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 96c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 973876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 9838d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 996471b825SIngo Molnar select BUILDTIME_EXTABLE_SORT 1006471b825SIngo Molnar select CLKEVT_I8253 1016471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1026471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1036471b825SIngo Molnar select DCACHE_WORD_ACCESS 10445471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 10545471cd9SLinus Torvalds select EDAC_SUPPORT 1066471b825SIngo Molnar select GENERIC_CLOCKEVENTS 1076471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1086471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1096471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1106471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 11161dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1126471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 1136471b825SIngo Molnar select GENERIC_FIND_FIRST_BIT 1146471b825SIngo Molnar select GENERIC_IOMAP 115c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1160fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 117ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1186471b825SIngo Molnar select GENERIC_IRQ_PROBE 119c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1206471b825SIngo Molnar select GENERIC_IRQ_SHOW 1216471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1226471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1236471b825SIngo Molnar select GENERIC_STRNCPY_FROM_USER 1246471b825SIngo Molnar select GENERIC_STRNLEN_USER 1256471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1267ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 12739656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 1287edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1296471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1306471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1316471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1326471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1336471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 1346471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 135b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 136d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1370609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1386471b825SIngo Molnar select HAVE_ARCH_KGDB 1399e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1409e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1411b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 142271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1436471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 144f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 145afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1466471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1476471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 148a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 149e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 150c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1512ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1526471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1536471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1546471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 155c1bd55f9SJosh Triplett select HAVE_COPY_THREAD_TLS 1566471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 1576471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1589c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 159677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 16006aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 161562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 16203f5781bSWang YanQing select HAVE_EBPF_JIT 16358340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 1646630a8e5SChristoph Hellwig select HAVE_EISA 1655f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 16667a929e0SChristoph Hellwig select HAVE_FAST_GUP 167644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 1686471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 1696471b825SIngo Molnar select HAVE_FUNCTION_GRAPH_TRACER 1706471b825SIngo Molnar select HAVE_FUNCTION_TRACER 1716b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 1720067f129SK.Prasad select HAVE_HW_BREAKPOINT 1736471b825SIngo Molnar select HAVE_IDE 1746471b825SIngo Molnar select HAVE_IOREMAP_PROT 1756471b825SIngo Molnar select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 1766471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 1776471b825SIngo Molnar select HAVE_KERNEL_BZIP2 1786471b825SIngo Molnar select HAVE_KERNEL_GZIP 1796471b825SIngo Molnar select HAVE_KERNEL_LZ4 1806471b825SIngo Molnar select HAVE_KERNEL_LZMA 1816471b825SIngo Molnar select HAVE_KERNEL_LZO 1826471b825SIngo Molnar select HAVE_KERNEL_XZ 1836471b825SIngo Molnar select HAVE_KPROBES 1846471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 185540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 1866471b825SIngo Molnar select HAVE_KRETPROBES 1876471b825SIngo Molnar select HAVE_KVM 1886471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 1896471b825SIngo Molnar select HAVE_MEMBLOCK_NODE_MAP 1900102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 191ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 1929f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 19342a0bb3fSPetr Mladek select HAVE_NMI 1946471b825SIngo Molnar select HAVE_OPROFILE 1956471b825SIngo Molnar select HAVE_OPTPROBES 1966471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 1976471b825SIngo Molnar select HAVE_PERF_EVENTS 198c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 19992e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 200eb01d42aSChristoph Hellwig select HAVE_PCI 201c5e63197SJiri Olsa select HAVE_PERF_REGS 202c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 20348a8b97cSPeter Zijlstra select HAVE_RCU_TABLE_FREE if PARAVIRT 2046471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 2056415b38bSJiri Slaby select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 2063c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 207d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 208c763ea26SIngo Molnar select HAVE_STACK_VALIDATION if X86_64 209d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2106471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2116471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2127c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2137ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 21405736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 215c0185808SThomas Gleixner select IRQ_FORCED_THREADING 21686596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2172eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 218625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2196471b825SIngo Molnar select PERF_EVENTS 2203195ef59SPrarit Bhargava select RTC_LIB 221d6faca40SArnd Bergmann select RTC_MC146818_LIB 2226471b825SIngo Molnar select SPARSE_IRQ 22383fe27eaSPranith Kumar select SRCU 2246471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 22515f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2266471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2276471b825SIngo Molnar select VIRT_TO_BUS 2286471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2290c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 2307d8330a5SBalbir Singh 231ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2323120e25eSJan Beulich def_bool y 2333120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 234ba7e4d13SIngo Molnar 23551b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 23651b26adaSLinus Torvalds string 23751b26adaSLinus Torvalds default "elf32-i386" if X86_32 23851b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 23951b26adaSLinus Torvalds 24073531905SSam Ravnborgconfig ARCH_DEFCONFIG 241b9b39bfbSSam Ravnborg string 24273531905SSam Ravnborg default "arch/x86/configs/i386_defconfig" if X86_32 24373531905SSam Ravnborg default "arch/x86/configs/x86_64_defconfig" if X86_64 244b9b39bfbSSam Ravnborg 2458d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2463c2362e6SHarvey Harrison def_bool y 2478d5fffb9SSam Ravnborg 2488d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2493c2362e6SHarvey Harrison def_bool y 2508d5fffb9SSam Ravnborg 2518d5fffb9SSam Ravnborgconfig MMU 2523c2362e6SHarvey Harrison def_bool y 2538d5fffb9SSam Ravnborg 2549e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 2559e08f57dSDaniel Cashman default 28 if 64BIT 2569e08f57dSDaniel Cashman default 8 2579e08f57dSDaniel Cashman 2589e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 2599e08f57dSDaniel Cashman default 32 if 64BIT 2609e08f57dSDaniel Cashman default 16 2619e08f57dSDaniel Cashman 2629e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 2639e08f57dSDaniel Cashman default 8 2649e08f57dSDaniel Cashman 2659e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 2669e08f57dSDaniel Cashman default 16 2679e08f57dSDaniel Cashman 2688d5fffb9SSam Ravnborgconfig SBUS 2698d5fffb9SSam Ravnborg bool 2708d5fffb9SSam Ravnborg 2718d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 2723120e25eSJan Beulich def_bool y 2733120e25eSJan Beulich depends on ISA_DMA_API 2748d5fffb9SSam Ravnborg 2758d5fffb9SSam Ravnborgconfig GENERIC_BUG 2763c2362e6SHarvey Harrison def_bool y 2778d5fffb9SSam Ravnborg depends on BUG 278b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 279b93a531eSJan Beulich 280b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 281b93a531eSJan Beulich bool 2828d5fffb9SSam Ravnborg 2838d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 2843120e25eSJan Beulich def_bool y 2853120e25eSJan Beulich depends on ISA_DMA_API 2868d5fffb9SSam Ravnborg 2871032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 2881032c0baSSam Ravnborg def_bool y 2891032c0baSSam Ravnborg 2909a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 2919a0b8415Svenkatesh.pallipadi@intel.com def_bool y 2928d5fffb9SSam Ravnborg 2931b27d05bSPekka Enbergconfig ARCH_HAS_CACHE_LINE_SIZE 2941b27d05bSPekka Enberg def_bool y 2951b27d05bSPekka Enberg 296316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT 297316d097cSDave Hansen def_bool y 298316d097cSDave Hansen 299dd5af90aSMike Travisconfig HAVE_SETUP_PER_CPU_AREA 30089c9c4c5SBrian Gerst def_bool y 301b32ef636Stravis@sgi.com 30208fc4580STejun Heoconfig NEED_PER_CPU_EMBED_FIRST_CHUNK 30308fc4580STejun Heo def_bool y 30408fc4580STejun Heo 30508fc4580STejun Heoconfig NEED_PER_CPU_PAGE_FIRST_CHUNK 30611124411STejun Heo def_bool y 30711124411STejun Heo 308801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 309801e4062SJohannes Berg def_bool y 310801e4062SJohannes Berg 311f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 312f4cb5700SJohannes Berg def_bool y 313f4cb5700SJohannes Berg 31453313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB 31553313b2cSSteve Capper def_bool y 31653313b2cSSteve Capper 3178d5fffb9SSam Ravnborgconfig ZONE_DMA32 318e0fd24a3SJan Beulich def_bool y if X86_64 3198d5fffb9SSam Ravnborg 3208d5fffb9SSam Ravnborgconfig AUDIT_ARCH 321e0fd24a3SJan Beulich def_bool y if X86_64 3228d5fffb9SSam Ravnborg 3236a11f75bSAkinobu Mitaconfig ARCH_SUPPORTS_DEBUG_PAGEALLOC 3246a11f75bSAkinobu Mita def_bool y 3256a11f75bSAkinobu Mita 326d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 327d6f2d75aSAndrey Ryabinin hex 328d6f2d75aSAndrey Ryabinin depends on KASAN 329d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 330d6f2d75aSAndrey Ryabinin 33169575d38SShane Wangconfig HAVE_INTEL_TXT 33269575d38SShane Wang def_bool y 3336ea30386SKees Cook depends on INTEL_IOMMU && ACPI 33469575d38SShane Wang 3356b0c3d44SSam Ravnborgconfig X86_32_SMP 3366b0c3d44SSam Ravnborg def_bool y 3376b0c3d44SSam Ravnborg depends on X86_32 && SMP 3386b0c3d44SSam Ravnborg 3396b0c3d44SSam Ravnborgconfig X86_64_SMP 3406b0c3d44SSam Ravnborg def_bool y 3416b0c3d44SSam Ravnborg depends on X86_64 && SMP 3426b0c3d44SSam Ravnborg 343ccbeed3aSTejun Heoconfig X86_32_LAZY_GS 344ccbeed3aSTejun Heo def_bool y 3458458f8c2SMasahiro Yamada depends on X86_32 && !STACKPROTECTOR 346ccbeed3aSTejun Heo 3472b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3482b144498SSrikar Dronamraju def_bool y 3492b144498SSrikar Dronamraju 350d20642f0SRob Herringconfig FIX_EARLYCON_MEM 351d20642f0SRob Herring def_bool y 352d20642f0SRob Herring 35394d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 35494d49eb3SKirill A. Shutemov bool 35594d49eb3SKirill A. Shutemov 35698233368SKirill A. Shutemovconfig PGTABLE_LEVELS 35798233368SKirill A. Shutemov int 35877ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 35998233368SKirill A. Shutemov default 4 if X86_64 36098233368SKirill A. Shutemov default 3 if X86_PAE 36198233368SKirill A. Shutemov default 2 36298233368SKirill A. Shutemov 3632a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3642a61f474SMasahiro Yamada bool 3652a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3662a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3672a61f474SMasahiro Yamada help 3682a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3692a61f474SMasahiro Yamada the compiler produces broken code. 3702a61f474SMasahiro Yamada 371506f1d07SSam Ravnborgmenu "Processor type and features" 372506f1d07SSam Ravnborg 3735ee71535SRandy Dunlapconfig ZONE_DMA 3745ee71535SRandy Dunlap bool "DMA memory allocation support" if EXPERT 3755ee71535SRandy Dunlap default y 3765ee71535SRandy Dunlap help 3775ee71535SRandy Dunlap DMA memory allocation support allows devices with less than 32-bit 3785ee71535SRandy Dunlap addressing to allocate within the first 16MB of address space. 3795ee71535SRandy Dunlap Disable if no such devices will be used. 3805ee71535SRandy Dunlap 3815ee71535SRandy Dunlap If unsure, say Y. 3825ee71535SRandy Dunlap 383506f1d07SSam Ravnborgconfig SMP 384506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 385506f1d07SSam Ravnborg ---help--- 386506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 3874a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 3884a474157SRobert Graffham than one CPU, say Y. 389506f1d07SSam Ravnborg 3904a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 391506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 392506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 3934a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 394506f1d07SSam Ravnborg will run faster if you say N here. 395506f1d07SSam Ravnborg 396506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 397506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 398506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 399506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 400506f1d07SSam Ravnborg 401506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 402506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 403506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 404506f1d07SSam Ravnborg 405cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4064f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 407506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 408506f1d07SSam Ravnborg 409506f1d07SSam Ravnborg If you don't know what to do here, say N. 410506f1d07SSam Ravnborg 4119def39beSJosh Triplettconfig X86_FEATURE_NAMES 4129def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4139def39beSJosh Triplett default y 4149def39beSJosh Triplett ---help--- 4159def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4169def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4179def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4189def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4199def39beSJosh Triplett 4209def39beSJosh Triplett If in doubt, say Y. 4219def39beSJosh Triplett 42206cd9a7dSYinghai Luconfig X86_X2APIC 42306cd9a7dSYinghai Lu bool "Support x2apic" 42419e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 42506cd9a7dSYinghai Lu ---help--- 42606cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 42706cd9a7dSYinghai Lu 42806cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 42906cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 43006cd9a7dSYinghai Lu 43106cd9a7dSYinghai Lu If you don't know what to do here, say N. 43206cd9a7dSYinghai Lu 4336695c85bSYinghai Luconfig X86_MPPARSE 4346e87f9b7SBin Gao bool "Enable MPS table" if ACPI || SFI 4357a527688SJan Beulich default y 4365ab74722SIngo Molnar depends on X86_LOCAL_APIC 4378f9ca475SIngo Molnar ---help--- 4386695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4396695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4406695c85bSYinghai Lu 441ddd70cf9SJun Nakajimaconfig GOLDFISH 442ddd70cf9SJun Nakajima def_bool y 443ddd70cf9SJun Nakajima depends on X86_GOLDFISH 444ddd70cf9SJun Nakajima 44576b04384SDavid Woodhouseconfig RETPOLINE 44676b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 44776b04384SDavid Woodhouse default y 448d5028ba8SPeter Zijlstra select STACK_VALIDATION if HAVE_STACK_VALIDATION 44976b04384SDavid Woodhouse help 45076b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 45176b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 45276b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 45376b04384SDavid Woodhouse support for full protection. The kernel may run slower. 