1b2441318SGreg Kroah-Hartman# SPDX-License-Identifier: GPL-2.0 2daa93fabSSam Ravnborg# Select 32 or 64 bit 3daa93fabSSam Ravnborgconfig 64BIT 4104daea1SMasahiro Yamada bool "64-bit kernel" if "$(ARCH)" = "x86" 5104daea1SMasahiro Yamada default "$(ARCH)" != "i386" 6a7f7f624SMasahiro Yamada help 7daa93fabSSam Ravnborg Say yes to build a 64-bit kernel - formerly known as x86_64 8daa93fabSSam Ravnborg Say no to build a 32-bit kernel - formerly known as i386 9daa93fabSSam Ravnborg 10daa93fabSSam Ravnborgconfig X86_32 113120e25eSJan Beulich def_bool y 123120e25eSJan Beulich depends on !64BIT 13341c787eSIngo Molnar # Options that are inherently 32-bit kernel only: 14341c787eSIngo Molnar select ARCH_WANT_IPC_PARSE_VERSION 15341c787eSIngo Molnar select CLKSRC_I8253 16341c787eSIngo Molnar select CLONE_BACKWARDS 17157e118bSThomas Gleixner select GENERIC_VDSO_32 18117ed454SThomas Gleixner select HAVE_DEBUG_STACKOVERFLOW 19157e118bSThomas Gleixner select KMAP_LOCAL 20341c787eSIngo Molnar select MODULES_USE_ELF_REL 21341c787eSIngo Molnar select OLD_SIGACTION 222ca408d9SBrian Gerst select ARCH_SPLIT_ARG64 23daa93fabSSam Ravnborg 24daa93fabSSam Ravnborgconfig X86_64 253120e25eSJan Beulich def_bool y 263120e25eSJan Beulich depends on 64BIT 27d94e0685SIngo Molnar # Options that are inherently 64-bit kernel only: 284eb0716eSAlexandre Ghiti select ARCH_HAS_GIGANTIC_PAGE 29c12d3362SArd Biesheuvel select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 30d94e0685SIngo Molnar select ARCH_USE_CMPXCHG_LOCKREF 31d94e0685SIngo Molnar select HAVE_ARCH_SOFT_DIRTY 32d94e0685SIngo Molnar select MODULES_USE_ELF_RELA 33f616ab59SChristoph Hellwig select NEED_DMA_MAP_STATE 3409230cbcSChristoph Hellwig select SWIOTLB 357facdc42SAl Viro select ARCH_HAS_ELFCORE_COMPAT 361032c0baSSam Ravnborg 37518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 38518049d9SSteven Rostedt (VMware) def_bool y 39518049d9SSteven Rostedt (VMware) depends on X86_32 40518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 41518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 42518049d9SSteven Rostedt (VMware) help 43518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 44518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 45518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 46518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 47518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 48d94e0685SIngo Molnar# 49d94e0685SIngo Molnar# Arch settings 50d94e0685SIngo Molnar# 51d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 52d94e0685SIngo Molnar# ported to 32-bit as well. ) 53d94e0685SIngo Molnar# 548d5fffb9SSam Ravnborgconfig X86 553c2362e6SHarvey Harrison def_bool y 56c763ea26SIngo Molnar # 57c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 58c763ea26SIngo Molnar # 596471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 606e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 61942fa985SYury Norov select ARCH_32BIT_OFF_T if X86_32 622a21ad57SThomas Gleixner select ARCH_CLOCKSOURCE_INIT 631e866974SAnshuman Khandual select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 6491024b3cSAnshuman Khandual select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM) 6591024b3cSAnshuman Khandual select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 6666f24fa7SAnshuman Khandual select ARCH_ENABLE_SPLIT_PMD_PTLOCK if X86_64 || X86_PAE 671e866974SAnshuman Khandual select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 6891dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 69c2280be8SAnshuman Khandual select ARCH_HAS_CACHE_LINE_SIZE 70fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 71399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 7221266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 73b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 746471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 7572d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 76316d097cSDave Hansen select ARCH_HAS_FILTER_PGPROT 776974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 78957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 790f1441b4SPeter Zijlstra select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 800c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 8110bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 820ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 83c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 8417596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 853010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 860aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 87ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 88d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 89d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 90ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 91ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 92ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 9325c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 94c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 957e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 966471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 976471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 9877fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 995e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 1003599fe12SThomas Gleixner select ARCH_STACKWALK 1012c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 1026471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 1035d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 1046471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 10514df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 106b33fff07SSami Tolvanen select ARCH_SUPPORTS_LTO_CLANG if X86_64 107b33fff07SSami Tolvanen select ARCH_SUPPORTS_LTO_CLANG_THIN if X86_64 1086471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 109dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1106471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1116471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1122ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 113ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 11481c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 115c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 1163876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 11759612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 11838d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 11910916706SShile Zhang select BUILDTIME_TABLE_SORT 1206471b825SIngo Molnar select CLKEVT_I8253 1216471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1226471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1236471b825SIngo