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" 68f9ca475SIngo Molnar ---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 17117ed454SThomas Gleixner select HAVE_DEBUG_STACKOVERFLOW 18341c787eSIngo Molnar select MODULES_USE_ELF_REL 19341c787eSIngo Molnar select OLD_SIGACTION 207ac87074SVincenzo Frascino select GENERIC_VDSO_32 21daa93fabSSam Ravnborg 22daa93fabSSam Ravnborgconfig X86_64 233120e25eSJan Beulich def_bool y 243120e25eSJan Beulich depends on 64BIT 25d94e0685SIngo Molnar # Options that are inherently 64-bit kernel only: 264eb0716eSAlexandre Ghiti select ARCH_HAS_GIGANTIC_PAGE 27d94e0685SIngo Molnar select ARCH_SUPPORTS_INT128 28d94e0685SIngo Molnar select ARCH_USE_CMPXCHG_LOCKREF 29d94e0685SIngo Molnar select HAVE_ARCH_SOFT_DIRTY 30d94e0685SIngo Molnar select MODULES_USE_ELF_RELA 31f616ab59SChristoph Hellwig select NEED_DMA_MAP_STATE 3209230cbcSChristoph Hellwig select SWIOTLB 33f8781c4aSDominik Brodowski select ARCH_HAS_SYSCALL_WRAPPER 341032c0baSSam Ravnborg 35518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 36518049d9SSteven Rostedt (VMware) def_bool y 37518049d9SSteven Rostedt (VMware) depends on X86_32 38518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 39518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 40518049d9SSteven Rostedt (VMware) help 41518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 42518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 43518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 44518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 45518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 46d94e0685SIngo Molnar# 47d94e0685SIngo Molnar# Arch settings 48d94e0685SIngo Molnar# 49d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 50d94e0685SIngo Molnar# ported to 32-bit as well. ) 51d94e0685SIngo Molnar# 528d5fffb9SSam Ravnborgconfig X86 533c2362e6SHarvey Harrison def_bool y 54c763ea26SIngo Molnar # 55c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 56c763ea26SIngo Molnar # 576471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 586e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 59942fa985SYury Norov select ARCH_32BIT_OFF_T if X86_32 606471b825SIngo Molnar select ARCH_CLOCKSOURCE_DATA 612a21ad57SThomas Gleixner select ARCH_CLOCKSOURCE_INIT 6291dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 6421266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 656471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 6672d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 67316d097cSDave Hansen select ARCH_HAS_FILTER_PGPROT 686974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 69957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 705c9a8750SDmitry Vyukov select ARCH_HAS_KCOV if X86_64 710c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 7210bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 73c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 7417596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 753010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 7639208aa7SKees Cook select ARCH_HAS_REFCOUNT 770aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78092b31aaSDan Williams select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 79d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 80d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 81ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 82ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 83ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 856471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 866471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 8777fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 885e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 893599fe12SThomas Gleixner select ARCH_STACKWALK 902c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 916471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 926471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 936471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 946471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 956471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 96ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 97c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 983876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 9938d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 1006471b825SIngo Molnar select BUILDTIME_EXTABLE_SORT 1016471b825SIngo Molnar select CLKEVT_I8253 1026471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1036471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1046471b825SIngo Molnar select DCACHE_WORD_ACCESS 10545471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 10645471cd9SLinus Torvalds select EDAC_SUPPORT 1076471b825SIngo Molnar select GENERIC_CLOCKEVENTS 1086471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1096471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1106471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1116471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 11261dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1136471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 1146471b825SIngo Molnar select GENERIC_FIND_FIRST_BIT 1156471b825SIngo Molnar select GENERIC_IOMAP 116c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1170fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 118ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1196471b825SIngo Molnar select GENERIC_IRQ_PROBE 120c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1216471b825SIngo Molnar select GENERIC_IRQ_SHOW 1226471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1236471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1246471b825SIngo Molnar select GENERIC_STRNCPY_FROM_USER 1256471b825SIngo Molnar select GENERIC_STRNLEN_USER 1266471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1277ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 12839656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 1297edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1306471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1316471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1326471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1336471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1346471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 1356471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 136b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 137d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1386471b825SIngo Molnar select HAVE_ARCH_KGDB 1399e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1409e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1411b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 142271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1436471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 144f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 145afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1466471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1476471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 148a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 149e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 150c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1512ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1526471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1536471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1546471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 155c1bd55f9SJosh Triplett select HAVE_COPY_THREAD_TLS 1566471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 1576471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1589c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 159677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 16006aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 16103f5781bSWang YanQing select HAVE_EBPF_JIT 16258340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 1636630a8e5SChristoph Hellwig select HAVE_EISA 1645f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 16567a929e0SChristoph Hellwig select HAVE_FAST_GUP 166644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 1676471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 1686471b825SIngo Molnar select HAVE_FUNCTION_GRAPH_TRACER 1696471b825SIngo Molnar select HAVE_FUNCTION_TRACER 1706b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 1710067f129SK.Prasad select HAVE_HW_BREAKPOINT 1726471b825SIngo Molnar select HAVE_IDE 1736471b825SIngo Molnar select HAVE_IOREMAP_PROT 1746471b825SIngo Molnar select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 1756471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 1766471b825SIngo Molnar select HAVE_KERNEL_BZIP2 1776471b825SIngo Molnar select HAVE_KERNEL_GZIP 1786471b825SIngo Molnar select HAVE_KERNEL_LZ4 1796471b825SIngo Molnar select HAVE_KERNEL_LZMA 1806471b825SIngo Molnar select HAVE_KERNEL_LZO 1816471b825SIngo Molnar select HAVE_KERNEL_XZ 1826471b825SIngo Molnar select HAVE_KPROBES 1836471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 184540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 1856471b825SIngo Molnar select HAVE_KRETPROBES 1866471b825SIngo Molnar select HAVE_KVM 1876471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 1886471b825SIngo Molnar select HAVE_MEMBLOCK_NODE_MAP 1890102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 190ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 1919f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 19242a0bb3fSPetr Mladek select HAVE_NMI 1936471b825SIngo Molnar select HAVE_OPROFILE 1946471b825SIngo Molnar select HAVE_OPTPROBES 1956471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 1966471b825SIngo Molnar select HAVE_PERF_EVENTS 197c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 19892e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 199eb01d42aSChristoph Hellwig select HAVE_PCI 200c5e63197SJiri Olsa select HAVE_PERF_REGS 201c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 20248a8b97cSPeter Zijlstra select HAVE_RCU_TABLE_FREE if PARAVIRT 2036471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 2046415b38bSJiri Slaby select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 2053c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 206d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 207c763ea26SIngo Molnar select HAVE_STACK_VALIDATION if X86_64 208d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2096471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2106471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2117c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2127ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 21305736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 214c0185808SThomas Gleixner select IRQ_FORCED_THREADING 21586596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2162eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 217625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2186471b825SIngo Molnar select PERF_EVENTS 2193195ef59SPrarit Bhargava select RTC_LIB 220d6faca40SArnd Bergmann select RTC_MC146818_LIB 2216471b825SIngo Molnar select SPARSE_IRQ 22283fe27eaSPranith Kumar select SRCU 2236471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 22415f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2256471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2266471b825SIngo Molnar select VIRT_TO_BUS 2276471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2280c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 2297d8330a5SBalbir Singh 230ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2313120e25eSJan Beulich def_bool y 2323120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 233ba7e4d13SIngo Molnar 23451b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 23551b26adaSLinus Torvalds string 23651b26adaSLinus Torvalds default "elf32-i386" if X86_32 23751b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 23851b26adaSLinus Torvalds 23973531905SSam Ravnborgconfig ARCH_DEFCONFIG 240b9b39bfbSSam Ravnborg string 24173531905SSam Ravnborg default "arch/x86/configs/i386_defconfig" if X86_32 24273531905SSam Ravnborg default "arch/x86/configs/x86_64_defconfig" if X86_64 243b9b39bfbSSam Ravnborg 2448d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2453c2362e6SHarvey Harrison def_bool y 2468d5fffb9SSam Ravnborg 2478d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2483c2362e6SHarvey Harrison def_bool y 2498d5fffb9SSam Ravnborg 2508d5fffb9SSam Ravnborgconfig MMU 2513c2362e6SHarvey Harrison def_bool y 2528d5fffb9SSam Ravnborg 2539e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 2549e08f57dSDaniel Cashman default 28 if 64BIT 2559e08f57dSDaniel Cashman default 8 2569e08f57dSDaniel Cashman 2579e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 2589e08f57dSDaniel Cashman default 32 if 64BIT 2599e08f57dSDaniel Cashman default 16 2609e08f57dSDaniel Cashman 2619e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 2629e08f57dSDaniel Cashman default 8 2639e08f57dSDaniel Cashman 2649e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 2659e08f57dSDaniel Cashman default 16 2669e08f57dSDaniel Cashman 2678d5fffb9SSam Ravnborgconfig SBUS 2688d5fffb9SSam Ravnborg bool 2698d5fffb9SSam Ravnborg 2708d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 2713120e25eSJan Beulich def_bool y 2723120e25eSJan Beulich depends on ISA_DMA_API 2738d5fffb9SSam Ravnborg 2748d5fffb9SSam Ravnborgconfig GENERIC_BUG 2753c2362e6SHarvey Harrison def_bool y 2768d5fffb9SSam Ravnborg depends on BUG 277b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 278b93a531eSJan Beulich 279b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 280b93a531eSJan Beulich bool 2818d5fffb9SSam Ravnborg 2828d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 2833120e25eSJan Beulich def_bool y 2843120e25eSJan Beulich depends on ISA_DMA_API 2858d5fffb9SSam Ravnborg 2861032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 2871032c0baSSam Ravnborg def_bool y 2881032c0baSSam Ravnborg 2899a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 2909a0b8415Svenkatesh.pallipadi@intel.com def_bool y 2918d5fffb9SSam Ravnborg 2921b27d05bSPekka Enbergconfig ARCH_HAS_CACHE_LINE_SIZE 2931b27d05bSPekka Enberg def_bool y 2941b27d05bSPekka Enberg 295316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT 296316d097cSDave Hansen def_bool y 297316d097cSDave Hansen 298dd5af90aSMike Travisconfig HAVE_SETUP_PER_CPU_AREA 29989c9c4c5SBrian Gerst def_bool y 300b32ef636Stravis@sgi.com 30108fc4580STejun Heoconfig NEED_PER_CPU_EMBED_FIRST_CHUNK 30208fc4580STejun Heo def_bool y 30308fc4580STejun Heo 30408fc4580STejun Heoconfig NEED_PER_CPU_PAGE_FIRST_CHUNK 30511124411STejun Heo def_bool y 30611124411STejun Heo 307801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 308801e4062SJohannes Berg def_bool y 309801e4062SJohannes Berg 310f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 311f4cb5700SJohannes Berg def_bool y 312f4cb5700SJohannes Berg 31353313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB 31453313b2cSSteve Capper def_bool y 31553313b2cSSteve Capper 3168d5fffb9SSam Ravnborgconfig ZONE_DMA32 317e0fd24a3SJan Beulich def_bool y if X86_64 3188d5fffb9SSam Ravnborg 3198d5fffb9SSam Ravnborgconfig AUDIT_ARCH 320e0fd24a3SJan Beulich def_bool y if X86_64 3218d5fffb9SSam Ravnborg 3226a11f75bSAkinobu Mitaconfig ARCH_SUPPORTS_DEBUG_PAGEALLOC 3236a11f75bSAkinobu Mita def_bool y 3246a11f75bSAkinobu Mita 325d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 326d6f2d75aSAndrey Ryabinin hex 327d6f2d75aSAndrey Ryabinin depends on KASAN 328d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 329d6f2d75aSAndrey Ryabinin 33069575d38SShane Wangconfig HAVE_INTEL_TXT 33169575d38SShane Wang def_bool y 3326ea30386SKees Cook depends on INTEL_IOMMU && ACPI 33369575d38SShane Wang 3346b0c3d44SSam Ravnborgconfig X86_32_SMP 3356b0c3d44SSam Ravnborg def_bool y 3366b0c3d44SSam Ravnborg depends on X86_32 && SMP 3376b0c3d44SSam Ravnborg 3386b0c3d44SSam Ravnborgconfig X86_64_SMP 3396b0c3d44SSam Ravnborg def_bool y 3406b0c3d44SSam Ravnborg depends on X86_64 && SMP 3416b0c3d44SSam Ravnborg 342ccbeed3aSTejun Heoconfig X86_32_LAZY_GS 343ccbeed3aSTejun Heo def_bool y 3448458f8c2SMasahiro Yamada depends on X86_32 && !STACKPROTECTOR 345ccbeed3aSTejun Heo 3462b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3472b144498SSrikar Dronamraju def_bool y 3482b144498SSrikar Dronamraju 349d20642f0SRob Herringconfig FIX_EARLYCON_MEM 350d20642f0SRob Herring def_bool y 351d20642f0SRob Herring 35294d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 35394d49eb3SKirill A. Shutemov bool 35494d49eb3SKirill A. Shutemov 35598233368SKirill A. Shutemovconfig PGTABLE_LEVELS 35698233368SKirill A. Shutemov int 35777ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 35898233368SKirill A. Shutemov default 4 if X86_64 35998233368SKirill A. Shutemov default 3 if X86_PAE 36098233368SKirill A. Shutemov default 2 36198233368SKirill A. Shutemov 3622a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3632a61f474SMasahiro Yamada bool 3642a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3652a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3662a61f474SMasahiro Yamada help 3672a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3682a61f474SMasahiro Yamada the compiler produces broken code. 3692a61f474SMasahiro Yamada 370506f1d07SSam Ravnborgmenu "Processor type and features" 371506f1d07SSam Ravnborg 3725ee71535SRandy Dunlapconfig ZONE_DMA 3735ee71535SRandy Dunlap bool "DMA memory allocation support" if EXPERT 3745ee71535SRandy Dunlap default y 3755ee71535SRandy Dunlap help 3765ee71535SRandy Dunlap DMA memory allocation support allows devices with less than 32-bit 3775ee71535SRandy Dunlap addressing to allocate within the first 16MB of address space. 