45476b04384SDavid Woodhouse 455e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 456e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4576fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 45859fe5a77SThomas Gleixner select KERNFS 459*e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 46078e99b4aSFenghua Yu help 461e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4626fe07ce3SBabu Moger 4636fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4646fe07ce3SBabu Moger usage by the CPU. 4656fe07ce3SBabu Moger 4666fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4676fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4686fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4696fe07ce3SBabu Moger 4706fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4716fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4726fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 47378e99b4aSFenghua Yu 47478e99b4aSFenghua Yu Say N if unsure. 47578e99b4aSFenghua Yu 4768425091fSRavikiran G Thirumalaiif X86_32 477a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 478a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 479a0d0bb4dSRandy Dunlap depends on SMP 480a0d0bb4dSRandy Dunlap ---help--- 481a0d0bb4dSRandy Dunlap This option is needed for the systems that have more than 8 CPUs 482a0d0bb4dSRandy Dunlap 483c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 484c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 485c5c606d9SRavikiran G Thirumalai default y 4868f9ca475SIngo Molnar ---help--- 48706ac8346SIngo Molnar If you disable this option then the kernel will only support 48806ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 48906ac8346SIngo Molnar systems out there.) 49006ac8346SIngo Molnar 4918425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 4928425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 493cb7b8023SBen Hutchings Goldfish (Android emulator) 4948425091fSRavikiran G Thirumalai AMD Elan 4958425091fSRavikiran G Thirumalai RDC R-321x SoC 4968425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 49783125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 4983f4110a4SThomas Gleixner Moorestown MID devices 49906ac8346SIngo Molnar 50006ac8346SIngo Molnar If you have one of these systems, or if you want to build a 50106ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5028425091fSRavikiran G Thirumalaiendif 50306ac8346SIngo Molnar 5048425091fSRavikiran G Thirumalaiif X86_64 5058425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5068425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5078425091fSRavikiran G Thirumalai default y 5088425091fSRavikiran G Thirumalai ---help--- 5098425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5108425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5118425091fSRavikiran G Thirumalai systems out there.) 5128425091fSRavikiran G Thirumalai 5138425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5148425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 51544b111b5SSteffen Persvold Numascale NumaChip 5168425091fSRavikiran G Thirumalai ScaleMP vSMP 5178425091fSRavikiran G Thirumalai SGI Ultraviolet 5188425091fSRavikiran G Thirumalai 5198425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5208425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5218425091fSRavikiran G Thirumalaiendif 522c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 523c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 52444b111b5SSteffen Persvoldconfig X86_NUMACHIP 52544b111b5SSteffen Persvold bool "Numascale NumaChip" 52644b111b5SSteffen Persvold depends on X86_64 52744b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 52844b111b5SSteffen Persvold depends on NUMA 52944b111b5SSteffen Persvold depends on SMP 53044b111b5SSteffen Persvold depends on X86_X2APIC 531f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 53244b111b5SSteffen Persvold ---help--- 53344b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 53444b111b5SSteffen Persvold enable more than ~168 cores. 53544b111b5SSteffen Persvold If you don't have one of these, you should say N here. 53603b48632SNick Piggin 5376a48565eSIngo Molnarconfig X86_VSMP 538c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5396276a074SBorislav Petkov select HYPERVISOR_GUEST 5406a48565eSIngo Molnar select PARAVIRT 5416a48565eSIngo Molnar depends on X86_64 && PCI 542c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 543ead91d4bSShai Fultheim depends on SMP 5448f9ca475SIngo Molnar ---help--- 5456a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5466a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5476a48565eSIngo Molnar if you have one of these machines. 5486a48565eSIngo Molnar 549c5c606d9SRavikiran G Thirumalaiconfig X86_UV 550c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 551c5c606d9SRavikiran G Thirumalai depends on X86_64 552c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 55354c28d29SJack Steiner depends on NUMA 5541ecb4ae5SAndrew Morton depends on EFI 5559d6c26e7SSuresh Siddha depends on X86_X2APIC 5561222e564SIngo Molnar depends on PCI 557c5c606d9SRavikiran G Thirumalai ---help--- 558c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 559c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 560c5c606d9SRavikiran G Thirumalai 561c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 562c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 563506f1d07SSam Ravnborg 564ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 565ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 566cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 567ddd70cf9SJun Nakajima ---help--- 568ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 569ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 570ddd70cf9SJun Nakajima Goldfish emulator say N here. 571ddd70cf9SJun Nakajima 572c751e17bSThomas Gleixnerconfig X86_INTEL_CE 573c751e17bSThomas Gleixner bool "CE4100 TV platform" 574c751e17bSThomas Gleixner depends on PCI 575c751e17bSThomas Gleixner depends on PCI_GODIRECT 5766084a6e2SJiang Liu depends on X86_IO_APIC 577c751e17bSThomas Gleixner depends on X86_32 578c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 57937bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 580da6b737bSSebastian Andrzej Siewior select OF 581da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 582c751e17bSThomas Gleixner ---help--- 583c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 584c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 585c751e17bSThomas Gleixner boxes and media devices. 586c751e17bSThomas Gleixner 5874cb9b00fSDavid Cohenconfig X86_INTEL_MID 58843605ef1SAlan Cox bool "Intel MID platform support" 58943605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 590edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 5911ea7c673SAlan Cox depends on PCI 5923fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 5931ea7c673SAlan Cox depends on X86_IO_APIC 5947c9c3a1eSAlan Cox select SFI 5954cb9b00fSDavid Cohen select I2C 5967c9c3a1eSAlan Cox select DW_APB_TIMER 5971ea7c673SAlan Cox select APB_TIMER 5981ea7c673SAlan Cox select INTEL_SCU_IPC 59915a713dfSMika Westerberg select MFD_INTEL_MSIC 6001ea7c673SAlan Cox ---help--- 6014cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6024cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6034cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6041ea7c673SAlan Cox 6054cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6064cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 60743605ef1SAlan Cox 6088bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6098bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6108bbc2a13SBryan O'Donoghue depends on X86_32 6118bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6128bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6138bbc2a13SBryan O'Donoghue depends on X86_TSC 6148bbc2a13SBryan O'Donoghue depends on PCI 6158bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6168bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6178bbc2a13SBryan O'Donoghue select IOSF_MBI 6188bbc2a13SBryan O'Donoghue select INTEL_IMR 6199ab6eb51SAndy Shevchenko select COMMON_CLK 6208bbc2a13SBryan O'Donoghue ---help--- 6218bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6228bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6238bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6248bbc2a13SBryan O'Donoghue 6253d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6263d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6275962dd22SSinan Kaya depends on X86 && ACPI && PCI 6283d48aab1SMika Westerberg select COMMON_CLK 6290f531431SMathias Nyman select PINCTRL 630eebb3e8dSAndy Shevchenko select IOSF_MBI 6313d48aab1SMika Westerberg ---help--- 6323d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6333d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6340f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6350f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6363d48aab1SMika Westerberg 63792082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 63892082a88SKen Xue bool "AMD ACPI2Platform devices support" 63992082a88SKen Xue depends on ACPI 64092082a88SKen Xue select COMMON_CLK 64192082a88SKen Xue select PINCTRL 64292082a88SKen Xue ---help--- 64392082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 64492082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 64592082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 64692082a88SKen Xue implemented under PINCTRL subsystem. 64792082a88SKen Xue 648ced3ce76SDavid E. Boxconfig IOSF_MBI 649ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 650ced3ce76SDavid E. Box depends on PCI 651ced3ce76SDavid E. Box ---help--- 652ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 653ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 654ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 655ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 656ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 657ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 658ced3ce76SDavid E. Box This list is not meant to be exclusive. 659ced3ce76SDavid E. Box - BayTrail 660ced3ce76SDavid E. Box - Braswell 661ced3ce76SDavid E. Box - Quark 662ced3ce76SDavid E. Box 663ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 664ced3ce76SDavid E. Box 665ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 666ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 667ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 668ed2226bdSDavid E. Box ---help--- 669ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 670ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 671ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 672ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 673ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 674ed2226bdSDavid E. Box device they want to access. 675ed2226bdSDavid E. Box 676ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 677ed2226bdSDavid E. Box 678c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 679c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 680506f1d07SSam Ravnborg depends on X86_32 681c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 682c5c606d9SRavikiran G Thirumalai select M486 683c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 684c5c606d9SRavikiran G Thirumalai ---help--- 685c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 686c5c606d9SRavikiran G Thirumalai as R-8610-(G). 687c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 688c5c606d9SRavikiran G Thirumalai 689e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 6909c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 6919c398017SIngo Molnar depends on X86_32 && SMP 692c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 6938f9ca475SIngo Molnar ---help--- 694b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 695b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 696b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 697b5660ba7SH. Peter Anvin one and will fallback to default. 698d49c4288SYinghai Lu 699c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 700d49c4288SYinghai Lu 701d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7026fc108a0SJan Beulich def_bool y 703d949f36fSLinus Torvalds # MCE code calls memory_failure(): 704d949f36fSLinus Torvalds depends on X86_MCE 705d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 706d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 707d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 708d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 709d949f36fSLinus Torvalds 71083125a3aSAlessandro Rubiniconfig STA2X11 71183125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 71283125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 71383125a3aSAlessandro Rubini select SWIOTLB 71483125a3aSAlessandro Rubini select MFD_STA2X11 7150145071bSLinus Walleij select GPIOLIB 71683125a3aSAlessandro Rubini ---help--- 71783125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 71883125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 71983125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 72083125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 72183125a3aSAlessandro Rubini standard PC machines. 72283125a3aSAlessandro Rubini 72382148d1dSShérabconfig X86_32_IRIS 72482148d1dSShérab tristate "Eurobraille/Iris poweroff module" 72582148d1dSShérab depends on X86_32 72682148d1dSShérab ---help--- 72782148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 72882148d1dSShérab to shut themselves down properly. A special I/O sequence is 72982148d1dSShérab needed to do so, which is what this module does at 73082148d1dSShérab kernel shutdown. 73182148d1dSShérab 73282148d1dSShérab This is only for Iris machines from EuroBraille. 73382148d1dSShérab 73482148d1dSShérab If unused, say N. 73582148d1dSShérab 736ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7373c2362e6SHarvey Harrison def_bool y 7383c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 739a87d0914SKen Chen depends on X86 7408f9ca475SIngo Molnar ---help--- 741506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 742506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 743506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 744506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 745506f1d07SSam Ravnborg 746506f1d07SSam Ravnborg If in doubt, say "Y". 747506f1d07SSam Ravnborg 7486276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7496276a074SBorislav Petkov bool "Linux guest support" 7508f9ca475SIngo Molnar ---help--- 7516276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7526276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7536276a074SBorislav Petkov setup. 754506f1d07SSam Ravnborg 7556276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7566276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 757506f1d07SSam Ravnborg 7586276a074SBorislav Petkovif HYPERVISOR_GUEST 759506f1d07SSam Ravnborg 760e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 761e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 7628f9ca475SIngo Molnar ---help--- 763e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 764e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 765e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 766e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 767e61bd94aSEduardo Pereira Habkost 768c00a280aSJuergen Grossconfig PARAVIRT_XXL 769c00a280aSJuergen Gross bool 770c00a280aSJuergen Gross 7716276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7726276a074SBorislav Petkov bool "paravirt-ops debugging" 7736276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 7746276a074SBorislav Petkov ---help--- 7756276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7766276a074SBorislav Petkov a paravirt_op is missing when it is called. 7776276a074SBorislav Petkov 778b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 779b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 7806ea30386SKees Cook depends on PARAVIRT && SMP 781b4ecc126SJeremy Fitzhardinge ---help--- 782b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 783b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 784b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 785b4ecc126SJeremy Fitzhardinge 7864c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 7874c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 788b4ecc126SJeremy Fitzhardinge 7894c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 790b4ecc126SJeremy Fitzhardinge 791ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 792ecca2502SZhao Yakui def_bool n 793ecca2502SZhao Yakui 7946276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 7956276a074SBorislav Petkov 7966276a074SBorislav Petkovconfig KVM_GUEST 7976276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 7986276a074SBorislav Petkov depends on PARAVIRT 7996276a074SBorislav Petkov select PARAVIRT_CLOCK 800a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 8016276a074SBorislav Petkov default y 8026276a074SBorislav Petkov ---help--- 8036276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8046276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8056276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8066276a074SBorislav Petkov underlying device model, the host provides the guest with 8076276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8086276a074SBorislav Petkov 809a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 810a1c4423bSMarcelo Tosatti def_bool n 811a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 812a1c4423bSMarcelo Tosatti help 813a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 814a1c4423bSMarcelo Tosatti 8157733607fSMaran Wilsonconfig PVH 8167733607fSMaran Wilson bool "Support for running PVH guests" 8177733607fSMaran Wilson ---help--- 8187733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8197733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8207733607fSMaran Wilson 8211e20eb85SSrivatsa Vaddagiriconfig KVM_DEBUG_FS 8221e20eb85SSrivatsa Vaddagiri bool "Enable debug information for KVM Guests in debugfs" 8231e20eb85SSrivatsa Vaddagiri depends on KVM_GUEST && DEBUG_FS 8241e20eb85SSrivatsa Vaddagiri ---help--- 8251e20eb85SSrivatsa Vaddagiri This option enables collection of various statistics for KVM guest. 