Molnar select DCACHE_WORD_ACCESS 12445471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 12545471cd9SLinus Torvalds select EDAC_SUPPORT 1266471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1276471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1286471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1296471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 13061dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1316471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 13227d6b4d1SThomas Gleixner select GENERIC_ENTRY 1336471b825SIngo Molnar select GENERIC_FIND_FIRST_BIT 1346471b825SIngo Molnar select GENERIC_IOMAP 135c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1360fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 137ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1386471b825SIngo Molnar select GENERIC_IRQ_PROBE 139c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1406471b825SIngo Molnar select GENERIC_IRQ_SHOW 1416471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1422ae27137SSteven Price select GENERIC_PTDUMP 1436471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1446471b825SIngo Molnar select GENERIC_STRNCPY_FROM_USER 1456471b825SIngo Molnar select GENERIC_STRNLEN_USER 1466471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1477ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 148550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 14939656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 15017e5888eSHans de Goede select HARDIRQS_SW_RESEND 1517edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1526471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1536471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1546471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1556471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1566471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 1576471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 158b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 159d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1600609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1611dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1626471b825SIngo Molnar select HAVE_ARCH_KGDB 1639e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1649e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1651b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 166271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1676471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 168f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 169afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1706471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1716471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 172a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 173b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1747677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 175e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 176fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 177c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1782ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1796471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1806471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1816471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 182d1f250e2SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 1836471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 1846dafca97SSami Tolvanen select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 1856471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1869c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 187677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 18806aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 18902a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 190562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 19103f5781bSWang YanQing select HAVE_EBPF_JIT 19258340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 1936630a8e5SChristoph Hellwig select HAVE_EISA 1945f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 19567a929e0SChristoph Hellwig select HAVE_FAST_GUP 196644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 1976471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 1986471b825SIngo Molnar select HAVE_FUNCTION_GRAPH_TRACER 1996471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2006b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2010067f129SK.Prasad select HAVE_HW_BREAKPOINT 2026471b825SIngo Molnar select HAVE_IDE 2036471b825SIngo Molnar select HAVE_IOREMAP_PROT 204624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2056471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2066471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2076471b825SIngo Molnar select HAVE_KERNEL_GZIP 2086471b825SIngo Molnar select HAVE_KERNEL_LZ4 2096471b825SIngo Molnar select HAVE_KERNEL_LZMA 2106471b825SIngo Molnar select HAVE_KERNEL_LZO 2116471b825SIngo Molnar select HAVE_KERNEL_XZ 212fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2136471b825SIngo Molnar select HAVE_KPROBES 2146471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 215540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2166471b825SIngo Molnar select HAVE_KRETPROBES 2176471b825SIngo Molnar select HAVE_KVM 2186471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2190102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 220ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2219f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 222be37c98dSKalesh Singh select HAVE_MOVE_PUD 22342a0bb3fSPetr Mladek select HAVE_NMI 2246471b825SIngo Molnar select HAVE_OPTPROBES 2256471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2266471b825SIngo Molnar select HAVE_PERF_EVENTS 227c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 22892e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 229eb01d42aSChristoph Hellwig select HAVE_PCI 230c5e63197SJiri Olsa select HAVE_PERF_REGS 231c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 232ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 23300998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2346471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 2356415b38bSJiri Slaby select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 2363c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 237cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 238d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 239c763ea26SIngo Molnar select HAVE_STACK_VALIDATION if X86_64 