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 27c12d3362SArd Biesheuvel select ARCH_SUPPORTS_INT128 if CC_HAS_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 760aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 77092b31aaSDan Williams select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 78d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 79d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 80ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 81ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 82ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 83c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 846471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 856471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 8677fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 875e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 883599fe12SThomas Gleixner select ARCH_STACKWALK 892c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 906471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 916471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 926471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 936471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 946471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 95ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 9681c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 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 10010916706SShile Zhang select BUILDTIME_TABLE_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 1232ae27137SSteven Price select GENERIC_PTDUMP 1246471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1256471b825SIngo Molnar select GENERIC_STRNCPY_FROM_USER 1266471b825SIngo Molnar select GENERIC_STRNLEN_USER 1276471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1287ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 129550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 13039656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 1317edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1326471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1336471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1346471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1356471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1366471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 1376471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 138b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 139d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1400609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1416471b825SIngo Molnar select HAVE_ARCH_KGDB 1429e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1439e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1441b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 145271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1466471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 147f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 148afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1496471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1506471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 151a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 152e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 153c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1542ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1556471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1566471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1576471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 158c1bd55f9SJosh Triplett select HAVE_COPY_THREAD_TLS 1596471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 1606471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1619c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 162677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 16306aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 164562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 16503f5781bSWang YanQing select HAVE_EBPF_JIT 16658340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 1676630a8e5SChristoph Hellwig select HAVE_EISA 1685f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 16967a929e0SChristoph Hellwig select HAVE_FAST_GUP 170644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 1716471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 1726471b825SIngo Molnar select HAVE_FUNCTION_GRAPH_TRACER 1736471b825SIngo Molnar select HAVE_FUNCTION_TRACER 1746b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 1750067f129SK.Prasad select HAVE_HW_BREAKPOINT 1766471b825SIngo Molnar select HAVE_IDE 1776471b825SIngo Molnar select HAVE_IOREMAP_PROT 1786471b825SIngo Molnar select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 1796471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 1806471b825SIngo Molnar select HAVE_KERNEL_BZIP2 1816471b825SIngo Molnar select HAVE_KERNEL_GZIP 1826471b825SIngo Molnar select HAVE_KERNEL_LZ4 1836471b825SIngo Molnar select HAVE_KERNEL_LZMA 1846471b825SIngo Molnar select HAVE_KERNEL_LZO 1856471b825SIngo Molnar select HAVE_KERNEL_XZ 1866471b825SIngo Molnar select HAVE_KPROBES 1876471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 188540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 1896471b825SIngo Molnar select HAVE_KRETPROBES 1906471b825SIngo Molnar select HAVE_KVM 1916471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 1926471b825SIngo Molnar select HAVE_MEMBLOCK_NODE_MAP 1930102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 194ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 1959f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 19642a0bb3fSPetr Mladek select HAVE_NMI 1976471b825SIngo Molnar select HAVE_OPROFILE 1986471b825SIngo Molnar select HAVE_OPTPROBES 1996471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2006471b825SIngo Molnar select HAVE_PERF_EVENTS 201c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 20292e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 203eb01d42aSChristoph Hellwig select HAVE_PCI 204c5e63197SJiri Olsa select HAVE_PERF_REGS 205c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 206ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2076471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 2086415b38bSJiri Slaby select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 2093c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 210d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 211c763ea26SIngo Molnar select HAVE_STACK_VALIDATION if X86_64 212d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2136471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2146471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2157c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2167ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 21705736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 218c0185808SThomas Gleixner select IRQ_FORCED_THREADING 21986596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2202eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 221625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2226471b825SIngo Molnar select PERF_EVENTS 2233195ef59SPrarit Bhargava select RTC_LIB 224d6faca40SArnd Bergmann select RTC_MC146818_LIB 2256471b825SIngo Molnar select SPARSE_IRQ 22683fe27eaSPranith Kumar select SRCU 2276471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 22815f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2296471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2306471b825SIngo Molnar select VIRT_TO_BUS 2316471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2320c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 233*9e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 2347d8330a5SBalbir Singh 235ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2363120e25eSJan Beulich def_bool y 2373120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 238ba7e4d13SIngo Molnar 23951b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 24051b26adaSLinus Torvalds string 24151b26adaSLinus Torvalds default "elf32-i386" if X86_32 24251b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 24351b26adaSLinus Torvalds 24473531905SSam Ravnborgconfig ARCH_DEFCONFIG 245b9b39bfbSSam Ravnborg string 24673531905SSam Ravnborg default "arch/x86/configs/i386_defconfig" if X86_32 24773531905SSam Ravnborg default "arch/x86/configs/x86_64_defconfig" if X86_64 248b9b39bfbSSam Ravnborg 2498d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2503c2362e6SHarvey Harrison def_bool y 2518d5fffb9SSam Ravnborg 2528d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2533c2362e6SHarvey Harrison def_bool y 2548d5fffb9SSam Ravnborg 2558d5fffb9SSam Ravnborgconfig MMU 2563c2362e6SHarvey Harrison def_bool y 2578d5fffb9SSam Ravnborg 2589e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 2599e08f57dSDaniel Cashman default 28 if 64BIT 2609e08f57dSDaniel Cashman default 8 2619e08f57dSDaniel Cashman 2629e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 2639e08f57dSDaniel Cashman default 32 if 64BIT 2649e08f57dSDaniel Cashman default 16 2659e08f57dSDaniel Cashman 2669e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 2679e08f57dSDaniel Cashman default 8 2689e08f57dSDaniel Cashman 2699e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 2709e08f57dSDaniel Cashman default 16 2719e08f57dSDaniel Cashman 2728d5fffb9SSam Ravnborgconfig SBUS 2738d5fffb9SSam Ravnborg bool 2748d5fffb9SSam Ravnborg 2758d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 2763120e25eSJan Beulich def_bool y 2773120e25eSJan Beulich depends on ISA_DMA_API 2788d5fffb9SSam Ravnborg 2798d5fffb9SSam Ravnborgconfig GENERIC_BUG 2803c2362e6SHarvey Harrison def_bool y 2818d5fffb9SSam Ravnborg depends on BUG 282b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 283b93a531eSJan Beulich 284b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 285b93a531eSJan Beulich bool 2868d5fffb9SSam Ravnborg 2878d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 2883120e25eSJan Beulich def_bool y 2893120e25eSJan Beulich depends on ISA_DMA_API 2908d5fffb9SSam Ravnborg 2911032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 2921032c0baSSam Ravnborg def_bool y 2931032c0baSSam Ravnborg 2949a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 2959a0b8415Svenkatesh.pallipadi@intel.com def_bool y 2968d5fffb9SSam Ravnborg 2971b27d05bSPekka Enbergconfig ARCH_HAS_CACHE_LINE_SIZE 2981b27d05bSPekka Enberg def_bool y 2991b27d05bSPekka Enberg 300316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT 301316d097cSDave Hansen def_bool y 302316d097cSDave Hansen 303dd5af90aSMike Travisconfig HAVE_SETUP_PER_CPU_AREA 30489c9c4c5SBrian Gerst def_bool y 305b32ef636Stravis@sgi.com 30608fc4580STejun Heoconfig NEED_PER_CPU_EMBED_FIRST_CHUNK 30708fc4580STejun Heo def_bool y 30808fc4580STejun Heo 30908fc4580STejun Heoconfig NEED_PER_CPU_PAGE_FIRST_CHUNK 31011124411STejun Heo def_bool y 31111124411STejun Heo 312801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 313801e4062SJohannes Berg def_bool y 314801e4062SJohannes Berg 315f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 316f4cb5700SJohannes Berg def_bool y 317f4cb5700SJohannes Berg 31853313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB 31953313b2cSSteve Capper def_bool y 32053313b2cSSteve Capper 3218d5fffb9SSam Ravnborgconfig ZONE_DMA32 322e0fd24a3SJan Beulich def_bool y if X86_64 3238d5fffb9SSam Ravnborg 3248d5fffb9SSam Ravnborgconfig AUDIT_ARCH 325e0fd24a3SJan Beulich def_bool y if X86_64 3268d5fffb9SSam Ravnborg 3276a11f75bSAkinobu Mitaconfig ARCH_SUPPORTS_DEBUG_PAGEALLOC 3286a11f75bSAkinobu Mita def_bool y 3296a11f75bSAkinobu Mita 330d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 331d6f2d75aSAndrey Ryabinin hex 332d6f2d75aSAndrey Ryabinin depends on KASAN 333d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 334d6f2d75aSAndrey Ryabinin 33569575d38SShane Wangconfig HAVE_INTEL_TXT 33669575d38SShane Wang def_bool y 3376ea30386SKees Cook depends on INTEL_IOMMU && ACPI 33869575d38SShane Wang 3396b0c3d44SSam Ravnborgconfig X86_32_SMP 3406b0c3d44SSam Ravnborg def_bool y 3416b0c3d44SSam Ravnborg depends on X86_32 && SMP 3426b0c3d44SSam Ravnborg 3436b0c3d44SSam Ravnborgconfig X86_64_SMP 3446b0c3d44SSam Ravnborg def_bool y 3456b0c3d44SSam Ravnborg depends on X86_64 && SMP 3466b0c3d44SSam Ravnborg 347ccbeed3aSTejun Heoconfig X86_32_LAZY_GS 348ccbeed3aSTejun Heo def_bool y 3498458f8c2SMasahiro Yamada depends on X86_32 && !STACKPROTECTOR 350ccbeed3aSTejun Heo 3512b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3522b144498SSrikar Dronamraju def_bool y 3532b144498SSrikar Dronamraju 354d20642f0SRob Herringconfig FIX_EARLYCON_MEM 355d20642f0SRob Herring def_bool y 356d20642f0SRob Herring 35794d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 35894d49eb3SKirill A. Shutemov bool 35994d49eb3SKirill A. Shutemov 36098233368SKirill A. Shutemovconfig PGTABLE_LEVELS 36198233368SKirill A. Shutemov int 36277ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 36398233368SKirill A. Shutemov default 4 if X86_64 36498233368SKirill A. Shutemov default 3 if X86_PAE 36598233368SKirill A. Shutemov default 2 36698233368SKirill A. Shutemov 3672a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3682a61f474SMasahiro Yamada bool 3692a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3702a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3712a61f474SMasahiro Yamada help 3722a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3732a61f474SMasahiro Yamada the compiler produces broken code. 3742a61f474SMasahiro Yamada 375506f1d07SSam Ravnborgmenu "Processor type and features" 376506f1d07SSam Ravnborg 3775ee71535SRandy Dunlapconfig ZONE_DMA 3785ee71535SRandy Dunlap bool "DMA memory allocation support" if EXPERT 3795ee71535SRandy Dunlap default y 3805ee71535SRandy Dunlap help 3815ee71535SRandy Dunlap DMA memory allocation support allows devices with less than 32-bit 3825ee71535SRandy Dunlap addressing to allocate within the first 16MB of address space. 3835ee71535SRandy Dunlap Disable if no such devices will be used. 3845ee71535SRandy Dunlap 3855ee71535SRandy Dunlap If unsure, say Y. 3865ee71535SRandy Dunlap 387506f1d07SSam Ravnborgconfig SMP 388506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 389506f1d07SSam Ravnborg ---help--- 390506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 3914a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 3924a474157SRobert Graffham than one CPU, say Y. 393506f1d07SSam Ravnborg 3944a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 395506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 396506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 3974a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 398506f1d07SSam Ravnborg will run faster if you say N here. 399506f1d07SSam Ravnborg 400506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 401506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 402506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 403506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 404506f1d07SSam Ravnborg 405506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 406506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 407506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 408506f1d07SSam Ravnborg 409cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4104f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 411506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 412506f1d07SSam Ravnborg 413506f1d07SSam Ravnborg If you don't know what to do here, say N. 414506f1d07SSam Ravnborg 4159def39beSJosh Triplettconfig X86_FEATURE_NAMES 4169def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4179def39beSJosh Triplett default y 4189def39beSJosh Triplett ---help--- 4199def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4209def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4219def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4229def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4239def39beSJosh Triplett 4249def39beSJosh Triplett If in doubt, say Y. 4259def39beSJosh Triplett 42606cd9a7dSYinghai Luconfig X86_X2APIC 42706cd9a7dSYinghai Lu bool "Support x2apic" 42819e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 42906cd9a7dSYinghai Lu ---help--- 43006cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 43106cd9a7dSYinghai Lu 43206cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 43306cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 43406cd9a7dSYinghai Lu 43506cd9a7dSYinghai Lu If you don't know what to do here, say N. 43606cd9a7dSYinghai Lu 4376695c85bSYinghai Luconfig X86_MPPARSE 4386e87f9b7SBin Gao bool "Enable MPS table" if ACPI || SFI 4397a527688SJan Beulich default y 4405ab74722SIngo Molnar depends on X86_LOCAL_APIC 4418f9ca475SIngo Molnar ---help--- 4426695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4436695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4446695c85bSYinghai Lu 445ddd70cf9SJun Nakajimaconfig GOLDFISH 446ddd70cf9SJun Nakajima def_bool y 447ddd70cf9SJun Nakajima depends on X86_GOLDFISH 448ddd70cf9SJun Nakajima 44976b04384SDavid Woodhouseconfig RETPOLINE 45076b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 45176b04384SDavid Woodhouse default y 452d5028ba8SPeter Zijlstra select STACK_VALIDATION if HAVE_STACK_VALIDATION 45376b04384SDavid Woodhouse help 45476b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 45576b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 45676b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 45776b04384SDavid Woodhouse support for full protection. The kernel may run slower. 