8261e20eb85SSrivatsa Vaddagiri Statistics are displayed in debugfs filesystem. Enabling this option 8271e20eb85SSrivatsa Vaddagiri may incur significant overhead. 8281e20eb85SSrivatsa Vaddagiri 8296276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8306276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8316276a074SBorislav Petkov depends on PARAVIRT 8326276a074SBorislav Petkov ---help--- 8336276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8346276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8356276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8366276a074SBorislav Petkov that, there can be a small performance impact. 8376276a074SBorislav Petkov 8386276a074SBorislav Petkov If in doubt, say N here. 8396276a074SBorislav Petkov 8407af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8417af192c9SGerd Hoffmann bool 8427af192c9SGerd Hoffmann 8434a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8444a362601SJan Kiszka bool "Jailhouse non-root cell support" 845abde587bSArnd Bergmann depends on X86_64 && PCI 84687e65d05SJan Kiszka select X86_PM_TIMER 8474a362601SJan Kiszka ---help--- 8484a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8494a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8504a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8514a362601SJan Kiszka 852ec7972c9SZhao Yakuiconfig ACRN_GUEST 853ec7972c9SZhao Yakui bool "ACRN Guest support" 854ec7972c9SZhao Yakui depends on X86_64 855498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 856ec7972c9SZhao Yakui help 857ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 858ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 859ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 860ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 861ec7972c9SZhao Yakui found in https://projectacrn.org/. 862ec7972c9SZhao Yakui 8636276a074SBorislav Petkovendif #HYPERVISOR_GUEST 86497349135SJeremy Fitzhardinge 865506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 866506f1d07SSam Ravnborg 867506f1d07SSam Ravnborgconfig HPET_TIMER 8683c2362e6SHarvey Harrison def_bool X86_64 869506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 8708f9ca475SIngo Molnar ---help--- 871506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 872506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 873506f1d07SSam Ravnborg present. 874506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 875506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 876506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8774e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 8784e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 879506f1d07SSam Ravnborg 880506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 881506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 882506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 883506f1d07SSam Ravnborg 884506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 885506f1d07SSam Ravnborg 886506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 8873c2362e6SHarvey Harrison def_bool y 8889d8af78bSBernhard Walle depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 889506f1d07SSam Ravnborg 890bb24c471SJacob Panconfig APB_TIMER 891933b9463SAlan Cox def_bool y if X86_INTEL_MID 892933b9463SAlan Cox prompt "Intel MID APB Timer Support" if X86_INTEL_MID 89306c3df49SJamie Iles select DW_APB_TIMER 894a0c3832aSAlan Cox depends on X86_INTEL_MID && SFI 895bb24c471SJacob Pan help 896bb24c471SJacob Pan APB timer is the replacement for 8254, HPET on X86 MID platforms. 897bb24c471SJacob Pan The APBT provides a stable time base on SMP 898bb24c471SJacob Pan systems, unlike the TSC, but it is more expensive to access, 899bb24c471SJacob Pan as it is off-chip. APB timers are always running regardless of CPU 900bb24c471SJacob Pan C states, they are used as per CPU clockevent device when possible. 901bb24c471SJacob Pan 9026a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 903506f1d07SSam Ravnborg# The code disables itself when not needed. 9047ae9392cSThomas Petazzoniconfig DMI 9057ae9392cSThomas Petazzoni default y 906cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9076a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 9088f9ca475SIngo Molnar ---help--- 9097ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9107ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9117ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9127ae9392cSThomas Petazzoni BIOS code. 9137ae9392cSThomas Petazzoni 914506f1d07SSam Ravnborgconfig GART_IOMMU 91538901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 916a4ce5a48SChristoph Hellwig select IOMMU_HELPER 917506f1d07SSam Ravnborg select SWIOTLB 91823ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 9198f9ca475SIngo Molnar ---help--- 920ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 921ced3c42cSIngo Molnar GART based hardware IOMMUs. 922ced3c42cSIngo Molnar 923ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 924ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 925ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 926ced3c42cSIngo Molnar 927ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 928ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 929ced3c42cSIngo Molnar 930ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 931ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 932ced3c42cSIngo Molnar 32-bit limited device. 933ced3c42cSIngo Molnar 934ced3c42cSIngo Molnar If unsure, say Y. 935506f1d07SSam Ravnborg 9361184dc2fSMike Travisconfig MAXSMP 937ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9386ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 93936f5101aSMike Travis select CPUMASK_OFFSTACK 9408f9ca475SIngo Molnar ---help--- 941ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9421184dc2fSMike Travis If unsure, say N. 943506f1d07SSam Ravnborg 944aec6487eSIngo Molnar# 945aec6487eSIngo Molnar# The maximum number of CPUs supported: 946aec6487eSIngo Molnar# 947aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 948aec6487eSIngo Molnar# and which can be configured interactively in the 949aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 950aec6487eSIngo Molnar# 951aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 952aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 953aec6487eSIngo Molnar# 954aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 955aec6487eSIngo Molnar# interactive configuration. ) 956aec6487eSIngo Molnar# 957a0d0bb4dSRandy Dunlap 958aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 959a0d0bb4dSRandy Dunlap int 960aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 961a0d0bb4dSRandy Dunlap default 1 if !SMP 962a0d0bb4dSRandy Dunlap default 2 963a0d0bb4dSRandy Dunlap 964aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 965a0d0bb4dSRandy Dunlap int 966a0d0bb4dSRandy Dunlap depends on X86_32 967aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 968aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 969a0d0bb4dSRandy Dunlap default 1 if !SMP 970a0d0bb4dSRandy Dunlap 971aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 972a0d0bb4dSRandy Dunlap int 973a0d0bb4dSRandy Dunlap depends on X86_64 9741edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9751edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 976a0d0bb4dSRandy Dunlap default 1 if !SMP 977aec6487eSIngo Molnar 978aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 979aec6487eSIngo Molnar int 980aec6487eSIngo Molnar depends on X86_32 981aec6487eSIngo Molnar default 32 if X86_BIGSMP 982aec6487eSIngo Molnar default 8 if SMP 983aec6487eSIngo Molnar default 1 if !SMP 984aec6487eSIngo Molnar 985aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 986aec6487eSIngo Molnar int 987aec6487eSIngo Molnar depends on X86_64 988a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 989a0d0bb4dSRandy Dunlap default 64 if SMP 990aec6487eSIngo Molnar default 1 if !SMP 991a0d0bb4dSRandy Dunlap 992506f1d07SSam Ravnborgconfig NR_CPUS 99336f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 994aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 995aec6487eSIngo Molnar default NR_CPUS_DEFAULT 9968f9ca475SIngo Molnar ---help--- 997506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 998bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 999cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1000506f1d07SSam Ravnborg minimum value which makes sense is 2. 1001506f1d07SSam Ravnborg 1002aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1003aec6487eSIngo Molnar to the kernel image. 1004506f1d07SSam Ravnborg 1005506f1d07SSam Ravnborgconfig SCHED_SMT 1006dbe73364SThomas Gleixner def_bool y if SMP 1007506f1d07SSam Ravnborg 1008506f1d07SSam Ravnborgconfig SCHED_MC 10093c2362e6SHarvey Harrison def_bool y 10103c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1011c8e56d20SBorislav Petkov depends on SMP 10128f9ca475SIngo Molnar ---help--- 1013506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1014506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1015506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1016506f1d07SSam Ravnborg 1017de966cf4STim Chenconfig SCHED_MC_PRIO 1018de966cf4STim Chen bool "CPU core priorities scheduler support" 10190a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10200a21fc12SIngo Molnar select X86_INTEL_PSTATE 10210a21fc12SIngo Molnar select CPU_FREQ 1022de966cf4STim Chen default y 10235e76b2abSTim Chen ---help--- 1024de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1025de966cf4STim Chen core ordering determined at manufacturing time, which allows 1026de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1027de966cf4STim Chen single threaded workloads) than others. 1028de966cf4STim Chen 1029de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1030de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1031de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1032de966cf4STim Chen overall system performance can be achieved. 1033de966cf4STim Chen 1034de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1035de966cf4STim Chen 1036de966cf4STim Chen If unsure say Y here. 10375e76b2abSTim Chen 103830b8b006SThomas Gleixnerconfig UP_LATE_INIT 103930b8b006SThomas Gleixner def_bool y 1040ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 104130b8b006SThomas Gleixner 1042506f1d07SSam Ravnborgconfig X86_UP_APIC 104350849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 104450849eefSJan Beulich default PCI_MSI 104538a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 10468f9ca475SIngo Molnar ---help--- 1047506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1048506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1049506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1050506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1051506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1052506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1053506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1054506f1d07SSam Ravnborg lockups. 1055506f1d07SSam Ravnborg 1056506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1057506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1058506f1d07SSam Ravnborg depends on X86_UP_APIC 10598f9ca475SIngo Molnar ---help--- 1060506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1061506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1062506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1063506f1d07SSam Ravnborg 1064506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1065506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1066506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1067506f1d07SSam Ravnborg 1068506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10693c2362e6SHarvey Harrison def_bool y 10700dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1071b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 107252f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1073506f1d07SSam Ravnborg 1074506f1d07SSam Ravnborgconfig X86_IO_APIC 1075b1da1e71SJan Beulich def_bool y 1076b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1077506f1d07SSam Ravnborg 107841b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 107941b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 108041b9eb26SStefan Assmann depends on X86_IO_APIC 10818f9ca475SIngo Molnar ---help--- 108241b9eb26SStefan Assmann This option enables a workaround that fixes a source of 108341b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 108441b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 108541b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 108641b9eb26SStefan Assmann 108741b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 108841b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 108941b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 109041b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 109141b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 109241b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 109341b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 109441b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 109541b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 109641b9eb26SStefan Assmann down (vital) interrupt lines. 109741b9eb26SStefan Assmann 109841b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 109941b9eb26SStefan Assmann increased on these systems. 110041b9eb26SStefan Assmann 1101506f1d07SSam Ravnborgconfig X86_MCE 1102bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1103648ed940SChen, Gong select GENERIC_ALLOCATOR 1104e57dbaf7SBorislav Petkov default y 1105506f1d07SSam Ravnborg ---help--- 1106bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1107bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1108506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1109bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11104efc0670SAndi Kleen 11115de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11125de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11135de97c9fSTony Luck depends on X86_MCE 11145de97c9fSTony Luck ---help--- 11155de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11165de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11175de97c9fSTony Luck rasdaemon solution. 11185de97c9fSTony Luck 1119506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11203c2362e6SHarvey Harrison def_bool y 11213c2362e6SHarvey Harrison prompt "Intel MCE features" 1122c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 11238f9ca475SIngo Molnar ---help--- 1124506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1125506f1d07SSam Ravnborg the thermal monitor. 1126506f1d07SSam Ravnborg 1127506f1d07SSam Ravnborgconfig X86_MCE_AMD 11283c2362e6SHarvey Harrison def_bool y 11293c2362e6SHarvey Harrison prompt "AMD MCE features" 1130f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 11318f9ca475SIngo Molnar ---help--- 1132506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1133506f1d07SSam Ravnborg the DRAM Error Threshold. 1134506f1d07SSam Ravnborg 11354efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11366fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1137c31d9633SAndi Kleen depends on X86_32 && X86_MCE 11384efc0670SAndi Kleen ---help--- 11394efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11405065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11414efc0670SAndi Kleen line. 11424efc0670SAndi Kleen 1143b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1144b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11456fc108a0SJan Beulich def_bool y 1146b2762686SAndi Kleen 1147ea149b36SAndi Kleenconfig X86_MCE_INJECT 1148bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1149ea149b36SAndi Kleen tristate "Machine check injector support" 1150ea149b36SAndi Kleen ---help--- 1151ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1152ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1153ea149b36SAndi Kleen QA it is safe to say n. 1154ea149b36SAndi Kleen 11554efc0670SAndi Kleenconfig X86_THERMAL_VECTOR 11564efc0670SAndi Kleen def_bool y 11575bb38adcSAndi Kleen depends on X86_MCE_INTEL 11584efc0670SAndi Kleen 115907dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1160e633c65aSKan Liang 11615aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11621e642812SIngo Molnar bool "Legacy VM86 support" 1163506f1d07SSam Ravnborg depends on X86_32 11648f9ca475SIngo Molnar ---help--- 11655aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11665aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11675aef51c3SAndy Lutomirski 11685aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11695aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11705aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11715aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11725aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 11731e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 11741e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 11751e642812SIngo Molnar mode might be faster than emulation and you might want to 11761e642812SIngo Molnar enable this option. 