240e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 2411e7e4788SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 2426ef869e0SMichal Hocko select HAVE_PREEMPT_DYNAMIC 243d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2446471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2456471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2467c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2477ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 24805736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 249c0185808SThomas Gleixner select IRQ_FORCED_THREADING 25086596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2512eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 252625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2536471b825SIngo Molnar select PERF_EVENTS 2543195ef59SPrarit Bhargava select RTC_LIB 255d6faca40SArnd Bergmann select RTC_MC146818_LIB 2566471b825SIngo Molnar select SPARSE_IRQ 25783fe27eaSPranith Kumar select SRCU 2581e7e4788SJosh Poimboeuf select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 2596471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 26015f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2616471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2626471b825SIngo Molnar select VIRT_TO_BUS 2633b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2646471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2650c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 2669e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 2677d8330a5SBalbir Singh 268ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2693120e25eSJan Beulich def_bool y 2703120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 271ba7e4d13SIngo Molnar 27251b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 27351b26adaSLinus Torvalds string 27451b26adaSLinus Torvalds default "elf32-i386" if X86_32 27551b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 27651b26adaSLinus Torvalds 2778d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2783c2362e6SHarvey Harrison def_bool y 2798d5fffb9SSam Ravnborg 2808d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2813c2362e6SHarvey Harrison def_bool y 2828d5fffb9SSam Ravnborg 2838d5fffb9SSam Ravnborgconfig MMU 2843c2362e6SHarvey Harrison def_bool y 2858d5fffb9SSam Ravnborg 2869e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 2879e08f57dSDaniel Cashman default 28 if 64BIT 2889e08f57dSDaniel Cashman default 8 2899e08f57dSDaniel Cashman 2909e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 2919e08f57dSDaniel Cashman default 32 if 64BIT 2929e08f57dSDaniel Cashman default 16 2939e08f57dSDaniel Cashman 2949e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 2959e08f57dSDaniel Cashman default 8 2969e08f57dSDaniel Cashman 2979e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 2989e08f57dSDaniel Cashman default 16 2999e08f57dSDaniel Cashman 3008d5fffb9SSam Ravnborgconfig SBUS 3018d5fffb9SSam Ravnborg bool 3028d5fffb9SSam Ravnborg 3038d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3043120e25eSJan Beulich def_bool y 3053120e25eSJan Beulich depends on ISA_DMA_API 3068d5fffb9SSam Ravnborg 3078d5fffb9SSam Ravnborgconfig GENERIC_BUG 3083c2362e6SHarvey Harrison def_bool y 3098d5fffb9SSam Ravnborg depends on BUG 310b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 311b93a531eSJan Beulich 312b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 313b93a531eSJan Beulich bool 3148d5fffb9SSam Ravnborg 3158d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3163120e25eSJan Beulich def_bool y 3173120e25eSJan Beulich depends on ISA_DMA_API 3188d5fffb9SSam Ravnborg 3191032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3201032c0baSSam Ravnborg def_bool y 3211032c0baSSam Ravnborg 3229a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3239a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3248d5fffb9SSam Ravnborg 325316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT 326316d097cSDave Hansen def_bool y 327316d097cSDave Hansen 328dd5af90aSMike Travisconfig HAVE_SETUP_PER_CPU_AREA 32989c9c4c5SBrian Gerst def_bool y 330b32ef636Stravis@sgi.com 33108fc4580STejun Heoconfig NEED_PER_CPU_EMBED_FIRST_CHUNK 33208fc4580STejun Heo def_bool y 33308fc4580STejun Heo 33408fc4580STejun Heoconfig NEED_PER_CPU_PAGE_FIRST_CHUNK 33511124411STejun Heo def_bool y 33611124411STejun Heo 337801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 338801e4062SJohannes Berg def_bool y 339801e4062SJohannes Berg 340f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 341f4cb5700SJohannes Berg def_bool y 342f4cb5700SJohannes Berg 34353313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB 34453313b2cSSteve Capper def_bool y 34553313b2cSSteve Capper 3468d5fffb9SSam Ravnborgconfig ZONE_DMA32 347e0fd24a3SJan Beulich def_bool y if X86_64 3488d5fffb9SSam Ravnborg 3498d5fffb9SSam Ravnborgconfig AUDIT_ARCH 350e0fd24a3SJan Beulich def_bool y if X86_64 3518d5fffb9SSam Ravnborg 352d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 353d6f2d75aSAndrey Ryabinin hex 354d6f2d75aSAndrey Ryabinin depends on KASAN 355d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 356d6f2d75aSAndrey Ryabinin 35769575d38SShane Wangconfig HAVE_INTEL_TXT 35869575d38SShane Wang def_bool y 3596ea30386SKees Cook depends on INTEL_IOMMU && ACPI 36069575d38SShane Wang 3616b0c3d44SSam Ravnborgconfig X86_32_SMP 3626b0c3d44SSam Ravnborg def_bool y 3636b0c3d44SSam Ravnborg depends on X86_32 && SMP 3646b0c3d44SSam Ravnborg 3656b0c3d44SSam Ravnborgconfig X86_64_SMP 3666b0c3d44SSam Ravnborg def_bool y 3676b0c3d44SSam Ravnborg depends on X86_64 && SMP 3686b0c3d44SSam Ravnborg 3692b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3702b144498SSrikar Dronamraju def_bool y 3712b144498SSrikar Dronamraju 372d20642f0SRob Herringconfig FIX_EARLYCON_MEM 373d20642f0SRob Herring def_bool y 374d20642f0SRob Herring 37594d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 37694d49eb3SKirill A. Shutemov bool 37794d49eb3SKirill A. Shutemov 37898233368SKirill A. Shutemovconfig PGTABLE_LEVELS 37998233368SKirill A. Shutemov int 38077ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 38198233368SKirill A. Shutemov default 4 if X86_64 38298233368SKirill A. Shutemov default 3 if X86_PAE 38398233368SKirill A. Shutemov default 2 38498233368SKirill A. Shutemov 3852a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3862a61f474SMasahiro Yamada bool 3872a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3882a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3892a61f474SMasahiro Yamada help 3902a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3913fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 3923fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 3932a61f474SMasahiro Yamada 394506f1d07SSam Ravnborgmenu "Processor type and features" 395506f1d07SSam Ravnborg 3965ee71535SRandy Dunlapconfig ZONE_DMA 3975ee71535SRandy Dunlap bool "DMA memory allocation support" if EXPERT 3985ee71535SRandy Dunlap default y 3995ee71535SRandy Dunlap help 4005ee71535SRandy Dunlap DMA memory allocation support allows devices with less than 32-bit 4015ee71535SRandy Dunlap addressing to allocate within the first 16MB of address space. 