45876b04384SDavid Woodhouse 459e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 460e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4616fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 46259fe5a77SThomas Gleixner select KERNFS 463e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 46478e99b4aSFenghua Yu help 465e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4666fe07ce3SBabu Moger 4676fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4686fe07ce3SBabu Moger usage by the CPU. 4696fe07ce3SBabu Moger 4706fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4716fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4726fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4736fe07ce3SBabu Moger 4746fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4756fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4766fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 47778e99b4aSFenghua Yu 47878e99b4aSFenghua Yu Say N if unsure. 47978e99b4aSFenghua Yu 4808425091fSRavikiran G Thirumalaiif X86_32 481a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 482a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 483a0d0bb4dSRandy Dunlap depends on SMP 484a0d0bb4dSRandy Dunlap ---help--- 485e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 486a0d0bb4dSRandy Dunlap 487c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 488c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 489c5c606d9SRavikiran G Thirumalai default y 4908f9ca475SIngo Molnar ---help--- 49106ac8346SIngo Molnar If you disable this option then the kernel will only support 49206ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 49306ac8346SIngo Molnar systems out there.) 49406ac8346SIngo Molnar 4958425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 4968425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 497cb7b8023SBen Hutchings Goldfish (Android emulator) 4988425091fSRavikiran G Thirumalai AMD Elan 4998425091fSRavikiran G Thirumalai RDC R-321x SoC 5008425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 50183125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5023f4110a4SThomas Gleixner Moorestown MID devices 50306ac8346SIngo Molnar 50406ac8346SIngo Molnar If you have one of these systems, or if you want to build a 50506ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5068425091fSRavikiran G Thirumalaiendif 50706ac8346SIngo Molnar 5088425091fSRavikiran G Thirumalaiif X86_64 5098425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5108425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5118425091fSRavikiran G Thirumalai default y 5128425091fSRavikiran G Thirumalai ---help--- 5138425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5148425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5158425091fSRavikiran G Thirumalai systems out there.) 5168425091fSRavikiran G Thirumalai 5178425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5188425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 51944b111b5SSteffen Persvold Numascale NumaChip 5208425091fSRavikiran G Thirumalai ScaleMP vSMP 5218425091fSRavikiran G Thirumalai SGI Ultraviolet 5228425091fSRavikiran G Thirumalai 5238425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5248425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5258425091fSRavikiran G Thirumalaiendif 526c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 527c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 52844b111b5SSteffen Persvoldconfig X86_NUMACHIP 52944b111b5SSteffen Persvold bool "Numascale NumaChip" 53044b111b5SSteffen Persvold depends on X86_64 53144b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 53244b111b5SSteffen Persvold depends on NUMA 53344b111b5SSteffen Persvold depends on SMP 53444b111b5SSteffen Persvold depends on X86_X2APIC 535f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 53644b111b5SSteffen Persvold ---help--- 53744b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 53844b111b5SSteffen Persvold enable more than ~168 cores. 53944b111b5SSteffen Persvold If you don't have one of these, you should say N here. 54003b48632SNick Piggin 5416a48565eSIngo Molnarconfig X86_VSMP 542c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5436276a074SBorislav Petkov select HYPERVISOR_GUEST 5446a48565eSIngo Molnar select PARAVIRT 5456a48565eSIngo Molnar depends on X86_64 && PCI 546c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 547ead91d4bSShai Fultheim depends on SMP 5488f9ca475SIngo Molnar ---help--- 5496a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5506a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5516a48565eSIngo Molnar if you have one of these machines. 5526a48565eSIngo Molnar 553c5c606d9SRavikiran G Thirumalaiconfig X86_UV 554c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 555c5c606d9SRavikiran G Thirumalai depends on X86_64 556c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 55754c28d29SJack Steiner depends on NUMA 5581ecb4ae5SAndrew Morton depends on EFI 5599d6c26e7SSuresh Siddha depends on X86_X2APIC 5601222e564SIngo Molnar depends on PCI 561c5c606d9SRavikiran G Thirumalai ---help--- 562c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 563c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 564c5c606d9SRavikiran G Thirumalai 565c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 566c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 567506f1d07SSam Ravnborg 568ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 569ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 570cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 571ddd70cf9SJun Nakajima ---help--- 572ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 573ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 574ddd70cf9SJun Nakajima Goldfish emulator say N here. 575ddd70cf9SJun Nakajima 576c751e17bSThomas Gleixnerconfig X86_INTEL_CE 577c751e17bSThomas Gleixner bool "CE4100 TV platform" 578c751e17bSThomas Gleixner depends on PCI 579c751e17bSThomas Gleixner depends on PCI_GODIRECT 5806084a6e2SJiang Liu depends on X86_IO_APIC 581c751e17bSThomas Gleixner depends on X86_32 582c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 58337bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 584da6b737bSSebastian Andrzej Siewior select OF 585da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 586c751e17bSThomas Gleixner ---help--- 587c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 588c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 589c751e17bSThomas Gleixner boxes and media devices. 590c751e17bSThomas Gleixner 5914cb9b00fSDavid Cohenconfig X86_INTEL_MID 59243605ef1SAlan Cox bool "Intel MID platform support" 59343605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 594edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 5951ea7c673SAlan Cox depends on PCI 5963fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 5971ea7c673SAlan Cox depends on X86_IO_APIC 5987c9c3a1eSAlan Cox select SFI 5994cb9b00fSDavid Cohen select I2C 6007c9c3a1eSAlan Cox select DW_APB_TIMER 6011ea7c673SAlan Cox select APB_TIMER 6021ea7c673SAlan Cox select INTEL_SCU_IPC 60315a713dfSMika Westerberg select MFD_INTEL_MSIC 6041ea7c673SAlan Cox ---help--- 6054cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6064cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6074cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6081ea7c673SAlan Cox 6094cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6104cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 61143605ef1SAlan Cox 6128bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6138bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6148bbc2a13SBryan O'Donoghue depends on X86_32 6158bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6168bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6178bbc2a13SBryan O'Donoghue depends on X86_TSC 6188bbc2a13SBryan O'Donoghue depends on PCI 6198bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6208bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6218bbc2a13SBryan O'Donoghue select IOSF_MBI 6228bbc2a13SBryan O'Donoghue select INTEL_IMR 6239ab6eb51SAndy Shevchenko select COMMON_CLK 6248bbc2a13SBryan O'Donoghue ---help--- 6258bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6268bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6278bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6288bbc2a13SBryan O'Donoghue 6293d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6303d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6315962dd22SSinan Kaya depends on X86 && ACPI && PCI 6323d48aab1SMika Westerberg select COMMON_CLK 6330f531431SMathias Nyman select PINCTRL 634eebb3e8dSAndy Shevchenko select IOSF_MBI 6353d48aab1SMika Westerberg ---help--- 6363d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6373d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6380f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6390f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6403d48aab1SMika Westerberg 64192082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 64292082a88SKen Xue bool "AMD ACPI2Platform devices support" 64392082a88SKen Xue depends on ACPI 64492082a88SKen Xue select COMMON_CLK 64592082a88SKen Xue select PINCTRL 64692082a88SKen Xue ---help--- 64792082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 64892082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 64992082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 65092082a88SKen Xue implemented under PINCTRL subsystem. 65192082a88SKen Xue 652ced3ce76SDavid E. Boxconfig IOSF_MBI 653ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 654ced3ce76SDavid E. Box depends on PCI 655ced3ce76SDavid E. Box ---help--- 656ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 657ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 658ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 659ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 660ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 661ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 662ced3ce76SDavid E. Box This list is not meant to be exclusive. 663ced3ce76SDavid E. Box - BayTrail 664ced3ce76SDavid E. Box - Braswell 665ced3ce76SDavid E. Box - Quark 666ced3ce76SDavid E. Box 667ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 668ced3ce76SDavid E. Box 669ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 670ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 671ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 672ed2226bdSDavid E. Box ---help--- 673ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 674ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 675ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 676ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 677ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 678ed2226bdSDavid E. Box device they want to access. 679ed2226bdSDavid E. Box 680ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 681ed2226bdSDavid E. Box 682c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 683c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 684506f1d07SSam Ravnborg depends on X86_32 685c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 686c5c606d9SRavikiran G Thirumalai select M486 687c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 688c5c606d9SRavikiran G Thirumalai ---help--- 689c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 690c5c606d9SRavikiran G Thirumalai as R-8610-(G). 691c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 692c5c606d9SRavikiran G Thirumalai 693e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 6949c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 6959c398017SIngo Molnar depends on X86_32 && SMP 696c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 6978f9ca475SIngo Molnar ---help--- 698b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 699b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 700b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 701b5660ba7SH. Peter Anvin one and will fallback to default. 702d49c4288SYinghai Lu 703c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 704d49c4288SYinghai Lu 705d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7066fc108a0SJan Beulich def_bool y 707d949f36fSLinus Torvalds # MCE code calls memory_failure(): 708d949f36fSLinus Torvalds depends on X86_MCE 709d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 710d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 711d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 712d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 713d949f36fSLinus Torvalds 71483125a3aSAlessandro Rubiniconfig STA2X11 71583125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 71683125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 71783125a3aSAlessandro Rubini select SWIOTLB 71883125a3aSAlessandro Rubini select MFD_STA2X11 7190145071bSLinus Walleij select GPIOLIB 72083125a3aSAlessandro Rubini ---help--- 72183125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 72283125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 72383125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 72483125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 72583125a3aSAlessandro Rubini standard PC machines. 72683125a3aSAlessandro Rubini 72782148d1dSShérabconfig X86_32_IRIS 72882148d1dSShérab tristate "Eurobraille/Iris poweroff module" 72982148d1dSShérab depends on X86_32 73082148d1dSShérab ---help--- 73182148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 73282148d1dSShérab to shut themselves down properly. A special I/O sequence is 73382148d1dSShérab needed to do so, which is what this module does at 73482148d1dSShérab kernel shutdown. 73582148d1dSShérab 73682148d1dSShérab This is only for Iris machines from EuroBraille. 73782148d1dSShérab 73882148d1dSShérab If unused, say N. 73982148d1dSShérab 740ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7413c2362e6SHarvey Harrison def_bool y 7423c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 743a87d0914SKen Chen depends on X86 7448f9ca475SIngo Molnar ---help--- 745506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 746506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 747506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 748506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 749506f1d07SSam Ravnborg 750506f1d07SSam Ravnborg If in doubt, say "Y". 751506f1d07SSam Ravnborg 7526276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7536276a074SBorislav Petkov bool "Linux guest support" 7548f9ca475SIngo Molnar ---help--- 7556276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7566276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7576276a074SBorislav Petkov setup. 758506f1d07SSam Ravnborg 7596276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7606276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 761506f1d07SSam Ravnborg 7626276a074SBorislav Petkovif HYPERVISOR_GUEST 763506f1d07SSam Ravnborg 764e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 765e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 7668f9ca475SIngo Molnar ---help--- 767e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 768e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 769e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 770e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 771e61bd94aSEduardo Pereira Habkost 772c00a280aSJuergen Grossconfig PARAVIRT_XXL 773c00a280aSJuergen Gross bool 774c00a280aSJuergen Gross 7756276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7766276a074SBorislav Petkov bool "paravirt-ops debugging" 7776276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 7786276a074SBorislav Petkov ---help--- 7796276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7806276a074SBorislav Petkov a paravirt_op is missing when it is called. 7816276a074SBorislav Petkov 782b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 783b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 7846ea30386SKees Cook depends on PARAVIRT && SMP 785b4ecc126SJeremy Fitzhardinge ---help--- 786b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 787b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 788b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 789b4ecc126SJeremy Fitzhardinge 7904c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 7914c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 792b4ecc126SJeremy Fitzhardinge 7934c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 794b4ecc126SJeremy Fitzhardinge 795ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 796ecca2502SZhao Yakui def_bool n 797ecca2502SZhao Yakui 7986276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 7996276a074SBorislav Petkov 8006276a074SBorislav Petkovconfig KVM_GUEST 8016276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8026276a074SBorislav Petkov depends on PARAVIRT 8036276a074SBorislav Petkov select PARAVIRT_CLOCK 804a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 8056276a074SBorislav Petkov default y 8066276a074SBorislav Petkov ---help--- 8076276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8086276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8096276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8106276a074SBorislav Petkov underlying device model, the host provides the guest with 8116276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8126276a074SBorislav Petkov 813a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 814a1c4423bSMarcelo Tosatti def_bool n 815a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 816a1c4423bSMarcelo Tosatti help 817a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 818a1c4423bSMarcelo Tosatti 8197733607fSMaran Wilsonconfig PVH 8207733607fSMaran Wilson bool "Support for running PVH guests" 8217733607fSMaran Wilson ---help--- 8227733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8237733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8247733607fSMaran Wilson 8251e20eb85SSrivatsa Vaddagiriconfig KVM_DEBUG_FS 8261e20eb85SSrivatsa Vaddagiri bool "Enable debug information for KVM Guests in debugfs" 8271e20eb85SSrivatsa Vaddagiri depends on KVM_GUEST && DEBUG_FS 8281e20eb85SSrivatsa Vaddagiri ---help--- 8291e20eb85SSrivatsa Vaddagiri This option enables collection of various statistics for KVM guest. 