11775aef51c3SAndy Lutomirski 11781e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 11791e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 11801e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 11811e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 11825aef51c3SAndy Lutomirski 11831e642812SIngo Molnar Enabling this option increases the complexity of the kernel 11841e642812SIngo Molnar and slows down exception handling a tiny bit. 11855aef51c3SAndy Lutomirski 11861e642812SIngo Molnar If unsure, say N here. 11875aef51c3SAndy Lutomirski 11885aef51c3SAndy Lutomirskiconfig VM86 11895aef51c3SAndy Lutomirski bool 11905aef51c3SAndy Lutomirski default X86_LEGACY_VM86 119134273f41SH. Peter Anvin 119234273f41SH. Peter Anvinconfig X86_16BIT 119334273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 119434273f41SH. Peter Anvin default y 1195a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 119634273f41SH. Peter Anvin ---help--- 119734273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 119834273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 119934273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 120034273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 120134273f41SH. Peter Anvin 120234273f41SH. Peter Anvinconfig X86_ESPFIX32 120334273f41SH. Peter Anvin def_bool y 120434273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1205506f1d07SSam Ravnborg 1206197725deSH. Peter Anvinconfig X86_ESPFIX64 1207197725deSH. Peter Anvin def_bool y 120834273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1209506f1d07SSam Ravnborg 12101ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12111ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12121ad83c85SAndy Lutomirski default y 12131ad83c85SAndy Lutomirski depends on X86_64 12141ad83c85SAndy Lutomirski ---help--- 12151ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12161ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12171ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12181ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12191ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12201ad83c85SAndy Lutomirski 0xffffffffff600?00. 12211ad83c85SAndy Lutomirski 12221ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12231ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12241ad83c85SAndy Lutomirski 12251ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12261ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12271ad83c85SAndy Lutomirski 1228111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1229111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1230a24ca997SThomas Gleixner default y 1231c8137aceSThomas Gleixner ---help--- 1232111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1233111e7b15SThomas Gleixner for legacy applications. 1234111e7b15SThomas Gleixner 1235c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1236c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1237c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1238c8137aceSThomas Gleixner capabilities and permission from potentially active security 1239c8137aceSThomas Gleixner modules. 1240c8137aceSThomas Gleixner 1241c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1242c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1243a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1244a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1245c8137aceSThomas Gleixner 1246506f1d07SSam Ravnborgconfig TOSHIBA 1247506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1248506f1d07SSam Ravnborg depends on X86_32 1249506f1d07SSam Ravnborg ---help--- 1250506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1251506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1252506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1253506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1254506f1d07SSam Ravnborg 1255506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1256506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1257506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1258506f1d07SSam Ravnborg 1259506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1260506f1d07SSam Ravnborg Say N otherwise. 1261506f1d07SSam Ravnborg 1262506f1d07SSam Ravnborgconfig I8K 1263039ae585SPali Rohár tristate "Dell i8k legacy laptop support" 1264949a9d70SJean Delvare select HWMON 1265039ae585SPali Rohár select SENSORS_DELL_SMM 1266506f1d07SSam Ravnborg ---help--- 1267039ae585SPali Rohár This option enables legacy /proc/i8k userspace interface in hwmon 1268039ae585SPali Rohár dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1269039ae585SPali Rohár temperature and allows controlling fan speeds of Dell laptops via 1270039ae585SPali Rohár System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1271039ae585SPali Rohár it reports also power and hotkey status. For fan speed control is 1272039ae585SPali Rohár needed userspace package i8kutils. 1273506f1d07SSam Ravnborg 1274039ae585SPali Rohár Say Y if you intend to run this kernel on old Dell laptops or want to 1275039ae585SPali Rohár use userspace package i8kutils. 1276506f1d07SSam Ravnborg Say N otherwise. 1277506f1d07SSam Ravnborg 1278506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12799ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12809ba16087SJan Beulich depends on X86_32 1281506f1d07SSam Ravnborg ---help--- 1282506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1283506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1284506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1285506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1286506f1d07SSam Ravnborg system. 1287506f1d07SSam Ravnborg 1288506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 12895e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1290506f1d07SSam Ravnborg 1291506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1292506f1d07SSam Ravnborg enable this option even if you don't need it. 1293506f1d07SSam Ravnborg Say N otherwise. 1294506f1d07SSam Ravnborg 1295506f1d07SSam Ravnborgconfig MICROCODE 12969a2bc335SBorislav Petkov bool "CPU microcode loading support" 12979a2bc335SBorislav Petkov default y 129880030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1299506f1d07SSam Ravnborg select FW_LOADER 1300506f1d07SSam Ravnborg ---help--- 1301506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13025f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13035f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13045f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13055f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13065f9c01aaSBorislav Petkov the Linux kernel. 1307506f1d07SSam Ravnborg 13085f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1309cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13105f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13115f9c01aaSBorislav Petkov initrd for microcode blobs. 1312506f1d07SSam Ravnborg 1313c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1314c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1315c508c46eSBenjamin Gilbert config option. 1316506f1d07SSam Ravnborg 13178d86f390SPeter Orubaconfig MICROCODE_INTEL 1318e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13198d86f390SPeter Oruba depends on MICROCODE 13208d86f390SPeter Oruba default MICROCODE 13218d86f390SPeter Oruba select FW_LOADER 13228f9ca475SIngo Molnar ---help--- 13238d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13248d86f390SPeter Oruba processors. 13258d86f390SPeter Oruba 1326b8989db9SAlan For the current Intel microcode data package go to 1327b8989db9SAlan <https://downloadcenter.intel.com> and search for 1328b8989db9SAlan 'Linux Processor Microcode Data File'. 13298d86f390SPeter Oruba 133080cc9f10SPeter Orubaconfig MICROCODE_AMD 1331e43f6e67SBorislav Petkov bool "AMD microcode loading support" 133280cc9f10SPeter Oruba depends on MICROCODE 133380cc9f10SPeter Oruba select FW_LOADER 13348f9ca475SIngo Molnar ---help--- 133580cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 133680cc9f10SPeter Oruba processors will be enabled. 133780cc9f10SPeter Oruba 1338506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1339c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1340c02f48e0SBorislav Petkov default n 1341506f1d07SSam Ravnborg depends on MICROCODE 1342c02f48e0SBorislav Petkov ---help--- 1343c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1344c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1345c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1346c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1347c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1348cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1349506f1d07SSam Ravnborg 1350506f1d07SSam Ravnborgconfig X86_MSR 1351506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 13528f9ca475SIngo Molnar ---help--- 1353506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1354506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1355506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1356506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1357506f1d07SSam Ravnborg systems. 1358506f1d07SSam Ravnborg 1359506f1d07SSam Ravnborgconfig X86_CPUID 1360506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 13618f9ca475SIngo Molnar ---help--- 1362506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1363506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1364506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1365506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1366506f1d07SSam Ravnborg 1367506f1d07SSam Ravnborgchoice 1368506f1d07SSam Ravnborg prompt "High Memory Support" 13696fc108a0SJan Beulich default HIGHMEM4G 1370506f1d07SSam Ravnborg depends on X86_32 1371506f1d07SSam Ravnborg 1372506f1d07SSam Ravnborgconfig NOHIGHMEM 1373506f1d07SSam Ravnborg bool "off" 1374506f1d07SSam Ravnborg ---help--- 1375506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1376506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1377506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1378506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1379506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1380506f1d07SSam Ravnborg "high memory". 1381506f1d07SSam Ravnborg 1382506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1383506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1384506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1385506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1386506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1387506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1388506f1d07SSam Ravnborg possible. 1389506f1d07SSam Ravnborg 1390506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1391506f1d07SSam Ravnborg answer "4GB" here. 1392506f1d07SSam Ravnborg 1393506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1394506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1395506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1396506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1397506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1398506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1399506f1d07SSam Ravnborg 1400506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1401506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1402506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1403506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1404506f1d07SSam Ravnborg kernel at boot time.) 1405506f1d07SSam Ravnborg 1406506f1d07SSam Ravnborg If unsure, say "off". 1407506f1d07SSam Ravnborg 1408506f1d07SSam Ravnborgconfig HIGHMEM4G 1409506f1d07SSam Ravnborg bool "4GB" 14108f9ca475SIngo Molnar ---help--- 1411506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1412506f1d07SSam Ravnborg gigabytes of physical RAM. 1413506f1d07SSam Ravnborg 1414506f1d07SSam Ravnborgconfig HIGHMEM64G 1415506f1d07SSam Ravnborg bool "64GB" 141669b8d3fcSMatthew Whitehead depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1417506f1d07SSam Ravnborg select X86_PAE 14188f9ca475SIngo Molnar ---help--- 1419506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1420506f1d07SSam Ravnborg gigabytes of physical RAM. 1421506f1d07SSam Ravnborg 1422506f1d07SSam Ravnborgendchoice 1423506f1d07SSam Ravnborg 1424506f1d07SSam Ravnborgchoice 14256a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1426506f1d07SSam Ravnborg default VMSPLIT_3G 1427506f1d07SSam Ravnborg depends on X86_32 14288f9ca475SIngo Molnar ---help--- 1429506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1430506f1d07SSam Ravnborg 1431506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1432506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1433506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1434506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1435506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1436506f1d07SSam Ravnborg available to user programs, making the address space there 1437506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1438506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1439506f1d07SSam Ravnborg kernel modules. 1440506f1d07SSam Ravnborg 1441506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1442506f1d07SSam Ravnborg option alone! 1443506f1d07SSam Ravnborg 1444506f1d07SSam Ravnborg config VMSPLIT_3G 1445506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1446506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1447506f1d07SSam Ravnborg depends on !X86_PAE 1448506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1449506f1d07SSam Ravnborg config VMSPLIT_2G 1450506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1451506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1452506f1d07SSam Ravnborg depends on !X86_PAE 1453506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1454506f1d07SSam Ravnborg config VMSPLIT_1G 1455506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1456506f1d07SSam Ravnborgendchoice 1457506f1d07SSam Ravnborg 1458506f1d07SSam Ravnborgconfig PAGE_OFFSET 1459506f1d07SSam Ravnborg hex 1460506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1461506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1462506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1463506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1464506f1d07SSam Ravnborg default 0xC0000000 1465506f1d07SSam Ravnborg depends on X86_32 1466506f1d07SSam Ravnborg 1467506f1d07SSam Ravnborgconfig HIGHMEM 14683c2362e6SHarvey Harrison def_bool y 1469506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1470506f1d07SSam Ravnborg 1471506f1d07SSam Ravnborgconfig X86_PAE 14729ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1473506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1474d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14759d99c712SChristian Melki select SWIOTLB 14768f9ca475SIngo Molnar ---help--- 1477506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1478506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1479506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1480506f1d07SSam Ravnborg consumes more pagetable space per process. 1481506f1d07SSam Ravnborg 148277ef56e4SKirill A. Shutemovconfig X86_5LEVEL 148377ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 148418ec1eafSKirill A. Shutemov default y 1485eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1486162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 148777ef56e4SKirill A. Shutemov depends on X86_64 148877ef56e4SKirill A. Shutemov ---help--- 148977ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 149077ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 149177ef56e4SKirill A. Shutemov physical address space. 149277ef56e4SKirill A. Shutemov 149377ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 149477ef56e4SKirill A. Shutemov 14956657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 14966657fca0SKirill A. Shutemov support 4- or 5-level paging. 149777ef56e4SKirill A. Shutemov 1498cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 149977ef56e4SKirill A. Shutemov information. 150077ef56e4SKirill A. Shutemov 150177ef56e4SKirill A. Shutemov Say N if unsure. 150277ef56e4SKirill A. Shutemov 150310971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1504e5008abeSLuis R. Rodriguez def_bool y 15052e1da13fSVlastimil Babka depends on X86_64 15068f9ca475SIngo Molnar ---help--- 150710971ab2SIngo Molnar Certain kernel features effectively disable kernel 150810971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 150910971ab2SIngo Molnar supports them), so don't confuse the user by printing 151010971ab2SIngo Molnar that we have them enabled. 15119e899816SNick Piggin 15125c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15135c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15145c280cf6SThomas Gleixner depends on DEBUG_FS 15155c280cf6SThomas Gleixner ---help--- 15165c280cf6SThomas Gleixner Expose statistics about the Change Page Attribute mechanims, which 1517a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15185c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15195c280cf6SThomas Gleixner 15207744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15217744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15227744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 152394d49eb3SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 1524ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 15259087c375STom Lendacky select ARCH_HAS_FORCE_DMA_UNENCRYPTED 15267744ccdbSTom Lendacky ---help--- 15277744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15287744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15297744ccdbSTom Lendacky Encryption (SME). 15307744ccdbSTom Lendacky 15317744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15327744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15337744ccdbSTom Lendacky default y 15347744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 15357744ccdbSTom Lendacky ---help--- 15367744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15377744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15387744ccdbSTom Lendacky 15397744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15407744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15417744ccdbSTom Lendacky 15427744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15437744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15447744ccdbSTom Lendacky 1545506f1d07SSam Ravnborg# Common NUMA Features 1546506f1d07SSam Ravnborgconfig NUMA 1547fd51b2d7SKOSAKI Motohiro bool "Numa Memory Allocation and Scheduler Support" 1548506f1d07SSam Ravnborg depends on SMP 1549b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1550b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15518f9ca475SIngo Molnar ---help--- 1552506f1d07SSam Ravnborg Enable NUMA (Non Uniform Memory Access) support. 