1886471b825SIngo Molnar select HAVE_IDE 1896471b825SIngo Molnar select HAVE_IOREMAP_PROT 190624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 1916471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 1926471b825SIngo Molnar select HAVE_KERNEL_BZIP2 1936471b825SIngo Molnar select HAVE_KERNEL_GZIP 1946471b825SIngo Molnar select HAVE_KERNEL_LZ4 1956471b825SIngo Molnar select HAVE_KERNEL_LZMA 1966471b825SIngo Molnar select HAVE_KERNEL_LZO 1976471b825SIngo Molnar select HAVE_KERNEL_XZ 198fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 1996471b825SIngo Molnar select HAVE_KPROBES 2006471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 201540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2026471b825SIngo Molnar select HAVE_KRETPROBES 2036471b825SIngo Molnar select HAVE_KVM 2046471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2050102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 206ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2079f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 208be37c98dSKalesh Singh select HAVE_MOVE_PUD 20942a0bb3fSPetr Mladek select HAVE_NMI 2106471b825SIngo Molnar select HAVE_OPROFILE 2116471b825SIngo Molnar select HAVE_OPTPROBES 2126471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2136471b825SIngo Molnar select HAVE_PERF_EVENTS 214c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 21592e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 216eb01d42aSChristoph Hellwig select HAVE_PCI 217c5e63197SJiri Olsa select HAVE_PERF_REGS 218c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 219ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 22000998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2216471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 2226415b38bSJiri Slaby select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 2233c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 224*cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 225d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 226c763ea26SIngo Molnar select HAVE_STACK_VALIDATION if X86_64 227e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 2281e7e4788SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 229d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2306471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2316471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2327c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2337ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 23405736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 235c0185808SThomas Gleixner select IRQ_FORCED_THREADING 23686596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2372eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 238625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2396471b825SIngo Molnar select PERF_EVENTS 2403195ef59SPrarit Bhargava select RTC_LIB 241d6faca40SArnd Bergmann select RTC_MC146818_LIB 2426471b825SIngo Molnar select SPARSE_IRQ 24383fe27eaSPranith Kumar select SRCU 2441e7e4788SJosh Poimboeuf select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 2456471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 24615f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2476471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2486471b825SIngo Molnar select VIRT_TO_BUS 2493b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2506471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2510c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 2529e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 2537d8330a5SBalbir Singh 254ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2553120e25eSJan Beulich def_bool y 2563120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 257ba7e4d13SIngo Molnar 25851b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 25951b26adaSLinus Torvalds string 26051b26adaSLinus Torvalds default "elf32-i386" if X86_32 26151b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 26251b26adaSLinus Torvalds 2638d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2643c2362e6SHarvey Harrison def_bool y 2658d5fffb9SSam Ravnborg 2668d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2673c2362e6SHarvey Harrison def_bool y 2688d5fffb9SSam Ravnborg 2698d5fffb9SSam Ravnborgconfig MMU 2703c2362e6SHarvey Harrison def_bool y 2718d5fffb9SSam Ravnborg 2729e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 2739e08f57dSDaniel Cashman default 28 if 64BIT 2749e08f57dSDaniel Cashman default 8 2759e08f57dSDaniel Cashman 2769e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 2779e08f57dSDaniel Cashman default 32 if 64BIT 2789e08f57dSDaniel Cashman default 16 2799e08f57dSDaniel Cashman 2809e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 2819e08f57dSDaniel Cashman default 8 2829e08f57dSDaniel Cashman 2839e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 2849e08f57dSDaniel Cashman default 16 2859e08f57dSDaniel Cashman 2868d5fffb9SSam Ravnborgconfig SBUS 2878d5fffb9SSam Ravnborg bool 2888d5fffb9SSam Ravnborg 2898d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 2903120e25eSJan Beulich def_bool y 2913120e25eSJan Beulich depends on ISA_DMA_API 2928d5fffb9SSam Ravnborg 2938d5fffb9SSam Ravnborgconfig GENERIC_BUG 2943c2362e6SHarvey Harrison def_bool y 2958d5fffb9SSam Ravnborg depends on BUG 296b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 297b93a531eSJan Beulich 298b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 299b93a531eSJan Beulich bool 3008d5fffb9SSam Ravnborg 3018d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3023120e25eSJan Beulich def_bool y 3033120e25eSJan Beulich depends on ISA_DMA_API 3048d5fffb9SSam Ravnborg 3051032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3061032c0baSSam Ravnborg def_bool y 3071032c0baSSam Ravnborg 3089a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3099a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3108d5fffb9SSam Ravnborg 3111b27d05bSPekka Enbergconfig ARCH_HAS_CACHE_LINE_SIZE 3121b27d05bSPekka Enberg def_bool y 3131b27d05bSPekka Enberg 314316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT 315316d097cSDave Hansen def_bool y 316316d097cSDave Hansen 317dd5af90aSMike Travisconfig HAVE_SETUP_PER_CPU_AREA 31889c9c4c5SBrian Gerst def_bool y 319b32ef636Stravis@sgi.com 32008fc4580STejun Heoconfig NEED_PER_CPU_EMBED_FIRST_CHUNK 32108fc4580STejun Heo def_bool y 32208fc4580STejun Heo 32308fc4580STejun Heoconfig NEED_PER_CPU_PAGE_FIRST_CHUNK 32411124411STejun Heo def_bool y 32511124411STejun Heo 326801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 327801e4062SJohannes Berg def_bool y 328801e4062SJohannes Berg 329f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 330f4cb5700SJohannes Berg def_bool y 331f4cb5700SJohannes Berg 33253313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB 33353313b2cSSteve Capper def_bool y 33453313b2cSSteve Capper 3358d5fffb9SSam Ravnborgconfig ZONE_DMA32 336e0fd24a3SJan Beulich def_bool y if X86_64 3378d5fffb9SSam Ravnborg 3388d5fffb9SSam Ravnborgconfig AUDIT_ARCH 339e0fd24a3SJan Beulich def_bool y if X86_64 3408d5fffb9SSam Ravnborg 341d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 342d6f2d75aSAndrey Ryabinin hex 343d6f2d75aSAndrey Ryabinin depends on KASAN 344d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 345d6f2d75aSAndrey Ryabinin 34669575d38SShane Wangconfig HAVE_INTEL_TXT 34769575d38SShane Wang def_bool y 3486ea30386SKees Cook depends on INTEL_IOMMU && ACPI 34969575d38SShane Wang 3506b0c3d44SSam Ravnborgconfig X86_32_SMP 3516b0c3d44SSam Ravnborg def_bool y 3526b0c3d44SSam Ravnborg depends on X86_32 && SMP 3536b0c3d44SSam Ravnborg 3546b0c3d44SSam Ravnborgconfig X86_64_SMP 3556b0c3d44SSam Ravnborg def_bool y 3566b0c3d44SSam Ravnborg depends on X86_64 && SMP 3576b0c3d44SSam Ravnborg 358ccbeed3aSTejun Heoconfig X86_32_LAZY_GS 359ccbeed3aSTejun Heo def_bool y 3608458f8c2SMasahiro Yamada depends on X86_32 && !STACKPROTECTOR 361ccbeed3aSTejun Heo 3622b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3632b144498SSrikar Dronamraju def_bool y 3642b144498SSrikar Dronamraju 365d20642f0SRob Herringconfig FIX_EARLYCON_MEM 366d20642f0SRob Herring def_bool y 367d20642f0SRob Herring 36894d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 36994d49eb3SKirill A. Shutemov bool 37094d49eb3SKirill A. Shutemov 37198233368SKirill A. Shutemovconfig PGTABLE_LEVELS 37298233368SKirill A. Shutemov int 37377ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 37498233368SKirill A. Shutemov default 4 if X86_64 37598233368SKirill A. Shutemov default 3 if X86_PAE 37698233368SKirill A. Shutemov default 2 37798233368SKirill A. Shutemov 3782a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3792a61f474SMasahiro Yamada bool 3802a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3812a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3822a61f474SMasahiro Yamada help 3832a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3842a61f474SMasahiro Yamada the compiler produces broken code. 3852a61f474SMasahiro Yamada 386506f1d07SSam Ravnborgmenu "Processor type and features" 387506f1d07SSam Ravnborg 3885ee71535SRandy Dunlapconfig ZONE_DMA 3895ee71535SRandy Dunlap bool "DMA memory allocation support" if EXPERT 3905ee71535SRandy Dunlap default y 3915ee71535SRandy Dunlap help 3925ee71535SRandy Dunlap DMA memory allocation support allows devices with less than 32-bit 3935ee71535SRandy Dunlap addressing to allocate within the first 16MB of address space. 3945ee71535SRandy Dunlap Disable if no such devices will be used. 3955ee71535SRandy Dunlap 3965ee71535SRandy Dunlap If unsure, say Y. 3975ee71535SRandy Dunlap 398506f1d07SSam Ravnborgconfig SMP 399506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 400a7f7f624SMasahiro Yamada help 401506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4024a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4034a474157SRobert Graffham than one CPU, say Y. 404506f1d07SSam Ravnborg 4054a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 406506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 407506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4084a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 409506f1d07SSam Ravnborg will run faster if you say N here. 410506f1d07SSam Ravnborg 411506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 412506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 413506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 414506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 415506f1d07SSam Ravnborg 416506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 417506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 418506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 419506f1d07SSam Ravnborg 420cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4214f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 422506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 423506f1d07SSam Ravnborg 424506f1d07SSam Ravnborg If you don't know what to do here, say N. 425506f1d07SSam Ravnborg 4269def39beSJosh Triplettconfig X86_FEATURE_NAMES 4279def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4289def39beSJosh Triplett default y 429a7f7f624SMasahiro Yamada help 4309def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4319def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4329def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4339def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4349def39beSJosh Triplett 4359def39beSJosh Triplett If in doubt, say Y. 4369def39beSJosh Triplett 43706cd9a7dSYinghai Luconfig X86_X2APIC 43806cd9a7dSYinghai Lu bool "Support x2apic" 43919e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 440a7f7f624SMasahiro Yamada help 44106cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 44206cd9a7dSYinghai Lu 44306cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 44406cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 44506cd9a7dSYinghai Lu 44606cd9a7dSYinghai Lu If you don't know what to do here, say N. 44706cd9a7dSYinghai Lu 4486695c85bSYinghai Luconfig X86_MPPARSE 4496e87f9b7SBin Gao bool "Enable MPS table" if ACPI || SFI 4507a527688SJan Beulich default y 4515ab74722SIngo Molnar depends on X86_LOCAL_APIC 452a7f7f624SMasahiro Yamada help 4536695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4546695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4556695c85bSYinghai Lu 456ddd70cf9SJun Nakajimaconfig GOLDFISH 457ddd70cf9SJun Nakajima def_bool y 458ddd70cf9SJun Nakajima depends on X86_GOLDFISH 459ddd70cf9SJun Nakajima 46076b04384SDavid Woodhouseconfig RETPOLINE 46176b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 46276b04384SDavid Woodhouse default y 46376b04384SDavid Woodhouse help 46476b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 46576b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 46676b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 46776b04384SDavid Woodhouse support for full protection. The kernel may run slower. 46876b04384SDavid Woodhouse 469e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 470e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4716fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 47259fe5a77SThomas Gleixner select KERNFS 473e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 47478e99b4aSFenghua Yu help 475e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4766fe07ce3SBabu Moger 4776fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4786fe07ce3SBabu Moger usage by the CPU. 4796fe07ce3SBabu Moger 4806fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4816fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4826fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4836fe07ce3SBabu Moger 4846fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4856fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4866fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 48778e99b4aSFenghua Yu 48878e99b4aSFenghua Yu Say N if unsure. 48978e99b4aSFenghua Yu 4908425091fSRavikiran G Thirumalaiif X86_32 491a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 492a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 493a0d0bb4dSRandy Dunlap depends on SMP 494a7f7f624SMasahiro Yamada help 495e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 496a0d0bb4dSRandy Dunlap 497c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 498c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 499c5c606d9SRavikiran G Thirumalai default y 500a7f7f624SMasahiro Yamada help 50106ac8346SIngo Molnar If you disable this option then the kernel will only support 50206ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 50306ac8346SIngo Molnar systems out there.) 50406ac8346SIngo Molnar 5058425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5068425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 507cb7b8023SBen Hutchings Goldfish (Android emulator) 5088425091fSRavikiran G Thirumalai AMD Elan 5098425091fSRavikiran G Thirumalai RDC R-321x SoC 5108425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 51183125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5123f4110a4SThomas Gleixner Moorestown MID devices 51306ac8346SIngo Molnar 51406ac8346SIngo Molnar If you have one of these systems, or if you want to build a 51506ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5168425091fSRavikiran G Thirumalaiendif 51706ac8346SIngo Molnar 5188425091fSRavikiran G Thirumalaiif X86_64 5198425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5208425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5218425091fSRavikiran G Thirumalai default y 522a7f7f624SMasahiro Yamada help 5238425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5248425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5258425091fSRavikiran G Thirumalai systems out there.) 5268425091fSRavikiran G Thirumalai 5278425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5288425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 52944b111b5SSteffen Persvold Numascale NumaChip 5308425091fSRavikiran G Thirumalai ScaleMP vSMP 5318425091fSRavikiran G Thirumalai SGI Ultraviolet 5328425091fSRavikiran G Thirumalai 5338425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5348425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5358425091fSRavikiran G Thirumalaiendif 536c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 537c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 53844b111b5SSteffen Persvoldconfig X86_NUMACHIP 53944b111b5SSteffen Persvold bool "Numascale NumaChip" 54044b111b5SSteffen Persvold depends on X86_64 54144b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 54244b111b5SSteffen Persvold depends on NUMA 54344b111b5SSteffen Persvold depends on SMP 54444b111b5SSteffen Persvold depends on X86_X2APIC 545f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 546a7f7f624SMasahiro Yamada help 54744b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 54844b111b5SSteffen Persvold enable more than ~168 cores. 