8301e20eb85SSrivatsa Vaddagiri Statistics are displayed in debugfs filesystem. Enabling this option 8311e20eb85SSrivatsa Vaddagiri may incur significant overhead. 8321e20eb85SSrivatsa Vaddagiri 8336276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8346276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8356276a074SBorislav Petkov depends on PARAVIRT 8366276a074SBorislav Petkov ---help--- 8376276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8386276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8396276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8406276a074SBorislav Petkov that, there can be a small performance impact. 8416276a074SBorislav Petkov 8426276a074SBorislav Petkov If in doubt, say N here. 8436276a074SBorislav Petkov 8447af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8457af192c9SGerd Hoffmann bool 8467af192c9SGerd Hoffmann 8474a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8484a362601SJan Kiszka bool "Jailhouse non-root cell support" 849abde587bSArnd Bergmann depends on X86_64 && PCI 85087e65d05SJan Kiszka select X86_PM_TIMER 8514a362601SJan Kiszka ---help--- 8524a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8534a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8544a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8554a362601SJan Kiszka 856ec7972c9SZhao Yakuiconfig ACRN_GUEST 857ec7972c9SZhao Yakui bool "ACRN Guest support" 858ec7972c9SZhao Yakui depends on X86_64 859498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 860ec7972c9SZhao Yakui help 861ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 862ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 863ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 864ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 865ec7972c9SZhao Yakui found in https://projectacrn.org/. 866ec7972c9SZhao Yakui 8676276a074SBorislav Petkovendif #HYPERVISOR_GUEST 86897349135SJeremy Fitzhardinge 869506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 870506f1d07SSam Ravnborg 871506f1d07SSam Ravnborgconfig HPET_TIMER 8723c2362e6SHarvey Harrison def_bool X86_64 873506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 8748f9ca475SIngo Molnar ---help--- 875506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 876506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 877506f1d07SSam Ravnborg present. 878506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 879506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 880506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8814e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 8824e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 883506f1d07SSam Ravnborg 884506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 885506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 886506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 887506f1d07SSam Ravnborg 888506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 889506f1d07SSam Ravnborg 890506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 8913c2362e6SHarvey Harrison def_bool y 8929d8af78bSBernhard Walle depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 893506f1d07SSam Ravnborg 894bb24c471SJacob Panconfig APB_TIMER 895933b9463SAlan Cox def_bool y if X86_INTEL_MID 896933b9463SAlan Cox prompt "Intel MID APB Timer Support" if X86_INTEL_MID 89706c3df49SJamie Iles select DW_APB_TIMER 898a0c3832aSAlan Cox depends on X86_INTEL_MID && SFI 899bb24c471SJacob Pan help 900bb24c471SJacob Pan APB timer is the replacement for 8254, HPET on X86 MID platforms. 901bb24c471SJacob Pan The APBT provides a stable time base on SMP 902bb24c471SJacob Pan systems, unlike the TSC, but it is more expensive to access, 903bb24c471SJacob Pan as it is off-chip. APB timers are always running regardless of CPU 904bb24c471SJacob Pan C states, they are used as per CPU clockevent device when possible. 905bb24c471SJacob Pan 9066a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 907506f1d07SSam Ravnborg# The code disables itself when not needed. 9087ae9392cSThomas Petazzoniconfig DMI 9097ae9392cSThomas Petazzoni default y 910cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9116a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 9128f9ca475SIngo Molnar ---help--- 9137ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9147ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9157ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9167ae9392cSThomas Petazzoni BIOS code. 9177ae9392cSThomas Petazzoni 918506f1d07SSam Ravnborgconfig GART_IOMMU 91938901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 920a4ce5a48SChristoph Hellwig select IOMMU_HELPER 921506f1d07SSam Ravnborg select SWIOTLB 92223ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 9238f9ca475SIngo Molnar ---help--- 924ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 925ced3c42cSIngo Molnar GART based hardware IOMMUs. 926ced3c42cSIngo Molnar 927ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 928ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 929ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 930ced3c42cSIngo Molnar 931ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 932ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 933ced3c42cSIngo Molnar 934ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 935ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 936ced3c42cSIngo Molnar 32-bit limited device. 937ced3c42cSIngo Molnar 938ced3c42cSIngo Molnar If unsure, say Y. 939506f1d07SSam Ravnborg 9401184dc2fSMike Travisconfig MAXSMP 941ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9426ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 94336f5101aSMike Travis select CPUMASK_OFFSTACK 9448f9ca475SIngo Molnar ---help--- 945ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9461184dc2fSMike Travis If unsure, say N. 947506f1d07SSam Ravnborg 948aec6487eSIngo Molnar# 949aec6487eSIngo Molnar# The maximum number of CPUs supported: 950aec6487eSIngo Molnar# 951aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 952aec6487eSIngo Molnar# and which can be configured interactively in the 953aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 954aec6487eSIngo Molnar# 955aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 956aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 957aec6487eSIngo Molnar# 958aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 959aec6487eSIngo Molnar# interactive configuration. ) 960aec6487eSIngo Molnar# 961a0d0bb4dSRandy Dunlap 962aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 963a0d0bb4dSRandy Dunlap int 964aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 965a0d0bb4dSRandy Dunlap default 1 if !SMP 966a0d0bb4dSRandy Dunlap default 2 967a0d0bb4dSRandy Dunlap 968aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 969a0d0bb4dSRandy Dunlap int 970a0d0bb4dSRandy Dunlap depends on X86_32 971aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 972aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 973a0d0bb4dSRandy Dunlap default 1 if !SMP 974a0d0bb4dSRandy Dunlap 975aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 976a0d0bb4dSRandy Dunlap int 977a0d0bb4dSRandy Dunlap depends on X86_64 9781edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9791edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 980a0d0bb4dSRandy Dunlap default 1 if !SMP 981aec6487eSIngo Molnar 982aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 983aec6487eSIngo Molnar int 984aec6487eSIngo Molnar depends on X86_32 985aec6487eSIngo Molnar default 32 if X86_BIGSMP 986aec6487eSIngo Molnar default 8 if SMP 987aec6487eSIngo Molnar default 1 if !SMP 988aec6487eSIngo Molnar 989aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 990aec6487eSIngo Molnar int 991aec6487eSIngo Molnar depends on X86_64 992a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 993a0d0bb4dSRandy Dunlap default 64 if SMP 994aec6487eSIngo Molnar default 1 if !SMP 995a0d0bb4dSRandy Dunlap 996506f1d07SSam Ravnborgconfig NR_CPUS 99736f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 998aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 999aec6487eSIngo Molnar default NR_CPUS_DEFAULT 10008f9ca475SIngo Molnar ---help--- 1001506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1002bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1003cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1004506f1d07SSam Ravnborg minimum value which makes sense is 2. 1005506f1d07SSam Ravnborg 1006aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1007aec6487eSIngo Molnar to the kernel image. 1008506f1d07SSam Ravnborg 1009506f1d07SSam Ravnborgconfig SCHED_SMT 1010dbe73364SThomas Gleixner def_bool y if SMP 1011506f1d07SSam Ravnborg 1012506f1d07SSam Ravnborgconfig SCHED_MC 10133c2362e6SHarvey Harrison def_bool y 10143c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1015c8e56d20SBorislav Petkov depends on SMP 10168f9ca475SIngo Molnar ---help--- 1017506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1018506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1019506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1020506f1d07SSam Ravnborg 1021de966cf4STim Chenconfig SCHED_MC_PRIO 1022de966cf4STim Chen bool "CPU core priorities scheduler support" 10230a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10240a21fc12SIngo Molnar select X86_INTEL_PSTATE 10250a21fc12SIngo Molnar select CPU_FREQ 1026de966cf4STim Chen default y 10275e76b2abSTim Chen ---help--- 1028de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1029de966cf4STim Chen core ordering determined at manufacturing time, which allows 1030de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1031de966cf4STim Chen single threaded workloads) than others. 1032de966cf4STim Chen 1033de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1034de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1035de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1036de966cf4STim Chen overall system performance can be achieved. 1037de966cf4STim Chen 1038de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1039de966cf4STim Chen 1040de966cf4STim Chen If unsure say Y here. 10415e76b2abSTim Chen 104230b8b006SThomas Gleixnerconfig UP_LATE_INIT 104330b8b006SThomas Gleixner def_bool y 1044ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 104530b8b006SThomas Gleixner 1046506f1d07SSam Ravnborgconfig X86_UP_APIC 104750849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 104850849eefSJan Beulich default PCI_MSI 104938a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 10508f9ca475SIngo Molnar ---help--- 1051506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1052506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1053506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1054506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1055506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1056506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1057506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1058506f1d07SSam Ravnborg lockups. 1059506f1d07SSam Ravnborg 1060506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1061506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1062506f1d07SSam Ravnborg depends on X86_UP_APIC 10638f9ca475SIngo Molnar ---help--- 1064506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1065506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1066506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1067506f1d07SSam Ravnborg 1068506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1069506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1070506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1071506f1d07SSam Ravnborg 1072506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10733c2362e6SHarvey Harrison def_bool y 10740dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1075b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 107652f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1077506f1d07SSam Ravnborg 1078506f1d07SSam Ravnborgconfig X86_IO_APIC 1079b1da1e71SJan Beulich def_bool y 1080b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1081506f1d07SSam Ravnborg 108241b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 108341b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 108441b9eb26SStefan Assmann depends on X86_IO_APIC 10858f9ca475SIngo Molnar ---help--- 108641b9eb26SStefan Assmann This option enables a workaround that fixes a source of 108741b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 108841b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 108941b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 109041b9eb26SStefan Assmann 109141b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 109241b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 109341b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 109441b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 109541b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 109641b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 109741b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 109841b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 109941b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 110041b9eb26SStefan Assmann down (vital) interrupt lines. 110141b9eb26SStefan Assmann 110241b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 110341b9eb26SStefan Assmann increased on these systems. 110441b9eb26SStefan Assmann 1105506f1d07SSam Ravnborgconfig X86_MCE 1106bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1107648ed940SChen, Gong select GENERIC_ALLOCATOR 1108e57dbaf7SBorislav Petkov default y 1109506f1d07SSam Ravnborg ---help--- 1110bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1111bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1112506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1113bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11144efc0670SAndi Kleen 11155de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11165de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11175de97c9fSTony Luck depends on X86_MCE 11185de97c9fSTony Luck ---help--- 11195de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11205de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11215de97c9fSTony Luck rasdaemon solution. 11225de97c9fSTony Luck 1123506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11243c2362e6SHarvey Harrison def_bool y 11253c2362e6SHarvey Harrison prompt "Intel MCE features" 1126c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 11278f9ca475SIngo Molnar ---help--- 1128506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1129506f1d07SSam Ravnborg the thermal monitor. 1130506f1d07SSam Ravnborg 1131506f1d07SSam Ravnborgconfig X86_MCE_AMD 11323c2362e6SHarvey Harrison def_bool y 11333c2362e6SHarvey Harrison prompt "AMD MCE features" 1134f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 11358f9ca475SIngo Molnar ---help--- 1136506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1137506f1d07SSam Ravnborg the DRAM Error Threshold. 1138506f1d07SSam Ravnborg 11394efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11406fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1141c31d9633SAndi Kleen depends on X86_32 && X86_MCE 11424efc0670SAndi Kleen ---help--- 11434efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11445065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11454efc0670SAndi Kleen line. 11464efc0670SAndi Kleen 1147b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1148b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11496fc108a0SJan Beulich def_bool y 1150b2762686SAndi Kleen 1151ea149b36SAndi Kleenconfig X86_MCE_INJECT 1152bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1153ea149b36SAndi Kleen tristate "Machine check injector support" 1154ea149b36SAndi Kleen ---help--- 1155ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1156ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1157ea149b36SAndi Kleen QA it is safe to say n. 1158ea149b36SAndi Kleen 11594efc0670SAndi Kleenconfig X86_THERMAL_VECTOR 11604efc0670SAndi Kleen def_bool y 11615bb38adcSAndi Kleen depends on X86_MCE_INTEL 11624efc0670SAndi Kleen 116307dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1164e633c65aSKan Liang 11655aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11661e642812SIngo Molnar bool "Legacy VM86 support" 1167506f1d07SSam Ravnborg depends on X86_32 11688f9ca475SIngo Molnar ---help--- 11695aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11705aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11715aef51c3SAndy Lutomirski 11725aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11735aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11745aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11755aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11765aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 11771e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 11781e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 11791e642812SIngo Molnar mode might be faster than emulation and you might want to 11801e642812SIngo Molnar enable this option. 