4025ee71535SRandy Dunlap Disable if no such devices will be used. 4035ee71535SRandy Dunlap 4045ee71535SRandy Dunlap If unsure, say Y. 4055ee71535SRandy Dunlap 406506f1d07SSam Ravnborgconfig SMP 407506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 408a7f7f624SMasahiro Yamada help 409506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4104a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4114a474157SRobert Graffham than one CPU, say Y. 412506f1d07SSam Ravnborg 4134a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 414506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 415506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4164a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 417506f1d07SSam Ravnborg will run faster if you say N here. 418506f1d07SSam Ravnborg 419506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 420506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 421506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 422506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 423506f1d07SSam Ravnborg 424506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 425506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 426506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 427506f1d07SSam Ravnborg 428cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4294f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 430506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 431506f1d07SSam Ravnborg 432506f1d07SSam Ravnborg If you don't know what to do here, say N. 433506f1d07SSam Ravnborg 4349def39beSJosh Triplettconfig X86_FEATURE_NAMES 4359def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4369def39beSJosh Triplett default y 437a7f7f624SMasahiro Yamada help 4389def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4399def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4409def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4419def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4429def39beSJosh Triplett 4439def39beSJosh Triplett If in doubt, say Y. 4449def39beSJosh Triplett 44506cd9a7dSYinghai Luconfig X86_X2APIC 44606cd9a7dSYinghai Lu bool "Support x2apic" 44719e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 448a7f7f624SMasahiro Yamada help 44906cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 45006cd9a7dSYinghai Lu 45106cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 45206cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 45306cd9a7dSYinghai Lu 45406cd9a7dSYinghai Lu If you don't know what to do here, say N. 45506cd9a7dSYinghai Lu 4566695c85bSYinghai Luconfig X86_MPPARSE 4574590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4587a527688SJan Beulich default y 4595ab74722SIngo Molnar depends on X86_LOCAL_APIC 460a7f7f624SMasahiro Yamada help 4616695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4626695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4636695c85bSYinghai Lu 464ddd70cf9SJun Nakajimaconfig GOLDFISH 465ddd70cf9SJun Nakajima def_bool y 466ddd70cf9SJun Nakajima depends on X86_GOLDFISH 467ddd70cf9SJun Nakajima 46876b04384SDavid Woodhouseconfig RETPOLINE 46976b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 47076b04384SDavid Woodhouse default y 47176b04384SDavid Woodhouse help 47276b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 47376b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 47476b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 47576b04384SDavid Woodhouse support for full protection. The kernel may run slower. 47676b04384SDavid Woodhouse 477e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 478e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4796fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48059fe5a77SThomas Gleixner select KERNFS 481e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48278e99b4aSFenghua Yu help 483e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4846fe07ce3SBabu Moger 4856fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4866fe07ce3SBabu Moger usage by the CPU. 4876fe07ce3SBabu Moger 4886fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4896fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4906fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4916fe07ce3SBabu Moger 4926fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4936fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4946fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 49578e99b4aSFenghua Yu 49678e99b4aSFenghua Yu Say N if unsure. 49778e99b4aSFenghua Yu 4988425091fSRavikiran G Thirumalaiif X86_32 499a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 500a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 501a0d0bb4dSRandy Dunlap depends on SMP 502a7f7f624SMasahiro Yamada help 503e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 504a0d0bb4dSRandy Dunlap 505c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 506c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 507c5c606d9SRavikiran G Thirumalai default y 508a7f7f624SMasahiro Yamada help 50906ac8346SIngo Molnar If you disable this option then the kernel will only support 51006ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51106ac8346SIngo Molnar systems out there.) 51206ac8346SIngo Molnar 5138425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5148425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 515cb7b8023SBen Hutchings Goldfish (Android emulator) 5168425091fSRavikiran G Thirumalai AMD Elan 5178425091fSRavikiran G Thirumalai RDC R-321x SoC 5188425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 51983125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5203f4110a4SThomas Gleixner Moorestown MID devices 52106ac8346SIngo Molnar 52206ac8346SIngo Molnar If you have one of these systems, or if you want to build a 52306ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5248425091fSRavikiran G Thirumalaiendif 52506ac8346SIngo Molnar 5268425091fSRavikiran G Thirumalaiif X86_64 5278425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5288425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5298425091fSRavikiran G Thirumalai default y 530a7f7f624SMasahiro Yamada help 5318425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5328425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5338425091fSRavikiran G Thirumalai systems out there.) 