54944b111b5SSteffen Persvold If you don't have one of these, you should say N here. 55003b48632SNick Piggin 5516a48565eSIngo Molnarconfig X86_VSMP 552c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5536276a074SBorislav Petkov select HYPERVISOR_GUEST 5546a48565eSIngo Molnar select PARAVIRT 5556a48565eSIngo Molnar depends on X86_64 && PCI 556c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 557ead91d4bSShai Fultheim depends on SMP 558a7f7f624SMasahiro Yamada help 5596a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5606a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5616a48565eSIngo Molnar if you have one of these machines. 5626a48565eSIngo Molnar 563c5c606d9SRavikiran G Thirumalaiconfig X86_UV 564c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 565c5c606d9SRavikiran G Thirumalai depends on X86_64 566c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 56754c28d29SJack Steiner depends on NUMA 5681ecb4ae5SAndrew Morton depends on EFI 5699d6c26e7SSuresh Siddha depends on X86_X2APIC 5701222e564SIngo Molnar depends on PCI 571a7f7f624SMasahiro Yamada help 572c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 573c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 574c5c606d9SRavikiran G Thirumalai 575c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 576c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 577506f1d07SSam Ravnborg 578ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 579ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 580cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 581a7f7f624SMasahiro Yamada help 582ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 583ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 584ddd70cf9SJun Nakajima Goldfish emulator say N here. 585ddd70cf9SJun Nakajima 586c751e17bSThomas Gleixnerconfig X86_INTEL_CE 587c751e17bSThomas Gleixner bool "CE4100 TV platform" 588c751e17bSThomas Gleixner depends on PCI 589c751e17bSThomas Gleixner depends on PCI_GODIRECT 5906084a6e2SJiang Liu depends on X86_IO_APIC 591c751e17bSThomas Gleixner depends on X86_32 592c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 59337bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 594da6b737bSSebastian Andrzej Siewior select OF 595da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 596a7f7f624SMasahiro Yamada help 597c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 598c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 599c751e17bSThomas Gleixner boxes and media devices. 600c751e17bSThomas Gleixner 6014cb9b00fSDavid Cohenconfig X86_INTEL_MID 60243605ef1SAlan Cox bool "Intel MID platform support" 60343605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 604edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6051ea7c673SAlan Cox depends on PCI 6063fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6071ea7c673SAlan Cox depends on X86_IO_APIC 6087c9c3a1eSAlan Cox select SFI 6094cb9b00fSDavid Cohen select I2C 6107c9c3a1eSAlan Cox select DW_APB_TIMER 6111ea7c673SAlan Cox select APB_TIMER 61254b34aa0SMika Westerberg select INTEL_SCU_PCI 61315a713dfSMika Westerberg select MFD_INTEL_MSIC 614a7f7f624SMasahiro Yamada help 6154cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6164cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6174cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6181ea7c673SAlan Cox 6194cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6204cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 62143605ef1SAlan Cox 6228bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6238bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6248bbc2a13SBryan O'Donoghue depends on X86_32 6258bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6268bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6278bbc2a13SBryan O'Donoghue depends on X86_TSC 6288bbc2a13SBryan O'Donoghue depends on PCI 6298bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6308bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6318bbc2a13SBryan O'Donoghue select IOSF_MBI 6328bbc2a13SBryan O'Donoghue select INTEL_IMR 6339ab6eb51SAndy Shevchenko select COMMON_CLK 634a7f7f624SMasahiro Yamada help 6358bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6368bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6378bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6388bbc2a13SBryan O'Donoghue 6393d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6403d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6415962dd22SSinan Kaya depends on X86 && ACPI && PCI 6423d48aab1SMika Westerberg select COMMON_CLK 6430f531431SMathias Nyman select PINCTRL 644eebb3e8dSAndy Shevchenko select IOSF_MBI 645a7f7f624SMasahiro Yamada help 6463d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6473d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6480f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6490f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6503d48aab1SMika Westerberg 65192082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 65292082a88SKen Xue bool "AMD ACPI2Platform devices support" 65392082a88SKen Xue depends on ACPI 65492082a88SKen Xue select COMMON_CLK 65592082a88SKen Xue select PINCTRL 656a7f7f624SMasahiro Yamada help 65792082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 65892082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 65992082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 66092082a88SKen Xue implemented under PINCTRL subsystem. 66192082a88SKen Xue 662ced3ce76SDavid E. Boxconfig IOSF_MBI 663ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 664ced3ce76SDavid E. Box depends on PCI 665a7f7f624SMasahiro Yamada help 666ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 667ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 668ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 669ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 670ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 671ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 672ced3ce76SDavid E. Box This list is not meant to be exclusive. 673ced3ce76SDavid E. Box - BayTrail 674ced3ce76SDavid E. Box - Braswell 675ced3ce76SDavid E. Box - Quark 676ced3ce76SDavid E. Box 677ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 678ced3ce76SDavid E. Box 679ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 680ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 681ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 682a7f7f624SMasahiro Yamada help 683ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 684ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 685ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 686ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 687ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 688ed2226bdSDavid E. Box device they want to access. 689ed2226bdSDavid E. Box 690ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 691ed2226bdSDavid E. Box 692c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 693c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 694506f1d07SSam Ravnborg depends on X86_32 695c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 696c5c606d9SRavikiran G Thirumalai select M486 697c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 698a7f7f624SMasahiro Yamada help 699c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 700c5c606d9SRavikiran G Thirumalai as R-8610-(G). 701c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 702c5c606d9SRavikiran G Thirumalai 703e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7049c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7059c398017SIngo Molnar depends on X86_32 && SMP 706c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 707a7f7f624SMasahiro Yamada help 708b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 709b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 710b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 711b5660ba7SH. Peter Anvin one and will fallback to default. 712d49c4288SYinghai Lu 713c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 714d49c4288SYinghai Lu 715d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7166fc108a0SJan Beulich def_bool y 717d949f36fSLinus Torvalds # MCE code calls memory_failure(): 718d949f36fSLinus Torvalds depends on X86_MCE 719d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 720d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 721d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 722d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 723d949f36fSLinus Torvalds 72483125a3aSAlessandro Rubiniconfig STA2X11 72583125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 72683125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 72783125a3aSAlessandro Rubini select SWIOTLB 72883125a3aSAlessandro Rubini select MFD_STA2X11 7290145071bSLinus Walleij select GPIOLIB 730a7f7f624SMasahiro Yamada help 73183125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 73283125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 73383125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 73483125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 73583125a3aSAlessandro Rubini standard PC machines. 73683125a3aSAlessandro Rubini 73782148d1dSShérabconfig X86_32_IRIS 73882148d1dSShérab tristate "Eurobraille/Iris poweroff module" 73982148d1dSShérab depends on X86_32 740a7f7f624SMasahiro Yamada help 74182148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 74282148d1dSShérab to shut themselves down properly. A special I/O sequence is 74382148d1dSShérab needed to do so, which is what this module does at 74482148d1dSShérab kernel shutdown. 74582148d1dSShérab 74682148d1dSShérab This is only for Iris machines from EuroBraille. 74782148d1dSShérab 74882148d1dSShérab If unused, say N. 74982148d1dSShérab 750ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7513c2362e6SHarvey Harrison def_bool y 7523c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 753a87d0914SKen Chen depends on X86 754a7f7f624SMasahiro Yamada help 755506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 756506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 757506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 758506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 759506f1d07SSam Ravnborg 760506f1d07SSam Ravnborg If in doubt, say "Y". 761506f1d07SSam Ravnborg 7626276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7636276a074SBorislav Petkov bool "Linux guest support" 764a7f7f624SMasahiro Yamada help 7656276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7666276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7676276a074SBorislav Petkov setup. 768506f1d07SSam Ravnborg 7696276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7706276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 771506f1d07SSam Ravnborg 7726276a074SBorislav Petkovif HYPERVISOR_GUEST 773506f1d07SSam Ravnborg 774e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 775e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 776a7f7f624SMasahiro Yamada help 777e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 778e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 779e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 780e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 781e61bd94aSEduardo Pereira Habkost 782c00a280aSJuergen Grossconfig PARAVIRT_XXL 783c00a280aSJuergen Gross bool 784c00a280aSJuergen Gross 7856276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7866276a074SBorislav Petkov bool "paravirt-ops debugging" 7876276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 788a7f7f624SMasahiro Yamada help 7896276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7906276a074SBorislav Petkov a paravirt_op is missing when it is called. 7916276a074SBorislav Petkov 792b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 793b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 7946ea30386SKees Cook depends on PARAVIRT && SMP 795a7f7f624SMasahiro Yamada help 796b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 797b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 798b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 799b4ecc126SJeremy Fitzhardinge 8004c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8014c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 802b4ecc126SJeremy Fitzhardinge 8034c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 804b4ecc126SJeremy Fitzhardinge 805ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 806ecca2502SZhao Yakui def_bool n 807ecca2502SZhao Yakui 8086276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8096276a074SBorislav Petkov 8106276a074SBorislav Petkovconfig KVM_GUEST 8116276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8126276a074SBorislav Petkov depends on PARAVIRT 8136276a074SBorislav Petkov select PARAVIRT_CLOCK 814a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 815b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8166276a074SBorislav Petkov default y 817a7f7f624SMasahiro Yamada help 8186276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8196276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8206276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8216276a074SBorislav Petkov underlying device model, the host provides the guest with 8226276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8236276a074SBorislav Petkov 824a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 825a1c4423bSMarcelo Tosatti def_bool n 826a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 827a1c4423bSMarcelo Tosatti help 828a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 829a1c4423bSMarcelo Tosatti 8307733607fSMaran Wilsonconfig PVH 8317733607fSMaran Wilson bool "Support for running PVH guests" 832a7f7f624SMasahiro Yamada help 8337733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8347733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8357733607fSMaran Wilson 8366276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8376276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8386276a074SBorislav Petkov depends on PARAVIRT 839a7f7f624SMasahiro Yamada help 8406276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8416276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8426276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8436276a074SBorislav Petkov that, there can be a small performance impact. 8446276a074SBorislav Petkov 8456276a074SBorislav Petkov If in doubt, say N here. 8466276a074SBorislav Petkov 8477af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8487af192c9SGerd Hoffmann bool 8497af192c9SGerd Hoffmann 8504a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8514a362601SJan Kiszka bool "Jailhouse non-root cell support" 852abde587bSArnd Bergmann depends on X86_64 && PCI 85387e65d05SJan Kiszka select X86_PM_TIMER 854a7f7f624SMasahiro Yamada help 8554a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8564a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8574a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8584a362601SJan Kiszka 859ec7972c9SZhao Yakuiconfig ACRN_GUEST 860ec7972c9SZhao Yakui bool "ACRN Guest support" 861ec7972c9SZhao Yakui depends on X86_64 862498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 863ec7972c9SZhao Yakui help 864ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 865ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 866ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 867ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 868ec7972c9SZhao Yakui found in https://projectacrn.org/. 869ec7972c9SZhao Yakui 8706276a074SBorislav Petkovendif #HYPERVISOR_GUEST 87197349135SJeremy Fitzhardinge 872506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 873506f1d07SSam Ravnborg 874506f1d07SSam Ravnborgconfig HPET_TIMER 8753c2362e6SHarvey Harrison def_bool X86_64 876506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 877a7f7f624SMasahiro Yamada help 878506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 879506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 880506f1d07SSam Ravnborg present. 