3785ee71535SRandy Dunlap Disable if no such devices will be used. 3795ee71535SRandy Dunlap 3805ee71535SRandy Dunlap If unsure, say Y. 3815ee71535SRandy Dunlap 382506f1d07SSam Ravnborgconfig SMP 383506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 384506f1d07SSam Ravnborg ---help--- 385506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 3864a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 3874a474157SRobert Graffham than one CPU, say Y. 388506f1d07SSam Ravnborg 3894a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 390506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 391506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 3924a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 393506f1d07SSam Ravnborg will run faster if you say N here. 394506f1d07SSam Ravnborg 395506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 396506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 397506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 398506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 399506f1d07SSam Ravnborg 400506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 401506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 402506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 403506f1d07SSam Ravnborg 404cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4054f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 406506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 407506f1d07SSam Ravnborg 408506f1d07SSam Ravnborg If you don't know what to do here, say N. 409506f1d07SSam Ravnborg 4109def39beSJosh Triplettconfig X86_FEATURE_NAMES 4119def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4129def39beSJosh Triplett default y 4139def39beSJosh Triplett ---help--- 4149def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4159def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4169def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4179def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4189def39beSJosh Triplett 4199def39beSJosh Triplett If in doubt, say Y. 4209def39beSJosh Triplett 42106cd9a7dSYinghai Luconfig X86_X2APIC 42206cd9a7dSYinghai Lu bool "Support x2apic" 42319e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 42406cd9a7dSYinghai Lu ---help--- 42506cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 42606cd9a7dSYinghai Lu 42706cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 42806cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 42906cd9a7dSYinghai Lu 43006cd9a7dSYinghai Lu If you don't know what to do here, say N. 43106cd9a7dSYinghai Lu 4326695c85bSYinghai Luconfig X86_MPPARSE 4336e87f9b7SBin Gao bool "Enable MPS table" if ACPI || SFI 4347a527688SJan Beulich default y 4355ab74722SIngo Molnar depends on X86_LOCAL_APIC 4368f9ca475SIngo Molnar ---help--- 4376695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4386695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4396695c85bSYinghai Lu 440ddd70cf9SJun Nakajimaconfig GOLDFISH 441ddd70cf9SJun Nakajima def_bool y 442ddd70cf9SJun Nakajima depends on X86_GOLDFISH 443ddd70cf9SJun Nakajima 44476b04384SDavid Woodhouseconfig RETPOLINE 44576b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 44676b04384SDavid Woodhouse default y 447d5028ba8SPeter Zijlstra select STACK_VALIDATION if HAVE_STACK_VALIDATION 44876b04384SDavid Woodhouse help 44976b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 45076b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 45176b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 45276b04384SDavid Woodhouse support for full protection. The kernel may run slower. 45376b04384SDavid Woodhouse 454e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 455e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4566fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 45759fe5a77SThomas Gleixner select KERNFS 45878e99b4aSFenghua Yu help 459e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4606fe07ce3SBabu Moger 4616fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4626fe07ce3SBabu Moger usage by the CPU. 4636fe07ce3SBabu Moger 4646fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4656fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4666fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4676fe07ce3SBabu Moger 4686fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4696fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4706fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 47178e99b4aSFenghua Yu 47278e99b4aSFenghua Yu Say N if unsure. 47378e99b4aSFenghua Yu 4748425091fSRavikiran G Thirumalaiif X86_32 475a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 476a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 477a0d0bb4dSRandy Dunlap depends on SMP 478a0d0bb4dSRandy Dunlap ---help--- 479a0d0bb4dSRandy Dunlap This option is needed for the systems that have more than 8 CPUs 480a0d0bb4dSRandy Dunlap 481c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 482c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 483c5c606d9SRavikiran G Thirumalai default y 4848f9ca475SIngo Molnar ---help--- 48506ac8346SIngo Molnar If you disable this option then the kernel will only support 48606ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 48706ac8346SIngo Molnar systems out there.) 48806ac8346SIngo Molnar 4898425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 4908425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 491cb7b8023SBen Hutchings Goldfish (Android emulator) 4928425091fSRavikiran G Thirumalai AMD Elan 4938425091fSRavikiran G Thirumalai RDC R-321x SoC 4948425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 49583125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 4963f4110a4SThomas Gleixner Moorestown MID devices 49706ac8346SIngo Molnar 49806ac8346SIngo Molnar If you have one of these systems, or if you want to build a 49906ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5008425091fSRavikiran G Thirumalaiendif 50106ac8346SIngo Molnar 5028425091fSRavikiran G Thirumalaiif X86_64 5038425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5048425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5058425091fSRavikiran G Thirumalai default y 5068425091fSRavikiran G Thirumalai ---help--- 5078425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5088425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5098425091fSRavikiran G Thirumalai systems out there.) 5108425091fSRavikiran G Thirumalai 5118425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5128425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 51344b111b5SSteffen Persvold Numascale NumaChip 5148425091fSRavikiran G Thirumalai ScaleMP vSMP 5158425091fSRavikiran G Thirumalai SGI Ultraviolet 5168425091fSRavikiran G Thirumalai 5178425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5188425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5198425091fSRavikiran G Thirumalaiendif 520c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 521c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 52244b111b5SSteffen Persvoldconfig X86_NUMACHIP 52344b111b5SSteffen Persvold bool "Numascale NumaChip" 52444b111b5SSteffen Persvold depends on X86_64 52544b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 52644b111b5SSteffen Persvold depends on NUMA 52744b111b5SSteffen Persvold depends on SMP 52844b111b5SSteffen Persvold depends on X86_X2APIC 529f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 53044b111b5SSteffen Persvold ---help--- 53144b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 53244b111b5SSteffen Persvold enable more than ~168 cores. 53344b111b5SSteffen Persvold If you don't have one of these, you should say N here. 53403b48632SNick Piggin 5356a48565eSIngo Molnarconfig X86_VSMP 536c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5376276a074SBorislav Petkov select HYPERVISOR_GUEST 5386a48565eSIngo Molnar select PARAVIRT 5396a48565eSIngo Molnar depends on X86_64 && PCI 540c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 541ead91d4bSShai Fultheim depends on SMP 5428f9ca475SIngo Molnar ---help--- 5436a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5446a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5456a48565eSIngo Molnar if you have one of these machines. 5466a48565eSIngo Molnar 547c5c606d9SRavikiran G Thirumalaiconfig X86_UV 548c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 549c5c606d9SRavikiran G Thirumalai depends on X86_64 550c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 55154c28d29SJack Steiner depends on NUMA 5521ecb4ae5SAndrew Morton depends on EFI 5539d6c26e7SSuresh Siddha depends on X86_X2APIC 5541222e564SIngo Molnar depends on PCI 555c5c606d9SRavikiran G Thirumalai ---help--- 556c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 557c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 558c5c606d9SRavikiran G Thirumalai 559c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 560c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 561506f1d07SSam Ravnborg 562ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 563ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 564cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 565ddd70cf9SJun Nakajima ---help--- 566ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 567ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 568ddd70cf9SJun Nakajima Goldfish emulator say N here. 569ddd70cf9SJun Nakajima 570c751e17bSThomas Gleixnerconfig X86_INTEL_CE 571c751e17bSThomas Gleixner bool "CE4100 TV platform" 572c751e17bSThomas Gleixner depends on PCI 573c751e17bSThomas Gleixner depends on PCI_GODIRECT 5746084a6e2SJiang Liu depends on X86_IO_APIC 575c751e17bSThomas Gleixner depends on X86_32 576c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 57737bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 578da6b737bSSebastian Andrzej Siewior select OF 579da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 580c751e17bSThomas Gleixner ---help--- 581c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 582c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 583c751e17bSThomas Gleixner boxes and media devices. 584c751e17bSThomas Gleixner 5854cb9b00fSDavid Cohenconfig X86_INTEL_MID 58643605ef1SAlan Cox bool "Intel MID platform support" 58743605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 588edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 5891ea7c673SAlan Cox depends on PCI 5903fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 5911ea7c673SAlan Cox depends on X86_IO_APIC 5927c9c3a1eSAlan Cox select SFI 5934cb9b00fSDavid Cohen select I2C 5947c9c3a1eSAlan Cox select DW_APB_TIMER 5951ea7c673SAlan Cox select APB_TIMER 5961ea7c673SAlan Cox select INTEL_SCU_IPC 59715a713dfSMika Westerberg select MFD_INTEL_MSIC 5981ea7c673SAlan Cox ---help--- 5994cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6004cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6014cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6021ea7c673SAlan Cox 6034cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6044cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 60543605ef1SAlan Cox 6068bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6078bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6088bbc2a13SBryan O'Donoghue depends on X86_32 6098bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6108bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6118bbc2a13SBryan O'Donoghue depends on X86_TSC 6128bbc2a13SBryan O'Donoghue depends on PCI 6138bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6148bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6158bbc2a13SBryan O'Donoghue select IOSF_MBI 6168bbc2a13SBryan O'Donoghue select INTEL_IMR 6179ab6eb51SAndy Shevchenko select COMMON_CLK 6188bbc2a13SBryan O'Donoghue ---help--- 6198bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6208bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6218bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6228bbc2a13SBryan O'Donoghue 6233d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6243d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6255962dd22SSinan Kaya depends on X86 && ACPI && PCI 6263d48aab1SMika Westerberg select COMMON_CLK 6270f531431SMathias Nyman select PINCTRL 628eebb3e8dSAndy Shevchenko select IOSF_MBI 6293d48aab1SMika Westerberg ---help--- 6303d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6313d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6320f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6330f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6343d48aab1SMika Westerberg 63592082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 63692082a88SKen Xue bool "AMD ACPI2Platform devices support" 63792082a88SKen Xue depends on ACPI 63892082a88SKen Xue select COMMON_CLK 63992082a88SKen Xue select PINCTRL 64092082a88SKen Xue ---help--- 64192082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 64292082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 64392082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 64492082a88SKen Xue implemented under PINCTRL subsystem. 64592082a88SKen Xue 646ced3ce76SDavid E. Boxconfig IOSF_MBI 647ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 648ced3ce76SDavid E. Box depends on PCI 649ced3ce76SDavid E. Box ---help--- 650ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 651ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 652ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 653ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 654ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 655ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 656ced3ce76SDavid E. Box This list is not meant to be exclusive. 657ced3ce76SDavid E. Box - BayTrail 658ced3ce76SDavid E. Box - Braswell 659ced3ce76SDavid E. Box - Quark 660ced3ce76SDavid E. Box 661ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 662ced3ce76SDavid E. Box 663ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 664ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 665ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 666ed2226bdSDavid E. Box ---help--- 667ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 668ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 669ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 670ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 671ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 672ed2226bdSDavid E. Box device they want to access. 673ed2226bdSDavid E. Box 674ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 675ed2226bdSDavid E. Box 676c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 677c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 678506f1d07SSam Ravnborg depends on X86_32 679c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 680c5c606d9SRavikiran G Thirumalai select M486 681c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 682c5c606d9SRavikiran G Thirumalai ---help--- 683c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 684c5c606d9SRavikiran G Thirumalai as R-8610-(G). 685c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 686c5c606d9SRavikiran G Thirumalai 687e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 6889c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 6899c398017SIngo Molnar depends on X86_32 && SMP 690c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 6918f9ca475SIngo Molnar ---help--- 692b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 693b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 694b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 695b5660ba7SH. Peter Anvin one and will fallback to default. 696d49c4288SYinghai Lu 697c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 698d49c4288SYinghai Lu 699d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7006fc108a0SJan Beulich def_bool y 701d949f36fSLinus Torvalds # MCE code calls memory_failure(): 702d949f36fSLinus Torvalds depends on X86_MCE 703d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 704d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 705d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 706d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 707d949f36fSLinus Torvalds 70883125a3aSAlessandro Rubiniconfig STA2X11 70983125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 71083125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 711b6e05477SChristoph Hellwig select ARCH_HAS_PHYS_TO_DMA 71283125a3aSAlessandro Rubini select SWIOTLB 71383125a3aSAlessandro Rubini select MFD_STA2X11 7140145071bSLinus Walleij select GPIOLIB 71583125a3aSAlessandro Rubini ---help--- 71683125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 71783125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 71883125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 71983125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 72083125a3aSAlessandro Rubini standard PC machines. 72183125a3aSAlessandro Rubini 72282148d1dSShérabconfig X86_32_IRIS 72382148d1dSShérab tristate "Eurobraille/Iris poweroff module" 72482148d1dSShérab depends on X86_32 72582148d1dSShérab ---help--- 72682148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 72782148d1dSShérab to shut themselves down properly. A special I/O sequence is 72882148d1dSShérab needed to do so, which is what this module does at 72982148d1dSShérab kernel shutdown. 73082148d1dSShérab 73182148d1dSShérab This is only for Iris machines from EuroBraille. 73282148d1dSShérab 73382148d1dSShérab If unused, say N. 73482148d1dSShérab 735ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7363c2362e6SHarvey Harrison def_bool y 7373c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 738a87d0914SKen Chen depends on X86 7398f9ca475SIngo Molnar ---help--- 740506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 741506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 742506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 743506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 744506f1d07SSam Ravnborg 745506f1d07SSam Ravnborg If in doubt, say "Y". 746506f1d07SSam Ravnborg 7476276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7486276a074SBorislav Petkov bool "Linux guest support" 7498f9ca475SIngo Molnar ---help--- 7506276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7516276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7526276a074SBorislav Petkov setup. 753506f1d07SSam Ravnborg 7546276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7556276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 756506f1d07SSam Ravnborg 7576276a074SBorislav Petkovif HYPERVISOR_GUEST 758506f1d07SSam Ravnborg 759e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 760e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 7618f9ca475SIngo Molnar ---help--- 762e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 763e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 764e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 765e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 766e61bd94aSEduardo Pereira Habkost 767c00a280aSJuergen Grossconfig PARAVIRT_XXL 768c00a280aSJuergen Gross bool 769c00a280aSJuergen Gross 7706276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7716276a074SBorislav Petkov bool "paravirt-ops debugging" 7726276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 7736276a074SBorislav Petkov ---help--- 7746276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7756276a074SBorislav Petkov a paravirt_op is missing when it is called. 