5348425091fSRavikiran G Thirumalai 5358425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5368425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 53744b111b5SSteffen Persvold Numascale NumaChip 5388425091fSRavikiran G Thirumalai ScaleMP vSMP 5398425091fSRavikiran G Thirumalai SGI Ultraviolet 5408425091fSRavikiran G Thirumalai 5418425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5428425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5438425091fSRavikiran G Thirumalaiendif 544c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 545c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 54644b111b5SSteffen Persvoldconfig X86_NUMACHIP 54744b111b5SSteffen Persvold bool "Numascale NumaChip" 54844b111b5SSteffen Persvold depends on X86_64 54944b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55044b111b5SSteffen Persvold depends on NUMA 55144b111b5SSteffen Persvold depends on SMP 55244b111b5SSteffen Persvold depends on X86_X2APIC 553f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 554a7f7f624SMasahiro Yamada help 55544b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 55644b111b5SSteffen Persvold enable more than ~168 cores. 55744b111b5SSteffen Persvold If you don't have one of these, you should say N here. 55803b48632SNick Piggin 5596a48565eSIngo Molnarconfig X86_VSMP 560c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5616276a074SBorislav Petkov select HYPERVISOR_GUEST 5626a48565eSIngo Molnar select PARAVIRT 5636a48565eSIngo Molnar depends on X86_64 && PCI 564c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 565ead91d4bSShai Fultheim depends on SMP 566a7f7f624SMasahiro Yamada help 5676a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5686a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5696a48565eSIngo Molnar if you have one of these machines. 5706a48565eSIngo Molnar 571c5c606d9SRavikiran G Thirumalaiconfig X86_UV 572c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 573c5c606d9SRavikiran G Thirumalai depends on X86_64 574c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 57554c28d29SJack Steiner depends on NUMA 5761ecb4ae5SAndrew Morton depends on EFI 577c2209ea5SIngo Molnar depends on KEXEC_CORE 5789d6c26e7SSuresh Siddha depends on X86_X2APIC 5791222e564SIngo Molnar depends on PCI 580a7f7f624SMasahiro Yamada help 581c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 582c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 583c5c606d9SRavikiran G Thirumalai 584c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 585c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 586506f1d07SSam Ravnborg 587ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 588ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 589cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 590a7f7f624SMasahiro Yamada help 591ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 592ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 593ddd70cf9SJun Nakajima Goldfish emulator say N here. 594ddd70cf9SJun Nakajima 595c751e17bSThomas Gleixnerconfig X86_INTEL_CE 596c751e17bSThomas Gleixner bool "CE4100 TV platform" 597c751e17bSThomas Gleixner depends on PCI 598c751e17bSThomas Gleixner depends on PCI_GODIRECT 5996084a6e2SJiang Liu depends on X86_IO_APIC 600c751e17bSThomas Gleixner depends on X86_32 601c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60237bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 603da6b737bSSebastian Andrzej Siewior select OF 604da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 605a7f7f624SMasahiro Yamada help 606c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 607c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 608c751e17bSThomas Gleixner boxes and media devices. 609c751e17bSThomas Gleixner 6104cb9b00fSDavid Cohenconfig X86_INTEL_MID 61143605ef1SAlan Cox bool "Intel MID platform support" 61243605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 613edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6141ea7c673SAlan Cox depends on PCI 6153fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6161ea7c673SAlan Cox depends on X86_IO_APIC 6174cb9b00fSDavid Cohen select I2C 6187c9c3a1eSAlan Cox select DW_APB_TIMER 6191ea7c673SAlan Cox select APB_TIMER 62054b34aa0SMika Westerberg select INTEL_SCU_PCI 62115a713dfSMika Westerberg select MFD_INTEL_MSIC 622a7f7f624SMasahiro Yamada help 6234cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6244cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6254cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6261ea7c673SAlan Cox 6274cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6284cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 62943605ef1SAlan Cox 6308bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6318bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6328bbc2a13SBryan O'Donoghue depends on X86_32 6338bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6348bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6358bbc2a13SBryan O'Donoghue depends on X86_TSC 6368bbc2a13SBryan O'Donoghue depends on PCI 6378bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6388bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6398bbc2a13SBryan O'Donoghue select IOSF_MBI 6408bbc2a13SBryan O'Donoghue select INTEL_IMR 6419ab6eb51SAndy Shevchenko select COMMON_CLK 642a7f7f624SMasahiro Yamada help 6438bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6448bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6458bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6468bbc2a13SBryan O'Donoghue 6473d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6483d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6495962dd22SSinan Kaya depends on X86 && ACPI && PCI 6503d48aab1SMika Westerberg select COMMON_CLK 6510f531431SMathias Nyman select PINCTRL 652eebb3e8dSAndy Shevchenko select IOSF_MBI 653a7f7f624SMasahiro Yamada help 6543d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6553d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6560f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6570f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6583d48aab1SMika Westerberg 65992082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 66092082a88SKen Xue bool "AMD ACPI2Platform devices support" 66192082a88SKen Xue depends on ACPI 66292082a88SKen Xue select COMMON_CLK 66392082a88SKen Xue select PINCTRL 664a7f7f624SMasahiro Yamada help 66592082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 66692082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 66792082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 66892082a88SKen Xue implemented under PINCTRL subsystem. 