1553fd51b2d7SKOSAKI Motohiro 1554506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1555506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1556506f1d07SSam Ravnborg NUMA awareness to the kernel. 1557506f1d07SSam Ravnborg 1558c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1559fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1560fd51b2d7SKOSAKI Motohiro 1561b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15627cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1563fd51b2d7SKOSAKI Motohiro 1564fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1565506f1d07SSam Ravnborg 1566eec1d4faSHans Rosenfeldconfig AMD_NUMA 15673c2362e6SHarvey Harrison def_bool y 15683c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15695da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 15708f9ca475SIngo Molnar ---help--- 1571eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1572eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1573eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1574eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1575eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1576506f1d07SSam Ravnborg 1577506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15783c2362e6SHarvey Harrison def_bool y 15793c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1580506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1581506f1d07SSam Ravnborg select ACPI_NUMA 15828f9ca475SIngo Molnar ---help--- 1583506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1584506f1d07SSam Ravnborg 15856ec6e0d9SSuresh Siddha# Some NUMA nodes have memory ranges that span 15866ec6e0d9SSuresh Siddha# other nodes. Even though a pfn is valid and 15876ec6e0d9SSuresh Siddha# between a node's start and end pfns, it may not 15886ec6e0d9SSuresh Siddha# reside on that node. See memmap_init_zone() 15896ec6e0d9SSuresh Siddha# for details. 15906ec6e0d9SSuresh Siddhaconfig NODES_SPAN_OTHER_NODES 15916ec6e0d9SSuresh Siddha def_bool y 15926ec6e0d9SSuresh Siddha depends on X86_64_ACPI_NUMA 15936ec6e0d9SSuresh Siddha 1594506f1d07SSam Ravnborgconfig NUMA_EMU 1595506f1d07SSam Ravnborg bool "NUMA emulation" 15961b7e03efSTejun Heo depends on NUMA 15978f9ca475SIngo Molnar ---help--- 1598506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1599506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1600506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1601506f1d07SSam Ravnborg 1602506f1d07SSam Ravnborgconfig NODES_SHIFT 1603d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 160451591e31SDavid Rientjes range 1 10 160551591e31SDavid Rientjes default "10" if MAXSMP 1606506f1d07SSam Ravnborg default "6" if X86_64 1607506f1d07SSam Ravnborg default "3" 1608506f1d07SSam Ravnborg depends on NEED_MULTIPLE_NODES 16098f9ca475SIngo Molnar ---help--- 16101184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1611692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1612506f1d07SSam Ravnborg 1613506f1d07SSam Ravnborgconfig ARCH_HAVE_MEMORY_PRESENT 16143c2362e6SHarvey Harrison def_bool y 1615506f1d07SSam Ravnborg depends on X86_32 && DISCONTIGMEM 1616506f1d07SSam Ravnborg 1617506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1618506f1d07SSam Ravnborg def_bool y 16193b16651fSTejun Heo depends on X86_32 && !NUMA 1620506f1d07SSam Ravnborg 1621506f1d07SSam Ravnborgconfig ARCH_DISCONTIGMEM_ENABLE 16222792107dSMike Rapoport def_bool n 1623b263295dSChristoph Lameter depends on NUMA && X86_32 16242792107dSMike Rapoport depends on BROKEN 1625b263295dSChristoph Lameter 1626506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1627506f1d07SSam Ravnborg def_bool y 16286ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1629506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1630506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1631506f1d07SSam Ravnborg 16323b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16336ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16343b16651fSTejun Heo 1635506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1636506f1d07SSam Ravnborg def_bool y 1637b263295dSChristoph Lameter depends on ARCH_SPARSEMEM_ENABLE 1638506f1d07SSam Ravnborg 1639506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1640a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16413120e25eSJan Beulich depends on X86_64 && MEMORY_HOTPLUG 1642a0842b70SToshi Kani help 1643a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1644cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1645a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1646506f1d07SSam Ravnborg 16473b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16483b16651fSTejun Heo def_bool y 16493b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16503b16651fSTejun Heo 1651a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1652a29815a3SAvi Kivity hex 1653a29815a3SAvi Kivity default 0 if X86_32 1654a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1655a29815a3SAvi Kivity 16567a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16577a67832cSDan Williams bool 16587a67832cSDan Williams 1659ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16607a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16619f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16629f53f9faSDan Williams depends on BLK_DEV 16637a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16649f53f9faSDan Williams select LIBNVDIMM 1665ec776ef6SChristoph Hellwig help 1666ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1667ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1668ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1669ec776ef6SChristoph Hellwig they can be used for persistent storage. 1670ec776ef6SChristoph Hellwig 1671ec776ef6SChristoph Hellwig Say Y if unsure. 1672ec776ef6SChristoph Hellwig 1673506f1d07SSam Ravnborgconfig HIGHPTE 1674506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16756fc108a0SJan Beulich depends on HIGHMEM 16768f9ca475SIngo Molnar ---help--- 1677506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1678506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1679506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1680506f1d07SSam Ravnborg entries in high memory. 1681506f1d07SSam Ravnborg 16829f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16839f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 16848f9ca475SIngo Molnar ---help--- 16859f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16869f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16879f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16889f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16899f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16909f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16919f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16928c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16939f077871SJeremy Fitzhardinge 16949f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16959f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16969f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16979f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16989f077871SJeremy Fitzhardinge 16999f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 17009f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 17019f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 17029f077871SJeremy Fitzhardinge memory. 17039f077871SJeremy Fitzhardinge 1704c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1705c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1706c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1707c885df50SJeremy Fitzhardinge default y 17088f9ca475SIngo Molnar ---help--- 1709c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1710c885df50SJeremy Fitzhardinge on or off. 1711c885df50SJeremy Fitzhardinge 17129ea77bdbSH. Peter Anvinconfig X86_RESERVE_LOW 1713d0cd7425SH. Peter Anvin int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1714d0cd7425SH. Peter Anvin default 64 1715d0cd7425SH. Peter Anvin range 4 640 17168f9ca475SIngo Molnar ---help--- 1717d0cd7425SH. Peter Anvin Specify the amount of low memory to reserve for the BIOS. 1718fc381519SIngo Molnar 1719d0cd7425SH. Peter Anvin The first page contains BIOS data structures that the kernel 1720d0cd7425SH. Peter Anvin must not use, so that page must always be reserved. 1721fc381519SIngo Molnar 1722d0cd7425SH. Peter Anvin By default we reserve the first 64K of physical RAM, as a 1723d0cd7425SH. Peter Anvin number of BIOSes are known to corrupt that memory range 1724d0cd7425SH. Peter Anvin during events such as suspend/resume or monitor cable 1725d0cd7425SH. Peter Anvin insertion, so it must not be used by the kernel. 1726fc381519SIngo Molnar 1727d0cd7425SH. Peter Anvin You can set this to 4 if you are absolutely sure that you 1728d0cd7425SH. Peter Anvin trust the BIOS to get all its memory reservations and usages 1729d0cd7425SH. Peter Anvin right. If you know your BIOS have problems beyond the 1730d0cd7425SH. Peter Anvin default 64K area, you can set this to 640 to avoid using the 1731d0cd7425SH. Peter Anvin entire low memory range. 1732d0cd7425SH. Peter Anvin 1733d0cd7425SH. Peter Anvin If you have doubts about the BIOS (e.g. suspend/resume does 1734d0cd7425SH. Peter Anvin not work or there's kernel crashes after certain hardware 1735d0cd7425SH. Peter Anvin hotplug events) then you might want to enable 1736d0cd7425SH. Peter Anvin X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1737d0cd7425SH. Peter Anvin typical corruption patterns. 1738d0cd7425SH. Peter Anvin 1739d0cd7425SH. Peter Anvin Leave this to the default value of 64 if you are unsure. 1740fc381519SIngo Molnar 1741506f1d07SSam Ravnborgconfig MATH_EMULATION 1742506f1d07SSam Ravnborg bool 1743a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 174487d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1745506f1d07SSam Ravnborg ---help--- 1746506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1747506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1748506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1749506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1750506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1751506f1d07SSam Ravnborg coprocessor or this emulation. 1752506f1d07SSam Ravnborg 1753506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1754506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1755506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1756506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1757506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1758506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1759506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1760506f1d07SSam Ravnborg intend to use this kernel on different machines. 1761506f1d07SSam Ravnborg 1762506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1763506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1764506f1d07SSam Ravnborg 1765506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1766506f1d07SSam Ravnborg kernel, it won't hurt. 1767506f1d07SSam Ravnborg 1768506f1d07SSam Ravnborgconfig MTRR 17696fc108a0SJan Beulich def_bool y 17706a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1771506f1d07SSam Ravnborg ---help--- 1772506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1773506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1774506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1775506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1776506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1777506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1778506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1779506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1780506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1781506f1d07SSam Ravnborg 1782506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1783506f1d07SSam Ravnborg control registers on other processors can be easily supported 1784506f1d07SSam Ravnborg as well: 1785506f1d07SSam Ravnborg 1786506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1787506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1788506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1789506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1790506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1791506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1792506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1793506f1d07SSam Ravnborg 1794506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1795506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1796506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1797506f1d07SSam Ravnborg 1798506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1799506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1800506f1d07SSam Ravnborg 1801cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1802506f1d07SSam Ravnborg 180395ffa243SYinghai Luconfig MTRR_SANITIZER 18042ffb3501SYinghai Lu def_bool y 180595ffa243SYinghai Lu prompt "MTRR cleanup support" 180695ffa243SYinghai Lu depends on MTRR 18078f9ca475SIngo Molnar ---help--- 1808aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1809aba3728cSThomas Gleixner add writeback entries. 181095ffa243SYinghai Lu 1811aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1812692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1813aba3728cSThomas Gleixner mtrr_chunk_size. 181495ffa243SYinghai Lu 18152ffb3501SYinghai Lu If unsure, say Y. 181695ffa243SYinghai Lu 181795ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1818f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1819f5098d62SYinghai Lu range 0 1 1820f5098d62SYinghai Lu default "0" 182195ffa243SYinghai Lu depends on MTRR_SANITIZER 18228f9ca475SIngo Molnar ---help--- 1823f5098d62SYinghai Lu Enable mtrr cleanup default value 182495ffa243SYinghai Lu 182512031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 182612031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 182712031a62SYinghai Lu range 0 7 182812031a62SYinghai Lu default "1" 182912031a62SYinghai Lu depends on MTRR_SANITIZER 18308f9ca475SIngo Molnar ---help--- 183112031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1832aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 183312031a62SYinghai Lu 18342e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18356fc108a0SJan Beulich def_bool y 18366a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18372a8a2719SIngo Molnar depends on MTRR 18388f9ca475SIngo Molnar ---help--- 18392e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1840042b78e4SVenki Pallipadi 18412e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18422e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18432e5d9c85Svenkatesh.pallipadi@intel.com 18442e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1845042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18462e5d9c85Svenkatesh.pallipadi@intel.com 18472e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18482e5d9c85Svenkatesh.pallipadi@intel.com 184946cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 185046cf98cdSVenkatesh Pallipadi def_bool y 185146cf98cdSVenkatesh Pallipadi depends on X86_PAT 185246cf98cdSVenkatesh Pallipadi 1853628c6246SH. Peter Anvinconfig ARCH_RANDOM 1854628c6246SH. Peter Anvin def_bool y 1855628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1856628c6246SH. Peter Anvin ---help--- 1857628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1858628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1859628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1860628c6246SH. Peter Anvin secure hardware random number generator. 1861628c6246SH. Peter Anvin 186251ae4a2dSH. Peter Anvinconfig X86_SMAP 186351ae4a2dSH. Peter Anvin def_bool y 186451ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 186551ae4a2dSH. Peter Anvin ---help--- 186651ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 186751ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 186851ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 186951ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 187051ae4a2dSH. Peter Anvin 187151ae4a2dSH. Peter Anvin If unsure, say Y. 187251ae4a2dSH. Peter Anvin 1873b971880fSBabu Mogerconfig X86_UMIP 1874796ebc81SRicardo Neri def_bool y 1875b971880fSBabu Moger depends on CPU_SUP_INTEL || CPU_SUP_AMD 1876b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1877aa35f896SRicardo Neri ---help--- 1878b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1879b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1880b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1881b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1882b971880fSBabu Moger information about the hardware state. 1883796ebc81SRicardo Neri 1884796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1885796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1886796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1887796ebc81SRicardo Neri results are dummy. 