11815aef51c3SAndy Lutomirski 11821e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 11831e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 11841e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 11851e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 11865aef51c3SAndy Lutomirski 11871e642812SIngo Molnar Enabling this option increases the complexity of the kernel 11881e642812SIngo Molnar and slows down exception handling a tiny bit. 11895aef51c3SAndy Lutomirski 11901e642812SIngo Molnar If unsure, say N here. 11915aef51c3SAndy Lutomirski 11925aef51c3SAndy Lutomirskiconfig VM86 11935aef51c3SAndy Lutomirski bool 11945aef51c3SAndy Lutomirski default X86_LEGACY_VM86 119534273f41SH. Peter Anvin 119634273f41SH. Peter Anvinconfig X86_16BIT 119734273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 119834273f41SH. Peter Anvin default y 1199a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 120034273f41SH. Peter Anvin ---help--- 120134273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 120234273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 120334273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 120434273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 120534273f41SH. Peter Anvin 120634273f41SH. Peter Anvinconfig X86_ESPFIX32 120734273f41SH. Peter Anvin def_bool y 120834273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1209506f1d07SSam Ravnborg 1210197725deSH. Peter Anvinconfig X86_ESPFIX64 1211197725deSH. Peter Anvin def_bool y 121234273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1213506f1d07SSam Ravnborg 12141ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12151ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12161ad83c85SAndy Lutomirski default y 12171ad83c85SAndy Lutomirski depends on X86_64 12181ad83c85SAndy Lutomirski ---help--- 12191ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12201ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12211ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12221ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12231ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12241ad83c85SAndy Lutomirski 0xffffffffff600?00. 12251ad83c85SAndy Lutomirski 12261ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12271ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12281ad83c85SAndy Lutomirski 12291ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12301ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12311ad83c85SAndy Lutomirski 1232111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1233111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1234a24ca997SThomas Gleixner default y 1235c8137aceSThomas Gleixner ---help--- 1236111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1237111e7b15SThomas Gleixner for legacy applications. 1238111e7b15SThomas Gleixner 1239c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1240c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1241c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1242c8137aceSThomas Gleixner capabilities and permission from potentially active security 1243c8137aceSThomas Gleixner modules. 1244c8137aceSThomas Gleixner 1245c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1246c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1247a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1248a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1249c8137aceSThomas Gleixner 1250506f1d07SSam Ravnborgconfig TOSHIBA 1251506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1252506f1d07SSam Ravnborg depends on X86_32 1253506f1d07SSam Ravnborg ---help--- 1254506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1255506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1256506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1257506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1258506f1d07SSam Ravnborg 1259506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1260506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1261506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1262506f1d07SSam Ravnborg 1263506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1264506f1d07SSam Ravnborg Say N otherwise. 1265506f1d07SSam Ravnborg 1266506f1d07SSam Ravnborgconfig I8K 1267039ae585SPali Rohár tristate "Dell i8k legacy laptop support" 1268949a9d70SJean Delvare select HWMON 1269039ae585SPali Rohár select SENSORS_DELL_SMM 1270506f1d07SSam Ravnborg ---help--- 1271039ae585SPali Rohár This option enables legacy /proc/i8k userspace interface in hwmon 1272039ae585SPali Rohár dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1273039ae585SPali Rohár temperature and allows controlling fan speeds of Dell laptops via 1274039ae585SPali Rohár System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1275039ae585SPali Rohár it reports also power and hotkey status. For fan speed control is 1276039ae585SPali Rohár needed userspace package i8kutils. 1277506f1d07SSam Ravnborg 1278039ae585SPali Rohár Say Y if you intend to run this kernel on old Dell laptops or want to 1279039ae585SPali Rohár use userspace package i8kutils. 1280506f1d07SSam Ravnborg Say N otherwise. 1281506f1d07SSam Ravnborg 1282506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12839ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12849ba16087SJan Beulich depends on X86_32 1285506f1d07SSam Ravnborg ---help--- 1286506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1287506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1288506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1289506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1290506f1d07SSam Ravnborg system. 1291506f1d07SSam Ravnborg 1292506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 12935e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1294506f1d07SSam Ravnborg 1295506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1296506f1d07SSam Ravnborg enable this option even if you don't need it. 1297506f1d07SSam Ravnborg Say N otherwise. 1298506f1d07SSam Ravnborg 1299506f1d07SSam Ravnborgconfig MICROCODE 13009a2bc335SBorislav Petkov bool "CPU microcode loading support" 13019a2bc335SBorislav Petkov default y 130280030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1303506f1d07SSam Ravnborg select FW_LOADER 1304506f1d07SSam Ravnborg ---help--- 1305506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13065f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13075f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13085f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13095f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13105f9c01aaSBorislav Petkov the Linux kernel. 1311506f1d07SSam Ravnborg 13125f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1313cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13145f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13155f9c01aaSBorislav Petkov initrd for microcode blobs. 1316506f1d07SSam Ravnborg 1317c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1318c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1319c508c46eSBenjamin Gilbert config option. 1320506f1d07SSam Ravnborg 13218d86f390SPeter Orubaconfig MICROCODE_INTEL 1322e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13238d86f390SPeter Oruba depends on MICROCODE 13248d86f390SPeter Oruba default MICROCODE 13258d86f390SPeter Oruba select FW_LOADER 13268f9ca475SIngo Molnar ---help--- 13278d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13288d86f390SPeter Oruba processors. 13298d86f390SPeter Oruba 1330b8989db9SAlan For the current Intel microcode data package go to 1331b8989db9SAlan <https://downloadcenter.intel.com> and search for 1332b8989db9SAlan 'Linux Processor Microcode Data File'. 13338d86f390SPeter Oruba 133480cc9f10SPeter Orubaconfig MICROCODE_AMD 1335e43f6e67SBorislav Petkov bool "AMD microcode loading support" 133680cc9f10SPeter Oruba depends on MICROCODE 133780cc9f10SPeter Oruba select FW_LOADER 13388f9ca475SIngo Molnar ---help--- 133980cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 134080cc9f10SPeter Oruba processors will be enabled. 134180cc9f10SPeter Oruba 1342506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1343c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1344c02f48e0SBorislav Petkov default n 1345506f1d07SSam Ravnborg depends on MICROCODE 1346c02f48e0SBorislav Petkov ---help--- 1347c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1348c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1349c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1350c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1351c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1352cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1353506f1d07SSam Ravnborg 1354506f1d07SSam Ravnborgconfig X86_MSR 1355506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 13568f9ca475SIngo Molnar ---help--- 1357506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1358506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1359506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1360506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1361506f1d07SSam Ravnborg systems. 1362506f1d07SSam Ravnborg 1363506f1d07SSam Ravnborgconfig X86_CPUID 1364506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 13658f9ca475SIngo Molnar ---help--- 1366506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1367506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1368506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1369506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1370506f1d07SSam Ravnborg 1371506f1d07SSam Ravnborgchoice 1372506f1d07SSam Ravnborg prompt "High Memory Support" 13736fc108a0SJan Beulich default HIGHMEM4G 1374506f1d07SSam Ravnborg depends on X86_32 1375506f1d07SSam Ravnborg 1376506f1d07SSam Ravnborgconfig NOHIGHMEM 1377506f1d07SSam Ravnborg bool "off" 1378506f1d07SSam Ravnborg ---help--- 1379506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1380506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1381506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1382506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1383506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1384506f1d07SSam Ravnborg "high memory". 1385506f1d07SSam Ravnborg 1386506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1387506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1388506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1389506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1390506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1391506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1392506f1d07SSam Ravnborg possible. 1393506f1d07SSam Ravnborg 1394506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1395506f1d07SSam Ravnborg answer "4GB" here. 1396506f1d07SSam Ravnborg 1397506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1398506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1399506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1400506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1401506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1402506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1403506f1d07SSam Ravnborg 1404506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1405506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1406506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1407506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1408506f1d07SSam Ravnborg kernel at boot time.) 1409506f1d07SSam Ravnborg 1410506f1d07SSam Ravnborg If unsure, say "off". 1411506f1d07SSam Ravnborg 1412506f1d07SSam Ravnborgconfig HIGHMEM4G 1413506f1d07SSam Ravnborg bool "4GB" 14148f9ca475SIngo Molnar ---help--- 1415506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1416506f1d07SSam Ravnborg gigabytes of physical RAM. 1417506f1d07SSam Ravnborg 1418506f1d07SSam Ravnborgconfig HIGHMEM64G 1419506f1d07SSam Ravnborg bool "64GB" 142069b8d3fcSMatthew Whitehead depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1421506f1d07SSam Ravnborg select X86_PAE 14228f9ca475SIngo Molnar ---help--- 1423506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1424506f1d07SSam Ravnborg gigabytes of physical RAM. 1425506f1d07SSam Ravnborg 1426506f1d07SSam Ravnborgendchoice 1427506f1d07SSam Ravnborg 1428506f1d07SSam Ravnborgchoice 14296a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1430506f1d07SSam Ravnborg default VMSPLIT_3G 1431506f1d07SSam Ravnborg depends on X86_32 14328f9ca475SIngo Molnar ---help--- 1433506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1434506f1d07SSam Ravnborg 1435506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1436506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1437506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1438506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1439506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1440506f1d07SSam Ravnborg available to user programs, making the address space there 1441506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1442506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1443506f1d07SSam Ravnborg kernel modules. 1444506f1d07SSam Ravnborg 1445506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1446506f1d07SSam Ravnborg option alone! 1447506f1d07SSam Ravnborg 1448506f1d07SSam Ravnborg config VMSPLIT_3G 1449506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1450506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1451506f1d07SSam Ravnborg depends on !X86_PAE 1452506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1453506f1d07SSam Ravnborg config VMSPLIT_2G 1454506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1455506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1456506f1d07SSam Ravnborg depends on !X86_PAE 1457506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1458506f1d07SSam Ravnborg config VMSPLIT_1G 1459506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1460506f1d07SSam Ravnborgendchoice 1461506f1d07SSam Ravnborg 1462506f1d07SSam Ravnborgconfig PAGE_OFFSET 1463506f1d07SSam Ravnborg hex 1464506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1465506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1466506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1467506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1468506f1d07SSam Ravnborg default 0xC0000000 1469506f1d07SSam Ravnborg depends on X86_32 1470506f1d07SSam Ravnborg 1471506f1d07SSam Ravnborgconfig HIGHMEM 14723c2362e6SHarvey Harrison def_bool y 1473506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1474506f1d07SSam Ravnborg 1475506f1d07SSam Ravnborgconfig X86_PAE 14769ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1477506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1478d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14799d99c712SChristian Melki select SWIOTLB 14808f9ca475SIngo Molnar ---help--- 1481506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1482506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1483506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1484506f1d07SSam Ravnborg consumes more pagetable space per process. 1485506f1d07SSam Ravnborg 148677ef56e4SKirill A. Shutemovconfig X86_5LEVEL 148777ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 148818ec1eafSKirill A. Shutemov default y 1489eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1490162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 149177ef56e4SKirill A. Shutemov depends on X86_64 149277ef56e4SKirill A. Shutemov ---help--- 149377ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 149477ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 149577ef56e4SKirill A. Shutemov physical address space. 149677ef56e4SKirill A. Shutemov 149777ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 149877ef56e4SKirill A. Shutemov 14996657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15006657fca0SKirill A. Shutemov support 4- or 5-level paging. 150177ef56e4SKirill A. Shutemov 1502cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 150377ef56e4SKirill A. Shutemov information. 150477ef56e4SKirill A. Shutemov 150577ef56e4SKirill A. Shutemov Say N if unsure. 150677ef56e4SKirill A. Shutemov 150710971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1508e5008abeSLuis R. Rodriguez def_bool y 15092e1da13fSVlastimil Babka depends on X86_64 15108f9ca475SIngo Molnar ---help--- 151110971ab2SIngo Molnar Certain kernel features effectively disable kernel 151210971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 151310971ab2SIngo Molnar supports them), so don't confuse the user by printing 151410971ab2SIngo Molnar that we have them enabled. 15159e899816SNick Piggin 15165c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15175c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15185c280cf6SThomas Gleixner depends on DEBUG_FS 15195c280cf6SThomas Gleixner ---help--- 1520b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1521a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15225c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15235c280cf6SThomas Gleixner 15247744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15257744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15267744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 152794d49eb3SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 1528ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 15299087c375STom Lendacky select ARCH_HAS_FORCE_DMA_UNENCRYPTED 15307744ccdbSTom Lendacky ---help--- 15317744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15327744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15337744ccdbSTom Lendacky Encryption (SME). 