7766276a074SBorislav Petkov 777b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 778b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 7796ea30386SKees Cook depends on PARAVIRT && SMP 780b4ecc126SJeremy Fitzhardinge ---help--- 781b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 782b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 783b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 784b4ecc126SJeremy Fitzhardinge 7854c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 7864c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 787b4ecc126SJeremy Fitzhardinge 7884c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 789b4ecc126SJeremy Fitzhardinge 790ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 791ecca2502SZhao Yakui def_bool n 792ecca2502SZhao Yakui 7936276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 7946276a074SBorislav Petkov 7956276a074SBorislav Petkovconfig KVM_GUEST 7966276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 7976276a074SBorislav Petkov depends on PARAVIRT 7986276a074SBorislav Petkov select PARAVIRT_CLOCK 799a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 8006276a074SBorislav Petkov default y 8016276a074SBorislav Petkov ---help--- 8026276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8036276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8046276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8056276a074SBorislav Petkov underlying device model, the host provides the guest with 8066276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8076276a074SBorislav Petkov 808a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 809a1c4423bSMarcelo Tosatti def_bool n 810a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 811a1c4423bSMarcelo Tosatti help 812a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 813a1c4423bSMarcelo Tosatti 8147733607fSMaran Wilsonconfig PVH 8157733607fSMaran Wilson bool "Support for running PVH guests" 8167733607fSMaran Wilson ---help--- 8177733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8187733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8197733607fSMaran Wilson 8201e20eb85SSrivatsa Vaddagiriconfig KVM_DEBUG_FS 8211e20eb85SSrivatsa Vaddagiri bool "Enable debug information for KVM Guests in debugfs" 8221e20eb85SSrivatsa Vaddagiri depends on KVM_GUEST && DEBUG_FS 8231e20eb85SSrivatsa Vaddagiri ---help--- 8241e20eb85SSrivatsa Vaddagiri This option enables collection of various statistics for KVM guest. 8251e20eb85SSrivatsa Vaddagiri Statistics are displayed in debugfs filesystem. Enabling this option 8261e20eb85SSrivatsa Vaddagiri may incur significant overhead. 8271e20eb85SSrivatsa Vaddagiri 8286276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8296276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8306276a074SBorislav Petkov depends on PARAVIRT 8316276a074SBorislav Petkov ---help--- 8326276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8336276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8346276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8356276a074SBorislav Petkov that, there can be a small performance impact. 8366276a074SBorislav Petkov 8376276a074SBorislav Petkov If in doubt, say N here. 8386276a074SBorislav Petkov 8397af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8407af192c9SGerd Hoffmann bool 8417af192c9SGerd Hoffmann 8424a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8434a362601SJan Kiszka bool "Jailhouse non-root cell support" 844abde587bSArnd Bergmann depends on X86_64 && PCI 84587e65d05SJan Kiszka select X86_PM_TIMER 8464a362601SJan Kiszka ---help--- 8474a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8484a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8494a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8504a362601SJan Kiszka 851ec7972c9SZhao Yakuiconfig ACRN_GUEST 852ec7972c9SZhao Yakui bool "ACRN Guest support" 853ec7972c9SZhao Yakui depends on X86_64 854498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 855ec7972c9SZhao Yakui help 856ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 857ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 858ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 859ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 860ec7972c9SZhao Yakui found in https://projectacrn.org/. 861ec7972c9SZhao Yakui 8626276a074SBorislav Petkovendif #HYPERVISOR_GUEST 86397349135SJeremy Fitzhardinge 864506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 865506f1d07SSam Ravnborg 866506f1d07SSam Ravnborgconfig HPET_TIMER 8673c2362e6SHarvey Harrison def_bool X86_64 868506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 8698f9ca475SIngo Molnar ---help--- 870506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 871506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 872506f1d07SSam Ravnborg present. 873506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 874506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 875506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8764e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 8774e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 878506f1d07SSam Ravnborg 879506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 880506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 881506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 882506f1d07SSam Ravnborg 883506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 884506f1d07SSam Ravnborg 885506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 8863c2362e6SHarvey Harrison def_bool y 8879d8af78bSBernhard Walle depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 888506f1d07SSam Ravnborg 889bb24c471SJacob Panconfig APB_TIMER 890933b9463SAlan Cox def_bool y if X86_INTEL_MID 891933b9463SAlan Cox prompt "Intel MID APB Timer Support" if X86_INTEL_MID 89206c3df49SJamie Iles select DW_APB_TIMER 893a0c3832aSAlan Cox depends on X86_INTEL_MID && SFI 894bb24c471SJacob Pan help 895bb24c471SJacob Pan APB timer is the replacement for 8254, HPET on X86 MID platforms. 896bb24c471SJacob Pan The APBT provides a stable time base on SMP 897bb24c471SJacob Pan systems, unlike the TSC, but it is more expensive to access, 898bb24c471SJacob Pan as it is off-chip. APB timers are always running regardless of CPU 899bb24c471SJacob Pan C states, they are used as per CPU clockevent device when possible. 900bb24c471SJacob Pan 9016a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 902506f1d07SSam Ravnborg# The code disables itself when not needed. 9037ae9392cSThomas Petazzoniconfig DMI 9047ae9392cSThomas Petazzoni default y 905cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9066a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 9078f9ca475SIngo Molnar ---help--- 9087ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9097ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9107ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9117ae9392cSThomas Petazzoni BIOS code. 9127ae9392cSThomas Petazzoni 913506f1d07SSam Ravnborgconfig GART_IOMMU 91438901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 915a4ce5a48SChristoph Hellwig select IOMMU_HELPER 916506f1d07SSam Ravnborg select SWIOTLB 91723ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 9188f9ca475SIngo Molnar ---help--- 919ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 920ced3c42cSIngo Molnar GART based hardware IOMMUs. 921ced3c42cSIngo Molnar 922ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 923ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 924ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 925ced3c42cSIngo Molnar 926ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 927ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 928ced3c42cSIngo Molnar 929ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 930ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 931ced3c42cSIngo Molnar 32-bit limited device. 932ced3c42cSIngo Molnar 933ced3c42cSIngo Molnar If unsure, say Y. 934506f1d07SSam Ravnborg 935506f1d07SSam Ravnborgconfig CALGARY_IOMMU 936506f1d07SSam Ravnborg bool "IBM Calgary IOMMU support" 937a4ce5a48SChristoph Hellwig select IOMMU_HELPER 938506f1d07SSam Ravnborg select SWIOTLB 9396ea30386SKees Cook depends on X86_64 && PCI 9408f9ca475SIngo Molnar ---help--- 941506f1d07SSam Ravnborg Support for hardware IOMMUs in IBM's xSeries x366 and x460 942506f1d07SSam Ravnborg systems. Needed to run systems with more than 3GB of memory 943506f1d07SSam Ravnborg properly with 32-bit PCI devices that do not support DAC 944506f1d07SSam Ravnborg (Double Address Cycle). Calgary also supports bus level 945506f1d07SSam Ravnborg isolation, where all DMAs pass through the IOMMU. This 946506f1d07SSam Ravnborg prevents them from going anywhere except their intended 947506f1d07SSam Ravnborg destination. This catches hard-to-find kernel bugs and 948506f1d07SSam Ravnborg mis-behaving drivers and devices that do not use the DMA-API 949506f1d07SSam Ravnborg properly to set up their DMA buffers. The IOMMU can be 950506f1d07SSam Ravnborg turned off at boot time with the iommu=off parameter. 951506f1d07SSam Ravnborg Normally the kernel will make the right choice by itself. 952506f1d07SSam Ravnborg If unsure, say Y. 953506f1d07SSam Ravnborg 954506f1d07SSam Ravnborgconfig CALGARY_IOMMU_ENABLED_BY_DEFAULT 9553c2362e6SHarvey Harrison def_bool y 9563c2362e6SHarvey Harrison prompt "Should Calgary be enabled by default?" 957506f1d07SSam Ravnborg depends on CALGARY_IOMMU 9588f9ca475SIngo Molnar ---help--- 959506f1d07SSam Ravnborg Should Calgary be enabled by default? if you choose 'y', Calgary 960506f1d07SSam Ravnborg will be used (if it exists). If you choose 'n', Calgary will not be 961506f1d07SSam Ravnborg used even if it exists. If you choose 'n' and would like to use 962506f1d07SSam Ravnborg Calgary anyway, pass 'iommu=calgary' on the kernel command line. 963506f1d07SSam Ravnborg If unsure, say Y. 964506f1d07SSam Ravnborg 9651184dc2fSMike Travisconfig MAXSMP 966ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9676ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 96836f5101aSMike Travis select CPUMASK_OFFSTACK 9698f9ca475SIngo Molnar ---help--- 970ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9711184dc2fSMike Travis If unsure, say N. 972506f1d07SSam Ravnborg 973aec6487eSIngo Molnar# 974aec6487eSIngo Molnar# The maximum number of CPUs supported: 975aec6487eSIngo Molnar# 976aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 977aec6487eSIngo Molnar# and which can be configured interactively in the 978aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 979aec6487eSIngo Molnar# 980aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 981aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 982aec6487eSIngo Molnar# 983aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 984aec6487eSIngo Molnar# interactive configuration. ) 985aec6487eSIngo Molnar# 986a0d0bb4dSRandy Dunlap 987aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 988a0d0bb4dSRandy Dunlap int 989aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 990a0d0bb4dSRandy Dunlap default 1 if !SMP 991a0d0bb4dSRandy Dunlap default 2 992a0d0bb4dSRandy Dunlap 993aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 994a0d0bb4dSRandy Dunlap int 995a0d0bb4dSRandy Dunlap depends on X86_32 996aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 997aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 998a0d0bb4dSRandy Dunlap default 1 if !SMP 999a0d0bb4dSRandy Dunlap 1000aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 1001a0d0bb4dSRandy Dunlap int 1002a0d0bb4dSRandy Dunlap depends on X86_64 1003aec6487eSIngo Molnar default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 1004aec6487eSIngo Molnar default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 1005a0d0bb4dSRandy Dunlap default 1 if !SMP 1006aec6487eSIngo Molnar 1007aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1008aec6487eSIngo Molnar int 1009aec6487eSIngo Molnar depends on X86_32 1010aec6487eSIngo Molnar default 32 if X86_BIGSMP 1011aec6487eSIngo Molnar default 8 if SMP 1012aec6487eSIngo Molnar default 1 if !SMP 1013aec6487eSIngo Molnar 1014aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1015aec6487eSIngo Molnar int 1016aec6487eSIngo Molnar depends on X86_64 1017a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1018a0d0bb4dSRandy Dunlap default 64 if SMP 1019aec6487eSIngo Molnar default 1 if !SMP 1020a0d0bb4dSRandy Dunlap 1021506f1d07SSam Ravnborgconfig NR_CPUS 102236f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1023aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1024aec6487eSIngo Molnar default NR_CPUS_DEFAULT 10258f9ca475SIngo Molnar ---help--- 1026506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1027bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1028cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1029506f1d07SSam Ravnborg minimum value which makes sense is 2. 1030506f1d07SSam Ravnborg 1031aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1032aec6487eSIngo Molnar to the kernel image. 1033506f1d07SSam Ravnborg 1034506f1d07SSam Ravnborgconfig SCHED_SMT 1035dbe73364SThomas Gleixner def_bool y if SMP 1036506f1d07SSam Ravnborg 1037506f1d07SSam Ravnborgconfig SCHED_MC 10383c2362e6SHarvey Harrison def_bool y 10393c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1040c8e56d20SBorislav Petkov depends on SMP 10418f9ca475SIngo Molnar ---help--- 1042506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1043506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1044506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1045506f1d07SSam Ravnborg 1046de966cf4STim Chenconfig SCHED_MC_PRIO 1047de966cf4STim Chen bool "CPU core priorities scheduler support" 10480a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10490a21fc12SIngo Molnar select X86_INTEL_PSTATE 10500a21fc12SIngo Molnar select CPU_FREQ 1051de966cf4STim Chen default y 10525e76b2abSTim Chen ---help--- 1053de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1054de966cf4STim Chen core ordering determined at manufacturing time, which allows 1055de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1056de966cf4STim Chen single threaded workloads) than others. 1057de966cf4STim Chen 1058de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1059de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1060de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1061de966cf4STim Chen overall system performance can be achieved. 1062de966cf4STim Chen 1063de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1064de966cf4STim Chen 1065de966cf4STim Chen If unsure say Y here. 10665e76b2abSTim Chen 106730b8b006SThomas Gleixnerconfig UP_LATE_INIT 106830b8b006SThomas Gleixner def_bool y 1069ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 107030b8b006SThomas Gleixner 1071506f1d07SSam Ravnborgconfig X86_UP_APIC 107250849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 107350849eefSJan Beulich default PCI_MSI 107438a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 10758f9ca475SIngo Molnar ---help--- 1076506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1077506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1078506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1079506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1080506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1081506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1082506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1083506f1d07SSam Ravnborg lockups. 1084506f1d07SSam Ravnborg 1085506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1086506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1087506f1d07SSam Ravnborg depends on X86_UP_APIC 10888f9ca475SIngo Molnar ---help--- 1089506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1090506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1091506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1092506f1d07SSam Ravnborg 1093506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1094506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1095506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1096506f1d07SSam Ravnborg 1097506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10983c2362e6SHarvey Harrison def_bool y 10990dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1100b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 110152f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1102506f1d07SSam Ravnborg 1103506f1d07SSam Ravnborgconfig X86_IO_APIC 1104b1da1e71SJan Beulich def_bool y 1105b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1106506f1d07SSam Ravnborg 110741b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 110841b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 110941b9eb26SStefan Assmann depends on X86_IO_APIC 11108f9ca475SIngo Molnar ---help--- 111141b9eb26SStefan Assmann This option enables a workaround that fixes a source of 111241b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 111341b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 111441b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 111541b9eb26SStefan Assmann 111641b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 111741b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 111841b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 111941b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 112041b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 112141b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 112241b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 112341b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 112441b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 112541b9eb26SStefan Assmann down (vital) interrupt lines. 112641b9eb26SStefan Assmann 112741b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 112841b9eb26SStefan Assmann increased on these systems. 