66992082a88SKen Xue 670ced3ce76SDavid E. Boxconfig IOSF_MBI 671ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 672ced3ce76SDavid E. Box depends on PCI 673a7f7f624SMasahiro Yamada help 674ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 675ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 676ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 677ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 678ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 679ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 680ced3ce76SDavid E. Box This list is not meant to be exclusive. 681ced3ce76SDavid E. Box - BayTrail 682ced3ce76SDavid E. Box - Braswell 683ced3ce76SDavid E. Box - Quark 684ced3ce76SDavid E. Box 685ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 686ced3ce76SDavid E. Box 687ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 688ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 689ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 690a7f7f624SMasahiro Yamada help 691ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 692ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 693ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 694ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 695ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 696ed2226bdSDavid E. Box device they want to access. 697ed2226bdSDavid E. Box 698ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 699ed2226bdSDavid E. Box 700c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 701c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 702506f1d07SSam Ravnborg depends on X86_32 703c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 704c5c606d9SRavikiran G Thirumalai select M486 705c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 706a7f7f624SMasahiro Yamada help 707c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 708c5c606d9SRavikiran G Thirumalai as R-8610-(G). 709c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 710c5c606d9SRavikiran G Thirumalai 711e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7129c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7139c398017SIngo Molnar depends on X86_32 && SMP 714c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 715a7f7f624SMasahiro Yamada help 716b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 717b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 718b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 719b5660ba7SH. Peter Anvin one and will fallback to default. 720d49c4288SYinghai Lu 721c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 722d49c4288SYinghai Lu 723d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7246fc108a0SJan Beulich def_bool y 725d949f36fSLinus Torvalds # MCE code calls memory_failure(): 726d949f36fSLinus Torvalds depends on X86_MCE 727d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 728d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 729d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 730d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 731d949f36fSLinus Torvalds 73283125a3aSAlessandro Rubiniconfig STA2X11 73383125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73483125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 73583125a3aSAlessandro Rubini select SWIOTLB 73683125a3aSAlessandro Rubini select MFD_STA2X11 7370145071bSLinus Walleij select GPIOLIB 738a7f7f624SMasahiro Yamada help 73983125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 74083125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 74183125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74283125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74383125a3aSAlessandro Rubini standard PC machines. 74483125a3aSAlessandro Rubini 74582148d1dSShérabconfig X86_32_IRIS 74682148d1dSShérab tristate "Eurobraille/Iris poweroff module" 74782148d1dSShérab depends on X86_32 748a7f7f624SMasahiro Yamada help 74982148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 75082148d1dSShérab to shut themselves down properly. A special I/O sequence is 75182148d1dSShérab needed to do so, which is what this module does at 75282148d1dSShérab kernel shutdown. 75382148d1dSShérab 75482148d1dSShérab This is only for Iris machines from EuroBraille. 75582148d1dSShérab 75682148d1dSShérab If unused, say N. 75782148d1dSShérab 758ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7593c2362e6SHarvey Harrison def_bool y 7603c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 761a87d0914SKen Chen depends on X86 762a7f7f624SMasahiro Yamada help 763506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 764506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 765506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 766506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 767506f1d07SSam Ravnborg 768506f1d07SSam Ravnborg If in doubt, say "Y". 769506f1d07SSam Ravnborg 7706276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7716276a074SBorislav Petkov bool "Linux guest support" 772a7f7f624SMasahiro Yamada help 7736276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7746276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7756276a074SBorislav Petkov setup. 776506f1d07SSam Ravnborg 7776276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7786276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 779506f1d07SSam Ravnborg 7806276a074SBorislav Petkovif HYPERVISOR_GUEST 781506f1d07SSam Ravnborg 782e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 783e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 784a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 785a7f7f624SMasahiro Yamada help 786e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 787e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 788e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 789e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 790e61bd94aSEduardo Pereira Habkost 791c00a280aSJuergen Grossconfig PARAVIRT_XXL 792c00a280aSJuergen Gross bool 793c00a280aSJuergen Gross 7946276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7956276a074SBorislav Petkov bool "paravirt-ops debugging" 7966276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 797a7f7f624SMasahiro Yamada help 7986276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7996276a074SBorislav Petkov a paravirt_op is missing when it is called. 