15347744ccdbSTom Lendacky 15357744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15367744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15377744ccdbSTom Lendacky default y 15387744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 15397744ccdbSTom Lendacky ---help--- 15407744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15417744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15427744ccdbSTom Lendacky 15437744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15447744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15457744ccdbSTom Lendacky 15467744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15477744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15487744ccdbSTom Lendacky 1549506f1d07SSam Ravnborg# Common NUMA Features 1550506f1d07SSam Ravnborgconfig NUMA 1551e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1552506f1d07SSam Ravnborg depends on SMP 1553b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1554b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15558f9ca475SIngo Molnar ---help--- 1556e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1557fd51b2d7SKOSAKI Motohiro 1558506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1559506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1560506f1d07SSam Ravnborg NUMA awareness to the kernel. 1561506f1d07SSam Ravnborg 1562c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1563fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1564fd51b2d7SKOSAKI Motohiro 1565b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15667cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1567fd51b2d7SKOSAKI Motohiro 1568fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1569506f1d07SSam Ravnborg 1570eec1d4faSHans Rosenfeldconfig AMD_NUMA 15713c2362e6SHarvey Harrison def_bool y 15723c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15735da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 15748f9ca475SIngo Molnar ---help--- 1575eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1576eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1577eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1578eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1579eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1580506f1d07SSam Ravnborg 1581506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15823c2362e6SHarvey Harrison def_bool y 15833c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1584506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1585506f1d07SSam Ravnborg select ACPI_NUMA 15868f9ca475SIngo Molnar ---help--- 1587506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1588506f1d07SSam Ravnborg 15896ec6e0d9SSuresh Siddha# Some NUMA nodes have memory ranges that span 15906ec6e0d9SSuresh Siddha# other nodes. Even though a pfn is valid and 15916ec6e0d9SSuresh Siddha# between a node's start and end pfns, it may not 15926ec6e0d9SSuresh Siddha# reside on that node. See memmap_init_zone() 15936ec6e0d9SSuresh Siddha# for details. 15946ec6e0d9SSuresh Siddhaconfig NODES_SPAN_OTHER_NODES 15956ec6e0d9SSuresh Siddha def_bool y 15966ec6e0d9SSuresh Siddha depends on X86_64_ACPI_NUMA 15976ec6e0d9SSuresh Siddha 1598506f1d07SSam Ravnborgconfig NUMA_EMU 1599506f1d07SSam Ravnborg bool "NUMA emulation" 16001b7e03efSTejun Heo depends on NUMA 16018f9ca475SIngo Molnar ---help--- 1602506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1603506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1604506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1605506f1d07SSam Ravnborg 1606506f1d07SSam Ravnborgconfig NODES_SHIFT 1607d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 160851591e31SDavid Rientjes range 1 10 160951591e31SDavid Rientjes default "10" if MAXSMP 1610506f1d07SSam Ravnborg default "6" if X86_64 1611506f1d07SSam Ravnborg default "3" 1612506f1d07SSam Ravnborg depends on NEED_MULTIPLE_NODES 16138f9ca475SIngo Molnar ---help--- 16141184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1615692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1616506f1d07SSam Ravnborg 1617506f1d07SSam Ravnborgconfig ARCH_HAVE_MEMORY_PRESENT 16183c2362e6SHarvey Harrison def_bool y 1619506f1d07SSam Ravnborg depends on X86_32 && DISCONTIGMEM 1620506f1d07SSam Ravnborg 1621506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1622506f1d07SSam Ravnborg def_bool y 16233b16651fSTejun Heo depends on X86_32 && !NUMA 1624506f1d07SSam Ravnborg 1625506f1d07SSam Ravnborgconfig ARCH_DISCONTIGMEM_ENABLE 16262792107dSMike Rapoport def_bool n 1627b263295dSChristoph Lameter depends on NUMA && X86_32 16282792107dSMike Rapoport depends on BROKEN 1629b263295dSChristoph Lameter 1630506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1631506f1d07SSam Ravnborg def_bool y 16326ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1633506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1634506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1635506f1d07SSam Ravnborg 16363b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16376ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16383b16651fSTejun Heo 1639506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1640506f1d07SSam Ravnborg def_bool y 1641b263295dSChristoph Lameter depends on ARCH_SPARSEMEM_ENABLE 1642506f1d07SSam Ravnborg 1643506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1644a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16453120e25eSJan Beulich depends on X86_64 && MEMORY_HOTPLUG 1646a0842b70SToshi Kani help 1647a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1648cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1649a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1650506f1d07SSam Ravnborg 16513b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16523b16651fSTejun Heo def_bool y 16533b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16543b16651fSTejun Heo 1655a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1656a29815a3SAvi Kivity hex 1657a29815a3SAvi Kivity default 0 if X86_32 1658a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1659a29815a3SAvi Kivity 16607a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16617a67832cSDan Williams bool 16627a67832cSDan Williams 1663ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16647a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16659f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16669f53f9faSDan Williams depends on BLK_DEV 16677a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16689f53f9faSDan Williams select LIBNVDIMM 1669ec776ef6SChristoph Hellwig help 1670ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1671ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1672ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1673ec776ef6SChristoph Hellwig they can be used for persistent storage. 1674ec776ef6SChristoph Hellwig 1675ec776ef6SChristoph Hellwig Say Y if unsure. 1676ec776ef6SChristoph Hellwig 1677506f1d07SSam Ravnborgconfig HIGHPTE 1678506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16796fc108a0SJan Beulich depends on HIGHMEM 16808f9ca475SIngo Molnar ---help--- 1681506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1682506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1683506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1684506f1d07SSam Ravnborg entries in high memory. 1685506f1d07SSam Ravnborg 16869f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16879f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 16888f9ca475SIngo Molnar ---help--- 16899f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16909f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16919f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16929f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16939f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16949f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16959f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16968c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16979f077871SJeremy Fitzhardinge 16989f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16999f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 17009f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 17019f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 17029f077871SJeremy Fitzhardinge 17039f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 17049f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 17059f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 17069f077871SJeremy Fitzhardinge memory. 17079f077871SJeremy Fitzhardinge 1708c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1709c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1710c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1711c885df50SJeremy Fitzhardinge default y 17128f9ca475SIngo Molnar ---help--- 1713c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1714c885df50SJeremy Fitzhardinge on or off. 1715c885df50SJeremy Fitzhardinge 17169ea77bdbSH. Peter Anvinconfig X86_RESERVE_LOW 1717d0cd7425SH. Peter Anvin int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1718d0cd7425SH. Peter Anvin default 64 1719d0cd7425SH. Peter Anvin range 4 640 17208f9ca475SIngo Molnar ---help--- 1721d0cd7425SH. Peter Anvin Specify the amount of low memory to reserve for the BIOS. 1722fc381519SIngo Molnar 1723d0cd7425SH. Peter Anvin The first page contains BIOS data structures that the kernel 1724d0cd7425SH. Peter Anvin must not use, so that page must always be reserved. 1725fc381519SIngo Molnar 1726d0cd7425SH. Peter Anvin By default we reserve the first 64K of physical RAM, as a 1727d0cd7425SH. Peter Anvin number of BIOSes are known to corrupt that memory range 1728d0cd7425SH. Peter Anvin during events such as suspend/resume or monitor cable 1729d0cd7425SH. Peter Anvin insertion, so it must not be used by the kernel. 1730fc381519SIngo Molnar 1731d0cd7425SH. Peter Anvin You can set this to 4 if you are absolutely sure that you 1732d0cd7425SH. Peter Anvin trust the BIOS to get all its memory reservations and usages 1733d0cd7425SH. Peter Anvin right. If you know your BIOS have problems beyond the 1734d0cd7425SH. Peter Anvin default 64K area, you can set this to 640 to avoid using the 1735d0cd7425SH. Peter Anvin entire low memory range. 1736d0cd7425SH. Peter Anvin 1737d0cd7425SH. Peter Anvin If you have doubts about the BIOS (e.g. suspend/resume does 1738d0cd7425SH. Peter Anvin not work or there's kernel crashes after certain hardware 1739d0cd7425SH. Peter Anvin hotplug events) then you might want to enable 1740d0cd7425SH. Peter Anvin X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1741d0cd7425SH. Peter Anvin typical corruption patterns. 1742d0cd7425SH. Peter Anvin 1743d0cd7425SH. Peter Anvin Leave this to the default value of 64 if you are unsure. 1744fc381519SIngo Molnar 1745506f1d07SSam Ravnborgconfig MATH_EMULATION 1746506f1d07SSam Ravnborg bool 1747a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 174887d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1749506f1d07SSam Ravnborg ---help--- 1750506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1751506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1752506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1753506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1754506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1755506f1d07SSam Ravnborg coprocessor or this emulation. 1756506f1d07SSam Ravnborg 1757506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1758506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1759506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1760506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1761506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1762506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1763506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1764506f1d07SSam Ravnborg intend to use this kernel on different machines. 1765506f1d07SSam Ravnborg 1766506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1767506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1768506f1d07SSam Ravnborg 1769506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1770506f1d07SSam Ravnborg kernel, it won't hurt. 1771506f1d07SSam Ravnborg 1772506f1d07SSam Ravnborgconfig MTRR 17736fc108a0SJan Beulich def_bool y 17746a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1775506f1d07SSam Ravnborg ---help--- 1776506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1777506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1778506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1779506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1780506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1781506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1782506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1783506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1784506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1785506f1d07SSam Ravnborg 1786506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1787506f1d07SSam Ravnborg control registers on other processors can be easily supported 1788506f1d07SSam Ravnborg as well: 1789506f1d07SSam Ravnborg 1790506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1791506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1792506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1793506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1794506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1795506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1796506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1797506f1d07SSam Ravnborg 1798506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1799506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1800506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1801506f1d07SSam Ravnborg 1802506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1803506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1804506f1d07SSam Ravnborg 1805cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1806506f1d07SSam Ravnborg 180795ffa243SYinghai Luconfig MTRR_SANITIZER 18082ffb3501SYinghai Lu def_bool y 180995ffa243SYinghai Lu prompt "MTRR cleanup support" 181095ffa243SYinghai Lu depends on MTRR 18118f9ca475SIngo Molnar ---help--- 1812aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1813aba3728cSThomas Gleixner add writeback entries. 181495ffa243SYinghai Lu 1815aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1816692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1817aba3728cSThomas Gleixner mtrr_chunk_size. 181895ffa243SYinghai Lu 18192ffb3501SYinghai Lu If unsure, say Y. 182095ffa243SYinghai Lu 182195ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1822f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1823f5098d62SYinghai Lu range 0 1 1824f5098d62SYinghai Lu default "0" 182595ffa243SYinghai Lu depends on MTRR_SANITIZER 18268f9ca475SIngo Molnar ---help--- 1827f5098d62SYinghai Lu Enable mtrr cleanup default value 182895ffa243SYinghai Lu 182912031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 183012031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 183112031a62SYinghai Lu range 0 7 183212031a62SYinghai Lu default "1" 183312031a62SYinghai Lu depends on MTRR_SANITIZER 18348f9ca475SIngo Molnar ---help--- 183512031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1836aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 183712031a62SYinghai Lu 18382e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18396fc108a0SJan Beulich def_bool y 18406a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18412a8a2719SIngo Molnar depends on MTRR 18428f9ca475SIngo Molnar ---help--- 18432e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1844042b78e4SVenki Pallipadi 18452e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18462e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18472e5d9c85Svenkatesh.pallipadi@intel.com 18482e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1849042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18502e5d9c85Svenkatesh.pallipadi@intel.com 18512e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18522e5d9c85Svenkatesh.pallipadi@intel.com 185346cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 185446cf98cdSVenkatesh Pallipadi def_bool y 185546cf98cdSVenkatesh Pallipadi depends on X86_PAT 185646cf98cdSVenkatesh Pallipadi 1857628c6246SH. Peter Anvinconfig ARCH_RANDOM 1858628c6246SH. Peter Anvin def_bool y 1859628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1860628c6246SH. Peter Anvin ---help--- 1861628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1862628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1863628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1864628c6246SH. Peter Anvin secure hardware random number generator. 