112941b9eb26SStefan Assmann 1130506f1d07SSam Ravnborgconfig X86_MCE 1131bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1132648ed940SChen, Gong select GENERIC_ALLOCATOR 1133e57dbaf7SBorislav Petkov default y 1134506f1d07SSam Ravnborg ---help--- 1135bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1136bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1137506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1138bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11394efc0670SAndi Kleen 11405de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11415de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11425de97c9fSTony Luck depends on X86_MCE 11435de97c9fSTony Luck ---help--- 11445de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11455de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11465de97c9fSTony Luck rasdaemon solution. 11475de97c9fSTony Luck 1148506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11493c2362e6SHarvey Harrison def_bool y 11503c2362e6SHarvey Harrison prompt "Intel MCE features" 1151c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 11528f9ca475SIngo Molnar ---help--- 1153506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1154506f1d07SSam Ravnborg the thermal monitor. 1155506f1d07SSam Ravnborg 1156506f1d07SSam Ravnborgconfig X86_MCE_AMD 11573c2362e6SHarvey Harrison def_bool y 11583c2362e6SHarvey Harrison prompt "AMD MCE features" 1159f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 11608f9ca475SIngo Molnar ---help--- 1161506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1162506f1d07SSam Ravnborg the DRAM Error Threshold. 1163506f1d07SSam Ravnborg 11644efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11656fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1166c31d9633SAndi Kleen depends on X86_32 && X86_MCE 11674efc0670SAndi Kleen ---help--- 11684efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11695065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11704efc0670SAndi Kleen line. 11714efc0670SAndi Kleen 1172b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1173b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11746fc108a0SJan Beulich def_bool y 1175b2762686SAndi Kleen 1176ea149b36SAndi Kleenconfig X86_MCE_INJECT 1177bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1178ea149b36SAndi Kleen tristate "Machine check injector support" 1179ea149b36SAndi Kleen ---help--- 1180ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1181ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1182ea149b36SAndi Kleen QA it is safe to say n. 1183ea149b36SAndi Kleen 11844efc0670SAndi Kleenconfig X86_THERMAL_VECTOR 11854efc0670SAndi Kleen def_bool y 11865bb38adcSAndi Kleen depends on X86_MCE_INTEL 11874efc0670SAndi Kleen 118807dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1189e633c65aSKan Liang 11905aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11911e642812SIngo Molnar bool "Legacy VM86 support" 1192506f1d07SSam Ravnborg depends on X86_32 11938f9ca475SIngo Molnar ---help--- 11945aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11955aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11965aef51c3SAndy Lutomirski 11975aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11985aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11995aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 12005aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 12015aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12021e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12031e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12041e642812SIngo Molnar mode might be faster than emulation and you might want to 12051e642812SIngo Molnar enable this option. 12065aef51c3SAndy Lutomirski 12071e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12081e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12091e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12101e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12115aef51c3SAndy Lutomirski 12121e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12131e642812SIngo Molnar and slows down exception handling a tiny bit. 12145aef51c3SAndy Lutomirski 12151e642812SIngo Molnar If unsure, say N here. 12165aef51c3SAndy Lutomirski 12175aef51c3SAndy Lutomirskiconfig VM86 12185aef51c3SAndy Lutomirski bool 12195aef51c3SAndy Lutomirski default X86_LEGACY_VM86 122034273f41SH. Peter Anvin 122134273f41SH. Peter Anvinconfig X86_16BIT 122234273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 122334273f41SH. Peter Anvin default y 1224a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 122534273f41SH. Peter Anvin ---help--- 122634273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 122734273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 122834273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 122934273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 123034273f41SH. Peter Anvin 123134273f41SH. Peter Anvinconfig X86_ESPFIX32 123234273f41SH. Peter Anvin def_bool y 123334273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1234506f1d07SSam Ravnborg 1235197725deSH. Peter Anvinconfig X86_ESPFIX64 1236197725deSH. Peter Anvin def_bool y 123734273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1238506f1d07SSam Ravnborg 12391ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12401ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12411ad83c85SAndy Lutomirski default y 12421ad83c85SAndy Lutomirski depends on X86_64 12431ad83c85SAndy Lutomirski ---help--- 12441ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12451ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12461ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12471ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12481ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12491ad83c85SAndy Lutomirski 0xffffffffff600?00. 12501ad83c85SAndy Lutomirski 12511ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12521ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12531ad83c85SAndy Lutomirski 12541ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12551ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12561ad83c85SAndy Lutomirski 1257506f1d07SSam Ravnborgconfig TOSHIBA 1258506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1259506f1d07SSam Ravnborg depends on X86_32 1260506f1d07SSam Ravnborg ---help--- 1261506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1262506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1263506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1264506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1265506f1d07SSam Ravnborg 1266506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1267506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1268506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1269506f1d07SSam Ravnborg 1270506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1271506f1d07SSam Ravnborg Say N otherwise. 1272506f1d07SSam Ravnborg 1273506f1d07SSam Ravnborgconfig I8K 1274039ae585SPali Rohár tristate "Dell i8k legacy laptop support" 1275949a9d70SJean Delvare select HWMON 1276039ae585SPali Rohár select SENSORS_DELL_SMM 1277506f1d07SSam Ravnborg ---help--- 1278039ae585SPali Rohár This option enables legacy /proc/i8k userspace interface in hwmon 1279039ae585SPali Rohár dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1280039ae585SPali Rohár temperature and allows controlling fan speeds of Dell laptops via 1281039ae585SPali Rohár System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1282039ae585SPali Rohár it reports also power and hotkey status. For fan speed control is 1283039ae585SPali Rohár needed userspace package i8kutils. 1284506f1d07SSam Ravnborg 1285039ae585SPali Rohár Say Y if you intend to run this kernel on old Dell laptops or want to 1286039ae585SPali Rohár use userspace package i8kutils. 1287506f1d07SSam Ravnborg Say N otherwise. 1288506f1d07SSam Ravnborg 1289506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12909ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12919ba16087SJan Beulich depends on X86_32 1292506f1d07SSam Ravnborg ---help--- 1293506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1294506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1295506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1296506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1297506f1d07SSam Ravnborg system. 1298506f1d07SSam Ravnborg 1299506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13005e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1301506f1d07SSam Ravnborg 1302506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1303506f1d07SSam Ravnborg enable this option even if you don't need it. 1304506f1d07SSam Ravnborg Say N otherwise. 1305506f1d07SSam Ravnborg 1306506f1d07SSam Ravnborgconfig MICROCODE 13079a2bc335SBorislav Petkov bool "CPU microcode loading support" 13089a2bc335SBorislav Petkov default y 130980030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1310506f1d07SSam Ravnborg select FW_LOADER 1311506f1d07SSam Ravnborg ---help--- 1312506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13135f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13145f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13155f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13165f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13175f9c01aaSBorislav Petkov the Linux kernel. 1318506f1d07SSam Ravnborg 13195f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1320cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13215f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13225f9c01aaSBorislav Petkov initrd for microcode blobs. 1323506f1d07SSam Ravnborg 1324c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1325c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1326c508c46eSBenjamin Gilbert config option. 1327506f1d07SSam Ravnborg 13288d86f390SPeter Orubaconfig MICROCODE_INTEL 1329e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13308d86f390SPeter Oruba depends on MICROCODE 13318d86f390SPeter Oruba default MICROCODE 13328d86f390SPeter Oruba select FW_LOADER 13338f9ca475SIngo Molnar ---help--- 13348d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13358d86f390SPeter Oruba processors. 13368d86f390SPeter Oruba 1337b8989db9SAlan For the current Intel microcode data package go to 1338b8989db9SAlan <https://downloadcenter.intel.com> and search for 1339b8989db9SAlan 'Linux Processor Microcode Data File'. 13408d86f390SPeter Oruba 134180cc9f10SPeter Orubaconfig MICROCODE_AMD 1342e43f6e67SBorislav Petkov bool "AMD microcode loading support" 134380cc9f10SPeter Oruba depends on MICROCODE 134480cc9f10SPeter Oruba select FW_LOADER 13458f9ca475SIngo Molnar ---help--- 134680cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 134780cc9f10SPeter Oruba processors will be enabled. 134880cc9f10SPeter Oruba 1349506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1350c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1351c02f48e0SBorislav Petkov default n 1352506f1d07SSam Ravnborg depends on MICROCODE 1353c02f48e0SBorislav Petkov ---help--- 1354c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1355c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1356c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1357c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1358c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1359cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1360506f1d07SSam Ravnborg 1361506f1d07SSam Ravnborgconfig X86_MSR 1362506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 13638f9ca475SIngo Molnar ---help--- 1364506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1365506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1366506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1367506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1368506f1d07SSam Ravnborg systems. 1369506f1d07SSam Ravnborg 1370506f1d07SSam Ravnborgconfig X86_CPUID 1371506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 13728f9ca475SIngo Molnar ---help--- 1373506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1374506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1375506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1376506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1377506f1d07SSam Ravnborg 1378506f1d07SSam Ravnborgchoice 1379506f1d07SSam Ravnborg prompt "High Memory Support" 13806fc108a0SJan Beulich default HIGHMEM4G 1381506f1d07SSam Ravnborg depends on X86_32 1382506f1d07SSam Ravnborg 1383506f1d07SSam Ravnborgconfig NOHIGHMEM 1384506f1d07SSam Ravnborg bool "off" 1385506f1d07SSam Ravnborg ---help--- 1386506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1387506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1388506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1389506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1390506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1391506f1d07SSam Ravnborg "high memory". 1392506f1d07SSam Ravnborg 1393506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1394506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1395506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1396506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1397506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1398506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1399506f1d07SSam Ravnborg possible. 1400506f1d07SSam Ravnborg 1401506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1402506f1d07SSam Ravnborg answer "4GB" here. 1403506f1d07SSam Ravnborg 1404506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1405506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1406506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1407506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1408506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1409506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1410506f1d07SSam Ravnborg 1411506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1412506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1413506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1414506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1415506f1d07SSam Ravnborg kernel at boot time.) 1416506f1d07SSam Ravnborg 1417506f1d07SSam Ravnborg If unsure, say "off". 1418506f1d07SSam Ravnborg 1419506f1d07SSam Ravnborgconfig HIGHMEM4G 1420506f1d07SSam Ravnborg bool "4GB" 14218f9ca475SIngo Molnar ---help--- 1422506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1423506f1d07SSam Ravnborg gigabytes of physical RAM. 1424506f1d07SSam Ravnborg 1425506f1d07SSam Ravnborgconfig HIGHMEM64G 1426506f1d07SSam Ravnborg bool "64GB" 142769b8d3fcSMatthew Whitehead depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1428506f1d07SSam Ravnborg select X86_PAE 14298f9ca475SIngo Molnar ---help--- 1430506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1431506f1d07SSam Ravnborg gigabytes of physical RAM. 1432506f1d07SSam Ravnborg 1433506f1d07SSam Ravnborgendchoice 1434506f1d07SSam Ravnborg 1435506f1d07SSam Ravnborgchoice 14366a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1437506f1d07SSam Ravnborg default VMSPLIT_3G 1438506f1d07SSam Ravnborg depends on X86_32 14398f9ca475SIngo Molnar ---help--- 1440506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1441506f1d07SSam Ravnborg 1442506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1443506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1444506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1445506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1446506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1447506f1d07SSam Ravnborg available to user programs, making the address space there 1448506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1449506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1450506f1d07SSam Ravnborg kernel modules. 1451506f1d07SSam Ravnborg 1452506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1453506f1d07SSam Ravnborg option alone! 1454506f1d07SSam Ravnborg 1455506f1d07SSam Ravnborg config VMSPLIT_3G 1456506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1457506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1458506f1d07SSam Ravnborg depends on !X86_PAE 1459506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1460506f1d07SSam Ravnborg config VMSPLIT_2G 1461506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1462506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1463506f1d07SSam Ravnborg depends on !X86_PAE 1464506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1465506f1d07SSam Ravnborg config VMSPLIT_1G 1466506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1467506f1d07SSam Ravnborgendchoice 1468506f1d07SSam Ravnborg 1469506f1d07SSam Ravnborgconfig PAGE_OFFSET 1470506f1d07SSam Ravnborg hex 1471506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1472506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1473506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1474506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1475506f1d07SSam Ravnborg default 0xC0000000 1476506f1d07SSam Ravnborg depends on X86_32 1477506f1d07SSam Ravnborg 1478506f1d07SSam Ravnborgconfig HIGHMEM 14793c2362e6SHarvey Harrison def_bool y 1480506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1481506f1d07SSam Ravnborg 1482506f1d07SSam Ravnborgconfig X86_PAE 14839ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1484506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1485d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14869d99c712SChristian Melki select SWIOTLB 14878f9ca475SIngo Molnar ---help--- 1488506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1489506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1490506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1491506f1d07SSam Ravnborg consumes more pagetable space per process. 1492506f1d07SSam Ravnborg 149377ef56e4SKirill A. Shutemovconfig X86_5LEVEL 149477ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 1495eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1496162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 149777ef56e4SKirill A. Shutemov depends on X86_64 149877ef56e4SKirill A. Shutemov ---help--- 149977ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 150077ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 150177ef56e4SKirill A. Shutemov physical address space. 150277ef56e4SKirill A. Shutemov 150377ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 150477ef56e4SKirill A. Shutemov 15056657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15066657fca0SKirill A. Shutemov support 4- or 5-level paging. 