1888aa35f896SRicardo Neri 188972e9b5feSDave Hansenconfig X86_INTEL_MPX 189072e9b5feSDave Hansen prompt "Intel MPX (Memory Protection Extensions)" 189172e9b5feSDave Hansen def_bool n 1892df3735c5SRik van Riel # Note: only available in 64-bit mode due to VMA flags shortage 1893df3735c5SRik van Riel depends on CPU_SUP_INTEL && X86_64 1894df3735c5SRik van Riel select ARCH_USES_HIGH_VMA_FLAGS 189572e9b5feSDave Hansen ---help--- 189672e9b5feSDave Hansen MPX provides hardware features that can be used in 189772e9b5feSDave Hansen conjunction with compiler-instrumented code to check 189872e9b5feSDave Hansen memory references. It is designed to detect buffer 189972e9b5feSDave Hansen overflow or underflow bugs. 190072e9b5feSDave Hansen 190172e9b5feSDave Hansen This option enables running applications which are 190272e9b5feSDave Hansen instrumented or otherwise use MPX. It does not use MPX 190372e9b5feSDave Hansen itself inside the kernel or to protect the kernel 190472e9b5feSDave Hansen against bad memory references. 190572e9b5feSDave Hansen 190672e9b5feSDave Hansen Enabling this option will make the kernel larger: 190772e9b5feSDave Hansen ~8k of kernel text and 36 bytes of data on a 64-bit 190872e9b5feSDave Hansen defconfig. It adds a long to the 'mm_struct' which 190972e9b5feSDave Hansen will increase the kernel memory overhead of each 191072e9b5feSDave Hansen process and adds some branches to paths used during 191172e9b5feSDave Hansen exec() and munmap(). 191272e9b5feSDave Hansen 1913cb1aaebeSMauro Carvalho Chehab For details, see Documentation/x86/intel_mpx.rst 191472e9b5feSDave Hansen 191572e9b5feSDave Hansen If unsure, say N. 191672e9b5feSDave Hansen 191735e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 1918284244a9SDave Hansen prompt "Intel Memory Protection Keys" 191935e97790SDave Hansen def_bool y 1920284244a9SDave Hansen # Note: only available in 64-bit mode 192135e97790SDave Hansen depends on CPU_SUP_INTEL && X86_64 192252c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 192352c8e601SIngo Molnar select ARCH_HAS_PKEYS 1924284244a9SDave Hansen ---help--- 1925284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1926284244a9SDave Hansen page-based protections, but without requiring modification of the 1927284244a9SDave Hansen page tables when an application changes protection domains. 1928284244a9SDave Hansen 19291eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1930284244a9SDave Hansen 1931284244a9SDave Hansen If unsure, say y. 193235e97790SDave Hansen 1933db616173SMichal Hockochoice 1934db616173SMichal Hocko prompt "TSX enable mode" 1935db616173SMichal Hocko depends on CPU_SUP_INTEL 1936db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1937db616173SMichal Hocko help 1938db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1939db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1940db616173SMichal Hocko can lead to a noticeable performance boost. 1941db616173SMichal Hocko 1942db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1943db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1944db616173SMichal Hocko will be more of those attacks discovered in the future. 1945db616173SMichal Hocko 1946db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1947db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1948db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1949db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1950db616173SMichal Hocko for the particular machine. 1951db616173SMichal Hocko 1952db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1953db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1954db616173SMichal Hocko details. 1955db616173SMichal Hocko 1956db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1957db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1958db616173SMichal Hocko relevant. 1959db616173SMichal Hocko 1960db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1961db616173SMichal Hocko bool "off" 1962db616173SMichal Hocko help 1963db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1964db616173SMichal Hocko 1965db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1966db616173SMichal Hocko bool "on" 1967db616173SMichal Hocko help 1968db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1969db616173SMichal Hocko line parameter. 1970db616173SMichal Hocko 1971db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1972db616173SMichal Hocko bool "auto" 1973db616173SMichal Hocko help 1974db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1975db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1976db616173SMichal Hockoendchoice 1977db616173SMichal Hocko 1978506f1d07SSam Ravnborgconfig EFI 19799ba16087SJan Beulich bool "EFI runtime service support" 19805b83683fSHuang, Ying depends on ACPI 1981f6ce5002SSergey Vlasov select UCS2_STRING 1982022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 1983506f1d07SSam Ravnborg ---help--- 19848b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1985506f1d07SSam Ravnborg available (such as the EFI variable services). 1986506f1d07SSam Ravnborg 19878b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19888b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19898b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19908b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19918b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19928b2cb7a8SHuang, Ying platforms. 1993506f1d07SSam Ravnborg 1994291f3632SMatt Flemingconfig EFI_STUB 1995291f3632SMatt Fleming bool "EFI stub support" 1996b16d8c23SMatt Fleming depends on EFI && !X86_USE_3DNOW 19977b2a583aSMatt Fleming select RELOCATABLE 1998291f3632SMatt Fleming ---help--- 1999291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 2000291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 2001291f3632SMatt Fleming 20024f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 20030c759662SMatt Fleming 20047d453eeeSMatt Flemingconfig EFI_MIXED 20057d453eeeSMatt Fleming bool "EFI mixed-mode support" 20067d453eeeSMatt Fleming depends on EFI_STUB && X86_64 20077d453eeeSMatt Fleming ---help--- 20087d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 20097d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 20107d453eeeSMatt Fleming mode. 20117d453eeeSMatt Fleming 20127d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 20137d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 20147d453eeeSMatt Fleming the EFI handover protocol must be used. 20157d453eeeSMatt Fleming 20167d453eeeSMatt Fleming If unsure, say N. 20177d453eeeSMatt Fleming 2018506f1d07SSam Ravnborgconfig SECCOMP 20193c2362e6SHarvey Harrison def_bool y 20203c2362e6SHarvey Harrison prompt "Enable seccomp to safely compute untrusted bytecode" 20218f9ca475SIngo Molnar ---help--- 2022506f1d07SSam Ravnborg This kernel feature is useful for number crunching applications 2023506f1d07SSam Ravnborg that may need to compute untrusted bytecode during their 2024506f1d07SSam Ravnborg execution. By using pipes or other transports made available to 2025506f1d07SSam Ravnborg the process as file descriptors supporting the read/write 2026506f1d07SSam Ravnborg syscalls, it's possible to isolate those applications in 2027506f1d07SSam Ravnborg their own address space using seccomp. Once seccomp is 20289c0bbee8SAlexey Dobriyan enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2029506f1d07SSam Ravnborg and the task is only allowed to execute a few safe syscalls 2030506f1d07SSam Ravnborg defined by each seccomp mode. 2031506f1d07SSam Ravnborg 2032506f1d07SSam Ravnborg If unsure, say Y. Only embedded should say N here. 2033506f1d07SSam Ravnborg 20348636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2035506f1d07SSam Ravnborg 2036506f1d07SSam Ravnborgconfig KEXEC 2037506f1d07SSam Ravnborg bool "kexec system call" 20382965faa5SDave Young select KEXEC_CORE 20398f9ca475SIngo Molnar ---help--- 2040506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2041506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2042506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2043506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2044506f1d07SSam Ravnborg 2045506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2046506f1d07SSam Ravnborg 2047506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2048506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2049bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2050bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2051bf220695SGeert Uytterhoeven made. 2052506f1d07SSam Ravnborg 205374ca317cSVivek Goyalconfig KEXEC_FILE 205474ca317cSVivek Goyal bool "kexec file based system call" 20552965faa5SDave Young select KEXEC_CORE 205674ca317cSVivek Goyal select BUILD_BIN2C 205774ca317cSVivek Goyal depends on X86_64 205874ca317cSVivek Goyal depends on CRYPTO=y 205974ca317cSVivek Goyal depends on CRYPTO_SHA256=y 206074ca317cSVivek Goyal ---help--- 206174ca317cSVivek Goyal This is new version of kexec system call. This system call is 206274ca317cSVivek Goyal file based and takes file descriptors as system call argument 206374ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 206474ca317cSVivek Goyal accepted by previous system call. 206574ca317cSVivek Goyal 2066b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2067b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2068b799a09fSAKASHI Takahiro 206999d5cadfSJiri Bohacconfig KEXEC_SIG 20708e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 207174ca317cSVivek Goyal depends on KEXEC_FILE 20728e7d8381SVivek Goyal ---help--- 207399d5cadfSJiri Bohac 207499d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 207599d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 207699d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 207799d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 207899d5cadfSJiri Bohac 207999d5cadfSJiri Bohac In addition to this option, you need to enable signature 208099d5cadfSJiri Bohac verification for the corresponding kernel image type being 208199d5cadfSJiri Bohac loaded in order for this to work. 208299d5cadfSJiri Bohac 208399d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 208499d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 208599d5cadfSJiri Bohac depends on KEXEC_SIG 208699d5cadfSJiri Bohac ---help--- 20878e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2088d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20898e7d8381SVivek Goyal 20908e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20918e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 209299d5cadfSJiri Bohac depends on KEXEC_SIG 20938e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20948e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 20958e7d8381SVivek Goyal ---help--- 20968e7d8381SVivek Goyal Enable bzImage signature verification support. 20978e7d8381SVivek Goyal 2098506f1d07SSam Ravnborgconfig CRASH_DUMP 209904b69447SPavel Machek bool "kernel crash dumps" 2100506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 21018f9ca475SIngo Molnar ---help--- 2102506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2103506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2104506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2105506f1d07SSam Ravnborg a specially reserved region and then later executed after 2106506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2107506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2108506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2109506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2110330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2111506f1d07SSam Ravnborg 21123ab83521SHuang Yingconfig KEXEC_JUMP 21136ea30386SKees Cook bool "kexec jump" 2114fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 21158f9ca475SIngo Molnar ---help--- 211689081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 211789081d17SHuang Ying code in physical address mode via KEXEC 21183ab83521SHuang Ying 2119506f1d07SSam Ravnborgconfig PHYSICAL_START 21206a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2121ceefccc9SH. Peter Anvin default "0x1000000" 21228f9ca475SIngo Molnar ---help--- 2123506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2124506f1d07SSam Ravnborg 2125506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2126506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2127506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2128506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2129506f1d07SSam Ravnborg address. 2130506f1d07SSam Ravnborg 2131506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2132506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2133506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2134506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2135506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2136506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2137506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2138506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2139506f1d07SSam Ravnborg 2140ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2141ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2142ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2143ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2144ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2145ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2146ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2147330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2148ceefccc9SH. Peter Anvin for more details about crash dumps. 2149506f1d07SSam Ravnborg 2150506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2151506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2152506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2153506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2154506f1d07SSam Ravnborg is present because there are users out there who continue to use 2155506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2156506f1d07SSam Ravnborg line. 2157506f1d07SSam Ravnborg 2158506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2159506f1d07SSam Ravnborg 2160506f1d07SSam Ravnborgconfig RELOCATABLE 216126717808SH. Peter Anvin bool "Build a relocatable kernel" 216226717808SH. Peter Anvin default y 21638f9ca475SIngo Molnar ---help--- 2164506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2165506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2166506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2167506f1d07SSam Ravnborg but are discarded at runtime. 2168506f1d07SSam Ravnborg 2169506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2170506f1d07SSam Ravnborg must live at a different physical address than the primary 2171506f1d07SSam Ravnborg kernel. 2172506f1d07SSam Ravnborg 2173506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2174506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21758ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2176506f1d07SSam Ravnborg 21778ab3820fSKees Cookconfig RANDOMIZE_BASE 2178e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21798ab3820fSKees Cook depends on RELOCATABLE 21806807c846SIngo Molnar default y 21818ab3820fSKees Cook ---help--- 2182e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2183e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2184e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2185e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2186e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2187e8581e3dSBaoquan He code internals. 2188e8581e3dSBaoquan He 2189ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2190ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2191ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2192ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2193ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2194ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2195ed9f007eSKees Cook 2196ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2197ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2198ed9f007eSKees Cook 512MB (8 bits of entropy). 21998ab3820fSKees Cook 2200a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2201e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2202e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2203ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2204ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2205ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2206ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2207ed9f007eSKees Cook theoretically possible, but the implementations are further 2208ed9f007eSKees Cook limited due to memory layouts. 2209e8581e3dSBaoquan He 22106807c846SIngo Molnar If unsure, say Y. 2211da2b6fb9SKees Cook 22128ab3820fSKees Cook# Relocation on x86 needs some additional build support 2213845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2214845adf72SH. Peter Anvin def_bool y 22158ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2216845adf72SH. Peter Anvin 2217506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2218a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 22198ab3820fSKees Cook default "0x200000" 2220a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2221a0215061SKees Cook range 0x200000 0x1000000 if X86_64 22228f9ca475SIngo Molnar ---help--- 2223506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2224506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2225506f1d07SSam Ravnborg address which meets above alignment restriction. 2226506f1d07SSam Ravnborg 2227506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2228506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2229506f1d07SSam Ravnborg address aligned to above value and run from there. 2230506f1d07SSam Ravnborg 2231506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2232506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2233506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2234506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2235506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2236506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2237506f1d07SSam Ravnborg above alignment restrictions. 