1865628c6246SH. Peter Anvin 186651ae4a2dSH. Peter Anvinconfig X86_SMAP 186751ae4a2dSH. Peter Anvin def_bool y 186851ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 186951ae4a2dSH. Peter Anvin ---help--- 187051ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 187151ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 187251ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 187351ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 187451ae4a2dSH. Peter Anvin 187551ae4a2dSH. Peter Anvin If unsure, say Y. 187651ae4a2dSH. Peter Anvin 1877b971880fSBabu Mogerconfig X86_UMIP 1878796ebc81SRicardo Neri def_bool y 1879b971880fSBabu Moger depends on CPU_SUP_INTEL || CPU_SUP_AMD 1880b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1881aa35f896SRicardo Neri ---help--- 1882b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1883b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1884b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1885b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1886b971880fSBabu Moger information about the hardware state. 1887796ebc81SRicardo Neri 1888796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1889796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1890796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1891796ebc81SRicardo Neri results are dummy. 1892aa35f896SRicardo Neri 189335e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 1894284244a9SDave Hansen prompt "Intel Memory Protection Keys" 189535e97790SDave Hansen def_bool y 1896284244a9SDave Hansen # Note: only available in 64-bit mode 189735e97790SDave Hansen depends on CPU_SUP_INTEL && X86_64 189852c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 189952c8e601SIngo Molnar select ARCH_HAS_PKEYS 1900284244a9SDave Hansen ---help--- 1901284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1902284244a9SDave Hansen page-based protections, but without requiring modification of the 1903284244a9SDave Hansen page tables when an application changes protection domains. 1904284244a9SDave Hansen 19051eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1906284244a9SDave Hansen 1907284244a9SDave Hansen If unsure, say y. 190835e97790SDave Hansen 1909db616173SMichal Hockochoice 1910db616173SMichal Hocko prompt "TSX enable mode" 1911db616173SMichal Hocko depends on CPU_SUP_INTEL 1912db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1913db616173SMichal Hocko help 1914db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1915db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1916db616173SMichal Hocko can lead to a noticeable performance boost. 1917db616173SMichal Hocko 1918db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1919db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1920db616173SMichal Hocko will be more of those attacks discovered in the future. 1921db616173SMichal Hocko 1922db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1923db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1924db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1925db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1926db616173SMichal Hocko for the particular machine. 1927db616173SMichal Hocko 1928db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1929db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1930db616173SMichal Hocko details. 1931db616173SMichal Hocko 1932db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1933db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1934db616173SMichal Hocko relevant. 1935db616173SMichal Hocko 1936db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1937db616173SMichal Hocko bool "off" 1938db616173SMichal Hocko help 1939db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1940db616173SMichal Hocko 1941db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1942db616173SMichal Hocko bool "on" 1943db616173SMichal Hocko help 1944db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1945db616173SMichal Hocko line parameter. 1946db616173SMichal Hocko 1947db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1948db616173SMichal Hocko bool "auto" 1949db616173SMichal Hocko help 1950db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1951db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1952db616173SMichal Hockoendchoice 1953db616173SMichal Hocko 1954506f1d07SSam Ravnborgconfig EFI 19559ba16087SJan Beulich bool "EFI runtime service support" 19565b83683fSHuang, Ying depends on ACPI 1957f6ce5002SSergey Vlasov select UCS2_STRING 1958022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 1959506f1d07SSam Ravnborg ---help--- 19608b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1961506f1d07SSam Ravnborg available (such as the EFI variable services). 1962506f1d07SSam Ravnborg 19638b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19648b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19658b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19668b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19678b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19688b2cb7a8SHuang, Ying platforms. 1969506f1d07SSam Ravnborg 1970291f3632SMatt Flemingconfig EFI_STUB 1971291f3632SMatt Fleming bool "EFI stub support" 1972b16d8c23SMatt Fleming depends on EFI && !X86_USE_3DNOW 19738f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19747b2a583aSMatt Fleming select RELOCATABLE 1975291f3632SMatt Fleming ---help--- 1976291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1977291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1978291f3632SMatt Fleming 19794f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19800c759662SMatt Fleming 19817d453eeeSMatt Flemingconfig EFI_MIXED 19827d453eeeSMatt Fleming bool "EFI mixed-mode support" 19837d453eeeSMatt Fleming depends on EFI_STUB && X86_64 19847d453eeeSMatt Fleming ---help--- 19857d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19867d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19877d453eeeSMatt Fleming mode. 19887d453eeeSMatt Fleming 19897d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19907d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19917d453eeeSMatt Fleming the EFI handover protocol must be used. 19927d453eeeSMatt Fleming 19937d453eeeSMatt Fleming If unsure, say N. 19947d453eeeSMatt Fleming 1995506f1d07SSam Ravnborgconfig SECCOMP 19963c2362e6SHarvey Harrison def_bool y 19973c2362e6SHarvey Harrison prompt "Enable seccomp to safely compute untrusted bytecode" 19988f9ca475SIngo Molnar ---help--- 1999506f1d07SSam Ravnborg This kernel feature is useful for number crunching applications 2000506f1d07SSam Ravnborg that may need to compute untrusted bytecode during their 2001506f1d07SSam Ravnborg execution. By using pipes or other transports made available to 2002506f1d07SSam Ravnborg the process as file descriptors supporting the read/write 2003506f1d07SSam Ravnborg syscalls, it's possible to isolate those applications in 2004506f1d07SSam Ravnborg their own address space using seccomp. Once seccomp is 20059c0bbee8SAlexey Dobriyan enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2006506f1d07SSam Ravnborg and the task is only allowed to execute a few safe syscalls 2007506f1d07SSam Ravnborg defined by each seccomp mode. 2008506f1d07SSam Ravnborg 2009506f1d07SSam Ravnborg If unsure, say Y. Only embedded should say N here. 2010506f1d07SSam Ravnborg 20118636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2012506f1d07SSam Ravnborg 2013506f1d07SSam Ravnborgconfig KEXEC 2014506f1d07SSam Ravnborg bool "kexec system call" 20152965faa5SDave Young select KEXEC_CORE 20168f9ca475SIngo Molnar ---help--- 2017506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2018506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2019506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2020506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2021506f1d07SSam Ravnborg 2022506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2023506f1d07SSam Ravnborg 2024506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2025506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2026bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2027bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2028bf220695SGeert Uytterhoeven made. 2029506f1d07SSam Ravnborg 203074ca317cSVivek Goyalconfig KEXEC_FILE 203174ca317cSVivek Goyal bool "kexec file based system call" 20322965faa5SDave Young select KEXEC_CORE 203374ca317cSVivek Goyal select BUILD_BIN2C 203474ca317cSVivek Goyal depends on X86_64 203574ca317cSVivek Goyal depends on CRYPTO=y 203674ca317cSVivek Goyal depends on CRYPTO_SHA256=y 203774ca317cSVivek Goyal ---help--- 203874ca317cSVivek Goyal This is new version of kexec system call. This system call is 203974ca317cSVivek Goyal file based and takes file descriptors as system call argument 204074ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 204174ca317cSVivek Goyal accepted by previous system call. 204274ca317cSVivek Goyal 2043b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2044b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2045b799a09fSAKASHI Takahiro 204699d5cadfSJiri Bohacconfig KEXEC_SIG 20478e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 204874ca317cSVivek Goyal depends on KEXEC_FILE 20498e7d8381SVivek Goyal ---help--- 205099d5cadfSJiri Bohac 205199d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 205299d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 205399d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 205499d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 205599d5cadfSJiri Bohac 205699d5cadfSJiri Bohac In addition to this option, you need to enable signature 205799d5cadfSJiri Bohac verification for the corresponding kernel image type being 205899d5cadfSJiri Bohac loaded in order for this to work. 205999d5cadfSJiri Bohac 206099d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 206199d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 206299d5cadfSJiri Bohac depends on KEXEC_SIG 206399d5cadfSJiri Bohac ---help--- 20648e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2065d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20668e7d8381SVivek Goyal 20678e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20688e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 206999d5cadfSJiri Bohac depends on KEXEC_SIG 20708e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20718e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 20728e7d8381SVivek Goyal ---help--- 20738e7d8381SVivek Goyal Enable bzImage signature verification support. 20748e7d8381SVivek Goyal 2075506f1d07SSam Ravnborgconfig CRASH_DUMP 207604b69447SPavel Machek bool "kernel crash dumps" 2077506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 20788f9ca475SIngo Molnar ---help--- 2079506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2080506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2081506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2082506f1d07SSam Ravnborg a specially reserved region and then later executed after 2083506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2084506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2085506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2086506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2087330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2088506f1d07SSam Ravnborg 20893ab83521SHuang Yingconfig KEXEC_JUMP 20906ea30386SKees Cook bool "kexec jump" 2091fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 20928f9ca475SIngo Molnar ---help--- 209389081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 209489081d17SHuang Ying code in physical address mode via KEXEC 20953ab83521SHuang Ying 2096506f1d07SSam Ravnborgconfig PHYSICAL_START 20976a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2098ceefccc9SH. Peter Anvin default "0x1000000" 20998f9ca475SIngo Molnar ---help--- 2100506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2101506f1d07SSam Ravnborg 2102506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2103506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2104506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2105506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2106506f1d07SSam Ravnborg address. 2107506f1d07SSam Ravnborg 2108506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2109506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2110506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2111506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2112506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2113506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2114506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2115506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2116506f1d07SSam Ravnborg 2117ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2118ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2119ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2120ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2121ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2122ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2123ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2124330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2125ceefccc9SH. Peter Anvin for more details about crash dumps. 2126506f1d07SSam Ravnborg 2127506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2128506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2129506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2130506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2131506f1d07SSam Ravnborg is present because there are users out there who continue to use 2132506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2133506f1d07SSam Ravnborg line. 2134506f1d07SSam Ravnborg 2135506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2136506f1d07SSam Ravnborg 2137506f1d07SSam Ravnborgconfig RELOCATABLE 213826717808SH. Peter Anvin bool "Build a relocatable kernel" 213926717808SH. Peter Anvin default y 21408f9ca475SIngo Molnar ---help--- 2141506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2142506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2143506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2144506f1d07SSam Ravnborg but are discarded at runtime. 2145506f1d07SSam Ravnborg 2146506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2147506f1d07SSam Ravnborg must live at a different physical address than the primary 2148506f1d07SSam Ravnborg kernel. 2149506f1d07SSam Ravnborg 2150506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2151506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21528ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2153506f1d07SSam Ravnborg 21548ab3820fSKees Cookconfig RANDOMIZE_BASE 2155e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21568ab3820fSKees Cook depends on RELOCATABLE 21576807c846SIngo Molnar default y 21588ab3820fSKees Cook ---help--- 2159e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2160e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2161e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2162e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2163e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2164e8581e3dSBaoquan He code internals. 2165e8581e3dSBaoquan He 2166ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2167ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2168ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2169ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2170ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2171ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2172ed9f007eSKees Cook 2173ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2174ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2175ed9f007eSKees Cook 512MB (8 bits of entropy). 21768ab3820fSKees Cook 2177a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2178e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2179e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2180ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2181ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2182ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2183ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2184ed9f007eSKees Cook theoretically possible, but the implementations are further 2185ed9f007eSKees Cook limited due to memory layouts. 2186e8581e3dSBaoquan He 21876807c846SIngo Molnar If unsure, say Y. 2188da2b6fb9SKees Cook 21898ab3820fSKees Cook# Relocation on x86 needs some additional build support 2190845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2191845adf72SH. Peter Anvin def_bool y 21928ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2193845adf72SH. Peter Anvin 2194506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2195a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21968ab3820fSKees Cook default "0x200000" 2197a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2198a0215061SKees Cook range 0x200000 0x1000000 if X86_64 21998f9ca475SIngo Molnar ---help--- 2200506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2201506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2202506f1d07SSam Ravnborg address which meets above alignment restriction. 2203506f1d07SSam Ravnborg 2204506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2205506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2206506f1d07SSam Ravnborg address aligned to above value and run from there. 2207506f1d07SSam Ravnborg 2208506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2209506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2210506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2211506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2212506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2213506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2214506f1d07SSam Ravnborg above alignment restrictions. 2215506f1d07SSam Ravnborg 2216a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2217a0215061SKees Cook this value must be a multiple of 0x200000. 