150777ef56e4SKirill A. Shutemov 1508cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 150977ef56e4SKirill A. Shutemov information. 151077ef56e4SKirill A. Shutemov 151177ef56e4SKirill A. Shutemov Say N if unsure. 151277ef56e4SKirill A. Shutemov 151310971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1514e5008abeSLuis R. Rodriguez def_bool y 15152e1da13fSVlastimil Babka depends on X86_64 15168f9ca475SIngo Molnar ---help--- 151710971ab2SIngo Molnar Certain kernel features effectively disable kernel 151810971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 151910971ab2SIngo Molnar supports them), so don't confuse the user by printing 152010971ab2SIngo Molnar that we have them enabled. 15219e899816SNick Piggin 15225c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15235c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15245c280cf6SThomas Gleixner depends on DEBUG_FS 15255c280cf6SThomas Gleixner ---help--- 15265c280cf6SThomas Gleixner Expose statistics about the Change Page Attribute mechanims, which 1527a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15285c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15295c280cf6SThomas Gleixner 15307744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15317744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15327744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 153394d49eb3SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 1534ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 15359087c375STom Lendacky select ARCH_HAS_FORCE_DMA_UNENCRYPTED 15367744ccdbSTom Lendacky ---help--- 15377744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15387744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15397744ccdbSTom Lendacky Encryption (SME). 15407744ccdbSTom Lendacky 15417744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15427744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15437744ccdbSTom Lendacky default y 15447744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 15457744ccdbSTom Lendacky ---help--- 15467744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15477744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15487744ccdbSTom Lendacky 15497744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15507744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15517744ccdbSTom Lendacky 15527744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15537744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15547744ccdbSTom Lendacky 1555506f1d07SSam Ravnborg# Common NUMA Features 1556506f1d07SSam Ravnborgconfig NUMA 1557fd51b2d7SKOSAKI Motohiro bool "Numa Memory Allocation and Scheduler Support" 1558506f1d07SSam Ravnborg depends on SMP 1559b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1560b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15618f9ca475SIngo Molnar ---help--- 1562506f1d07SSam Ravnborg Enable NUMA (Non Uniform Memory Access) support. 1563fd51b2d7SKOSAKI Motohiro 1564506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1565506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1566506f1d07SSam Ravnborg NUMA awareness to the kernel. 1567506f1d07SSam Ravnborg 1568c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1569fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1570fd51b2d7SKOSAKI Motohiro 1571b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15727cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1573fd51b2d7SKOSAKI Motohiro 1574fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1575506f1d07SSam Ravnborg 1576eec1d4faSHans Rosenfeldconfig AMD_NUMA 15773c2362e6SHarvey Harrison def_bool y 15783c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15795da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 15808f9ca475SIngo Molnar ---help--- 1581eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1582eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1583eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1584eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1585eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1586506f1d07SSam Ravnborg 1587506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15883c2362e6SHarvey Harrison def_bool y 15893c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1590506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1591506f1d07SSam Ravnborg select ACPI_NUMA 15928f9ca475SIngo Molnar ---help--- 1593506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1594506f1d07SSam Ravnborg 15956ec6e0d9SSuresh Siddha# Some NUMA nodes have memory ranges that span 15966ec6e0d9SSuresh Siddha# other nodes. Even though a pfn is valid and 15976ec6e0d9SSuresh Siddha# between a node's start and end pfns, it may not 15986ec6e0d9SSuresh Siddha# reside on that node. See memmap_init_zone() 15996ec6e0d9SSuresh Siddha# for details. 16006ec6e0d9SSuresh Siddhaconfig NODES_SPAN_OTHER_NODES 16016ec6e0d9SSuresh Siddha def_bool y 16026ec6e0d9SSuresh Siddha depends on X86_64_ACPI_NUMA 16036ec6e0d9SSuresh Siddha 1604506f1d07SSam Ravnborgconfig NUMA_EMU 1605506f1d07SSam Ravnborg bool "NUMA emulation" 16061b7e03efSTejun Heo depends on NUMA 16078f9ca475SIngo Molnar ---help--- 1608506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1609506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1610506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1611506f1d07SSam Ravnborg 1612506f1d07SSam Ravnborgconfig NODES_SHIFT 1613d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 161451591e31SDavid Rientjes range 1 10 161551591e31SDavid Rientjes default "10" if MAXSMP 1616506f1d07SSam Ravnborg default "6" if X86_64 1617506f1d07SSam Ravnborg default "3" 1618506f1d07SSam Ravnborg depends on NEED_MULTIPLE_NODES 16198f9ca475SIngo Molnar ---help--- 16201184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1621692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1622506f1d07SSam Ravnborg 1623506f1d07SSam Ravnborgconfig ARCH_HAVE_MEMORY_PRESENT 16243c2362e6SHarvey Harrison def_bool y 1625506f1d07SSam Ravnborg depends on X86_32 && DISCONTIGMEM 1626506f1d07SSam Ravnborg 1627506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1628506f1d07SSam Ravnborg def_bool y 16293b16651fSTejun Heo depends on X86_32 && !NUMA 1630506f1d07SSam Ravnborg 1631506f1d07SSam Ravnborgconfig ARCH_DISCONTIGMEM_ENABLE 16322792107dSMike Rapoport def_bool n 1633b263295dSChristoph Lameter depends on NUMA && X86_32 16342792107dSMike Rapoport depends on BROKEN 1635b263295dSChristoph Lameter 1636506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1637506f1d07SSam Ravnborg def_bool y 16386ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1639506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1640506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1641506f1d07SSam Ravnborg 16423b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16436ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16443b16651fSTejun Heo 1645506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1646506f1d07SSam Ravnborg def_bool y 1647b263295dSChristoph Lameter depends on ARCH_SPARSEMEM_ENABLE 1648506f1d07SSam Ravnborg 1649506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1650a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16513120e25eSJan Beulich depends on X86_64 && MEMORY_HOTPLUG 1652a0842b70SToshi Kani help 1653a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1654cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1655a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1656506f1d07SSam Ravnborg 16573b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16583b16651fSTejun Heo def_bool y 16593b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16603b16651fSTejun Heo 1661a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1662a29815a3SAvi Kivity hex 1663a29815a3SAvi Kivity default 0 if X86_32 1664a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1665a29815a3SAvi Kivity 16667a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16677a67832cSDan Williams bool 16687a67832cSDan Williams 1669ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16707a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16719f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16729f53f9faSDan Williams depends on BLK_DEV 16737a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16749f53f9faSDan Williams select LIBNVDIMM 1675ec776ef6SChristoph Hellwig help 1676ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1677ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1678ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1679ec776ef6SChristoph Hellwig they can be used for persistent storage. 1680ec776ef6SChristoph Hellwig 1681ec776ef6SChristoph Hellwig Say Y if unsure. 1682ec776ef6SChristoph Hellwig 1683506f1d07SSam Ravnborgconfig HIGHPTE 1684506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16856fc108a0SJan Beulich depends on HIGHMEM 16868f9ca475SIngo Molnar ---help--- 1687506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1688506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1689506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1690506f1d07SSam Ravnborg entries in high memory. 1691506f1d07SSam Ravnborg 16929f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16939f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 16948f9ca475SIngo Molnar ---help--- 16959f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16969f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16979f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16989f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16999f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 17009f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 17019f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 17028c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 17039f077871SJeremy Fitzhardinge 17049f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 17059f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 17069f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 17079f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 17089f077871SJeremy Fitzhardinge 17099f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 17109f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 17119f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 17129f077871SJeremy Fitzhardinge memory. 17139f077871SJeremy Fitzhardinge 1714c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1715c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1716c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1717c885df50SJeremy Fitzhardinge default y 17188f9ca475SIngo Molnar ---help--- 1719c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1720c885df50SJeremy Fitzhardinge on or off. 1721c885df50SJeremy Fitzhardinge 17229ea77bdbSH. Peter Anvinconfig X86_RESERVE_LOW 1723d0cd7425SH. Peter Anvin int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1724d0cd7425SH. Peter Anvin default 64 1725d0cd7425SH. Peter Anvin range 4 640 17268f9ca475SIngo Molnar ---help--- 1727d0cd7425SH. Peter Anvin Specify the amount of low memory to reserve for the BIOS. 1728fc381519SIngo Molnar 1729d0cd7425SH. Peter Anvin The first page contains BIOS data structures that the kernel 1730d0cd7425SH. Peter Anvin must not use, so that page must always be reserved. 1731fc381519SIngo Molnar 1732d0cd7425SH. Peter Anvin By default we reserve the first 64K of physical RAM, as a 1733d0cd7425SH. Peter Anvin number of BIOSes are known to corrupt that memory range 1734d0cd7425SH. Peter Anvin during events such as suspend/resume or monitor cable 1735d0cd7425SH. Peter Anvin insertion, so it must not be used by the kernel. 1736fc381519SIngo Molnar 1737d0cd7425SH. Peter Anvin You can set this to 4 if you are absolutely sure that you 1738d0cd7425SH. Peter Anvin trust the BIOS to get all its memory reservations and usages 1739d0cd7425SH. Peter Anvin right. If you know your BIOS have problems beyond the 1740d0cd7425SH. Peter Anvin default 64K area, you can set this to 640 to avoid using the 1741d0cd7425SH. Peter Anvin entire low memory range. 1742d0cd7425SH. Peter Anvin 1743d0cd7425SH. Peter Anvin If you have doubts about the BIOS (e.g. suspend/resume does 1744d0cd7425SH. Peter Anvin not work or there's kernel crashes after certain hardware 1745d0cd7425SH. Peter Anvin hotplug events) then you might want to enable 1746d0cd7425SH. Peter Anvin X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1747d0cd7425SH. Peter Anvin typical corruption patterns. 1748d0cd7425SH. Peter Anvin 1749d0cd7425SH. Peter Anvin Leave this to the default value of 64 if you are unsure. 1750fc381519SIngo Molnar 1751506f1d07SSam Ravnborgconfig MATH_EMULATION 1752506f1d07SSam Ravnborg bool 1753a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1754506f1d07SSam Ravnborg prompt "Math emulation" if X86_32 1755506f1d07SSam Ravnborg ---help--- 1756506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1757506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1758506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1759506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1760506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1761506f1d07SSam Ravnborg coprocessor or this emulation. 1762506f1d07SSam Ravnborg 1763506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1764506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1765506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1766506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1767506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1768506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1769506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1770506f1d07SSam Ravnborg intend to use this kernel on different machines. 1771506f1d07SSam Ravnborg 1772506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1773506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1774506f1d07SSam Ravnborg 1775506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1776506f1d07SSam Ravnborg kernel, it won't hurt. 1777506f1d07SSam Ravnborg 1778506f1d07SSam Ravnborgconfig MTRR 17796fc108a0SJan Beulich def_bool y 17806a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1781506f1d07SSam Ravnborg ---help--- 1782506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1783506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1784506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1785506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1786506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1787506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1788506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1789506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1790506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1791506f1d07SSam Ravnborg 1792506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1793506f1d07SSam Ravnborg control registers on other processors can be easily supported 1794506f1d07SSam Ravnborg as well: 1795506f1d07SSam Ravnborg 1796506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1797506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1798506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1799506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1800506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1801506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1802506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1803506f1d07SSam Ravnborg 1804506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1805506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1806506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1807506f1d07SSam Ravnborg 1808506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1809506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1810506f1d07SSam Ravnborg 1811cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1812506f1d07SSam Ravnborg 181395ffa243SYinghai Luconfig MTRR_SANITIZER 18142ffb3501SYinghai Lu def_bool y 181595ffa243SYinghai Lu prompt "MTRR cleanup support" 181695ffa243SYinghai Lu depends on MTRR 18178f9ca475SIngo Molnar ---help--- 1818aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1819aba3728cSThomas Gleixner add writeback entries. 182095ffa243SYinghai Lu 1821aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1822692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1823aba3728cSThomas Gleixner mtrr_chunk_size. 182495ffa243SYinghai Lu 18252ffb3501SYinghai Lu If unsure, say Y. 182695ffa243SYinghai Lu 182795ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1828f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1829f5098d62SYinghai Lu range 0 1 1830f5098d62SYinghai Lu default "0" 183195ffa243SYinghai Lu depends on MTRR_SANITIZER 18328f9ca475SIngo Molnar ---help--- 1833f5098d62SYinghai Lu Enable mtrr cleanup default value 183495ffa243SYinghai Lu 183512031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 183612031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 183712031a62SYinghai Lu range 0 7 183812031a62SYinghai Lu default "1" 183912031a62SYinghai Lu depends on MTRR_SANITIZER 18408f9ca475SIngo Molnar ---help--- 184112031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1842aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 184312031a62SYinghai Lu 18442e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18456fc108a0SJan Beulich def_bool y 18466a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18472a8a2719SIngo Molnar depends on MTRR 18488f9ca475SIngo Molnar ---help--- 18492e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1850042b78e4SVenki Pallipadi 18512e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18522e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18532e5d9c85Svenkatesh.pallipadi@intel.com 18542e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1855042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18562e5d9c85Svenkatesh.pallipadi@intel.com 18572e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18582e5d9c85Svenkatesh.pallipadi@intel.com 185946cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 186046cf98cdSVenkatesh Pallipadi def_bool y 186146cf98cdSVenkatesh Pallipadi depends on X86_PAT 186246cf98cdSVenkatesh Pallipadi 1863628c6246SH. Peter Anvinconfig ARCH_RANDOM 1864628c6246SH. Peter Anvin def_bool y 1865628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1866628c6246SH. Peter Anvin ---help--- 1867628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1868628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1869628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1870628c6246SH. Peter Anvin secure hardware random number generator. 