881506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 882506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 883506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8844e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 8854e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 886506f1d07SSam Ravnborg 887506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 888506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 889506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 890506f1d07SSam Ravnborg 891506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 892506f1d07SSam Ravnborg 893506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 8943c2362e6SHarvey Harrison def_bool y 8959d8af78bSBernhard Walle depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 896506f1d07SSam Ravnborg 897bb24c471SJacob Panconfig APB_TIMER 898933b9463SAlan Cox def_bool y if X86_INTEL_MID 899933b9463SAlan Cox prompt "Intel MID APB Timer Support" if X86_INTEL_MID 90006c3df49SJamie Iles select DW_APB_TIMER 901a0c3832aSAlan Cox depends on X86_INTEL_MID && SFI 902bb24c471SJacob Pan help 903bb24c471SJacob Pan APB timer is the replacement for 8254, HPET on X86 MID platforms. 904bb24c471SJacob Pan The APBT provides a stable time base on SMP 905bb24c471SJacob Pan systems, unlike the TSC, but it is more expensive to access, 906bb24c471SJacob Pan as it is off-chip. APB timers are always running regardless of CPU 907bb24c471SJacob Pan C states, they are used as per CPU clockevent device when possible. 908bb24c471SJacob Pan 9096a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 910506f1d07SSam Ravnborg# The code disables itself when not needed. 9117ae9392cSThomas Petazzoniconfig DMI 9127ae9392cSThomas Petazzoni default y 913cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9146a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 915a7f7f624SMasahiro Yamada help 9167ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9177ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9187ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9197ae9392cSThomas Petazzoni BIOS code. 9207ae9392cSThomas Petazzoni 921506f1d07SSam Ravnborgconfig GART_IOMMU 92238901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9232f9237d4SChristoph Hellwig select DMA_OPS 924a4ce5a48SChristoph Hellwig select IOMMU_HELPER 925506f1d07SSam Ravnborg select SWIOTLB 92623ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 927a7f7f624SMasahiro Yamada help 928ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 929ced3c42cSIngo Molnar GART based hardware IOMMUs. 930ced3c42cSIngo Molnar 931ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 932ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 933ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 934ced3c42cSIngo Molnar 935ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 936ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 937ced3c42cSIngo Molnar 938ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 939ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 940ced3c42cSIngo Molnar 32-bit limited device. 941ced3c42cSIngo Molnar 942ced3c42cSIngo Molnar If unsure, say Y. 943506f1d07SSam Ravnborg 9441184dc2fSMike Travisconfig MAXSMP 945ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9466ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 94736f5101aSMike Travis select CPUMASK_OFFSTACK 948a7f7f624SMasahiro Yamada help 949ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9501184dc2fSMike Travis If unsure, say N. 951506f1d07SSam Ravnborg 952aec6487eSIngo Molnar# 953aec6487eSIngo Molnar# The maximum number of CPUs supported: 954aec6487eSIngo Molnar# 955aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 956aec6487eSIngo Molnar# and which can be configured interactively in the 957aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 958aec6487eSIngo Molnar# 959aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 960aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 961aec6487eSIngo Molnar# 962aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 963aec6487eSIngo Molnar# interactive configuration. ) 964aec6487eSIngo Molnar# 965a0d0bb4dSRandy Dunlap 966aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 967a0d0bb4dSRandy Dunlap int 968aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 969a0d0bb4dSRandy Dunlap default 1 if !SMP 970a0d0bb4dSRandy Dunlap default 2 971a0d0bb4dSRandy Dunlap 972aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 973a0d0bb4dSRandy Dunlap int 974a0d0bb4dSRandy Dunlap depends on X86_32 975aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 976aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 977a0d0bb4dSRandy Dunlap default 1 if !SMP 978a0d0bb4dSRandy Dunlap 979aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 980a0d0bb4dSRandy Dunlap int 981a0d0bb4dSRandy Dunlap depends on X86_64 9821edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9831edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 984a0d0bb4dSRandy Dunlap default 1 if !SMP 985aec6487eSIngo Molnar 986aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 987aec6487eSIngo Molnar int 988aec6487eSIngo Molnar depends on X86_32 989aec6487eSIngo Molnar default 32 if X86_BIGSMP 990aec6487eSIngo Molnar default 8 if SMP 991aec6487eSIngo Molnar default 1 if !SMP 992aec6487eSIngo Molnar 993aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 994aec6487eSIngo Molnar int 995aec6487eSIngo Molnar depends on X86_64 996a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 997a0d0bb4dSRandy Dunlap default 64 if SMP 998aec6487eSIngo Molnar default 1 if !SMP 999a0d0bb4dSRandy Dunlap 1000506f1d07SSam Ravnborgconfig NR_CPUS 100136f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1002aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1003aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1004a7f7f624SMasahiro Yamada help 1005506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1006bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1007cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1008506f1d07SSam Ravnborg minimum value which makes sense is 2. 1009506f1d07SSam Ravnborg 1010aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1011aec6487eSIngo Molnar to the kernel image. 1012506f1d07SSam Ravnborg 1013506f1d07SSam Ravnborgconfig SCHED_SMT 1014dbe73364SThomas Gleixner def_bool y if SMP 1015506f1d07SSam Ravnborg 1016506f1d07SSam Ravnborgconfig SCHED_MC 10173c2362e6SHarvey Harrison def_bool y 10183c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1019c8e56d20SBorislav Petkov depends on SMP 1020a7f7f624SMasahiro Yamada help 1021506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1022506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1023506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1024506f1d07SSam Ravnborg 1025de966cf4STim Chenconfig SCHED_MC_PRIO 1026de966cf4STim Chen bool "CPU core priorities scheduler support" 10270a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10280a21fc12SIngo Molnar select X86_INTEL_PSTATE 10290a21fc12SIngo Molnar select CPU_FREQ 1030de966cf4STim Chen default y 1031a7f7f624SMasahiro Yamada help 1032de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1033de966cf4STim Chen core ordering determined at manufacturing time, which allows 1034de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1035de966cf4STim Chen single threaded workloads) than others. 1036de966cf4STim Chen 1037de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1038de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1039de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1040de966cf4STim Chen overall system performance can be achieved. 1041de966cf4STim Chen 1042de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1043de966cf4STim Chen 1044de966cf4STim Chen If unsure say Y here. 10455e76b2abSTim Chen 104630b8b006SThomas Gleixnerconfig UP_LATE_INIT 104730b8b006SThomas Gleixner def_bool y 1048ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 104930b8b006SThomas Gleixner 1050506f1d07SSam Ravnborgconfig X86_UP_APIC 105150849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 105250849eefSJan Beulich default PCI_MSI 105338a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1054a7f7f624SMasahiro Yamada help 1055506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1056506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1057506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1058506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1059506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1060506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1061506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1062506f1d07SSam Ravnborg lockups. 1063506f1d07SSam Ravnborg 1064506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1065506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1066506f1d07SSam Ravnborg depends on X86_UP_APIC 1067a7f7f624SMasahiro Yamada help 1068506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1069506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1070506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1071506f1d07SSam Ravnborg 1072506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1073506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1074506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1075506f1d07SSam Ravnborg 1076506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10773c2362e6SHarvey Harrison def_bool y 10780dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1079b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 108052f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1081506f1d07SSam Ravnborg 1082506f1d07SSam Ravnborgconfig X86_IO_APIC 1083b1da1e71SJan Beulich def_bool y 1084b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1085506f1d07SSam Ravnborg 108641b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 108741b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 108841b9eb26SStefan Assmann depends on X86_IO_APIC 1089a7f7f624SMasahiro Yamada help 109041b9eb26SStefan Assmann This option enables a workaround that fixes a source of 109141b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 109241b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 109341b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 109441b9eb26SStefan Assmann 109541b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 109641b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 109741b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 109841b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 109941b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 110041b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 110141b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 110241b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 110341b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 110441b9eb26SStefan Assmann down (vital) interrupt lines. 110541b9eb26SStefan Assmann 110641b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 110741b9eb26SStefan Assmann increased on these systems. 110841b9eb26SStefan Assmann 1109506f1d07SSam Ravnborgconfig X86_MCE 1110bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1111648ed940SChen, Gong select GENERIC_ALLOCATOR 1112e57dbaf7SBorislav Petkov default y 1113a7f7f624SMasahiro Yamada help 1114bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1115bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1116506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1117bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11184efc0670SAndi Kleen 11195de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11205de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11215de97c9fSTony Luck depends on X86_MCE 1122a7f7f624SMasahiro Yamada help 11235de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11245de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11255de97c9fSTony Luck rasdaemon solution. 11265de97c9fSTony Luck 1127506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11283c2362e6SHarvey Harrison def_bool y 11293c2362e6SHarvey Harrison prompt "Intel MCE features" 1130c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1131a7f7f624SMasahiro Yamada help 1132506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1133506f1d07SSam Ravnborg the thermal monitor. 1134506f1d07SSam Ravnborg 1135506f1d07SSam Ravnborgconfig X86_MCE_AMD 11363c2362e6SHarvey Harrison def_bool y 11373c2362e6SHarvey Harrison prompt "AMD MCE features" 1138f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1139a7f7f624SMasahiro Yamada help 1140506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1141506f1d07SSam Ravnborg the DRAM Error Threshold. 1142506f1d07SSam Ravnborg 11434efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11446fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1145c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1146a7f7f624SMasahiro Yamada help 11474efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11485065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11494efc0670SAndi Kleen line. 11504efc0670SAndi Kleen 1151b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1152b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11536fc108a0SJan Beulich def_bool y 1154b2762686SAndi Kleen 1155ea149b36SAndi Kleenconfig X86_MCE_INJECT 1156bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1157ea149b36SAndi Kleen tristate "Machine check injector support" 1158a7f7f624SMasahiro Yamada help 1159ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1160ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1161ea149b36SAndi Kleen QA it is safe to say n. 1162ea149b36SAndi Kleen 11634efc0670SAndi Kleenconfig X86_THERMAL_VECTOR 11644efc0670SAndi Kleen def_bool y 11655bb38adcSAndi Kleen depends on X86_MCE_INTEL 11664efc0670SAndi Kleen 116707dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1168e633c65aSKan Liang 11695aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11701e642812SIngo Molnar bool "Legacy VM86 support" 1171506f1d07SSam Ravnborg depends on X86_32 1172a7f7f624SMasahiro Yamada help 11735aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11745aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11755aef51c3SAndy Lutomirski 11765aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11775aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11785aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11795aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11805aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 11811e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 11821e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 11831e642812SIngo Molnar mode might be faster than emulation and you might want to 11841e642812SIngo Molnar enable this option. 11855aef51c3SAndy Lutomirski 11861e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 11871e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 11881e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 11891e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 11905aef51c3SAndy Lutomirski 11911e642812SIngo Molnar Enabling this option increases the complexity of the kernel 11921e642812SIngo Molnar and slows down exception handling a tiny bit. 11935aef51c3SAndy Lutomirski 11941e642812SIngo Molnar If unsure, say N here. 11955aef51c3SAndy Lutomirski 11965aef51c3SAndy Lutomirskiconfig VM86 11975aef51c3SAndy Lutomirski bool 11985aef51c3SAndy Lutomirski default X86_LEGACY_VM86 119934273f41SH. Peter Anvin 120034273f41SH. Peter Anvinconfig X86_16BIT 120134273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 120234273f41SH. Peter Anvin default y 1203a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1204a7f7f624SMasahiro Yamada help 120534273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 120634273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 120734273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 120834273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 120934273f41SH. Peter Anvin 121034273f41SH. Peter Anvinconfig X86_ESPFIX32 121134273f41SH. Peter Anvin def_bool y 121234273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1213506f1d07SSam Ravnborg 1214197725deSH. Peter Anvinconfig X86_ESPFIX64 1215197725deSH. Peter Anvin def_bool y 121634273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1217506f1d07SSam Ravnborg 12181ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12191ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12201ad83c85SAndy Lutomirski default y 12211ad83c85SAndy Lutomirski depends on X86_64 1222a7f7f624SMasahiro Yamada help 12231ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12241ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12251ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12261ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12271ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12281ad83c85SAndy Lutomirski 0xffffffffff600?00. 12291ad83c85SAndy Lutomirski 12301ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12311ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12321ad83c85SAndy Lutomirski 12331ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12341ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12351ad83c85SAndy Lutomirski 1236111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1237111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1238a24ca997SThomas Gleixner default y 1239a7f7f624SMasahiro Yamada help 1240111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1241111e7b15SThomas Gleixner for legacy applications. 