2218a0215061SKees Cook 2219506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2220506f1d07SSam Ravnborg 2221eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2222eedb92abSKirill A. Shutemov bool 2223eedb92abSKirill A. Shutemov ---help--- 2224eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2225eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2226eedb92abSKirill A. Shutemov 22270483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22280483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22290483e1faSThomas Garnier depends on X86_64 22300483e1faSThomas Garnier depends on RANDOMIZE_BASE 2231eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22320483e1faSThomas Garnier default RANDOMIZE_BASE 22330483e1faSThomas Garnier ---help--- 22340483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22350483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22360483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22370483e1faSThomas Garnier 22380483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22390483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22400483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22410483e1faSThomas Garnier addresses for each memory section. 22420483e1faSThomas Garnier 22436807c846SIngo Molnar If unsure, say Y. 22440483e1faSThomas Garnier 224590397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 224690397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 224790397a41SThomas Garnier depends on RANDOMIZE_MEMORY 224890397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 224990397a41SThomas Garnier default "0x0" 225090397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 225190397a41SThomas Garnier range 0x0 0x40 225290397a41SThomas Garnier ---help--- 225390397a41SThomas Garnier Define the padding in terabytes added to the existing physical 225490397a41SThomas Garnier memory size during kernel memory randomization. It is useful 225590397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 225690397a41SThomas Garnier address randomization. 225790397a41SThomas Garnier 225890397a41SThomas Garnier If unsure, leave at the default value. 225990397a41SThomas Garnier 2260506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2261bebd024eSThomas Gleixner def_bool y 226240b31360SStephen Rothwell depends on SMP 2263506f1d07SSam Ravnborg 226480aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 226580aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22662c922cd0SKees Cook depends on HOTPLUG_CPU 226780aa1dffSFenghua Yu ---help--- 226880aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 226980aa1dffSFenghua Yu 227080aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 227180aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 227280aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 227380aa1dffSFenghua Yu 227480aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 227580aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 227680aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 227780aa1dffSFenghua Yu 227880aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 227980aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 228080aa1dffSFenghua Yu 228180aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 228280aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 228380aa1dffSFenghua Yu be other CPU0 dependencies. 228480aa1dffSFenghua Yu 228580aa1dffSFenghua Yu Please make sure the dependencies are under your control before 228680aa1dffSFenghua Yu you enable this feature. 228780aa1dffSFenghua Yu 228880aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 228980aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 229080aa1dffSFenghua Yu parameter cpu0_hotplug. 229180aa1dffSFenghua Yu 2292a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2293a71c8bc5SFenghua Yu def_bool n 2294a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22952c922cd0SKees Cook depends on HOTPLUG_CPU 2296a71c8bc5SFenghua Yu ---help--- 2297a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2298a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2299a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2300a71c8bc5SFenghua Yu 2301a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2302a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2303a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2304a71c8bc5SFenghua Yu 2305a71c8bc5SFenghua Yu If unsure, say N. 2306a71c8bc5SFenghua Yu 2307506f1d07SSam Ravnborgconfig COMPAT_VDSO 2308b0b49f26SAndy Lutomirski def_bool n 2309b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2310953fee1dSIngo Molnar depends on COMPAT_32 23118f9ca475SIngo Molnar ---help--- 2312b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2313b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2314b0b49f26SAndy Lutomirski indicated in its segment table. 2315e84446deSRandy Dunlap 2316b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2317b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2318b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2319b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2320b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2321506f1d07SSam Ravnborg 2322b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2323b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2324b0b49f26SAndy Lutomirski 2325b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2326b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2327b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2328b0b49f26SAndy Lutomirski 2329b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2330b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2331506f1d07SSam Ravnborg 23323dc33bd3SKees Cookchoice 23333dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23343dc33bd3SKees Cook depends on X86_64 2335625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23363dc33bd3SKees Cook help 23373dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23383dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23393dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23403dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23413dc33bd3SKees Cook 23423dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2343bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23443dc33bd3SKees Cook 23453dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23463dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23473dc33bd3SKees Cook to improve security. 23483dc33bd3SKees Cook 2349bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23503dc33bd3SKees Cook 23513dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2352bd49e16eSAndy Lutomirski bool "Full emulation" 23533dc33bd3SKees Cook help 2354bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2355bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2356bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2357bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2358bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2359bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2360bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2361bd49e16eSAndy Lutomirski 2362bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2363bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2364bd49e16eSAndy Lutomirski 2365bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2366bd49e16eSAndy Lutomirski bool "Emulate execution only" 2367bd49e16eSAndy Lutomirski help 2368bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2369bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2370bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2371bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2372bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2373bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2374bd49e16eSAndy Lutomirski buffer. 23753dc33bd3SKees Cook 23763dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23773dc33bd3SKees Cook bool "None" 23783dc33bd3SKees Cook help 23793dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23803dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23813dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23823dc33bd3SKees Cook will be reported to dmesg, so that either old or 23833dc33bd3SKees Cook malicious userspace programs can be identified. 23843dc33bd3SKees Cook 23853dc33bd3SKees Cookendchoice 23863dc33bd3SKees Cook 2387516cbf37STim Birdconfig CMDLINE_BOOL 2388516cbf37STim Bird bool "Built-in kernel command line" 23898f9ca475SIngo Molnar ---help--- 2390516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2391516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2392516cbf37STim Bird necessary or convenient to provide some or all of the 2393516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2394516cbf37STim Bird to not rely on the boot loader to provide them.) 2395516cbf37STim Bird 2396516cbf37STim Bird To compile command line arguments into the kernel, 2397516cbf37STim Bird set this option to 'Y', then fill in the 239869711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2399516cbf37STim Bird 2400516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2401516cbf37STim Bird should leave this option set to 'N'. 2402516cbf37STim Bird 2403516cbf37STim Birdconfig CMDLINE 2404516cbf37STim Bird string "Built-in kernel command string" 2405516cbf37STim Bird depends on CMDLINE_BOOL 2406516cbf37STim Bird default "" 24078f9ca475SIngo Molnar ---help--- 2408516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2409516cbf37STim Bird image and used at boot time. If the boot loader provides a 2410516cbf37STim Bird command line at boot time, it is appended to this string to 2411516cbf37STim Bird form the full kernel command line, when the system boots. 2412516cbf37STim Bird 2413516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2414516cbf37STim Bird change this behavior. 2415516cbf37STim Bird 2416516cbf37STim Bird In most cases, the command line (whether built-in or provided 2417516cbf37STim Bird by the boot loader) should specify the device for the root 2418516cbf37STim Bird file system. 2419516cbf37STim Bird 2420516cbf37STim Birdconfig CMDLINE_OVERRIDE 2421516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2422516cbf37STim Bird depends on CMDLINE_BOOL 24238f9ca475SIngo Molnar ---help--- 2424516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2425516cbf37STim Bird command line, and use ONLY the built-in command line. 2426516cbf37STim Bird 2427516cbf37STim Bird This is used to work around broken boot loaders. This should 2428516cbf37STim Bird be set to 'N' under normal conditions. 2429516cbf37STim Bird 2430a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2431a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2432a5b9e5a2SAndy Lutomirski default y 2433a5b9e5a2SAndy Lutomirski ---help--- 2434a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2435a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2436a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2437a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2438a5b9e5a2SAndy Lutomirski threading libraries. 2439a5b9e5a2SAndy Lutomirski 2440a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2441a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2442a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2443a5b9e5a2SAndy Lutomirski 2444a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2445a5b9e5a2SAndy Lutomirski 2446b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2447b700e7f0SSeth Jennings 2448506f1d07SSam Ravnborgendmenu 2449506f1d07SSam Ravnborg 24503072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24513072e413SMichal Hocko def_bool y 24523072e413SMichal Hocko depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 24533072e413SMichal Hocko 2454506f1d07SSam Ravnborgconfig ARCH_ENABLE_MEMORY_HOTPLUG 2455506f1d07SSam Ravnborg def_bool y 2456506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2457506f1d07SSam Ravnborg 245835551053SGary Hadeconfig ARCH_ENABLE_MEMORY_HOTREMOVE 245935551053SGary Hade def_bool y 246035551053SGary Hade depends on MEMORY_HOTPLUG 246135551053SGary Hade 2462e534c7c5SLee Schermerhornconfig USE_PERCPU_NUMA_NODE_ID 2463645a7919STejun Heo def_bool y 2464e534c7c5SLee Schermerhorn depends on NUMA 2465e534c7c5SLee Schermerhorn 24669491846fSKirill A. Shutemovconfig ARCH_ENABLE_SPLIT_PMD_PTLOCK 24679491846fSKirill A. Shutemov def_bool y 24689491846fSKirill A. Shutemov depends on X86_64 || X86_PAE 24699491846fSKirill A. Shutemov 2470c177c81eSNaoya Horiguchiconfig ARCH_ENABLE_HUGEPAGE_MIGRATION 2471c177c81eSNaoya Horiguchi def_bool y 2472c177c81eSNaoya Horiguchi depends on X86_64 && HUGETLB_PAGE && MIGRATION 2473c177c81eSNaoya Horiguchi 24749c670ea3SNaoya Horiguchiconfig ARCH_ENABLE_THP_MIGRATION 24759c670ea3SNaoya Horiguchi def_bool y 24769c670ea3SNaoya Horiguchi depends on X86_64 && TRANSPARENT_HUGEPAGE 24779c670ea3SNaoya Horiguchi 2478da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2479e279b6c1SSam Ravnborg 2480e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 24813c2362e6SHarvey Harrison def_bool y 248244556530SZhimin Gu depends on HIBERNATION 2483e279b6c1SSam Ravnborg 2484e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2485e279b6c1SSam Ravnborg 2486e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2487e279b6c1SSam Ravnborg 2488efafc8b2SFeng Tangsource "drivers/sfi/Kconfig" 2489efafc8b2SFeng Tang 2490a6b68076SAndi Kleenconfig X86_APM_BOOT 24916fc108a0SJan Beulich def_bool y 2492282e5aabSPaul Bolle depends on APM 2493a6b68076SAndi Kleen 2494e279b6c1SSam Ravnborgmenuconfig APM 2495e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2496efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2497e279b6c1SSam Ravnborg ---help--- 2498e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2499e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2500e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2501e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2502e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2503e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2504e279b6c1SSam Ravnborg 2505e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2506e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2507e279b6c1SSam Ravnborg 2508e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2509e279b6c1SSam Ravnborg machines with more than one CPU. 2510e279b6c1SSam Ravnborg 2511e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2512151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 25132dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2514e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2515e279b6c1SSam Ravnborg 2516e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2517e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2518e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2519e279b6c1SSam Ravnborg 2520e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2521e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2522e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2523e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2524e279b6c1SSam Ravnborg 2525e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2526e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2527e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2528e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2529e279b6c1SSam Ravnborg APM in your BIOS). 2530e279b6c1SSam Ravnborg 2531e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2532e279b6c1SSam Ravnborg "weird" problems: 2533e279b6c1SSam Ravnborg 2534e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2535e279b6c1SSam Ravnborg enabled. 2536e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2537e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2538e279b6c1SSam Ravnborg the "no387" option to the kernel 2539e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2540e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2541e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2542e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2543e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2544e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2545e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2546e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2547e279b6c1SSam Ravnborg 11) exchange RAM chips 2548e279b6c1SSam Ravnborg 12) exchange the motherboard. 2549e279b6c1SSam Ravnborg 2550e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2551e279b6c1SSam Ravnborg module will be called apm. 2552e279b6c1SSam Ravnborg 2553e279b6c1SSam Ravnborgif APM 2554e279b6c1SSam Ravnborg 2555e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2556e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 25578f9ca475SIngo Molnar ---help--- 2558e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2559e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2560e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2561e279b6c1SSam Ravnborg 2562e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2563e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2564e279b6c1SSam Ravnborg ---help--- 2565e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2566e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2567e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2568e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2569e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2570e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2571e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2572e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2573e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2574e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2575e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2576e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2577e279b6c1SSam Ravnborg this feature. 