1871628c6246SH. Peter Anvin 187251ae4a2dSH. Peter Anvinconfig X86_SMAP 187351ae4a2dSH. Peter Anvin def_bool y 187451ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 187551ae4a2dSH. Peter Anvin ---help--- 187651ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 187751ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 187851ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 187951ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 188051ae4a2dSH. Peter Anvin 188151ae4a2dSH. Peter Anvin If unsure, say Y. 188251ae4a2dSH. Peter Anvin 1883aa35f896SRicardo Nericonfig X86_INTEL_UMIP 1884796ebc81SRicardo Neri def_bool y 1885aa35f896SRicardo Neri depends on CPU_SUP_INTEL 1886aa35f896SRicardo Neri prompt "Intel User Mode Instruction Prevention" if EXPERT 1887aa35f896SRicardo Neri ---help--- 1888aa35f896SRicardo Neri The User Mode Instruction Prevention (UMIP) is a security 1889aa35f896SRicardo Neri feature in newer Intel processors. If enabled, a general 1890796ebc81SRicardo Neri protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1891796ebc81SRicardo Neri or STR instructions are executed in user mode. These instructions 1892796ebc81SRicardo Neri unnecessarily expose information about the hardware state. 1893796ebc81SRicardo Neri 1894796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1895796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1896796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1897796ebc81SRicardo Neri results are dummy. 1898aa35f896SRicardo Neri 189972e9b5feSDave Hansenconfig X86_INTEL_MPX 190072e9b5feSDave Hansen prompt "Intel MPX (Memory Protection Extensions)" 190172e9b5feSDave Hansen def_bool n 1902df3735c5SRik van Riel # Note: only available in 64-bit mode due to VMA flags shortage 1903df3735c5SRik van Riel depends on CPU_SUP_INTEL && X86_64 1904df3735c5SRik van Riel select ARCH_USES_HIGH_VMA_FLAGS 190572e9b5feSDave Hansen ---help--- 190672e9b5feSDave Hansen MPX provides hardware features that can be used in 190772e9b5feSDave Hansen conjunction with compiler-instrumented code to check 190872e9b5feSDave Hansen memory references. It is designed to detect buffer 190972e9b5feSDave Hansen overflow or underflow bugs. 191072e9b5feSDave Hansen 191172e9b5feSDave Hansen This option enables running applications which are 191272e9b5feSDave Hansen instrumented or otherwise use MPX. It does not use MPX 191372e9b5feSDave Hansen itself inside the kernel or to protect the kernel 191472e9b5feSDave Hansen against bad memory references. 191572e9b5feSDave Hansen 191672e9b5feSDave Hansen Enabling this option will make the kernel larger: 191772e9b5feSDave Hansen ~8k of kernel text and 36 bytes of data on a 64-bit 191872e9b5feSDave Hansen defconfig. It adds a long to the 'mm_struct' which 191972e9b5feSDave Hansen will increase the kernel memory overhead of each 192072e9b5feSDave Hansen process and adds some branches to paths used during 192172e9b5feSDave Hansen exec() and munmap(). 192272e9b5feSDave Hansen 1923cb1aaebeSMauro Carvalho Chehab For details, see Documentation/x86/intel_mpx.rst 192472e9b5feSDave Hansen 192572e9b5feSDave Hansen If unsure, say N. 192672e9b5feSDave Hansen 192735e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 1928284244a9SDave Hansen prompt "Intel Memory Protection Keys" 192935e97790SDave Hansen def_bool y 1930284244a9SDave Hansen # Note: only available in 64-bit mode 193135e97790SDave Hansen depends on CPU_SUP_INTEL && X86_64 193252c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 193352c8e601SIngo Molnar select ARCH_HAS_PKEYS 1934284244a9SDave Hansen ---help--- 1935284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1936284244a9SDave Hansen page-based protections, but without requiring modification of the 1937284244a9SDave Hansen page tables when an application changes protection domains. 1938284244a9SDave Hansen 19391eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1940284244a9SDave Hansen 1941284244a9SDave Hansen If unsure, say y. 194235e97790SDave Hansen 1943*db616173SMichal Hockochoice 1944*db616173SMichal Hocko prompt "TSX enable mode" 1945*db616173SMichal Hocko depends on CPU_SUP_INTEL 1946*db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1947*db616173SMichal Hocko help 1948*db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1949*db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1950*db616173SMichal Hocko can lead to a noticeable performance boost. 1951*db616173SMichal Hocko 1952*db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1953*db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1954*db616173SMichal Hocko will be more of those attacks discovered in the future. 1955*db616173SMichal Hocko 1956*db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1957*db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1958*db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1959*db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1960*db616173SMichal Hocko for the particular machine. 1961*db616173SMichal Hocko 1962*db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1963*db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1964*db616173SMichal Hocko details. 1965*db616173SMichal Hocko 1966*db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1967*db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1968*db616173SMichal Hocko relevant. 1969*db616173SMichal Hocko 1970*db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1971*db616173SMichal Hocko bool "off" 1972*db616173SMichal Hocko help 1973*db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1974*db616173SMichal Hocko 1975*db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1976*db616173SMichal Hocko bool "on" 1977*db616173SMichal Hocko help 1978*db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1979*db616173SMichal Hocko line parameter. 1980*db616173SMichal Hocko 1981*db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1982*db616173SMichal Hocko bool "auto" 1983*db616173SMichal Hocko help 1984*db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1985*db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1986*db616173SMichal Hockoendchoice 1987*db616173SMichal Hocko 1988506f1d07SSam Ravnborgconfig EFI 19899ba16087SJan Beulich bool "EFI runtime service support" 19905b83683fSHuang, Ying depends on ACPI 1991f6ce5002SSergey Vlasov select UCS2_STRING 1992022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 1993506f1d07SSam Ravnborg ---help--- 19948b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1995506f1d07SSam Ravnborg available (such as the EFI variable services). 1996506f1d07SSam Ravnborg 19978b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19988b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19998b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 20008b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 20018b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 20028b2cb7a8SHuang, Ying platforms. 2003506f1d07SSam Ravnborg 2004291f3632SMatt Flemingconfig EFI_STUB 2005291f3632SMatt Fleming bool "EFI stub support" 2006b16d8c23SMatt Fleming depends on EFI && !X86_USE_3DNOW 20077b2a583aSMatt Fleming select RELOCATABLE 2008291f3632SMatt Fleming ---help--- 2009291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 2010291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 2011291f3632SMatt Fleming 20124f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 20130c759662SMatt Fleming 20147d453eeeSMatt Flemingconfig EFI_MIXED 20157d453eeeSMatt Fleming bool "EFI mixed-mode support" 20167d453eeeSMatt Fleming depends on EFI_STUB && X86_64 20177d453eeeSMatt Fleming ---help--- 20187d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 20197d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 20207d453eeeSMatt Fleming mode. 20217d453eeeSMatt Fleming 20227d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 20237d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 20247d453eeeSMatt Fleming the EFI handover protocol must be used. 20257d453eeeSMatt Fleming 20267d453eeeSMatt Fleming If unsure, say N. 20277d453eeeSMatt Fleming 2028506f1d07SSam Ravnborgconfig SECCOMP 20293c2362e6SHarvey Harrison def_bool y 20303c2362e6SHarvey Harrison prompt "Enable seccomp to safely compute untrusted bytecode" 20318f9ca475SIngo Molnar ---help--- 2032506f1d07SSam Ravnborg This kernel feature is useful for number crunching applications 2033506f1d07SSam Ravnborg that may need to compute untrusted bytecode during their 2034506f1d07SSam Ravnborg execution. By using pipes or other transports made available to 2035506f1d07SSam Ravnborg the process as file descriptors supporting the read/write 2036506f1d07SSam Ravnborg syscalls, it's possible to isolate those applications in 2037506f1d07SSam Ravnborg their own address space using seccomp. Once seccomp is 20389c0bbee8SAlexey Dobriyan enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2039506f1d07SSam Ravnborg and the task is only allowed to execute a few safe syscalls 2040506f1d07SSam Ravnborg defined by each seccomp mode. 2041506f1d07SSam Ravnborg 2042506f1d07SSam Ravnborg If unsure, say Y. Only embedded should say N here. 2043506f1d07SSam Ravnborg 20448636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2045506f1d07SSam Ravnborg 2046506f1d07SSam Ravnborgconfig KEXEC 2047506f1d07SSam Ravnborg bool "kexec system call" 20482965faa5SDave Young select KEXEC_CORE 20498f9ca475SIngo Molnar ---help--- 2050506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2051506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2052506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2053506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2054506f1d07SSam Ravnborg 2055506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2056506f1d07SSam Ravnborg 2057506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2058506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2059bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2060bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2061bf220695SGeert Uytterhoeven made. 2062506f1d07SSam Ravnborg 206374ca317cSVivek Goyalconfig KEXEC_FILE 206474ca317cSVivek Goyal bool "kexec file based system call" 20652965faa5SDave Young select KEXEC_CORE 206674ca317cSVivek Goyal select BUILD_BIN2C 206774ca317cSVivek Goyal depends on X86_64 206874ca317cSVivek Goyal depends on CRYPTO=y 206974ca317cSVivek Goyal depends on CRYPTO_SHA256=y 207074ca317cSVivek Goyal ---help--- 207174ca317cSVivek Goyal This is new version of kexec system call. This system call is 207274ca317cSVivek Goyal file based and takes file descriptors as system call argument 207374ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 207474ca317cSVivek Goyal accepted by previous system call. 207574ca317cSVivek Goyal 2076b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2077b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2078b799a09fSAKASHI Takahiro 207999d5cadfSJiri Bohacconfig KEXEC_SIG 20808e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 208174ca317cSVivek Goyal depends on KEXEC_FILE 20828e7d8381SVivek Goyal ---help--- 208399d5cadfSJiri Bohac 208499d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 208599d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 208699d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 208799d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 208899d5cadfSJiri Bohac 208999d5cadfSJiri Bohac In addition to this option, you need to enable signature 209099d5cadfSJiri Bohac verification for the corresponding kernel image type being 209199d5cadfSJiri Bohac loaded in order for this to work. 209299d5cadfSJiri Bohac 209399d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 209499d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 209599d5cadfSJiri Bohac depends on KEXEC_SIG 209699d5cadfSJiri Bohac ---help--- 20978e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2098d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20998e7d8381SVivek Goyal 21008e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 21018e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 210299d5cadfSJiri Bohac depends on KEXEC_SIG 21038e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 21048e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 21058e7d8381SVivek Goyal ---help--- 21068e7d8381SVivek Goyal Enable bzImage signature verification support. 21078e7d8381SVivek Goyal 2108506f1d07SSam Ravnborgconfig CRASH_DUMP 210904b69447SPavel Machek bool "kernel crash dumps" 2110506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 21118f9ca475SIngo Molnar ---help--- 2112506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2113506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2114506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2115506f1d07SSam Ravnborg a specially reserved region and then later executed after 2116506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2117506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2118506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2119506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2120330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2121506f1d07SSam Ravnborg 21223ab83521SHuang Yingconfig KEXEC_JUMP 21236ea30386SKees Cook bool "kexec jump" 2124fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 21258f9ca475SIngo Molnar ---help--- 212689081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 212789081d17SHuang Ying code in physical address mode via KEXEC 21283ab83521SHuang Ying 2129506f1d07SSam Ravnborgconfig PHYSICAL_START 21306a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2131ceefccc9SH. Peter Anvin default "0x1000000" 21328f9ca475SIngo Molnar ---help--- 2133506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2134506f1d07SSam Ravnborg 2135506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2136506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2137506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2138506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2139506f1d07SSam Ravnborg address. 2140506f1d07SSam Ravnborg 2141506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2142506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2143506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2144506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2145506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2146506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2147506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2148506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2149506f1d07SSam Ravnborg 2150ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2151ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2152ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2153ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2154ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2155ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2156ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2157330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2158ceefccc9SH. Peter Anvin for more details about crash dumps. 2159506f1d07SSam Ravnborg 2160506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2161506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2162506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2163506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2164506f1d07SSam Ravnborg is present because there are users out there who continue to use 2165506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2166506f1d07SSam Ravnborg line. 2167506f1d07SSam Ravnborg 2168506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2169506f1d07SSam Ravnborg 2170506f1d07SSam Ravnborgconfig RELOCATABLE 217126717808SH. Peter Anvin bool "Build a relocatable kernel" 217226717808SH. Peter Anvin default y 21738f9ca475SIngo Molnar ---help--- 2174506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2175506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2176506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2177506f1d07SSam Ravnborg but are discarded at runtime. 2178506f1d07SSam Ravnborg 2179506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2180506f1d07SSam Ravnborg must live at a different physical address than the primary 2181506f1d07SSam Ravnborg kernel. 2182506f1d07SSam Ravnborg 2183506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2184506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21858ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2186506f1d07SSam Ravnborg 21878ab3820fSKees Cookconfig RANDOMIZE_BASE 2188e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21898ab3820fSKees Cook depends on RELOCATABLE 21906807c846SIngo Molnar default y 21918ab3820fSKees Cook ---help--- 2192e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2193e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2194e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2195e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2196e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2197e8581e3dSBaoquan He code internals. 2198e8581e3dSBaoquan He 2199ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2200ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2201ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2202ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2203ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2204ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2205ed9f007eSKees Cook 2206ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2207ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2208ed9f007eSKees Cook 512MB (8 bits of entropy). 22098ab3820fSKees Cook 2210a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2211e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2212e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2213ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2214ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2215ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2216ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2217ed9f007eSKees Cook theoretically possible, but the implementations are further 2218ed9f007eSKees Cook limited due to memory layouts. 