1242111e7b15SThomas Gleixner 1243c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1244c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1245c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1246c8137aceSThomas Gleixner capabilities and permission from potentially active security 1247c8137aceSThomas Gleixner modules. 1248c8137aceSThomas Gleixner 1249c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1250c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1251a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1252a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1253c8137aceSThomas Gleixner 1254506f1d07SSam Ravnborgconfig TOSHIBA 1255506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1256506f1d07SSam Ravnborg depends on X86_32 1257a7f7f624SMasahiro Yamada help 1258506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1259506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1260506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1261506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1262506f1d07SSam Ravnborg 1263506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1264506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1265506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1266506f1d07SSam Ravnborg 1267506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1268506f1d07SSam Ravnborg Say N otherwise. 1269506f1d07SSam Ravnborg 1270506f1d07SSam Ravnborgconfig I8K 1271039ae585SPali Rohár tristate "Dell i8k legacy laptop support" 1272949a9d70SJean Delvare select HWMON 1273039ae585SPali Rohár select SENSORS_DELL_SMM 1274a7f7f624SMasahiro Yamada help 1275039ae585SPali Rohár This option enables legacy /proc/i8k userspace interface in hwmon 1276039ae585SPali Rohár dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1277039ae585SPali Rohár temperature and allows controlling fan speeds of Dell laptops via 1278039ae585SPali Rohár System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1279039ae585SPali Rohár it reports also power and hotkey status. For fan speed control is 1280039ae585SPali Rohár needed userspace package i8kutils. 1281506f1d07SSam Ravnborg 1282039ae585SPali Rohár Say Y if you intend to run this kernel on old Dell laptops or want to 1283039ae585SPali Rohár use userspace package i8kutils. 1284506f1d07SSam Ravnborg Say N otherwise. 1285506f1d07SSam Ravnborg 1286506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12879ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12889ba16087SJan Beulich depends on X86_32 1289a7f7f624SMasahiro Yamada help 1290506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1291506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1292506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1293506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1294506f1d07SSam Ravnborg system. 1295506f1d07SSam Ravnborg 1296506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 12975e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1298506f1d07SSam Ravnborg 1299506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1300506f1d07SSam Ravnborg enable this option even if you don't need it. 1301506f1d07SSam Ravnborg Say N otherwise. 1302506f1d07SSam Ravnborg 1303506f1d07SSam Ravnborgconfig MICROCODE 13049a2bc335SBorislav Petkov bool "CPU microcode loading support" 13059a2bc335SBorislav Petkov default y 130680030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1307a7f7f624SMasahiro Yamada help 1308506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13095f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13105f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13115f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13125f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13135f9c01aaSBorislav Petkov the Linux kernel. 1314506f1d07SSam Ravnborg 13155f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1316cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13175f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13185f9c01aaSBorislav Petkov initrd for microcode blobs. 1319506f1d07SSam Ravnborg 1320c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1321c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1322c508c46eSBenjamin Gilbert config option. 1323506f1d07SSam Ravnborg 13248d86f390SPeter Orubaconfig MICROCODE_INTEL 1325e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13268d86f390SPeter Oruba depends on MICROCODE 13278d86f390SPeter Oruba default MICROCODE 1328a7f7f624SMasahiro Yamada help 13298d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13308d86f390SPeter Oruba processors. 13318d86f390SPeter Oruba 1332b8989db9SAlan For the current Intel microcode data package go to 1333b8989db9SAlan <https://downloadcenter.intel.com> and search for 1334b8989db9SAlan 'Linux Processor Microcode Data File'. 13358d86f390SPeter Oruba 133680cc9f10SPeter Orubaconfig MICROCODE_AMD 1337e43f6e67SBorislav Petkov bool "AMD microcode loading support" 133880cc9f10SPeter Oruba depends on MICROCODE 1339a7f7f624SMasahiro Yamada help 134080cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 134180cc9f10SPeter Oruba processors will be enabled. 134280cc9f10SPeter Oruba 1343506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1344c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1345c02f48e0SBorislav Petkov default n 1346506f1d07SSam Ravnborg depends on MICROCODE 1347a7f7f624SMasahiro Yamada help 1348c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1349c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1350c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1351c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1352c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1353cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1354506f1d07SSam Ravnborg 1355506f1d07SSam Ravnborgconfig X86_MSR 1356506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1357a7f7f624SMasahiro Yamada help 1358506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1359506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1360506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1361506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1362506f1d07SSam Ravnborg systems. 1363506f1d07SSam Ravnborg 1364506f1d07SSam Ravnborgconfig X86_CPUID 1365506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1366a7f7f624SMasahiro Yamada help 1367506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1368506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1369506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1370506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1371506f1d07SSam Ravnborg 1372506f1d07SSam Ravnborgchoice 1373506f1d07SSam Ravnborg prompt "High Memory Support" 13746fc108a0SJan Beulich default HIGHMEM4G 1375506f1d07SSam Ravnborg depends on X86_32 1376506f1d07SSam Ravnborg 1377506f1d07SSam Ravnborgconfig NOHIGHMEM 1378506f1d07SSam Ravnborg bool "off" 1379a7f7f624SMasahiro Yamada help 1380506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1381506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1382506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1383506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1384506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1385506f1d07SSam Ravnborg "high memory". 1386506f1d07SSam Ravnborg 1387506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1388506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1389506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1390506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1391506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1392506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1393506f1d07SSam Ravnborg possible. 1394506f1d07SSam Ravnborg 1395506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1396506f1d07SSam Ravnborg answer "4GB" here. 1397506f1d07SSam Ravnborg 1398506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1399506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1400506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1401506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1402506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1403506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1404506f1d07SSam Ravnborg 1405506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1406506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1407506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1408506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1409506f1d07SSam Ravnborg kernel at boot time.) 1410506f1d07SSam Ravnborg 1411506f1d07SSam Ravnborg If unsure, say "off". 1412506f1d07SSam Ravnborg 1413506f1d07SSam Ravnborgconfig HIGHMEM4G 1414506f1d07SSam Ravnborg bool "4GB" 1415a7f7f624SMasahiro Yamada help 1416506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1417506f1d07SSam Ravnborg gigabytes of physical RAM. 1418506f1d07SSam Ravnborg 1419506f1d07SSam Ravnborgconfig HIGHMEM64G 1420506f1d07SSam Ravnborg bool "64GB" 142169b8d3fcSMatthew Whitehead depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1422506f1d07SSam Ravnborg select X86_PAE 1423a7f7f624SMasahiro Yamada help 1424506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1425506f1d07SSam Ravnborg gigabytes of physical RAM. 1426506f1d07SSam Ravnborg 1427506f1d07SSam Ravnborgendchoice 1428506f1d07SSam Ravnborg 1429506f1d07SSam Ravnborgchoice 14306a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1431506f1d07SSam Ravnborg default VMSPLIT_3G 1432506f1d07SSam Ravnborg depends on X86_32 1433a7f7f624SMasahiro Yamada help 1434506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1435506f1d07SSam Ravnborg 1436506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1437506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1438506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1439506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1440506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1441506f1d07SSam Ravnborg available to user programs, making the address space there 1442506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1443506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1444506f1d07SSam Ravnborg kernel modules. 1445506f1d07SSam Ravnborg 1446506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1447506f1d07SSam Ravnborg option alone! 1448506f1d07SSam Ravnborg 1449506f1d07SSam Ravnborg config VMSPLIT_3G 1450506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1451506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1452506f1d07SSam Ravnborg depends on !X86_PAE 1453506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1454506f1d07SSam Ravnborg config VMSPLIT_2G 1455506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1456506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1457506f1d07SSam Ravnborg depends on !X86_PAE 1458506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1459506f1d07SSam Ravnborg config VMSPLIT_1G 1460506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1461506f1d07SSam Ravnborgendchoice 1462506f1d07SSam Ravnborg 1463506f1d07SSam Ravnborgconfig PAGE_OFFSET 1464506f1d07SSam Ravnborg hex 1465506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1466506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1467506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1468506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1469506f1d07SSam Ravnborg default 0xC0000000 1470506f1d07SSam Ravnborg depends on X86_32 1471506f1d07SSam Ravnborg 1472506f1d07SSam Ravnborgconfig HIGHMEM 14733c2362e6SHarvey Harrison def_bool y 1474506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1475506f1d07SSam Ravnborg 1476506f1d07SSam Ravnborgconfig X86_PAE 14779ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1478506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1479d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14809d99c712SChristian Melki select SWIOTLB 1481a7f7f624SMasahiro Yamada help 1482506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1483506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1484506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1485506f1d07SSam Ravnborg consumes more pagetable space per process. 1486506f1d07SSam Ravnborg 148777ef56e4SKirill A. Shutemovconfig X86_5LEVEL 148877ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 148918ec1eafSKirill A. Shutemov default y 1490eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1491162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 149277ef56e4SKirill A. Shutemov depends on X86_64 1493a7f7f624SMasahiro Yamada help 149477ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 149577ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 149677ef56e4SKirill A. Shutemov physical address space. 149777ef56e4SKirill A. Shutemov 149877ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 149977ef56e4SKirill A. Shutemov 15006657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15016657fca0SKirill A. Shutemov support 4- or 5-level paging. 150277ef56e4SKirill A. Shutemov 1503cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 150477ef56e4SKirill A. Shutemov information. 150577ef56e4SKirill A. Shutemov 150677ef56e4SKirill A. Shutemov Say N if unsure. 150777ef56e4SKirill A. Shutemov 150810971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1509e5008abeSLuis R. Rodriguez def_bool y 15102e1da13fSVlastimil Babka depends on X86_64 1511a7f7f624SMasahiro Yamada help 151210971ab2SIngo Molnar Certain kernel features effectively disable kernel 151310971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 151410971ab2SIngo Molnar supports them), so don't confuse the user by printing 151510971ab2SIngo Molnar that we have them enabled. 15169e899816SNick Piggin 15175c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15185c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15195c280cf6SThomas Gleixner depends on DEBUG_FS 1520a7f7f624SMasahiro Yamada help 1521b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1522a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15235c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15245c280cf6SThomas Gleixner 15257744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15267744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15277744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 152882fef0adSDavid Rientjes select DMA_COHERENT_POOL 152994d49eb3SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 1530ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 15319087c375STom Lendacky select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1532597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1533a7f7f624SMasahiro Yamada help 15347744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15357744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15367744ccdbSTom Lendacky Encryption (SME). 15377744ccdbSTom Lendacky 15387744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15397744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15407744ccdbSTom Lendacky default y 15417744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1542a7f7f624SMasahiro Yamada help 15437744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15447744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15457744ccdbSTom Lendacky 15467744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15477744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15487744ccdbSTom Lendacky 15497744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15507744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15517744ccdbSTom Lendacky 1552506f1d07SSam Ravnborg# Common NUMA Features 1553506f1d07SSam Ravnborgconfig NUMA 1554e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1555506f1d07SSam Ravnborg depends on SMP 1556b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1557b5660ba7SH. Peter Anvin default y if X86_BIGSMP 1558a7f7f624SMasahiro Yamada help 1559e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1560fd51b2d7SKOSAKI Motohiro 1561506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1562506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1563506f1d07SSam Ravnborg NUMA awareness to the kernel. 