8006276a074SBorislav Petkov 801b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 802b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8036ea30386SKees Cook depends on PARAVIRT && SMP 804a7f7f624SMasahiro Yamada help 805b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 806b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 807b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 808b4ecc126SJeremy Fitzhardinge 8094c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8104c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 811b4ecc126SJeremy Fitzhardinge 8124c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 813b4ecc126SJeremy Fitzhardinge 814ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 815ecca2502SZhao Yakui def_bool n 816ecca2502SZhao Yakui 8176276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8186276a074SBorislav Petkov 8196276a074SBorislav Petkovconfig KVM_GUEST 8206276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8216276a074SBorislav Petkov depends on PARAVIRT 8226276a074SBorislav Petkov select PARAVIRT_CLOCK 823a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 824b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8256276a074SBorislav Petkov default y 826a7f7f624SMasahiro Yamada help 8276276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8286276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8296276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8306276a074SBorislav Petkov underlying device model, the host provides the guest with 8316276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8326276a074SBorislav Petkov 833a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 834a1c4423bSMarcelo Tosatti def_bool n 835a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 836a1c4423bSMarcelo Tosatti help 837a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 838a1c4423bSMarcelo Tosatti 8397733607fSMaran Wilsonconfig PVH 8407733607fSMaran Wilson bool "Support for running PVH guests" 841a7f7f624SMasahiro Yamada help 8427733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8437733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8447733607fSMaran Wilson 8456276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8466276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8476276a074SBorislav Petkov depends on PARAVIRT 848a7f7f624SMasahiro Yamada help 8496276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8506276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8516276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8526276a074SBorislav Petkov that, there can be a small performance impact. 8536276a074SBorislav Petkov 8546276a074SBorislav Petkov If in doubt, say N here. 8556276a074SBorislav Petkov 8567af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8577af192c9SGerd Hoffmann bool 8587af192c9SGerd Hoffmann 8594a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8604a362601SJan Kiszka bool "Jailhouse non-root cell support" 861abde587bSArnd Bergmann depends on X86_64 && PCI 86287e65d05SJan Kiszka select X86_PM_TIMER 863a7f7f624SMasahiro Yamada help 8644a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8654a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8664a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8674a362601SJan Kiszka 868ec7972c9SZhao Yakuiconfig ACRN_GUEST 869ec7972c9SZhao Yakui bool "ACRN Guest support" 870ec7972c9SZhao Yakui depends on X86_64 871498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 872ec7972c9SZhao Yakui help 873ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 874ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 875ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 876ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 877ec7972c9SZhao Yakui found in https://projectacrn.org/. 878ec7972c9SZhao Yakui 8796276a074SBorislav Petkovendif #HYPERVISOR_GUEST 88097349135SJeremy Fitzhardinge 881506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 882506f1d07SSam Ravnborg 883506f1d07SSam Ravnborgconfig HPET_TIMER 8843c2362e6SHarvey Harrison def_bool X86_64 885506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 886a7f7f624SMasahiro Yamada help 887506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 888506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 889506f1d07SSam Ravnborg present. 890506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 891506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 892506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8934e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 8944e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 895506f1d07SSam Ravnborg 896506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 897506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 898506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 899506f1d07SSam Ravnborg 900506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 901506f1d07SSam Ravnborg 902506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9033c2362e6SHarvey Harrison def_bool y 9043228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 905506f1d07SSam Ravnborg 9066a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 907506f1d07SSam Ravnborg# The code disables itself when not needed. 9087ae9392cSThomas Petazzoniconfig DMI 9097ae9392cSThomas Petazzoni default y 910cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9116a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 912a7f7f624SMasahiro Yamada help 9137ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9147ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9157ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9167ae9392cSThomas Petazzoni BIOS code. 9177ae9392cSThomas Petazzoni 918506f1d07SSam Ravnborgconfig GART_IOMMU 91938901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9202f9237d4SChristoph Hellwig select DMA_OPS 921a4ce5a48SChristoph Hellwig select IOMMU_HELPER 922506f1d07SSam Ravnborg select SWIOTLB 92323ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 924a7f7f624SMasahiro Yamada help 925ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 926ced3c42cSIngo Molnar GART based hardware IOMMUs. 927ced3c42cSIngo Molnar 928ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 929ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 930ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 931ced3c42cSIngo Molnar 932ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 933ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 934ced3c42cSIngo Molnar 935ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 936ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 937ced3c42cSIngo Molnar 32-bit limited device. 