2219e8581e3dSBaoquan He 22206807c846SIngo Molnar If unsure, say Y. 2221da2b6fb9SKees Cook 22228ab3820fSKees Cook# Relocation on x86 needs some additional build support 2223845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2224845adf72SH. Peter Anvin def_bool y 22258ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2226845adf72SH. Peter Anvin 2227506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2228a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 22298ab3820fSKees Cook default "0x200000" 2230a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2231a0215061SKees Cook range 0x200000 0x1000000 if X86_64 22328f9ca475SIngo Molnar ---help--- 2233506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2234506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2235506f1d07SSam Ravnborg address which meets above alignment restriction. 2236506f1d07SSam Ravnborg 2237506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2238506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2239506f1d07SSam Ravnborg address aligned to above value and run from there. 2240506f1d07SSam Ravnborg 2241506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2242506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2243506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2244506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2245506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2246506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2247506f1d07SSam Ravnborg above alignment restrictions. 2248506f1d07SSam Ravnborg 2249a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2250a0215061SKees Cook this value must be a multiple of 0x200000. 2251a0215061SKees Cook 2252506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2253506f1d07SSam Ravnborg 2254eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2255eedb92abSKirill A. Shutemov bool 2256eedb92abSKirill A. Shutemov ---help--- 2257eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2258eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2259eedb92abSKirill A. Shutemov 22600483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22610483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22620483e1faSThomas Garnier depends on X86_64 22630483e1faSThomas Garnier depends on RANDOMIZE_BASE 2264eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22650483e1faSThomas Garnier default RANDOMIZE_BASE 22660483e1faSThomas Garnier ---help--- 22670483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22680483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22690483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22700483e1faSThomas Garnier 22710483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22720483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22730483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22740483e1faSThomas Garnier addresses for each memory section. 22750483e1faSThomas Garnier 22766807c846SIngo Molnar If unsure, say Y. 22770483e1faSThomas Garnier 227890397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 227990397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 228090397a41SThomas Garnier depends on RANDOMIZE_MEMORY 228190397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 228290397a41SThomas Garnier default "0x0" 228390397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 228490397a41SThomas Garnier range 0x0 0x40 228590397a41SThomas Garnier ---help--- 228690397a41SThomas Garnier Define the padding in terabytes added to the existing physical 228790397a41SThomas Garnier memory size during kernel memory randomization. It is useful 228890397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 228990397a41SThomas Garnier address randomization. 229090397a41SThomas Garnier 229190397a41SThomas Garnier If unsure, leave at the default value. 229290397a41SThomas Garnier 2293506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2294bebd024eSThomas Gleixner def_bool y 229540b31360SStephen Rothwell depends on SMP 2296506f1d07SSam Ravnborg 229780aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 229880aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22992c922cd0SKees Cook depends on HOTPLUG_CPU 230080aa1dffSFenghua Yu ---help--- 230180aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 230280aa1dffSFenghua Yu 230380aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 230480aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 230580aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 230680aa1dffSFenghua Yu 230780aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 230880aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 230980aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 231080aa1dffSFenghua Yu 231180aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 231280aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 231380aa1dffSFenghua Yu 231480aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 231580aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 231680aa1dffSFenghua Yu be other CPU0 dependencies. 231780aa1dffSFenghua Yu 231880aa1dffSFenghua Yu Please make sure the dependencies are under your control before 231980aa1dffSFenghua Yu you enable this feature. 232080aa1dffSFenghua Yu 232180aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 232280aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 232380aa1dffSFenghua Yu parameter cpu0_hotplug. 232480aa1dffSFenghua Yu 2325a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2326a71c8bc5SFenghua Yu def_bool n 2327a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 23282c922cd0SKees Cook depends on HOTPLUG_CPU 2329a71c8bc5SFenghua Yu ---help--- 2330a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2331a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2332a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2333a71c8bc5SFenghua Yu 2334a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2335a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2336a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2337a71c8bc5SFenghua Yu 2338a71c8bc5SFenghua Yu If unsure, say N. 2339a71c8bc5SFenghua Yu 2340506f1d07SSam Ravnborgconfig COMPAT_VDSO 2341b0b49f26SAndy Lutomirski def_bool n 2342b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2343953fee1dSIngo Molnar depends on COMPAT_32 23448f9ca475SIngo Molnar ---help--- 2345b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2346b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2347b0b49f26SAndy Lutomirski indicated in its segment table. 2348e84446deSRandy Dunlap 2349b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2350b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2351b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2352b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2353b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2354506f1d07SSam Ravnborg 2355b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2356b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2357b0b49f26SAndy Lutomirski 2358b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2359b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2360b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2361b0b49f26SAndy Lutomirski 2362b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2363b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2364506f1d07SSam Ravnborg 23653dc33bd3SKees Cookchoice 23663dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23673dc33bd3SKees Cook depends on X86_64 2368625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23693dc33bd3SKees Cook help 23703dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23713dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23723dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23733dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23743dc33bd3SKees Cook 23753dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2376bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23773dc33bd3SKees Cook 23783dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23793dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23803dc33bd3SKees Cook to improve security. 23813dc33bd3SKees Cook 2382bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23833dc33bd3SKees Cook 23843dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2385bd49e16eSAndy Lutomirski bool "Full emulation" 23863dc33bd3SKees Cook help 2387bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2388bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2389bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2390bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2391bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2392bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2393bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2394bd49e16eSAndy Lutomirski 2395bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2396bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2397bd49e16eSAndy Lutomirski 2398bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2399bd49e16eSAndy Lutomirski bool "Emulate execution only" 2400bd49e16eSAndy Lutomirski help 2401bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2402bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2403bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2404bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2405bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2406bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2407bd49e16eSAndy Lutomirski buffer. 24083dc33bd3SKees Cook 24093dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 24103dc33bd3SKees Cook bool "None" 24113dc33bd3SKees Cook help 24123dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 24133dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 24143dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 24153dc33bd3SKees Cook will be reported to dmesg, so that either old or 24163dc33bd3SKees Cook malicious userspace programs can be identified. 24173dc33bd3SKees Cook 24183dc33bd3SKees Cookendchoice 24193dc33bd3SKees Cook 2420516cbf37STim Birdconfig CMDLINE_BOOL 2421516cbf37STim Bird bool "Built-in kernel command line" 24228f9ca475SIngo Molnar ---help--- 2423516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2424516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2425516cbf37STim Bird necessary or convenient to provide some or all of the 2426516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2427516cbf37STim Bird to not rely on the boot loader to provide them.) 2428516cbf37STim Bird 2429516cbf37STim Bird To compile command line arguments into the kernel, 2430516cbf37STim Bird set this option to 'Y', then fill in the 243169711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2432516cbf37STim Bird 2433516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2434516cbf37STim Bird should leave this option set to 'N'. 2435516cbf37STim Bird 2436516cbf37STim Birdconfig CMDLINE 2437516cbf37STim Bird string "Built-in kernel command string" 2438516cbf37STim Bird depends on CMDLINE_BOOL 2439516cbf37STim Bird default "" 24408f9ca475SIngo Molnar ---help--- 2441516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2442516cbf37STim Bird image and used at boot time. If the boot loader provides a 2443516cbf37STim Bird command line at boot time, it is appended to this string to 2444516cbf37STim Bird form the full kernel command line, when the system boots. 2445516cbf37STim Bird 2446516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2447516cbf37STim Bird change this behavior. 2448516cbf37STim Bird 2449516cbf37STim Bird In most cases, the command line (whether built-in or provided 2450516cbf37STim Bird by the boot loader) should specify the device for the root 2451516cbf37STim Bird file system. 2452516cbf37STim Bird 2453516cbf37STim Birdconfig CMDLINE_OVERRIDE 2454516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2455516cbf37STim Bird depends on CMDLINE_BOOL 24568f9ca475SIngo Molnar ---help--- 2457516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2458516cbf37STim Bird command line, and use ONLY the built-in command line. 2459516cbf37STim Bird 2460516cbf37STim Bird This is used to work around broken boot loaders. This should 2461516cbf37STim Bird be set to 'N' under normal conditions. 2462516cbf37STim Bird 2463a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2464a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2465a5b9e5a2SAndy Lutomirski default y 2466a5b9e5a2SAndy Lutomirski ---help--- 2467a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2468a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2469a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2470a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2471a5b9e5a2SAndy Lutomirski threading libraries. 2472a5b9e5a2SAndy Lutomirski 2473a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2474a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2475a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2476a5b9e5a2SAndy Lutomirski 2477a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2478a5b9e5a2SAndy Lutomirski 2479b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2480b700e7f0SSeth Jennings 2481506f1d07SSam Ravnborgendmenu 2482506f1d07SSam Ravnborg 24833072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24843072e413SMichal Hocko def_bool y 24853072e413SMichal Hocko depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 24863072e413SMichal Hocko 2487506f1d07SSam Ravnborgconfig ARCH_ENABLE_MEMORY_HOTPLUG 2488506f1d07SSam Ravnborg def_bool y 2489506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2490506f1d07SSam Ravnborg 249135551053SGary Hadeconfig ARCH_ENABLE_MEMORY_HOTREMOVE 249235551053SGary Hade def_bool y 249335551053SGary Hade depends on MEMORY_HOTPLUG 249435551053SGary Hade 2495e534c7c5SLee Schermerhornconfig USE_PERCPU_NUMA_NODE_ID 2496645a7919STejun Heo def_bool y 2497e534c7c5SLee Schermerhorn depends on NUMA 2498e534c7c5SLee Schermerhorn 24999491846fSKirill A. Shutemovconfig ARCH_ENABLE_SPLIT_PMD_PTLOCK 25009491846fSKirill A. Shutemov def_bool y 25019491846fSKirill A. Shutemov depends on X86_64 || X86_PAE 25029491846fSKirill A. Shutemov 2503c177c81eSNaoya Horiguchiconfig ARCH_ENABLE_HUGEPAGE_MIGRATION 2504c177c81eSNaoya Horiguchi def_bool y 2505c177c81eSNaoya Horiguchi depends on X86_64 && HUGETLB_PAGE && MIGRATION 2506c177c81eSNaoya Horiguchi 25079c670ea3SNaoya Horiguchiconfig ARCH_ENABLE_THP_MIGRATION 25089c670ea3SNaoya Horiguchi def_bool y 25099c670ea3SNaoya Horiguchi depends on X86_64 && TRANSPARENT_HUGEPAGE 25109c670ea3SNaoya Horiguchi 2511da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2512e279b6c1SSam Ravnborg 2513e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 25143c2362e6SHarvey Harrison def_bool y 251544556530SZhimin Gu depends on HIBERNATION 2516e279b6c1SSam Ravnborg 2517e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2518e279b6c1SSam Ravnborg 2519e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2520e279b6c1SSam Ravnborg 2521efafc8b2SFeng Tangsource "drivers/sfi/Kconfig" 2522efafc8b2SFeng Tang 2523a6b68076SAndi Kleenconfig X86_APM_BOOT 25246fc108a0SJan Beulich def_bool y 2525282e5aabSPaul Bolle depends on APM 2526a6b68076SAndi Kleen 2527e279b6c1SSam Ravnborgmenuconfig APM 2528e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2529efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2530e279b6c1SSam Ravnborg ---help--- 2531e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2532e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2533e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2534e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2535e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2536e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2537e279b6c1SSam Ravnborg 2538e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2539e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2540e279b6c1SSam Ravnborg 2541e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2542e279b6c1SSam Ravnborg machines with more than one CPU. 2543e279b6c1SSam Ravnborg 2544e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2545151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 25462dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2547e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2548e279b6c1SSam Ravnborg 2549e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2550e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2551e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2552e279b6c1SSam Ravnborg 2553e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2554e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2555e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2556e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2557e279b6c1SSam Ravnborg 2558e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2559e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2560e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2561e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2562e279b6c1SSam Ravnborg APM in your BIOS). 2563e279b6c1SSam Ravnborg 2564e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2565e279b6c1SSam Ravnborg "weird" problems: 2566e279b6c1SSam Ravnborg 2567e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2568e279b6c1SSam Ravnborg enabled. 2569e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2570e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2571e279b6c1SSam Ravnborg the "no387" option to the kernel 2572e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2573e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2574e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2575e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2576e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2577e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2578e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2579e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2580e279b6c1SSam Ravnborg 11) exchange RAM chips 2581e279b6c1SSam Ravnborg 12) exchange the motherboard. 