1564506f1d07SSam Ravnborg 1565c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1566fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1567fd51b2d7SKOSAKI Motohiro 1568b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15697cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1570fd51b2d7SKOSAKI Motohiro 1571fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1572506f1d07SSam Ravnborg 1573eec1d4faSHans Rosenfeldconfig AMD_NUMA 15743c2362e6SHarvey Harrison def_bool y 15753c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15765da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1577a7f7f624SMasahiro Yamada help 1578eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1579eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1580eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1581eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1582eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1583506f1d07SSam Ravnborg 1584506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15853c2362e6SHarvey Harrison def_bool y 15863c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1587506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1588506f1d07SSam Ravnborg select ACPI_NUMA 1589a7f7f624SMasahiro Yamada help 1590506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1591506f1d07SSam Ravnborg 1592506f1d07SSam Ravnborgconfig NUMA_EMU 1593506f1d07SSam Ravnborg bool "NUMA emulation" 15941b7e03efSTejun Heo depends on NUMA 1595a7f7f624SMasahiro Yamada help 1596506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1597506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1598506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1599506f1d07SSam Ravnborg 1600506f1d07SSam Ravnborgconfig NODES_SHIFT 1601d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 160251591e31SDavid Rientjes range 1 10 160351591e31SDavid Rientjes default "10" if MAXSMP 1604506f1d07SSam Ravnborg default "6" if X86_64 1605506f1d07SSam Ravnborg default "3" 1606506f1d07SSam Ravnborg depends on NEED_MULTIPLE_NODES 1607a7f7f624SMasahiro Yamada help 16081184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1609692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1610506f1d07SSam Ravnborg 1611506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1612506f1d07SSam Ravnborg def_bool y 16133b16651fSTejun Heo depends on X86_32 && !NUMA 1614506f1d07SSam Ravnborg 1615506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1616506f1d07SSam Ravnborg def_bool y 16176ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1618506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1619506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1620506f1d07SSam Ravnborg 16213b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16226ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16233b16651fSTejun Heo 1624506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1625506f1d07SSam Ravnborg def_bool y 1626b263295dSChristoph Lameter depends on ARCH_SPARSEMEM_ENABLE 1627506f1d07SSam Ravnborg 1628506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1629a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16303120e25eSJan Beulich depends on X86_64 && MEMORY_HOTPLUG 1631a0842b70SToshi Kani help 1632a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1633cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1634a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1635506f1d07SSam Ravnborg 16363b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16373b16651fSTejun Heo def_bool y 16383b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16393b16651fSTejun Heo 1640a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1641a29815a3SAvi Kivity hex 1642a29815a3SAvi Kivity default 0 if X86_32 1643a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1644a29815a3SAvi Kivity 16457a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16467a67832cSDan Williams bool 16477a67832cSDan Williams 1648ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16497a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16509f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16519f53f9faSDan Williams depends on BLK_DEV 16527a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16537b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16549f53f9faSDan Williams select LIBNVDIMM 1655ec776ef6SChristoph Hellwig help 1656ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1657ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1658ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1659ec776ef6SChristoph Hellwig they can be used for persistent storage. 1660ec776ef6SChristoph Hellwig 1661ec776ef6SChristoph Hellwig Say Y if unsure. 1662ec776ef6SChristoph Hellwig 1663506f1d07SSam Ravnborgconfig HIGHPTE 1664506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16656fc108a0SJan Beulich depends on HIGHMEM 1666a7f7f624SMasahiro Yamada help 1667506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1668506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1669506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1670506f1d07SSam Ravnborg entries in high memory. 1671506f1d07SSam Ravnborg 16729f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16739f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1674a7f7f624SMasahiro Yamada help 16759f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16769f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16779f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16789f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16799f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16809f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16819f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16828c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16839f077871SJeremy Fitzhardinge 16849f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16859f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16869f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16879f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16889f077871SJeremy Fitzhardinge 16899f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16909f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16919f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16929f077871SJeremy Fitzhardinge memory. 16939f077871SJeremy Fitzhardinge 1694c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1695c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1696c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1697c885df50SJeremy Fitzhardinge default y 1698a7f7f624SMasahiro Yamada help 1699c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1700c885df50SJeremy Fitzhardinge on or off. 1701c885df50SJeremy Fitzhardinge 17029ea77bdbSH. Peter Anvinconfig X86_RESERVE_LOW 1703d0cd7425SH. Peter Anvin int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1704d0cd7425SH. Peter Anvin default 64 1705d0cd7425SH. Peter Anvin range 4 640 1706a7f7f624SMasahiro Yamada help 1707d0cd7425SH. Peter Anvin Specify the amount of low memory to reserve for the BIOS. 1708fc381519SIngo Molnar 1709d0cd7425SH. Peter Anvin The first page contains BIOS data structures that the kernel 1710d0cd7425SH. Peter Anvin must not use, so that page must always be reserved. 1711fc381519SIngo Molnar 1712d0cd7425SH. Peter Anvin By default we reserve the first 64K of physical RAM, as a 1713d0cd7425SH. Peter Anvin number of BIOSes are known to corrupt that memory range 1714d0cd7425SH. Peter Anvin during events such as suspend/resume or monitor cable 1715d0cd7425SH. Peter Anvin insertion, so it must not be used by the kernel. 1716fc381519SIngo Molnar 1717d0cd7425SH. Peter Anvin You can set this to 4 if you are absolutely sure that you 1718d0cd7425SH. Peter Anvin trust the BIOS to get all its memory reservations and usages 1719d0cd7425SH. Peter Anvin right. If you know your BIOS have problems beyond the 1720d0cd7425SH. Peter Anvin default 64K area, you can set this to 640 to avoid using the 1721d0cd7425SH. Peter Anvin entire low memory range. 1722d0cd7425SH. Peter Anvin 1723d0cd7425SH. Peter Anvin If you have doubts about the BIOS (e.g. suspend/resume does 1724d0cd7425SH. Peter Anvin not work or there's kernel crashes after certain hardware 1725d0cd7425SH. Peter Anvin hotplug events) then you might want to enable 1726d0cd7425SH. Peter Anvin X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1727d0cd7425SH. Peter Anvin typical corruption patterns. 1728d0cd7425SH. Peter Anvin 1729d0cd7425SH. Peter Anvin Leave this to the default value of 64 if you are unsure. 1730fc381519SIngo Molnar 1731506f1d07SSam Ravnborgconfig MATH_EMULATION 1732506f1d07SSam Ravnborg bool 1733a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 173487d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1735a7f7f624SMasahiro Yamada help 1736506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1737506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1738506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1739506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1740506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1741506f1d07SSam Ravnborg coprocessor or this emulation. 1742506f1d07SSam Ravnborg 1743506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1744506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1745506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1746506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1747506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1748506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1749506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1750506f1d07SSam Ravnborg intend to use this kernel on different machines. 1751506f1d07SSam Ravnborg 1752506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1753506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1754506f1d07SSam Ravnborg 1755506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1756506f1d07SSam Ravnborg kernel, it won't hurt. 1757506f1d07SSam Ravnborg 1758506f1d07SSam Ravnborgconfig MTRR 17596fc108a0SJan Beulich def_bool y 17606a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1761a7f7f624SMasahiro Yamada help 1762506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1763506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1764506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1765506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1766506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1767506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1768506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1769506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1770506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1771506f1d07SSam Ravnborg 1772506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1773506f1d07SSam Ravnborg control registers on other processors can be easily supported 1774506f1d07SSam Ravnborg as well: 1775506f1d07SSam Ravnborg 1776506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1777506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1778506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1779506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1780506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1781506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1782506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1783506f1d07SSam Ravnborg 1784506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1785506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1786506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1787506f1d07SSam Ravnborg 1788506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1789506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1790506f1d07SSam Ravnborg 1791cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1792506f1d07SSam Ravnborg 179395ffa243SYinghai Luconfig MTRR_SANITIZER 17942ffb3501SYinghai Lu def_bool y 179595ffa243SYinghai Lu prompt "MTRR cleanup support" 179695ffa243SYinghai Lu depends on MTRR 1797a7f7f624SMasahiro Yamada help 1798aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1799aba3728cSThomas Gleixner add writeback entries. 180095ffa243SYinghai Lu 1801aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1802692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1803aba3728cSThomas Gleixner mtrr_chunk_size. 180495ffa243SYinghai Lu 18052ffb3501SYinghai Lu If unsure, say Y. 180695ffa243SYinghai Lu 180795ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1808f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1809f5098d62SYinghai Lu range 0 1 1810f5098d62SYinghai Lu default "0" 181195ffa243SYinghai Lu depends on MTRR_SANITIZER 1812a7f7f624SMasahiro Yamada help 1813f5098d62SYinghai Lu Enable mtrr cleanup default value 181495ffa243SYinghai Lu 181512031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 181612031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 181712031a62SYinghai Lu range 0 7 181812031a62SYinghai Lu default "1" 181912031a62SYinghai Lu depends on MTRR_SANITIZER 1820a7f7f624SMasahiro Yamada help 182112031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1822aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 182312031a62SYinghai Lu 18242e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18256fc108a0SJan Beulich def_bool y 18266a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18272a8a2719SIngo Molnar depends on MTRR 1828a7f7f624SMasahiro Yamada help 18292e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1830042b78e4SVenki Pallipadi 18312e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18322e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18332e5d9c85Svenkatesh.pallipadi@intel.com 18342e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1835042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18362e5d9c85Svenkatesh.pallipadi@intel.com 18372e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18382e5d9c85Svenkatesh.pallipadi@intel.com 183946cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 184046cf98cdSVenkatesh Pallipadi def_bool y 184146cf98cdSVenkatesh Pallipadi depends on X86_PAT 184246cf98cdSVenkatesh Pallipadi 1843628c6246SH. Peter Anvinconfig ARCH_RANDOM 1844628c6246SH. Peter Anvin def_bool y 1845628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1846a7f7f624SMasahiro Yamada help 1847628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1848628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1849628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1850628c6246SH. Peter Anvin secure hardware random number generator. 1851628c6246SH. Peter Anvin 185251ae4a2dSH. Peter Anvinconfig X86_SMAP 185351ae4a2dSH. Peter Anvin def_bool y 185451ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 1855a7f7f624SMasahiro Yamada help 185651ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 185751ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 185851ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 185951ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 186051ae4a2dSH. Peter Anvin 186151ae4a2dSH. Peter Anvin If unsure, say Y. 186251ae4a2dSH. Peter Anvin 1863b971880fSBabu Mogerconfig X86_UMIP 1864796ebc81SRicardo Neri def_bool y 1865b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1866a7f7f624SMasahiro Yamada help 1867b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1868b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1869b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1870b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1871b971880fSBabu Moger information about the hardware state. 1872796ebc81SRicardo Neri 1873796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1874796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1875796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1876796ebc81SRicardo Neri results are dummy. 1877aa35f896SRicardo Neri 187835e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 187938f3e775SBabu Moger prompt "Memory Protection Keys" 188035e97790SDave Hansen def_bool y 1881284244a9SDave Hansen # Note: only available in 64-bit mode 188238f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 188352c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 188452c8e601SIngo Molnar select ARCH_HAS_PKEYS 1885a7f7f624SMasahiro Yamada help 1886284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1887284244a9SDave Hansen page-based protections, but without requiring modification of the 1888284244a9SDave Hansen page tables when an application changes protection domains. 1889284244a9SDave Hansen 18901eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1891284244a9SDave Hansen 1892284244a9SDave Hansen If unsure, say y. 189335e97790SDave Hansen 1894db616173SMichal Hockochoice 1895db616173SMichal Hocko prompt "TSX enable mode" 1896db616173SMichal Hocko depends on CPU_SUP_INTEL 1897db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1898db616173SMichal Hocko help 1899db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1900db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1901db616173SMichal Hocko can lead to a noticeable performance boost. 