2238506f1d07SSam Ravnborg 2239a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2240a0215061SKees Cook this value must be a multiple of 0x200000. 2241a0215061SKees Cook 2242506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2243506f1d07SSam Ravnborg 2244eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2245eedb92abSKirill A. Shutemov bool 2246eedb92abSKirill A. Shutemov ---help--- 2247eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2248eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2249eedb92abSKirill A. Shutemov 22500483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22510483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22520483e1faSThomas Garnier depends on X86_64 22530483e1faSThomas Garnier depends on RANDOMIZE_BASE 2254eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22550483e1faSThomas Garnier default RANDOMIZE_BASE 22560483e1faSThomas Garnier ---help--- 22570483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22580483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22590483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22600483e1faSThomas Garnier 22610483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22620483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22630483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22640483e1faSThomas Garnier addresses for each memory section. 22650483e1faSThomas Garnier 22666807c846SIngo Molnar If unsure, say Y. 22670483e1faSThomas Garnier 226890397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 226990397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 227090397a41SThomas Garnier depends on RANDOMIZE_MEMORY 227190397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 227290397a41SThomas Garnier default "0x0" 227390397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 227490397a41SThomas Garnier range 0x0 0x40 227590397a41SThomas Garnier ---help--- 227690397a41SThomas Garnier Define the padding in terabytes added to the existing physical 227790397a41SThomas Garnier memory size during kernel memory randomization. It is useful 227890397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 227990397a41SThomas Garnier address randomization. 228090397a41SThomas Garnier 228190397a41SThomas Garnier If unsure, leave at the default value. 228290397a41SThomas Garnier 2283506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2284bebd024eSThomas Gleixner def_bool y 228540b31360SStephen Rothwell depends on SMP 2286506f1d07SSam Ravnborg 228780aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 228880aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22892c922cd0SKees Cook depends on HOTPLUG_CPU 229080aa1dffSFenghua Yu ---help--- 229180aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 229280aa1dffSFenghua Yu 229380aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 229480aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 229580aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 229680aa1dffSFenghua Yu 229780aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 229880aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 229980aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 230080aa1dffSFenghua Yu 230180aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 230280aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 230380aa1dffSFenghua Yu 230480aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 230580aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 230680aa1dffSFenghua Yu be other CPU0 dependencies. 230780aa1dffSFenghua Yu 230880aa1dffSFenghua Yu Please make sure the dependencies are under your control before 230980aa1dffSFenghua Yu you enable this feature. 231080aa1dffSFenghua Yu 231180aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 231280aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 231380aa1dffSFenghua Yu parameter cpu0_hotplug. 231480aa1dffSFenghua Yu 2315a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2316a71c8bc5SFenghua Yu def_bool n 2317a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 23182c922cd0SKees Cook depends on HOTPLUG_CPU 2319a71c8bc5SFenghua Yu ---help--- 2320a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2321a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2322a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2323a71c8bc5SFenghua Yu 2324a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2325a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2326a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2327a71c8bc5SFenghua Yu 2328a71c8bc5SFenghua Yu If unsure, say N. 2329a71c8bc5SFenghua Yu 2330506f1d07SSam Ravnborgconfig COMPAT_VDSO 2331b0b49f26SAndy Lutomirski def_bool n 2332b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2333953fee1dSIngo Molnar depends on COMPAT_32 23348f9ca475SIngo Molnar ---help--- 2335b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2336b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2337b0b49f26SAndy Lutomirski indicated in its segment table. 2338e84446deSRandy Dunlap 2339b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2340b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2341b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2342b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2343b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2344506f1d07SSam Ravnborg 2345b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2346b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2347b0b49f26SAndy Lutomirski 2348b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2349b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2350b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2351b0b49f26SAndy Lutomirski 2352b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2353b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2354506f1d07SSam Ravnborg 23553dc33bd3SKees Cookchoice 23563dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23573dc33bd3SKees Cook depends on X86_64 2358625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23593dc33bd3SKees Cook help 23603dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23613dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23623dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23633dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23643dc33bd3SKees Cook 23653dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2366bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23673dc33bd3SKees Cook 23683dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23693dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23703dc33bd3SKees Cook to improve security. 23713dc33bd3SKees Cook 2372bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23733dc33bd3SKees Cook 23743dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2375bd49e16eSAndy Lutomirski bool "Full emulation" 23763dc33bd3SKees Cook help 2377bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2378bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2379bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2380bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2381bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2382bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2383bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2384bd49e16eSAndy Lutomirski 2385bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2386bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2387bd49e16eSAndy Lutomirski 2388bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2389bd49e16eSAndy Lutomirski bool "Emulate execution only" 2390bd49e16eSAndy Lutomirski help 2391bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2392bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2393bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2394bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2395bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2396bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2397bd49e16eSAndy Lutomirski buffer. 23983dc33bd3SKees Cook 23993dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 24003dc33bd3SKees Cook bool "None" 24013dc33bd3SKees Cook help 24023dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 24033dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 24043dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 24053dc33bd3SKees Cook will be reported to dmesg, so that either old or 24063dc33bd3SKees Cook malicious userspace programs can be identified. 24073dc33bd3SKees Cook 24083dc33bd3SKees Cookendchoice 24093dc33bd3SKees Cook 2410516cbf37STim Birdconfig CMDLINE_BOOL 2411516cbf37STim Bird bool "Built-in kernel command line" 24128f9ca475SIngo Molnar ---help--- 2413516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2414516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2415516cbf37STim Bird necessary or convenient to provide some or all of the 2416516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2417516cbf37STim Bird to not rely on the boot loader to provide them.) 2418516cbf37STim Bird 2419516cbf37STim Bird To compile command line arguments into the kernel, 2420516cbf37STim Bird set this option to 'Y', then fill in the 242169711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2422516cbf37STim Bird 2423516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2424516cbf37STim Bird should leave this option set to 'N'. 2425516cbf37STim Bird 2426516cbf37STim Birdconfig CMDLINE 2427516cbf37STim Bird string "Built-in kernel command string" 2428516cbf37STim Bird depends on CMDLINE_BOOL 2429516cbf37STim Bird default "" 24308f9ca475SIngo Molnar ---help--- 2431516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2432516cbf37STim Bird image and used at boot time. If the boot loader provides a 2433516cbf37STim Bird command line at boot time, it is appended to this string to 2434516cbf37STim Bird form the full kernel command line, when the system boots. 2435516cbf37STim Bird 2436516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2437516cbf37STim Bird change this behavior. 2438516cbf37STim Bird 2439516cbf37STim Bird In most cases, the command line (whether built-in or provided 2440516cbf37STim Bird by the boot loader) should specify the device for the root 2441516cbf37STim Bird file system. 2442516cbf37STim Bird 2443516cbf37STim Birdconfig CMDLINE_OVERRIDE 2444516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2445516cbf37STim Bird depends on CMDLINE_BOOL 24468f9ca475SIngo Molnar ---help--- 2447516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2448516cbf37STim Bird command line, and use ONLY the built-in command line. 2449516cbf37STim Bird 2450516cbf37STim Bird This is used to work around broken boot loaders. This should 2451516cbf37STim Bird be set to 'N' under normal conditions. 2452516cbf37STim Bird 2453a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2454a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2455a5b9e5a2SAndy Lutomirski default y 2456a5b9e5a2SAndy Lutomirski ---help--- 2457a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2458a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2459a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2460a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2461a5b9e5a2SAndy Lutomirski threading libraries. 2462a5b9e5a2SAndy Lutomirski 2463a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2464a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2465a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2466a5b9e5a2SAndy Lutomirski 2467a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2468a5b9e5a2SAndy Lutomirski 2469b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2470b700e7f0SSeth Jennings 2471506f1d07SSam Ravnborgendmenu 2472506f1d07SSam Ravnborg 24733072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24743072e413SMichal Hocko def_bool y 24753072e413SMichal Hocko depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 24763072e413SMichal Hocko 2477506f1d07SSam Ravnborgconfig ARCH_ENABLE_MEMORY_HOTPLUG 2478506f1d07SSam Ravnborg def_bool y 2479506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2480506f1d07SSam Ravnborg 248135551053SGary Hadeconfig ARCH_ENABLE_MEMORY_HOTREMOVE 248235551053SGary Hade def_bool y 248335551053SGary Hade depends on MEMORY_HOTPLUG 248435551053SGary Hade 2485e534c7c5SLee Schermerhornconfig USE_PERCPU_NUMA_NODE_ID 2486645a7919STejun Heo def_bool y 2487e534c7c5SLee Schermerhorn depends on NUMA 2488e534c7c5SLee Schermerhorn 24899491846fSKirill A. Shutemovconfig ARCH_ENABLE_SPLIT_PMD_PTLOCK 24909491846fSKirill A. Shutemov def_bool y 24919491846fSKirill A. Shutemov depends on X86_64 || X86_PAE 24929491846fSKirill A. Shutemov 2493c177c81eSNaoya Horiguchiconfig ARCH_ENABLE_HUGEPAGE_MIGRATION 2494c177c81eSNaoya Horiguchi def_bool y 2495c177c81eSNaoya Horiguchi depends on X86_64 && HUGETLB_PAGE && MIGRATION 2496c177c81eSNaoya Horiguchi 24979c670ea3SNaoya Horiguchiconfig ARCH_ENABLE_THP_MIGRATION 24989c670ea3SNaoya Horiguchi def_bool y 24999c670ea3SNaoya Horiguchi depends on X86_64 && TRANSPARENT_HUGEPAGE 25009c670ea3SNaoya Horiguchi 2501da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2502e279b6c1SSam Ravnborg 2503e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 25043c2362e6SHarvey Harrison def_bool y 250544556530SZhimin Gu depends on HIBERNATION 2506e279b6c1SSam Ravnborg 2507e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2508e279b6c1SSam Ravnborg 2509e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2510e279b6c1SSam Ravnborg 2511efafc8b2SFeng Tangsource "drivers/sfi/Kconfig" 2512efafc8b2SFeng Tang 2513a6b68076SAndi Kleenconfig X86_APM_BOOT 25146fc108a0SJan Beulich def_bool y 2515282e5aabSPaul Bolle depends on APM 2516a6b68076SAndi Kleen 2517e279b6c1SSam Ravnborgmenuconfig APM 2518e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2519efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2520e279b6c1SSam Ravnborg ---help--- 2521e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2522e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2523e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2524e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2525e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2526e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2527e279b6c1SSam Ravnborg 2528e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2529e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2530e279b6c1SSam Ravnborg 2531e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2532e279b6c1SSam Ravnborg machines with more than one CPU. 2533e279b6c1SSam Ravnborg 2534e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2535151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 25362dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2537e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2538e279b6c1SSam Ravnborg 2539e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2540e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2541e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2542e279b6c1SSam Ravnborg 2543e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2544e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2545e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2546e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2547e279b6c1SSam Ravnborg 2548e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2549e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2550e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2551e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2552e279b6c1SSam Ravnborg APM in your BIOS). 2553e279b6c1SSam Ravnborg 2554e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2555e279b6c1SSam Ravnborg "weird" problems: 2556e279b6c1SSam Ravnborg 2557e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2558e279b6c1SSam Ravnborg enabled. 2559e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2560e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2561e279b6c1SSam Ravnborg the "no387" option to the kernel 2562e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2563e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2564e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2565e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2566e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2567e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2568e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2569e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2570e279b6c1SSam Ravnborg 11) exchange RAM chips 2571e279b6c1SSam Ravnborg 12) exchange the motherboard. 2572e279b6c1SSam Ravnborg 2573e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2574e279b6c1SSam Ravnborg module will be called apm. 2575e279b6c1SSam Ravnborg 2576e279b6c1SSam Ravnborgif APM 2577e279b6c1SSam Ravnborg 2578e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2579e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 25808f9ca475SIngo Molnar ---help--- 2581e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2582e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2583e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2584e279b6c1SSam Ravnborg 2585e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2586e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2587e279b6c1SSam Ravnborg ---help--- 2588e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2589e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2590e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2591e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2592e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2593e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2594e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2595e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2596e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2597e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2598e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2599e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2600e279b6c1SSam Ravnborg this feature. 