2582e279b6c1SSam Ravnborg 2583e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2584e279b6c1SSam Ravnborg module will be called apm. 2585e279b6c1SSam Ravnborg 2586e279b6c1SSam Ravnborgif APM 2587e279b6c1SSam Ravnborg 2588e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2589e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 25908f9ca475SIngo Molnar ---help--- 2591e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2592e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2593e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2594e279b6c1SSam Ravnborg 2595e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2596e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2597e279b6c1SSam Ravnborg ---help--- 2598e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2599e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2600e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2601e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2602e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2603e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2604e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2605e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2606e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2607e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2608e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2609e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2610e279b6c1SSam Ravnborg this feature. 2611e279b6c1SSam Ravnborg 2612e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2613dd8af076SLen Brown depends on CPU_IDLE 2614e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 26158f9ca475SIngo Molnar ---help--- 2616e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2617e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2618e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2619e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2620e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2621e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2622e279b6c1SSam Ravnborg this option does nothing.) 2623e279b6c1SSam Ravnborg 2624e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2625e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 26268f9ca475SIngo Molnar ---help--- 2627e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2628e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2629e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2630e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2631e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2632e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2633e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2634e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2635e279b6c1SSam Ravnborg especially if you are using gpm. 2636e279b6c1SSam Ravnborg 2637e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2638e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 26398f9ca475SIngo Molnar ---help--- 2640e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2641e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2642e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2643e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2644e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2645e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2646e279b6c1SSam Ravnborg 2647e279b6c1SSam Ravnborgendif # APM 2648e279b6c1SSam Ravnborg 2649bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2650e279b6c1SSam Ravnborg 2651e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2652e279b6c1SSam Ravnborg 265327471fdbSAndy Henroidsource "drivers/idle/Kconfig" 265427471fdbSAndy Henroid 2655e279b6c1SSam Ravnborgendmenu 2656e279b6c1SSam Ravnborg 2657e279b6c1SSam Ravnborg 2658e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2659e279b6c1SSam Ravnborg 2660e279b6c1SSam Ravnborgchoice 2661e279b6c1SSam Ravnborg prompt "PCI access mode" 2662efefa6f6SIngo Molnar depends on X86_32 && PCI 2663e279b6c1SSam Ravnborg default PCI_GOANY 2664e279b6c1SSam Ravnborg ---help--- 2665e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2666e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2667e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2668e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2669e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2670e279b6c1SSam Ravnborg 2671e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2672e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2673e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2674e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2675e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2676e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2677e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2678e279b6c1SSam Ravnborg 2679e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2680e279b6c1SSam Ravnborg bool "BIOS" 2681e279b6c1SSam Ravnborg 2682e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2683e279b6c1SSam Ravnborg bool "MMConfig" 2684e279b6c1SSam Ravnborg 2685e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2686e279b6c1SSam Ravnborg bool "Direct" 2687e279b6c1SSam Ravnborg 26883ef0e1f8SAndres Salomonconfig PCI_GOOLPC 268976fb6570SDaniel Drake bool "OLPC XO-1" 26903ef0e1f8SAndres Salomon depends on OLPC 26913ef0e1f8SAndres Salomon 26922bdd1b03SAndres Salomonconfig PCI_GOANY 26932bdd1b03SAndres Salomon bool "Any" 26942bdd1b03SAndres Salomon 2695e279b6c1SSam Ravnborgendchoice 2696e279b6c1SSam Ravnborg 2697e279b6c1SSam Ravnborgconfig PCI_BIOS 26983c2362e6SHarvey Harrison def_bool y 2699efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2700e279b6c1SSam Ravnborg 2701e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2702e279b6c1SSam Ravnborgconfig PCI_DIRECT 27033c2362e6SHarvey Harrison def_bool y 27040aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2705e279b6c1SSam Ravnborg 2706e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2707b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2708b45c9f36SJan Kiszka default y 27098364e1f8SJan Kiszka depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2710b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2711e279b6c1SSam Ravnborg 27123ef0e1f8SAndres Salomonconfig PCI_OLPC 27132bdd1b03SAndres Salomon def_bool y 27142bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 27153ef0e1f8SAndres Salomon 2716b5401a96SAlex Nixonconfig PCI_XEN 2717b5401a96SAlex Nixon def_bool y 2718b5401a96SAlex Nixon depends on PCI && XEN 2719b5401a96SAlex Nixon select SWIOTLB_XEN 2720b5401a96SAlex Nixon 27218364e1f8SJan Kiszkaconfig MMCONF_FAM10H 27228364e1f8SJan Kiszka def_bool y 27238364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2724e279b6c1SSam Ravnborg 27253f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 27266a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 27276ea30386SKees Cook depends on PCI 27283f6ea84aSIra W. Snyder help 27293f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 27303f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 27313f6ea84aSIra W. Snyder not have ACPI. 27323f6ea84aSIra W. Snyder 273364a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 273464a5fed6SBjorn Helgaas is known to be incomplete. 273564a5fed6SBjorn Helgaas 273664a5fed6SBjorn Helgaas You should say N unless you know you need this. 273764a5fed6SBjorn Helgaas 27383a495511SWilliam Breathitt Grayconfig ISA_BUS 273917a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 27403a495511SWilliam Breathitt Gray help 274117a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 274217a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 274317a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 274417a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 274517a2a129SWilliam Breathitt Gray not have an ISA bus. 27463a495511SWilliam Breathitt Gray 27473a495511SWilliam Breathitt Gray If unsure, say N. 27483a495511SWilliam Breathitt Gray 27491c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2750e279b6c1SSam Ravnborgconfig ISA_DMA_API 27511c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 27521c00f016SDavid Rientjes default y 27531c00f016SDavid Rientjes help 27541c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 27551c00f016SDavid Rientjes If unsure, say Y. 2756e279b6c1SSam Ravnborg 275751e68d05SLinus Torvaldsif X86_32 275851e68d05SLinus Torvalds 2759e279b6c1SSam Ravnborgconfig ISA 2760e279b6c1SSam Ravnborg bool "ISA support" 27618f9ca475SIngo Molnar ---help--- 2762e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2763e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2764e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2765e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2766e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2767e279b6c1SSam Ravnborg 2768e279b6c1SSam Ravnborgconfig SCx200 2769e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 27708f9ca475SIngo Molnar ---help--- 2771e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2772e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2773e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2774e279b6c1SSam Ravnborg for other scx200_* drivers. 2775e279b6c1SSam Ravnborg 2776e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2777e279b6c1SSam Ravnborg 2778e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2779e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2780592913ecSJohn Stultz depends on SCx200 2781e279b6c1SSam Ravnborg default y 27828f9ca475SIngo Molnar ---help--- 2783e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2784e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2785e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2786e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2787e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2788e279b6c1SSam Ravnborg 27893ef0e1f8SAndres Salomonconfig OLPC 27903ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 279154008979SThomas Gleixner depends on !X86_PAE 27923c554946SAndres Salomon select GPIOLIB 2793dc3119e7SThomas Gleixner select OF 279445bb1674SDaniel Drake select OF_PROMTREE 2795b4e51854SGrant Likely select IRQ_DOMAIN 27960c3d931bSLubomir Rintel select OLPC_EC 27978f9ca475SIngo Molnar ---help--- 27983ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27993ef0e1f8SAndres Salomon XO hardware. 28003ef0e1f8SAndres Salomon 2801a3128588SDaniel Drakeconfig OLPC_XO1_PM 2802a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2803fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2804bf1ebf00SDaniel Drake ---help--- 280597c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2806bf1ebf00SDaniel Drake 2807cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2808cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2809cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2810cfee9597SDaniel Drake ---help--- 2811cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2812cfee9597SDaniel Drake programmable wakeup source. 2813cfee9597SDaniel Drake 28147feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 28157feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 281692e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2817ed8e47feSRandy Dunlap depends on INPUT=y 2818d8d01a63SDaniel Drake select POWER_SUPPLY 28197feda8e9SDaniel Drake ---help--- 28207feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 28217bc74b3dSDaniel Drake - EC-driven system wakeups 28227feda8e9SDaniel Drake - Power button 28237bc74b3dSDaniel Drake - Ebook switch 28242cf2baeaSDaniel Drake - Lid switch 2825e1040ac6SDaniel Drake - AC adapter status updates 2826e1040ac6SDaniel Drake - Battery status updates 28277feda8e9SDaniel Drake 2828a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2829a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2830d8d01a63SDaniel Drake depends on OLPC && ACPI 2831d8d01a63SDaniel Drake select POWER_SUPPLY 2832a0f30f59SDaniel Drake ---help--- 2833a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2834a0f30f59SDaniel Drake - EC-driven system wakeups 2835a0f30f59SDaniel Drake - AC adapter status updates 2836a0f30f59SDaniel Drake - Battery status updates 2837e279b6c1SSam Ravnborg 2838d4f3e350SEd Wildgooseconfig ALIX 2839d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2840d4f3e350SEd Wildgoose select GPIOLIB 2841d4f3e350SEd Wildgoose ---help--- 2842d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2843d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2844d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2845d4f3e350SEd Wildgoose get added here. 2846d4f3e350SEd Wildgoose 2847d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2848d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2849d4f3e350SEd Wildgoose 2850d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2851d4f3e350SEd Wildgoose 2852da4e3302SPhilip Prindevilleconfig NET5501 2853da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2854da4e3302SPhilip Prindeville select GPIOLIB 2855da4e3302SPhilip Prindeville ---help--- 2856da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2857da4e3302SPhilip Prindeville 28583197059aSPhilip A. Prindevilleconfig GEOS 28593197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28603197059aSPhilip A. Prindeville select GPIOLIB 28613197059aSPhilip A. Prindeville depends on DMI 28623197059aSPhilip A. Prindeville ---help--- 28633197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28643197059aSPhilip A. Prindeville 28657d029125SVivien Didelotconfig TS5500 28667d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28677d029125SVivien Didelot depends on MELAN 28687d029125SVivien Didelot select CHECK_SIGNATURE 28697d029125SVivien Didelot select NEW_LEDS 28707d029125SVivien Didelot select LEDS_CLASS 28717d029125SVivien Didelot ---help--- 28727d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28737d029125SVivien Didelot 2874e279b6c1SSam Ravnborgendif # X86_32 2875e279b6c1SSam Ravnborg 287623ac4ae8SAndreas Herrmannconfig AMD_NB 2877e279b6c1SSam Ravnborg def_bool y 28780e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2879e279b6c1SSam Ravnborg 2880e3263ab3SDavid Herrmannconfig X86_SYSFB 2881e3263ab3SDavid Herrmann bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2882e3263ab3SDavid Herrmann help 2883e3263ab3SDavid Herrmann Firmwares often provide initial graphics framebuffers so the BIOS, 2884e3263ab3SDavid Herrmann bootloader or kernel can show basic video-output during boot for 2885e3263ab3SDavid Herrmann user-guidance and debugging. Historically, x86 used the VESA BIOS 2886e3263ab3SDavid Herrmann Extensions and EFI-framebuffers for this, which are mostly limited 2887e3263ab3SDavid Herrmann to x86. 2888e3263ab3SDavid Herrmann This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2889e3263ab3SDavid Herrmann framebuffers so the new generic system-framebuffer drivers can be 2890e3263ab3SDavid Herrmann used on x86. If the framebuffer is not compatible with the generic 2891e3a5dc08SNikolas Nyby modes, it is advertised as fallback platform framebuffer so legacy 2892e3263ab3SDavid Herrmann drivers like efifb, vesafb and uvesafb can pick it up. 2893e3263ab3SDavid Herrmann If this option is not selected, all system framebuffers are always 2894e3263ab3SDavid Herrmann marked as fallback platform framebuffers as usual. 2895e3263ab3SDavid Herrmann 2896e3263ab3SDavid Herrmann Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2897e3263ab3SDavid Herrmann not be able to pick up generic system framebuffers if this option 2898e3263ab3SDavid Herrmann is selected. You are highly encouraged to enable simplefb as 2899e3263ab3SDavid Herrmann replacement if you select this option. simplefb can correctly deal 2900e3263ab3SDavid Herrmann with generic system framebuffers. But you should still keep vesafb 2901e3263ab3SDavid Herrmann and others enabled as fallback if a system framebuffer is 2902e3263ab3SDavid Herrmann incompatible with simplefb. 2903e3263ab3SDavid Herrmann 2904e3263ab3SDavid Herrmann If unsure, say Y. 2905e3263ab3SDavid Herrmann 2906e279b6c1SSam Ravnborgendmenu 2907e279b6c1SSam Ravnborg 2908e279b6c1SSam Ravnborg 29091572497cSChristoph Hellwigmenu "Binary Emulations" 2910e279b6c1SSam Ravnborg 2911e279b6c1SSam Ravnborgconfig IA32_EMULATION 2912e279b6c1SSam Ravnborg bool "IA32 Emulation" 2913e279b6c1SSam Ravnborg depends on X86_64 291439f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2915d1603990SRandy Dunlap select BINFMT_ELF 2916a97f52e6SRoland McGrath select COMPAT_BINFMT_ELF 291739f88911SIngo Molnar select COMPAT_OLD_SIGACTION 29188f9ca475SIngo Molnar ---help--- 29195fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 29205fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 29215fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2922e279b6c1SSam Ravnborg 2923e279b6c1SSam Ravnborgconfig IA32_AOUT 2924e279b6c1SSam Ravnborg tristate "IA32 a.out support" 29256b213e1bSDavid Woodhouse depends on IA32_EMULATION 2926eac61655SBorislav Petkov depends on BROKEN 29278f9ca475SIngo Molnar ---help--- 2928e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2929e279b6c1SSam Ravnborg 29300bf62763SH. Peter Anvinconfig X86_X32 29316ea30386SKees Cook bool "x32 ABI for 64-bit mode" 29329b54050bSBrian Gerst depends on X86_64 29335fd92e65SH. J. Lu ---help--- 29345fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 29355fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 29365fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 29375fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 29385fd92e65SH. J. Lu 29395fd92e65SH. J. Lu You will need a recent binutils (2.22 or later) with 29405fd92e65SH. J. Lu elf32_x86_64 support enabled to compile a kernel with this 29415fd92e65SH. J. Lu option set. 29425fd92e65SH. J. Lu 2943953fee1dSIngo Molnarconfig COMPAT_32 2944953fee1dSIngo Molnar def_bool y 2945953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2946953fee1dSIngo Molnar select HAVE_UID16 2947953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2948953fee1dSIngo Molnar 2949e279b6c1SSam Ravnborgconfig COMPAT 29503c2362e6SHarvey Harrison def_bool y 29510bf62763SH. Peter Anvin depends on IA32_EMULATION || X86_X32 2952e279b6c1SSam Ravnborg 29533120e25eSJan Beulichif COMPAT 2954e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 29553120e25eSJan Beulich def_bool y 2956e279b6c1SSam Ravnborg 2957e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 29583c2362e6SHarvey Harrison def_bool y 29593120e25eSJan Beulich depends on SYSVIPC 29603120e25eSJan Beulichendif 2961ee009e4aSDavid Howells 2962e279b6c1SSam Ravnborgendmenu 2963e279b6c1SSam Ravnborg 2964e279b6c1SSam Ravnborg 2965e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2966e5beae16SKeith Packard def_bool y 2967e5beae16SKeith Packard depends on X86_32 2968e5beae16SKeith Packard 29694692d77fSAlessandro Rubiniconfig X86_DEV_DMA_OPS 29704692d77fSAlessandro Rubini bool 2971f7219a53SAlessandro Rubini 2972e279b6c1SSam Ravnborgsource "drivers/firmware/Kconfig" 2973e279b6c1SSam Ravnborg 2974edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 2975