1902db616173SMichal Hocko 1903db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1904db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1905db616173SMichal Hocko will be more of those attacks discovered in the future. 1906db616173SMichal Hocko 1907db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1908db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1909db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1910db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1911db616173SMichal Hocko for the particular machine. 1912db616173SMichal Hocko 1913db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1914db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1915db616173SMichal Hocko details. 1916db616173SMichal Hocko 1917db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1918db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1919db616173SMichal Hocko relevant. 1920db616173SMichal Hocko 1921db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1922db616173SMichal Hocko bool "off" 1923db616173SMichal Hocko help 1924db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1925db616173SMichal Hocko 1926db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1927db616173SMichal Hocko bool "on" 1928db616173SMichal Hocko help 1929db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1930db616173SMichal Hocko line parameter. 1931db616173SMichal Hocko 1932db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1933db616173SMichal Hocko bool "auto" 1934db616173SMichal Hocko help 1935db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1936db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1937db616173SMichal Hockoendchoice 1938db616173SMichal Hocko 1939e7e05452SSean Christophersonconfig X86_SGX 1940e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1941e7e05452SSean Christopherson depends on X86_64 && CPU_SUP_INTEL 1942e7e05452SSean Christopherson depends on CRYPTO=y 1943e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1944e7e05452SSean Christopherson select SRCU 1945e7e05452SSean Christopherson select MMU_NOTIFIER 1946e7e05452SSean Christopherson help 1947e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1948e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1949e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1950e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1951e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1952e7e05452SSean Christopherson hardware. 1953e7e05452SSean Christopherson 1954e7e05452SSean Christopherson If unsure, say N. 1955e7e05452SSean Christopherson 1956506f1d07SSam Ravnborgconfig EFI 19579ba16087SJan Beulich bool "EFI runtime service support" 19585b83683fSHuang, Ying depends on ACPI 1959f6ce5002SSergey Vlasov select UCS2_STRING 1960022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 1961a7f7f624SMasahiro Yamada help 19628b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1963506f1d07SSam Ravnborg available (such as the EFI variable services). 1964506f1d07SSam Ravnborg 19658b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19668b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19678b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19688b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19698b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19708b2cb7a8SHuang, Ying platforms. 1971506f1d07SSam Ravnborg 1972291f3632SMatt Flemingconfig EFI_STUB 1973291f3632SMatt Fleming bool "EFI stub support" 1974b16d8c23SMatt Fleming depends on EFI && !X86_USE_3DNOW 19758f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19767b2a583aSMatt Fleming select RELOCATABLE 1977a7f7f624SMasahiro Yamada help 1978291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1979291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1980291f3632SMatt Fleming 19814f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19820c759662SMatt Fleming 19837d453eeeSMatt Flemingconfig EFI_MIXED 19847d453eeeSMatt Fleming bool "EFI mixed-mode support" 19857d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1986a7f7f624SMasahiro Yamada help 19877d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19887d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19897d453eeeSMatt Fleming mode. 19907d453eeeSMatt Fleming 19917d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19927d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19937d453eeeSMatt Fleming the EFI handover protocol must be used. 19947d453eeeSMatt Fleming 19957d453eeeSMatt Fleming If unsure, say N. 19967d453eeeSMatt Fleming 19978636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 1998506f1d07SSam Ravnborg 1999506f1d07SSam Ravnborgconfig KEXEC 2000506f1d07SSam Ravnborg bool "kexec system call" 20012965faa5SDave Young select KEXEC_CORE 2002a7f7f624SMasahiro Yamada help 2003506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2004506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2005506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2006506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2007506f1d07SSam Ravnborg 2008506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2009506f1d07SSam Ravnborg 2010506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2011506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2012bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2013bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2014bf220695SGeert Uytterhoeven made. 2015506f1d07SSam Ravnborg 201674ca317cSVivek Goyalconfig KEXEC_FILE 201774ca317cSVivek Goyal bool "kexec file based system call" 20182965faa5SDave Young select KEXEC_CORE 201974ca317cSVivek Goyal select BUILD_BIN2C 202074ca317cSVivek Goyal depends on X86_64 202174ca317cSVivek Goyal depends on CRYPTO=y 202274ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2023a7f7f624SMasahiro Yamada help 202474ca317cSVivek Goyal This is new version of kexec system call. This system call is 202574ca317cSVivek Goyal file based and takes file descriptors as system call argument 202674ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 202774ca317cSVivek Goyal accepted by previous system call. 202874ca317cSVivek Goyal 2029b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2030b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2031b799a09fSAKASHI Takahiro 203299d5cadfSJiri Bohacconfig KEXEC_SIG 20338e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 203474ca317cSVivek Goyal depends on KEXEC_FILE 2035a7f7f624SMasahiro Yamada help 203699d5cadfSJiri Bohac 203799d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 203899d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 203999d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 204099d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 204199d5cadfSJiri Bohac 204299d5cadfSJiri Bohac In addition to this option, you need to enable signature 204399d5cadfSJiri Bohac verification for the corresponding kernel image type being 204499d5cadfSJiri Bohac loaded in order for this to work. 204599d5cadfSJiri Bohac 204699d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 204799d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 204899d5cadfSJiri Bohac depends on KEXEC_SIG 2049a7f7f624SMasahiro Yamada help 20508e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2051d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20528e7d8381SVivek Goyal 20538e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20548e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 205599d5cadfSJiri Bohac depends on KEXEC_SIG 20568e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20578e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2058a7f7f624SMasahiro Yamada help 20598e7d8381SVivek Goyal Enable bzImage signature verification support. 20608e7d8381SVivek Goyal 2061506f1d07SSam Ravnborgconfig CRASH_DUMP 206204b69447SPavel Machek bool "kernel crash dumps" 2063506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2064a7f7f624SMasahiro Yamada help 2065506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2066506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2067506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2068506f1d07SSam Ravnborg a specially reserved region and then later executed after 2069506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2070506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2071506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2072506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2073330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2074506f1d07SSam Ravnborg 20753ab83521SHuang Yingconfig KEXEC_JUMP 20766ea30386SKees Cook bool "kexec jump" 2077fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2078a7f7f624SMasahiro Yamada help 207989081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 208089081d17SHuang Ying code in physical address mode via KEXEC 20813ab83521SHuang Ying 2082506f1d07SSam Ravnborgconfig PHYSICAL_START 20836a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2084ceefccc9SH. Peter Anvin default "0x1000000" 2085a7f7f624SMasahiro Yamada help 2086506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2087506f1d07SSam Ravnborg 2088506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2089506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2090506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2091506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2092506f1d07SSam Ravnborg address. 2093506f1d07SSam Ravnborg 2094506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2095506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2096506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2097506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2098506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2099506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2100506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2101506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2102506f1d07SSam Ravnborg 2103ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2104ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2105ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2106ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2107ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2108ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2109ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2110330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2111ceefccc9SH. Peter Anvin for more details about crash dumps. 2112506f1d07SSam Ravnborg 2113506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2114506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2115506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2116506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2117506f1d07SSam Ravnborg is present because there are users out there who continue to use 2118506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2119506f1d07SSam Ravnborg line. 2120506f1d07SSam Ravnborg 2121506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2122506f1d07SSam Ravnborg 2123506f1d07SSam Ravnborgconfig RELOCATABLE 212426717808SH. Peter Anvin bool "Build a relocatable kernel" 212526717808SH. Peter Anvin default y 2126a7f7f624SMasahiro Yamada help 2127506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2128506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2129506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2130506f1d07SSam Ravnborg but are discarded at runtime. 2131506f1d07SSam Ravnborg 2132506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2133506f1d07SSam Ravnborg must live at a different physical address than the primary 2134506f1d07SSam Ravnborg kernel. 2135506f1d07SSam Ravnborg 2136506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2137506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21388ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2139506f1d07SSam Ravnborg 21408ab3820fSKees Cookconfig RANDOMIZE_BASE 2141e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21428ab3820fSKees Cook depends on RELOCATABLE 21436807c846SIngo Molnar default y 2144a7f7f624SMasahiro Yamada help 2145e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2146e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2147e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2148e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2149e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2150e8581e3dSBaoquan He code internals. 2151e8581e3dSBaoquan He 2152ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2153ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2154ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2155ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2156ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2157ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2158ed9f007eSKees Cook 2159ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2160ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2161ed9f007eSKees Cook 512MB (8 bits of entropy). 21628ab3820fSKees Cook 2163a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2164e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2165e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2166ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2167ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2168ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2169ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2170ed9f007eSKees Cook theoretically possible, but the implementations are further 2171ed9f007eSKees Cook limited due to memory layouts. 2172e8581e3dSBaoquan He 21736807c846SIngo Molnar If unsure, say Y. 2174da2b6fb9SKees Cook 21758ab3820fSKees Cook# Relocation on x86 needs some additional build support 2176845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2177845adf72SH. Peter Anvin def_bool y 21788ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2179845adf72SH. Peter Anvin 2180506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2181a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21828ab3820fSKees Cook default "0x200000" 2183a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2184a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2185a7f7f624SMasahiro Yamada help 2186506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2187506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2188506f1d07SSam Ravnborg address which meets above alignment restriction. 2189506f1d07SSam Ravnborg 2190506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2191506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2192506f1d07SSam Ravnborg address aligned to above value and run from there. 2193506f1d07SSam Ravnborg 2194506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2195506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2196506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2197506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2198506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2199506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2200506f1d07SSam Ravnborg above alignment restrictions. 2201506f1d07SSam Ravnborg 2202a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2203a0215061SKees Cook this value must be a multiple of 0x200000. 2204a0215061SKees Cook 2205506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2206506f1d07SSam Ravnborg 2207eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2208eedb92abSKirill A. Shutemov bool 2209a7f7f624SMasahiro Yamada help 2210eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2211eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2212eedb92abSKirill A. Shutemov 22130483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22140483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22150483e1faSThomas Garnier depends on X86_64 22160483e1faSThomas Garnier depends on RANDOMIZE_BASE 2217eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22180483e1faSThomas Garnier default RANDOMIZE_BASE 2219a7f7f624SMasahiro Yamada help 22200483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22210483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22220483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22230483e1faSThomas Garnier 22240483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22250483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22260483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22270483e1faSThomas Garnier addresses for each memory section. 22280483e1faSThomas Garnier 22296807c846SIngo Molnar If unsure, say Y. 22300483e1faSThomas Garnier 223190397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 223290397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 223390397a41SThomas Garnier depends on RANDOMIZE_MEMORY 223490397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 223590397a41SThomas Garnier default "0x0" 223690397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 223790397a41SThomas Garnier range 0x0 0x40 2238a7f7f624SMasahiro Yamada help 223990397a41SThomas Garnier Define the padding in terabytes added to the existing physical 224090397a41SThomas Garnier memory size during kernel memory randomization. It is useful 224190397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 224290397a41SThomas Garnier address randomization. 