2578e279b6c1SSam Ravnborg 2579e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2580dd8af076SLen Brown depends on CPU_IDLE 2581e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 25828f9ca475SIngo Molnar ---help--- 2583e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2584e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2585e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2586e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2587e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2588e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2589e279b6c1SSam Ravnborg this option does nothing.) 2590e279b6c1SSam Ravnborg 2591e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2592e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 25938f9ca475SIngo Molnar ---help--- 2594e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2595e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2596e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2597e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2598e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2599e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2600e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2601e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2602e279b6c1SSam Ravnborg especially if you are using gpm. 2603e279b6c1SSam Ravnborg 2604e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2605e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 26068f9ca475SIngo Molnar ---help--- 2607e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2608e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2609e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2610e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2611e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2612e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2613e279b6c1SSam Ravnborg 2614e279b6c1SSam Ravnborgendif # APM 2615e279b6c1SSam Ravnborg 2616bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2617e279b6c1SSam Ravnborg 2618e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2619e279b6c1SSam Ravnborg 262027471fdbSAndy Henroidsource "drivers/idle/Kconfig" 262127471fdbSAndy Henroid 2622e279b6c1SSam Ravnborgendmenu 2623e279b6c1SSam Ravnborg 2624e279b6c1SSam Ravnborg 2625e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2626e279b6c1SSam Ravnborg 2627e279b6c1SSam Ravnborgchoice 2628e279b6c1SSam Ravnborg prompt "PCI access mode" 2629efefa6f6SIngo Molnar depends on X86_32 && PCI 2630e279b6c1SSam Ravnborg default PCI_GOANY 2631e279b6c1SSam Ravnborg ---help--- 2632e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2633e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2634e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2635e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2636e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2637e279b6c1SSam Ravnborg 2638e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2639e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2640e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2641e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2642e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2643e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2644e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2645e279b6c1SSam Ravnborg 2646e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2647e279b6c1SSam Ravnborg bool "BIOS" 2648e279b6c1SSam Ravnborg 2649e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2650e279b6c1SSam Ravnborg bool "MMConfig" 2651e279b6c1SSam Ravnborg 2652e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2653e279b6c1SSam Ravnborg bool "Direct" 2654e279b6c1SSam Ravnborg 26553ef0e1f8SAndres Salomonconfig PCI_GOOLPC 265676fb6570SDaniel Drake bool "OLPC XO-1" 26573ef0e1f8SAndres Salomon depends on OLPC 26583ef0e1f8SAndres Salomon 26592bdd1b03SAndres Salomonconfig PCI_GOANY 26602bdd1b03SAndres Salomon bool "Any" 26612bdd1b03SAndres Salomon 2662e279b6c1SSam Ravnborgendchoice 2663e279b6c1SSam Ravnborg 2664e279b6c1SSam Ravnborgconfig PCI_BIOS 26653c2362e6SHarvey Harrison def_bool y 2666efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2667e279b6c1SSam Ravnborg 2668e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2669e279b6c1SSam Ravnborgconfig PCI_DIRECT 26703c2362e6SHarvey Harrison def_bool y 26710aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2672e279b6c1SSam Ravnborg 2673e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2674b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2675b45c9f36SJan Kiszka default y 26768364e1f8SJan Kiszka depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2677b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2678e279b6c1SSam Ravnborg 26793ef0e1f8SAndres Salomonconfig PCI_OLPC 26802bdd1b03SAndres Salomon def_bool y 26812bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 26823ef0e1f8SAndres Salomon 2683b5401a96SAlex Nixonconfig PCI_XEN 2684b5401a96SAlex Nixon def_bool y 2685b5401a96SAlex Nixon depends on PCI && XEN 2686b5401a96SAlex Nixon select SWIOTLB_XEN 2687b5401a96SAlex Nixon 26888364e1f8SJan Kiszkaconfig MMCONF_FAM10H 26898364e1f8SJan Kiszka def_bool y 26908364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2691e279b6c1SSam Ravnborg 26923f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 26936a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 26946ea30386SKees Cook depends on PCI 26953f6ea84aSIra W. Snyder help 26963f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 26973f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 26983f6ea84aSIra W. Snyder not have ACPI. 26993f6ea84aSIra W. Snyder 270064a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 270164a5fed6SBjorn Helgaas is known to be incomplete. 270264a5fed6SBjorn Helgaas 270364a5fed6SBjorn Helgaas You should say N unless you know you need this. 270464a5fed6SBjorn Helgaas 27053a495511SWilliam Breathitt Grayconfig ISA_BUS 270617a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 27073a495511SWilliam Breathitt Gray help 270817a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 270917a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 271017a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 271117a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 271217a2a129SWilliam Breathitt Gray not have an ISA bus. 27133a495511SWilliam Breathitt Gray 27143a495511SWilliam Breathitt Gray If unsure, say N. 27153a495511SWilliam Breathitt Gray 27161c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2717e279b6c1SSam Ravnborgconfig ISA_DMA_API 27181c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 27191c00f016SDavid Rientjes default y 27201c00f016SDavid Rientjes help 27211c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 27221c00f016SDavid Rientjes If unsure, say Y. 2723e279b6c1SSam Ravnborg 272451e68d05SLinus Torvaldsif X86_32 272551e68d05SLinus Torvalds 2726e279b6c1SSam Ravnborgconfig ISA 2727e279b6c1SSam Ravnborg bool "ISA support" 27288f9ca475SIngo Molnar ---help--- 2729e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2730e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2731e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2732e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2733e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2734e279b6c1SSam Ravnborg 2735e279b6c1SSam Ravnborgconfig SCx200 2736e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 27378f9ca475SIngo Molnar ---help--- 2738e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2739e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2740e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2741e279b6c1SSam Ravnborg for other scx200_* drivers. 2742e279b6c1SSam Ravnborg 2743e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2744e279b6c1SSam Ravnborg 2745e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2746e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2747592913ecSJohn Stultz depends on SCx200 2748e279b6c1SSam Ravnborg default y 27498f9ca475SIngo Molnar ---help--- 2750e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2751e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2752e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2753e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2754e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2755e279b6c1SSam Ravnborg 27563ef0e1f8SAndres Salomonconfig OLPC 27573ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 275854008979SThomas Gleixner depends on !X86_PAE 27593c554946SAndres Salomon select GPIOLIB 2760dc3119e7SThomas Gleixner select OF 276145bb1674SDaniel Drake select OF_PROMTREE 2762b4e51854SGrant Likely select IRQ_DOMAIN 27630c3d931bSLubomir Rintel select OLPC_EC 27648f9ca475SIngo Molnar ---help--- 27653ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27663ef0e1f8SAndres Salomon XO hardware. 27673ef0e1f8SAndres Salomon 2768a3128588SDaniel Drakeconfig OLPC_XO1_PM 2769a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2770fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2771bf1ebf00SDaniel Drake ---help--- 277297c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2773bf1ebf00SDaniel Drake 2774cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2775cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2776cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2777cfee9597SDaniel Drake ---help--- 2778cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2779cfee9597SDaniel Drake programmable wakeup source. 2780cfee9597SDaniel Drake 27817feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 27827feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 278392e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2784ed8e47feSRandy Dunlap depends on INPUT=y 2785d8d01a63SDaniel Drake select POWER_SUPPLY 27867feda8e9SDaniel Drake ---help--- 27877feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 27887bc74b3dSDaniel Drake - EC-driven system wakeups 27897feda8e9SDaniel Drake - Power button 27907bc74b3dSDaniel Drake - Ebook switch 27912cf2baeaSDaniel Drake - Lid switch 2792e1040ac6SDaniel Drake - AC adapter status updates 2793e1040ac6SDaniel Drake - Battery status updates 27947feda8e9SDaniel Drake 2795a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2796a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2797d8d01a63SDaniel Drake depends on OLPC && ACPI 2798d8d01a63SDaniel Drake select POWER_SUPPLY 2799a0f30f59SDaniel Drake ---help--- 2800a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2801a0f30f59SDaniel Drake - EC-driven system wakeups 2802a0f30f59SDaniel Drake - AC adapter status updates 2803a0f30f59SDaniel Drake - Battery status updates 2804e279b6c1SSam Ravnborg 2805d4f3e350SEd Wildgooseconfig ALIX 2806d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2807d4f3e350SEd Wildgoose select GPIOLIB 2808d4f3e350SEd Wildgoose ---help--- 2809d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2810d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2811d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2812d4f3e350SEd Wildgoose get added here. 2813d4f3e350SEd Wildgoose 2814d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2815d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2816d4f3e350SEd Wildgoose 2817d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2818d4f3e350SEd Wildgoose 2819da4e3302SPhilip Prindevilleconfig NET5501 2820da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2821da4e3302SPhilip Prindeville select GPIOLIB 2822da4e3302SPhilip Prindeville ---help--- 2823da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2824da4e3302SPhilip Prindeville 28253197059aSPhilip A. Prindevilleconfig GEOS 28263197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28273197059aSPhilip A. Prindeville select GPIOLIB 28283197059aSPhilip A. Prindeville depends on DMI 28293197059aSPhilip A. Prindeville ---help--- 28303197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28313197059aSPhilip A. Prindeville 28327d029125SVivien Didelotconfig TS5500 28337d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28347d029125SVivien Didelot depends on MELAN 28357d029125SVivien Didelot select CHECK_SIGNATURE 28367d029125SVivien Didelot select NEW_LEDS 28377d029125SVivien Didelot select LEDS_CLASS 28387d029125SVivien Didelot ---help--- 28397d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28407d029125SVivien Didelot 2841e279b6c1SSam Ravnborgendif # X86_32 2842e279b6c1SSam Ravnborg 284323ac4ae8SAndreas Herrmannconfig AMD_NB 2844e279b6c1SSam Ravnborg def_bool y 28450e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2846e279b6c1SSam Ravnborg 2847e3263ab3SDavid Herrmannconfig X86_SYSFB 2848e3263ab3SDavid Herrmann bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2849e3263ab3SDavid Herrmann help 2850e3263ab3SDavid Herrmann Firmwares often provide initial graphics framebuffers so the BIOS, 2851e3263ab3SDavid Herrmann bootloader or kernel can show basic video-output during boot for 2852e3263ab3SDavid Herrmann user-guidance and debugging. Historically, x86 used the VESA BIOS 2853e3263ab3SDavid Herrmann Extensions and EFI-framebuffers for this, which are mostly limited 2854e3263ab3SDavid Herrmann to x86. 2855e3263ab3SDavid Herrmann This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2856e3263ab3SDavid Herrmann framebuffers so the new generic system-framebuffer drivers can be 2857e3263ab3SDavid Herrmann used on x86. If the framebuffer is not compatible with the generic 2858e3a5dc08SNikolas Nyby modes, it is advertised as fallback platform framebuffer so legacy 2859e3263ab3SDavid Herrmann drivers like efifb, vesafb and uvesafb can pick it up. 2860e3263ab3SDavid Herrmann If this option is not selected, all system framebuffers are always 2861e3263ab3SDavid Herrmann marked as fallback platform framebuffers as usual. 2862e3263ab3SDavid Herrmann 2863e3263ab3SDavid Herrmann Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2864e3263ab3SDavid Herrmann not be able to pick up generic system framebuffers if this option 2865e3263ab3SDavid Herrmann is selected. You are highly encouraged to enable simplefb as 2866e3263ab3SDavid Herrmann replacement if you select this option. simplefb can correctly deal 2867e3263ab3SDavid Herrmann with generic system framebuffers. But you should still keep vesafb 2868e3263ab3SDavid Herrmann and others enabled as fallback if a system framebuffer is 2869e3263ab3SDavid Herrmann incompatible with simplefb. 2870e3263ab3SDavid Herrmann 2871e3263ab3SDavid Herrmann If unsure, say Y. 2872e3263ab3SDavid Herrmann 2873e279b6c1SSam Ravnborgendmenu 2874e279b6c1SSam Ravnborg 2875e279b6c1SSam Ravnborg 28761572497cSChristoph Hellwigmenu "Binary Emulations" 2877e279b6c1SSam Ravnborg 2878e279b6c1SSam Ravnborgconfig IA32_EMULATION 2879e279b6c1SSam Ravnborg bool "IA32 Emulation" 2880e279b6c1SSam Ravnborg depends on X86_64 288139f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2882d1603990SRandy Dunlap select BINFMT_ELF 2883a97f52e6SRoland McGrath select COMPAT_BINFMT_ELF 288439f88911SIngo Molnar select COMPAT_OLD_SIGACTION 28858f9ca475SIngo Molnar ---help--- 28865fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 28875fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 28885fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2889e279b6c1SSam Ravnborg 2890e279b6c1SSam Ravnborgconfig IA32_AOUT 2891e279b6c1SSam Ravnborg tristate "IA32 a.out support" 28926b213e1bSDavid Woodhouse depends on IA32_EMULATION 2893eac61655SBorislav Petkov depends on BROKEN 28948f9ca475SIngo Molnar ---help--- 2895e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2896e279b6c1SSam Ravnborg 28970bf62763SH. Peter Anvinconfig X86_X32 28986ea30386SKees Cook bool "x32 ABI for 64-bit mode" 28999b54050bSBrian Gerst depends on X86_64 29005fd92e65SH. J. Lu ---help--- 29015fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 29025fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 29035fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 29045fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 29055fd92e65SH. J. Lu 29065fd92e65SH. J. Lu You will need a recent binutils (2.22 or later) with 29075fd92e65SH. J. Lu elf32_x86_64 support enabled to compile a kernel with this 29085fd92e65SH. J. Lu option set. 29095fd92e65SH. J. Lu 2910953fee1dSIngo Molnarconfig COMPAT_32 2911953fee1dSIngo Molnar def_bool y 2912953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2913953fee1dSIngo Molnar select HAVE_UID16 2914953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2915953fee1dSIngo Molnar 2916e279b6c1SSam Ravnborgconfig COMPAT 29173c2362e6SHarvey Harrison def_bool y 29180bf62763SH. Peter Anvin depends on IA32_EMULATION || X86_X32 2919e279b6c1SSam Ravnborg 29203120e25eSJan Beulichif COMPAT 2921e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 29223120e25eSJan Beulich def_bool y 2923e279b6c1SSam Ravnborg 2924e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 29253c2362e6SHarvey Harrison def_bool y 29263120e25eSJan Beulich depends on SYSVIPC 29273120e25eSJan Beulichendif 2928ee009e4aSDavid Howells 2929e279b6c1SSam Ravnborgendmenu 2930e279b6c1SSam Ravnborg 2931e279b6c1SSam Ravnborg 2932e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2933e5beae16SKeith Packard def_bool y 2934e5beae16SKeith Packard depends on X86_32 2935e5beae16SKeith Packard 2936e279b6c1SSam Ravnborgsource "drivers/firmware/Kconfig" 2937e279b6c1SSam Ravnborg 2938edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 2939