2601e279b6c1SSam Ravnborg 2602e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2603dd8af076SLen Brown depends on CPU_IDLE 2604e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 26058f9ca475SIngo Molnar ---help--- 2606e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2607e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2608e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2609e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2610e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2611e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2612e279b6c1SSam Ravnborg this option does nothing.) 2613e279b6c1SSam Ravnborg 2614e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2615e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 26168f9ca475SIngo Molnar ---help--- 2617e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2618e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2619e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2620e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2621e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2622e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2623e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2624e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2625e279b6c1SSam Ravnborg especially if you are using gpm. 2626e279b6c1SSam Ravnborg 2627e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2628e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 26298f9ca475SIngo Molnar ---help--- 2630e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2631e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2632e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2633e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2634e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2635e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2636e279b6c1SSam Ravnborg 2637e279b6c1SSam Ravnborgendif # APM 2638e279b6c1SSam Ravnborg 2639bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2640e279b6c1SSam Ravnborg 2641e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2642e279b6c1SSam Ravnborg 264327471fdbSAndy Henroidsource "drivers/idle/Kconfig" 264427471fdbSAndy Henroid 2645e279b6c1SSam Ravnborgendmenu 2646e279b6c1SSam Ravnborg 2647e279b6c1SSam Ravnborg 2648e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2649e279b6c1SSam Ravnborg 2650e279b6c1SSam Ravnborgchoice 2651e279b6c1SSam Ravnborg prompt "PCI access mode" 2652efefa6f6SIngo Molnar depends on X86_32 && PCI 2653e279b6c1SSam Ravnborg default PCI_GOANY 2654e279b6c1SSam Ravnborg ---help--- 2655e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2656e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2657e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2658e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2659e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2660e279b6c1SSam Ravnborg 2661e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2662e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2663e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2664e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2665e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2666e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2667e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2668e279b6c1SSam Ravnborg 2669e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2670e279b6c1SSam Ravnborg bool "BIOS" 2671e279b6c1SSam Ravnborg 2672e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2673e279b6c1SSam Ravnborg bool "MMConfig" 2674e279b6c1SSam Ravnborg 2675e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2676e279b6c1SSam Ravnborg bool "Direct" 2677e279b6c1SSam Ravnborg 26783ef0e1f8SAndres Salomonconfig PCI_GOOLPC 267976fb6570SDaniel Drake bool "OLPC XO-1" 26803ef0e1f8SAndres Salomon depends on OLPC 26813ef0e1f8SAndres Salomon 26822bdd1b03SAndres Salomonconfig PCI_GOANY 26832bdd1b03SAndres Salomon bool "Any" 26842bdd1b03SAndres Salomon 2685e279b6c1SSam Ravnborgendchoice 2686e279b6c1SSam Ravnborg 2687e279b6c1SSam Ravnborgconfig PCI_BIOS 26883c2362e6SHarvey Harrison def_bool y 2689efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2690e279b6c1SSam Ravnborg 2691e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2692e279b6c1SSam Ravnborgconfig PCI_DIRECT 26933c2362e6SHarvey Harrison def_bool y 26940aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2695e279b6c1SSam Ravnborg 2696e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2697b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2698b45c9f36SJan Kiszka default y 26998364e1f8SJan Kiszka depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2700b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2701e279b6c1SSam Ravnborg 27023ef0e1f8SAndres Salomonconfig PCI_OLPC 27032bdd1b03SAndres Salomon def_bool y 27042bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 27053ef0e1f8SAndres Salomon 2706b5401a96SAlex Nixonconfig PCI_XEN 2707b5401a96SAlex Nixon def_bool y 2708b5401a96SAlex Nixon depends on PCI && XEN 2709b5401a96SAlex Nixon select SWIOTLB_XEN 2710b5401a96SAlex Nixon 27118364e1f8SJan Kiszkaconfig MMCONF_FAM10H 27128364e1f8SJan Kiszka def_bool y 27138364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2714e279b6c1SSam Ravnborg 27153f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 27166a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 27176ea30386SKees Cook depends on PCI 27183f6ea84aSIra W. Snyder help 27193f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 27203f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 27213f6ea84aSIra W. Snyder not have ACPI. 27223f6ea84aSIra W. Snyder 272364a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 272464a5fed6SBjorn Helgaas is known to be incomplete. 272564a5fed6SBjorn Helgaas 272664a5fed6SBjorn Helgaas You should say N unless you know you need this. 272764a5fed6SBjorn Helgaas 27283a495511SWilliam Breathitt Grayconfig ISA_BUS 272917a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 27303a495511SWilliam Breathitt Gray help 273117a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 273217a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 273317a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 273417a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 273517a2a129SWilliam Breathitt Gray not have an ISA bus. 27363a495511SWilliam Breathitt Gray 27373a495511SWilliam Breathitt Gray If unsure, say N. 27383a495511SWilliam Breathitt Gray 27391c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2740e279b6c1SSam Ravnborgconfig ISA_DMA_API 27411c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 27421c00f016SDavid Rientjes default y 27431c00f016SDavid Rientjes help 27441c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 27451c00f016SDavid Rientjes If unsure, say Y. 2746e279b6c1SSam Ravnborg 274751e68d05SLinus Torvaldsif X86_32 274851e68d05SLinus Torvalds 2749e279b6c1SSam Ravnborgconfig ISA 2750e279b6c1SSam Ravnborg bool "ISA support" 27518f9ca475SIngo Molnar ---help--- 2752e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2753e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2754e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2755e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2756e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2757e279b6c1SSam Ravnborg 2758e279b6c1SSam Ravnborgconfig SCx200 2759e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 27608f9ca475SIngo Molnar ---help--- 2761e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2762e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2763e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2764e279b6c1SSam Ravnborg for other scx200_* drivers. 2765e279b6c1SSam Ravnborg 2766e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2767e279b6c1SSam Ravnborg 2768e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2769e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2770592913ecSJohn Stultz depends on SCx200 2771e279b6c1SSam Ravnborg default y 27728f9ca475SIngo Molnar ---help--- 2773e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2774e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2775e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2776e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2777e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2778e279b6c1SSam Ravnborg 27793ef0e1f8SAndres Salomonconfig OLPC 27803ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 278154008979SThomas Gleixner depends on !X86_PAE 27823c554946SAndres Salomon select GPIOLIB 2783dc3119e7SThomas Gleixner select OF 278445bb1674SDaniel Drake select OF_PROMTREE 2785b4e51854SGrant Likely select IRQ_DOMAIN 27860c3d931bSLubomir Rintel select OLPC_EC 27878f9ca475SIngo Molnar ---help--- 27883ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27893ef0e1f8SAndres Salomon XO hardware. 27903ef0e1f8SAndres Salomon 2791a3128588SDaniel Drakeconfig OLPC_XO1_PM 2792a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2793fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2794bf1ebf00SDaniel Drake ---help--- 279597c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2796bf1ebf00SDaniel Drake 2797cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2798cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2799cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2800cfee9597SDaniel Drake ---help--- 2801cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2802cfee9597SDaniel Drake programmable wakeup source. 2803cfee9597SDaniel Drake 28047feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 28057feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 280692e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2807ed8e47feSRandy Dunlap depends on INPUT=y 2808d8d01a63SDaniel Drake select POWER_SUPPLY 28097feda8e9SDaniel Drake ---help--- 28107feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 28117bc74b3dSDaniel Drake - EC-driven system wakeups 28127feda8e9SDaniel Drake - Power button 28137bc74b3dSDaniel Drake - Ebook switch 28142cf2baeaSDaniel Drake - Lid switch 2815e1040ac6SDaniel Drake - AC adapter status updates 2816e1040ac6SDaniel Drake - Battery status updates 28177feda8e9SDaniel Drake 2818a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2819a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2820d8d01a63SDaniel Drake depends on OLPC && ACPI 2821d8d01a63SDaniel Drake select POWER_SUPPLY 2822a0f30f59SDaniel Drake ---help--- 2823a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2824a0f30f59SDaniel Drake - EC-driven system wakeups 2825a0f30f59SDaniel Drake - AC adapter status updates 2826a0f30f59SDaniel Drake - Battery status updates 2827e279b6c1SSam Ravnborg 2828d4f3e350SEd Wildgooseconfig ALIX 2829d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2830d4f3e350SEd Wildgoose select GPIOLIB 2831d4f3e350SEd Wildgoose ---help--- 2832d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2833d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2834d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2835d4f3e350SEd Wildgoose get added here. 2836d4f3e350SEd Wildgoose 2837d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2838d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2839d4f3e350SEd Wildgoose 2840d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2841d4f3e350SEd Wildgoose 2842da4e3302SPhilip Prindevilleconfig NET5501 2843da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2844da4e3302SPhilip Prindeville select GPIOLIB 2845da4e3302SPhilip Prindeville ---help--- 2846da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2847da4e3302SPhilip Prindeville 28483197059aSPhilip A. Prindevilleconfig GEOS 28493197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28503197059aSPhilip A. Prindeville select GPIOLIB 28513197059aSPhilip A. Prindeville depends on DMI 28523197059aSPhilip A. Prindeville ---help--- 28533197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28543197059aSPhilip A. Prindeville 28557d029125SVivien Didelotconfig TS5500 28567d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28577d029125SVivien Didelot depends on MELAN 28587d029125SVivien Didelot select CHECK_SIGNATURE 28597d029125SVivien Didelot select NEW_LEDS 28607d029125SVivien Didelot select LEDS_CLASS 28617d029125SVivien Didelot ---help--- 28627d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28637d029125SVivien Didelot 2864e279b6c1SSam Ravnborgendif # X86_32 2865e279b6c1SSam Ravnborg 286623ac4ae8SAndreas Herrmannconfig AMD_NB 2867e279b6c1SSam Ravnborg def_bool y 28680e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2869e279b6c1SSam Ravnborg 2870e3263ab3SDavid Herrmannconfig X86_SYSFB 2871e3263ab3SDavid Herrmann bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2872e3263ab3SDavid Herrmann help 2873e3263ab3SDavid Herrmann Firmwares often provide initial graphics framebuffers so the BIOS, 2874e3263ab3SDavid Herrmann bootloader or kernel can show basic video-output during boot for 2875e3263ab3SDavid Herrmann user-guidance and debugging. Historically, x86 used the VESA BIOS 2876e3263ab3SDavid Herrmann Extensions and EFI-framebuffers for this, which are mostly limited 2877e3263ab3SDavid Herrmann to x86. 2878e3263ab3SDavid Herrmann This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2879e3263ab3SDavid Herrmann framebuffers so the new generic system-framebuffer drivers can be 2880e3263ab3SDavid Herrmann used on x86. If the framebuffer is not compatible with the generic 2881e3a5dc08SNikolas Nyby modes, it is advertised as fallback platform framebuffer so legacy 2882e3263ab3SDavid Herrmann drivers like efifb, vesafb and uvesafb can pick it up. 2883e3263ab3SDavid Herrmann If this option is not selected, all system framebuffers are always 2884e3263ab3SDavid Herrmann marked as fallback platform framebuffers as usual. 2885e3263ab3SDavid Herrmann 2886e3263ab3SDavid Herrmann Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2887e3263ab3SDavid Herrmann not be able to pick up generic system framebuffers if this option 2888e3263ab3SDavid Herrmann is selected. You are highly encouraged to enable simplefb as 2889e3263ab3SDavid Herrmann replacement if you select this option. simplefb can correctly deal 2890e3263ab3SDavid Herrmann with generic system framebuffers. But you should still keep vesafb 2891e3263ab3SDavid Herrmann and others enabled as fallback if a system framebuffer is 2892e3263ab3SDavid Herrmann incompatible with simplefb. 2893e3263ab3SDavid Herrmann 2894e3263ab3SDavid Herrmann If unsure, say Y. 2895e3263ab3SDavid Herrmann 2896e279b6c1SSam Ravnborgendmenu 2897e279b6c1SSam Ravnborg 2898e279b6c1SSam Ravnborg 28991572497cSChristoph Hellwigmenu "Binary Emulations" 2900e279b6c1SSam Ravnborg 2901e279b6c1SSam Ravnborgconfig IA32_EMULATION 2902e279b6c1SSam Ravnborg bool "IA32 Emulation" 2903e279b6c1SSam Ravnborg depends on X86_64 290439f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2905d1603990SRandy Dunlap select BINFMT_ELF 2906a97f52e6SRoland McGrath select COMPAT_BINFMT_ELF 290739f88911SIngo Molnar select COMPAT_OLD_SIGACTION 29088f9ca475SIngo Molnar ---help--- 29095fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 29105fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 29115fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2912e279b6c1SSam Ravnborg 2913e279b6c1SSam Ravnborgconfig IA32_AOUT 2914e279b6c1SSam Ravnborg tristate "IA32 a.out support" 29156b213e1bSDavid Woodhouse depends on IA32_EMULATION 2916eac61655SBorislav Petkov depends on BROKEN 29178f9ca475SIngo Molnar ---help--- 2918e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2919e279b6c1SSam Ravnborg 29200bf62763SH. Peter Anvinconfig X86_X32 29216ea30386SKees Cook bool "x32 ABI for 64-bit mode" 29229b54050bSBrian Gerst depends on X86_64 29235fd92e65SH. J. Lu ---help--- 29245fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 29255fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 29265fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 29275fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 29285fd92e65SH. J. Lu 29295fd92e65SH. J. Lu You will need a recent binutils (2.22 or later) with 29305fd92e65SH. J. Lu elf32_x86_64 support enabled to compile a kernel with this 29315fd92e65SH. J. Lu option set. 29325fd92e65SH. J. Lu 2933953fee1dSIngo Molnarconfig COMPAT_32 2934953fee1dSIngo Molnar def_bool y 2935953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2936953fee1dSIngo Molnar select HAVE_UID16 2937953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2938953fee1dSIngo Molnar 2939e279b6c1SSam Ravnborgconfig COMPAT 29403c2362e6SHarvey Harrison def_bool y 29410bf62763SH. Peter Anvin depends on IA32_EMULATION || X86_X32 2942e279b6c1SSam Ravnborg 29433120e25eSJan Beulichif COMPAT 2944e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 29453120e25eSJan Beulich def_bool y 2946e279b6c1SSam Ravnborg 2947e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 29483c2362e6SHarvey Harrison def_bool y 29493120e25eSJan Beulich depends on SYSVIPC 29503120e25eSJan Beulichendif 2951ee009e4aSDavid Howells 2952e279b6c1SSam Ravnborgendmenu 2953e279b6c1SSam Ravnborg 2954e279b6c1SSam Ravnborg 2955e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2956e5beae16SKeith Packard def_bool y 2957e5beae16SKeith Packard depends on X86_32 2958e5beae16SKeith Packard 29594692d77fSAlessandro Rubiniconfig X86_DEV_DMA_OPS 29604692d77fSAlessandro Rubini bool 2961f7219a53SAlessandro Rubini 2962e279b6c1SSam Ravnborgsource "drivers/firmware/Kconfig" 2963e279b6c1SSam Ravnborg 2964edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 2965