224390397a41SThomas Garnier 224490397a41SThomas Garnier If unsure, leave at the default value. 224590397a41SThomas Garnier 2246506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2247bebd024eSThomas Gleixner def_bool y 224840b31360SStephen Rothwell depends on SMP 2249506f1d07SSam Ravnborg 225080aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 225180aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22522c922cd0SKees Cook depends on HOTPLUG_CPU 2253a7f7f624SMasahiro Yamada help 225480aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 225580aa1dffSFenghua Yu 225680aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 225780aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 225880aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 225980aa1dffSFenghua Yu 226080aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 226180aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 226280aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 226380aa1dffSFenghua Yu 226480aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 226580aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 226680aa1dffSFenghua Yu 226780aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 226880aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 226980aa1dffSFenghua Yu be other CPU0 dependencies. 227080aa1dffSFenghua Yu 227180aa1dffSFenghua Yu Please make sure the dependencies are under your control before 227280aa1dffSFenghua Yu you enable this feature. 227380aa1dffSFenghua Yu 227480aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 227580aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 227680aa1dffSFenghua Yu parameter cpu0_hotplug. 227780aa1dffSFenghua Yu 2278a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2279a71c8bc5SFenghua Yu def_bool n 2280a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22812c922cd0SKees Cook depends on HOTPLUG_CPU 2282a7f7f624SMasahiro Yamada help 2283a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2284a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2285a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2286a71c8bc5SFenghua Yu 2287a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2288a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2289a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2290a71c8bc5SFenghua Yu 2291a71c8bc5SFenghua Yu If unsure, say N. 2292a71c8bc5SFenghua Yu 2293506f1d07SSam Ravnborgconfig COMPAT_VDSO 2294b0b49f26SAndy Lutomirski def_bool n 2295b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2296953fee1dSIngo Molnar depends on COMPAT_32 2297a7f7f624SMasahiro Yamada help 2298b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2299b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2300b0b49f26SAndy Lutomirski indicated in its segment table. 2301e84446deSRandy Dunlap 2302b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2303b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2304b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2305b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2306b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2307506f1d07SSam Ravnborg 2308b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2309b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2310b0b49f26SAndy Lutomirski 2311b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2312b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2313b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2314b0b49f26SAndy Lutomirski 2315b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2316b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2317506f1d07SSam Ravnborg 23183dc33bd3SKees Cookchoice 23193dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23203dc33bd3SKees Cook depends on X86_64 2321625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23223dc33bd3SKees Cook help 23233dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23243dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23253dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23263dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23273dc33bd3SKees Cook 23283dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2329bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23303dc33bd3SKees Cook 23313dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23323dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23333dc33bd3SKees Cook to improve security. 23343dc33bd3SKees Cook 2335bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23363dc33bd3SKees Cook 23373dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2338bd49e16eSAndy Lutomirski bool "Full emulation" 23393dc33bd3SKees Cook help 2340bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2341bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2342bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2343bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2344bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2345bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2346bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2347bd49e16eSAndy Lutomirski 2348bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2349bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2350bd49e16eSAndy Lutomirski 2351bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2352bd49e16eSAndy Lutomirski bool "Emulate execution only" 2353bd49e16eSAndy Lutomirski help 2354bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2355bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2356bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2357bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2358bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2359bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2360bd49e16eSAndy Lutomirski buffer. 23613dc33bd3SKees Cook 23623dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23633dc33bd3SKees Cook bool "None" 23643dc33bd3SKees Cook help 23653dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23663dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23673dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23683dc33bd3SKees Cook will be reported to dmesg, so that either old or 23693dc33bd3SKees Cook malicious userspace programs can be identified. 23703dc33bd3SKees Cook 23713dc33bd3SKees Cookendchoice 23723dc33bd3SKees Cook 2373516cbf37STim Birdconfig CMDLINE_BOOL 2374516cbf37STim Bird bool "Built-in kernel command line" 2375a7f7f624SMasahiro Yamada help 2376516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2377516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2378516cbf37STim Bird necessary or convenient to provide some or all of the 2379516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2380516cbf37STim Bird to not rely on the boot loader to provide them.) 2381516cbf37STim Bird 2382516cbf37STim Bird To compile command line arguments into the kernel, 2383516cbf37STim Bird set this option to 'Y', then fill in the 238469711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2385516cbf37STim Bird 2386516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2387516cbf37STim Bird should leave this option set to 'N'. 2388516cbf37STim Bird 2389516cbf37STim Birdconfig CMDLINE 2390516cbf37STim Bird string "Built-in kernel command string" 2391516cbf37STim Bird depends on CMDLINE_BOOL 2392516cbf37STim Bird default "" 2393a7f7f624SMasahiro Yamada help 2394516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2395516cbf37STim Bird image and used at boot time. If the boot loader provides a 2396516cbf37STim Bird command line at boot time, it is appended to this string to 2397516cbf37STim Bird form the full kernel command line, when the system boots. 2398516cbf37STim Bird 2399516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2400516cbf37STim Bird change this behavior. 2401516cbf37STim Bird 2402516cbf37STim Bird In most cases, the command line (whether built-in or provided 2403516cbf37STim Bird by the boot loader) should specify the device for the root 2404516cbf37STim Bird file system. 2405516cbf37STim Bird 2406516cbf37STim Birdconfig CMDLINE_OVERRIDE 2407516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2408645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2409a7f7f624SMasahiro Yamada help 2410516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2411516cbf37STim Bird command line, and use ONLY the built-in command line. 2412516cbf37STim Bird 2413516cbf37STim Bird This is used to work around broken boot loaders. This should 2414516cbf37STim Bird be set to 'N' under normal conditions. 2415516cbf37STim Bird 2416a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2417a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2418a5b9e5a2SAndy Lutomirski default y 2419a7f7f624SMasahiro Yamada help 2420a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2421a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2422a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2423a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2424a5b9e5a2SAndy Lutomirski threading libraries. 2425a5b9e5a2SAndy Lutomirski 2426a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2427a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2428a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2429a5b9e5a2SAndy Lutomirski 2430a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2431a5b9e5a2SAndy Lutomirski 2432b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2433b700e7f0SSeth Jennings 2434506f1d07SSam Ravnborgendmenu 2435506f1d07SSam Ravnborg 24363072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24373072e413SMichal Hocko def_bool y 24383072e413SMichal Hocko depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 24393072e413SMichal Hocko 2440506f1d07SSam Ravnborgconfig ARCH_ENABLE_MEMORY_HOTPLUG 2441506f1d07SSam Ravnborg def_bool y 2442506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2443506f1d07SSam Ravnborg 244435551053SGary Hadeconfig ARCH_ENABLE_MEMORY_HOTREMOVE 244535551053SGary Hade def_bool y 244635551053SGary Hade depends on MEMORY_HOTPLUG 244735551053SGary Hade 2448e534c7c5SLee Schermerhornconfig USE_PERCPU_NUMA_NODE_ID 2449645a7919STejun Heo def_bool y 2450e534c7c5SLee Schermerhorn depends on NUMA 2451e534c7c5SLee Schermerhorn 24529491846fSKirill A. Shutemovconfig ARCH_ENABLE_SPLIT_PMD_PTLOCK 24539491846fSKirill A. Shutemov def_bool y 24549491846fSKirill A. Shutemov depends on X86_64 || X86_PAE 24559491846fSKirill A. Shutemov 2456c177c81eSNaoya Horiguchiconfig ARCH_ENABLE_HUGEPAGE_MIGRATION 2457c177c81eSNaoya Horiguchi def_bool y 2458c177c81eSNaoya Horiguchi depends on X86_64 && HUGETLB_PAGE && MIGRATION 2459c177c81eSNaoya Horiguchi 24609c670ea3SNaoya Horiguchiconfig ARCH_ENABLE_THP_MIGRATION 24619c670ea3SNaoya Horiguchi def_bool y 24629c670ea3SNaoya Horiguchi depends on X86_64 && TRANSPARENT_HUGEPAGE 24639c670ea3SNaoya Horiguchi 2464da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2465e279b6c1SSam Ravnborg 2466e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 24673c2362e6SHarvey Harrison def_bool y 246844556530SZhimin Gu depends on HIBERNATION 2469e279b6c1SSam Ravnborg 2470e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2471e279b6c1SSam Ravnborg 2472e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2473e279b6c1SSam Ravnborg 2474efafc8b2SFeng Tangsource "drivers/sfi/Kconfig" 2475efafc8b2SFeng Tang 2476a6b68076SAndi Kleenconfig X86_APM_BOOT 24776fc108a0SJan Beulich def_bool y 2478282e5aabSPaul Bolle depends on APM 2479a6b68076SAndi Kleen 2480e279b6c1SSam Ravnborgmenuconfig APM 2481e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2482efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2483a7f7f624SMasahiro Yamada help 2484e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2485e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2486e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2487e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2488e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2489e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2490e279b6c1SSam Ravnborg 2491e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2492e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2493e279b6c1SSam Ravnborg 2494e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2495e279b6c1SSam Ravnborg machines with more than one CPU. 2496e279b6c1SSam Ravnborg 2497e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2498151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 24992dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2500e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2501e279b6c1SSam Ravnborg 2502e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2503e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2504e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2505e279b6c1SSam Ravnborg 2506e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2507e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2508e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2509e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2510e279b6c1SSam Ravnborg 2511e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2512e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2513e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2514e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2515e279b6c1SSam Ravnborg APM in your BIOS). 2516e279b6c1SSam Ravnborg 2517e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2518e279b6c1SSam Ravnborg "weird" problems: 2519e279b6c1SSam Ravnborg 2520e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2521e279b6c1SSam Ravnborg enabled. 2522e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2523e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2524e279b6c1SSam Ravnborg the "no387" option to the kernel 2525e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2526e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2527e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2528e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2529e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2530e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2531e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2532e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2533e279b6c1SSam Ravnborg 11) exchange RAM chips 2534e279b6c1SSam Ravnborg 12) exchange the motherboard. 2535e279b6c1SSam Ravnborg 2536e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2537e279b6c1SSam Ravnborg module will be called apm. 2538e279b6c1SSam Ravnborg 2539e279b6c1SSam Ravnborgif APM 2540e279b6c1SSam Ravnborg 2541e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2542e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2543a7f7f624SMasahiro Yamada help 2544e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2545e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2546e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2547e279b6c1SSam Ravnborg 2548e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2549e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2550a7f7f624SMasahiro Yamada help 2551e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2552e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2553e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2554e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2555e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2556e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2557e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2558e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2559e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2560e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2561e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2562e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2563e279b6c1SSam Ravnborg this feature. 2564e279b6c1SSam Ravnborg 2565e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2566dd8af076SLen Brown depends on CPU_IDLE 2567e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2568a7f7f624SMasahiro Yamada help 2569e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2570e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2571e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2572e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2573e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2574e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2575e279b6c1SSam Ravnborg this option does nothing.) 2576e279b6c1SSam Ravnborg 2577e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2578e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2579a7f7f624SMasahiro Yamada help 2580e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2581e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2582e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2583e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2584e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2585e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2586e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2587e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2588e279b6c1SSam Ravnborg especially if you are using gpm. 2589e279b6c1SSam Ravnborg 2590e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2591e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2592a7f7f624SMasahiro Yamada help 2593e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2594e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2595e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2596e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2597e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2598e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2599e279b6c1SSam Ravnborg 2600e279b6c1SSam Ravnborgendif # APM 2601e279b6c1SSam Ravnborg 2602bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2603e279b6c1SSam Ravnborg 2604e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2605e279b6c1SSam Ravnborg 260627471fdbSAndy Henroidsource "drivers/idle/Kconfig" 260727471fdbSAndy Henroid 2608e279b6c1SSam Ravnborgendmenu 2609e279b6c1SSam Ravnborg 2610e279b6c1SSam Ravnborg 2611e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2612e279b6c1SSam Ravnborg 2613e279b6c1SSam Ravnborgchoice 2614e279b6c1SSam Ravnborg prompt "PCI access mode" 2615efefa6f6SIngo Molnar depends on X86_32 && PCI 2616e279b6c1SSam Ravnborg default PCI_GOANY 2617a7f7f624SMasahiro Yamada help 2618e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2619e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2620e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2621e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2622e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2623e279b6c1SSam Ravnborg 2624e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2625e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2626e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2627e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2628e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2629e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2630e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2631e279b6c1SSam Ravnborg 2632e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2633e279b6c1SSam Ravnborg bool "BIOS" 2634e279b6c1SSam Ravnborg 2635e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2636e279b6c1SSam Ravnborg bool "MMConfig" 2637e279b6c1SSam Ravnborg 2638e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2639e279b6c1SSam Ravnborg bool "Direct" 2640e279b6c1SSam Ravnborg 26413ef0e1f8SAndres Salomonconfig PCI_GOOLPC 264276fb6570SDaniel Drake bool "OLPC XO-1" 26433ef0e1f8SAndres Salomon depends on OLPC 26443ef0e1f8SAndres Salomon 26452bdd1b03SAndres Salomonconfig PCI_GOANY 26462bdd1b03SAndres Salomon bool "Any" 26472bdd1b03SAndres Salomon 2648e279b6c1SSam Ravnborgendchoice 2649e279b6c1SSam Ravnborg 2650e279b6c1SSam Ravnborgconfig PCI_BIOS 26513c2362e6SHarvey Harrison def_bool y 2652efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2653e279b6c1SSam Ravnborg 2654e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2655e279b6c1SSam Ravnborgconfig PCI_DIRECT 26563c2362e6SHarvey Harrison def_bool y 26570aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2658e279b6c1SSam Ravnborg 2659e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2660b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2661b45c9f36SJan Kiszka default y 26628364e1f8SJan Kiszka depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2663b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2664e279b6c1SSam Ravnborg 26653ef0e1f8SAndres Salomonconfig PCI_OLPC 26662bdd1b03SAndres Salomon def_bool y 26672bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 26683ef0e1f8SAndres Salomon 2669b5401a96SAlex Nixonconfig PCI_XEN 2670b5401a96SAlex Nixon def_bool y 2671b5401a96SAlex Nixon depends on PCI && XEN 2672b5401a96SAlex Nixon select SWIOTLB_XEN 2673b5401a96SAlex Nixon 26748364e1f8SJan Kiszkaconfig MMCONF_FAM10H 26758364e1f8SJan Kiszka def_bool y 26768364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2677e279b6c1SSam Ravnborg 26783f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 26796a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 26806ea30386SKees Cook depends on PCI 26813f6ea84aSIra W. Snyder help 26823f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 26833f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 26843f6ea84aSIra W. Snyder not have ACPI. 26853f6ea84aSIra W. Snyder 268664a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 268764a5fed6SBjorn Helgaas is known to be incomplete. 268864a5fed6SBjorn Helgaas 268964a5fed6SBjorn Helgaas You should say N unless you know you need this. 269064a5fed6SBjorn Helgaas 26913a495511SWilliam Breathitt Grayconfig ISA_BUS 269217a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 26933a495511SWilliam Breathitt Gray help 269417a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 269517a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 269617a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 269717a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 269817a2a129SWilliam Breathitt Gray not have an ISA bus. 26993a495511SWilliam Breathitt Gray 27003a495511SWilliam Breathitt Gray If unsure, say N. 27013a495511SWilliam Breathitt Gray 27021c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2703e279b6c1SSam Ravnborgconfig ISA_DMA_API 27041c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 27051c00f016SDavid Rientjes default y 27061c00f016SDavid Rientjes help 27071c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 27081c00f016SDavid Rientjes If unsure, say Y. 2709e279b6c1SSam Ravnborg 271051e68d05SLinus Torvaldsif X86_32 271151e68d05SLinus Torvalds 2712e279b6c1SSam Ravnborgconfig ISA 2713e279b6c1SSam Ravnborg bool "ISA support" 2714a7f7f624SMasahiro Yamada help 2715e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2716e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2717e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2718e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2719e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2720e279b6c1SSam Ravnborg 2721e279b6c1SSam Ravnborgconfig SCx200 2722e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2723a7f7f624SMasahiro Yamada help 2724e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2725e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2726e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2727e279b6c1SSam Ravnborg for other scx200_* drivers. 2728e279b6c1SSam Ravnborg 2729e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2730e279b6c1SSam Ravnborg 2731e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2732e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2733592913ecSJohn Stultz depends on SCx200 2734e279b6c1SSam Ravnborg default y 2735a7f7f624SMasahiro Yamada help 2736e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2737e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2738e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2739e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2740e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2741e279b6c1SSam Ravnborg 27423ef0e1f8SAndres Salomonconfig OLPC 27433ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 274454008979SThomas Gleixner depends on !X86_PAE 27453c554946SAndres Salomon select GPIOLIB 2746dc3119e7SThomas Gleixner select OF 274745bb1674SDaniel Drake select OF_PROMTREE 2748b4e51854SGrant Likely select IRQ_DOMAIN 27490c3d931bSLubomir Rintel select OLPC_EC 2750a7f7f624SMasahiro Yamada help 27513ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27523ef0e1f8SAndres Salomon XO hardware. 27533ef0e1f8SAndres Salomon 2754a3128588SDaniel Drakeconfig OLPC_XO1_PM 2755a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2756fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2757a7f7f624SMasahiro Yamada help 275897c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2759bf1ebf00SDaniel Drake 2760cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2761cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2762cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2763a7f7f624SMasahiro Yamada help 2764cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2765cfee9597SDaniel Drake programmable wakeup source. 2766cfee9597SDaniel Drake 27677feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 27687feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 276992e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2770ed8e47feSRandy Dunlap depends on INPUT=y 2771d8d01a63SDaniel Drake select POWER_SUPPLY 2772a7f7f624SMasahiro Yamada help 27737feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 27747bc74b3dSDaniel Drake - EC-driven system wakeups 27757feda8e9SDaniel Drake - Power button 27767bc74b3dSDaniel Drake - Ebook switch 27772cf2baeaSDaniel Drake - Lid switch 2778e1040ac6SDaniel Drake - AC adapter status updates 2779e1040ac6SDaniel Drake - Battery status updates 27807feda8e9SDaniel Drake 2781a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2782a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2783d8d01a63SDaniel Drake depends on OLPC && ACPI 2784d8d01a63SDaniel Drake select POWER_SUPPLY 2785a7f7f624SMasahiro Yamada help 2786a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2787a0f30f59SDaniel Drake - EC-driven system wakeups 2788a0f30f59SDaniel Drake - AC adapter status updates 2789a0f30f59SDaniel Drake - Battery status updates 2790e279b6c1SSam Ravnborg 2791d4f3e350SEd Wildgooseconfig ALIX 2792d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2793d4f3e350SEd Wildgoose select GPIOLIB 2794a7f7f624SMasahiro Yamada help 2795d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2796d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2797d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2798d4f3e350SEd Wildgoose get added here. 2799d4f3e350SEd Wildgoose 2800d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2801d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2802d4f3e350SEd Wildgoose 2803d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2804d4f3e350SEd Wildgoose 2805da4e3302SPhilip Prindevilleconfig NET5501 2806da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2807da4e3302SPhilip Prindeville select GPIOLIB 2808a7f7f624SMasahiro Yamada help 2809da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2810da4e3302SPhilip Prindeville 28113197059aSPhilip A. Prindevilleconfig GEOS 28123197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28133197059aSPhilip A. Prindeville select GPIOLIB 28143197059aSPhilip A. Prindeville depends on DMI 2815a7f7f624SMasahiro Yamada help 28163197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28173197059aSPhilip A. Prindeville 28187d029125SVivien Didelotconfig TS5500 28197d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28207d029125SVivien Didelot depends on MELAN 28217d029125SVivien Didelot select CHECK_SIGNATURE 28227d029125SVivien Didelot select NEW_LEDS 28237d029125SVivien Didelot select LEDS_CLASS 2824a7f7f624SMasahiro Yamada help 28257d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28267d029125SVivien Didelot 2827e279b6c1SSam Ravnborgendif # X86_32 2828e279b6c1SSam Ravnborg 282923ac4ae8SAndreas Herrmannconfig AMD_NB 2830e279b6c1SSam Ravnborg def_bool y 28310e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2832e279b6c1SSam Ravnborg 2833e3263ab3SDavid Herrmannconfig X86_SYSFB 2834e3263ab3SDavid Herrmann bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2835e3263ab3SDavid Herrmann help 2836e3263ab3SDavid Herrmann Firmwares often provide initial graphics framebuffers so the BIOS, 2837e3263ab3SDavid Herrmann bootloader or kernel can show basic video-output during boot for 2838e3263ab3SDavid Herrmann user-guidance and debugging. Historically, x86 used the VESA BIOS 2839e3263ab3SDavid Herrmann Extensions and EFI-framebuffers for this, which are mostly limited 2840e3263ab3SDavid Herrmann to x86. 2841e3263ab3SDavid Herrmann This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2842e3263ab3SDavid Herrmann framebuffers so the new generic system-framebuffer drivers can be 2843e3263ab3SDavid Herrmann used on x86. If the framebuffer is not compatible with the generic 2844e3a5dc08SNikolas Nyby modes, it is advertised as fallback platform framebuffer so legacy 2845e3263ab3SDavid Herrmann drivers like efifb, vesafb and uvesafb can pick it up. 2846e3263ab3SDavid Herrmann If this option is not selected, all system framebuffers are always 2847e3263ab3SDavid Herrmann marked as fallback platform framebuffers as usual. 2848e3263ab3SDavid Herrmann 2849e3263ab3SDavid Herrmann Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2850e3263ab3SDavid Herrmann not be able to pick up generic system framebuffers if this option 2851e3263ab3SDavid Herrmann is selected. You are highly encouraged to enable simplefb as 2852e3263ab3SDavid Herrmann replacement if you select this option. simplefb can correctly deal 2853e3263ab3SDavid Herrmann with generic system framebuffers. But you should still keep vesafb 2854e3263ab3SDavid Herrmann and others enabled as fallback if a system framebuffer is 2855e3263ab3SDavid Herrmann incompatible with simplefb. 2856e3263ab3SDavid Herrmann 2857e3263ab3SDavid Herrmann If unsure, say Y. 2858e3263ab3SDavid Herrmann 2859e279b6c1SSam Ravnborgendmenu 2860e279b6c1SSam Ravnborg 2861e279b6c1SSam Ravnborg 28621572497cSChristoph Hellwigmenu "Binary Emulations" 2863e279b6c1SSam Ravnborg 2864e279b6c1SSam Ravnborgconfig IA32_EMULATION 2865e279b6c1SSam Ravnborg bool "IA32 Emulation" 2866e279b6c1SSam Ravnborg depends on X86_64 286739f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2868d1603990SRandy Dunlap select BINFMT_ELF 2869a97f52e6SRoland McGrath select COMPAT_BINFMT_ELF 287039f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2871a7f7f624SMasahiro Yamada help 28725fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 28735fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 28745fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2875e279b6c1SSam Ravnborg 2876e279b6c1SSam Ravnborgconfig IA32_AOUT 2877e279b6c1SSam Ravnborg tristate "IA32 a.out support" 28786b213e1bSDavid Woodhouse depends on IA32_EMULATION 2879eac61655SBorislav Petkov depends on BROKEN 2880a7f7f624SMasahiro Yamada help 2881e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2882e279b6c1SSam Ravnborg 28830bf62763SH. Peter Anvinconfig X86_X32 28846ea30386SKees Cook bool "x32 ABI for 64-bit mode" 28859b54050bSBrian Gerst depends on X86_64 2886a7f7f624SMasahiro Yamada help 28875fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 28885fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 28895fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 28905fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 28915fd92e65SH. J. Lu 28925fd92e65SH. J. Lu You will need a recent binutils (2.22 or later) with 28935fd92e65SH. J. Lu elf32_x86_64 support enabled to compile a kernel with this 28945fd92e65SH. J. Lu option set. 28955fd92e65SH. J. Lu 2896953fee1dSIngo Molnarconfig COMPAT_32 2897953fee1dSIngo Molnar def_bool y 2898953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2899953fee1dSIngo Molnar select HAVE_UID16 2900953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2901953fee1dSIngo Molnar 2902e279b6c1SSam Ravnborgconfig COMPAT 29033c2362e6SHarvey Harrison def_bool y 29040bf62763SH. Peter Anvin depends on IA32_EMULATION || X86_X32 2905e279b6c1SSam Ravnborg 29063120e25eSJan Beulichif COMPAT 2907e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 29083120e25eSJan Beulich def_bool y 2909e279b6c1SSam Ravnborg 2910e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 29113c2362e6SHarvey Harrison def_bool y 29123120e25eSJan Beulich depends on SYSVIPC 29133120e25eSJan Beulichendif 2914ee009e4aSDavid Howells 2915e279b6c1SSam Ravnborgendmenu 2916e279b6c1SSam Ravnborg 2917e279b6c1SSam Ravnborg 2918e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2919e5beae16SKeith Packard def_bool y 2920e5beae16SKeith Packard depends on X86_32 2921e5beae16SKeith Packard 2922e279b6c1SSam Ravnborgsource "drivers/firmware/Kconfig" 2923e279b6c1SSam Ravnborg 2924edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 29255e8ebd84SJason A. Donenfeld 29265e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2927