938ced3c42cSIngo Molnar 939ced3c42cSIngo Molnar If unsure, say Y. 940506f1d07SSam Ravnborg 9411184dc2fSMike Travisconfig MAXSMP 942ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9436ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 94436f5101aSMike Travis select CPUMASK_OFFSTACK 945a7f7f624SMasahiro Yamada help 946ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9471184dc2fSMike Travis If unsure, say N. 948506f1d07SSam Ravnborg 949aec6487eSIngo Molnar# 950aec6487eSIngo Molnar# The maximum number of CPUs supported: 951aec6487eSIngo Molnar# 952aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 953aec6487eSIngo Molnar# and which can be configured interactively in the 954aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 955aec6487eSIngo Molnar# 956aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 957aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 958aec6487eSIngo Molnar# 959aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 960aec6487eSIngo Molnar# interactive configuration. ) 961aec6487eSIngo Molnar# 962a0d0bb4dSRandy Dunlap 963aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 964a0d0bb4dSRandy Dunlap int 965aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 966a0d0bb4dSRandy Dunlap default 1 if !SMP 967a0d0bb4dSRandy Dunlap default 2 968a0d0bb4dSRandy Dunlap 969aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 970a0d0bb4dSRandy Dunlap int 971a0d0bb4dSRandy Dunlap depends on X86_32 972aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 973aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 974a0d0bb4dSRandy Dunlap default 1 if !SMP 975a0d0bb4dSRandy Dunlap 976aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 977a0d0bb4dSRandy Dunlap int 978a0d0bb4dSRandy Dunlap depends on X86_64 9791edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9801edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 981a0d0bb4dSRandy Dunlap default 1 if !SMP 982aec6487eSIngo Molnar 983aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 984aec6487eSIngo Molnar int 985aec6487eSIngo Molnar depends on X86_32 986aec6487eSIngo Molnar default 32 if X86_BIGSMP 987aec6487eSIngo Molnar default 8 if SMP 988aec6487eSIngo Molnar default 1 if !SMP 989aec6487eSIngo Molnar 990aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 991aec6487eSIngo Molnar int 992aec6487eSIngo Molnar depends on X86_64 993a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 994a0d0bb4dSRandy Dunlap default 64 if SMP 995aec6487eSIngo Molnar default 1 if !SMP 996a0d0bb4dSRandy Dunlap 997506f1d07SSam Ravnborgconfig NR_CPUS 99836f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 999aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1000aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1001a7f7f624SMasahiro Yamada help 1002506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1003bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1004cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1005506f1d07SSam Ravnborg minimum value which makes sense is 2. 1006506f1d07SSam Ravnborg 1007aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1008aec6487eSIngo Molnar to the kernel image. 1009506f1d07SSam Ravnborg 1010506f1d07SSam Ravnborgconfig SCHED_SMT 1011dbe73364SThomas Gleixner def_bool y if SMP 1012506f1d07SSam Ravnborg 1013506f1d07SSam Ravnborgconfig SCHED_MC 10143c2362e6SHarvey Harrison def_bool y 10153c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1016c8e56d20SBorislav Petkov depends on SMP 1017a7f7f624SMasahiro Yamada help 1018506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1019506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1020506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1021506f1d07SSam Ravnborg 1022de966cf4STim Chenconfig SCHED_MC_PRIO 1023de966cf4STim Chen bool "CPU core priorities scheduler support" 10240a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10250a21fc12SIngo Molnar select X86_INTEL_PSTATE 10260a21fc12SIngo Molnar select CPU_FREQ 1027de966cf4STim Chen default y 1028a7f7f624SMasahiro Yamada help 1029de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1030de966cf4STim Chen core ordering determined at manufacturing time, which allows 1031de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1032de966cf4STim Chen single threaded workloads) than others. 1033de966cf4STim Chen 1034de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1035de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1036de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1037de966cf4STim Chen overall system performance can be achieved. 1038de966cf4STim Chen 1039de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1040de966cf4STim Chen 1041de966cf4STim Chen If unsure say Y here. 10425e76b2abSTim Chen 104330b8b006SThomas Gleixnerconfig UP_LATE_INIT 104430b8b006SThomas Gleixner def_bool y 1045ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 104630b8b006SThomas Gleixner 1047506f1d07SSam Ravnborgconfig X86_UP_APIC 104850849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 104950849eefSJan Beulich default PCI_MSI 105038a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1051a7f7f624SMasahiro Yamada help 1052506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1053506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1054506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1055506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1056506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1057506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1058506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1059506f1d07SSam Ravnborg lockups. 1060506f1d07SSam Ravnborg 1061506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1062506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1063506f1d07SSam Ravnborg depends on X86_UP_APIC 1064a7f7f624SMasahiro Yamada help 1065506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1066506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1067506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1068506f1d07SSam Ravnborg 1069506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1070506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1071506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1072506f1d07SSam Ravnborg 1073506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10743c2362e6SHarvey Harrison def_bool y 10750dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1076b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 107752f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1078506f1d07SSam Ravnborg 1079506f1d07SSam Ravnborgconfig X86_IO_APIC 1080b1da1e71SJan Beulich def_bool y 1081b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1082506f1d07SSam Ravnborg 108341b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 108441b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 108541b9eb26SStefan Assmann depends on X86_IO_APIC 1086a7f7f624SMasahiro Yamada help 108741b9eb26SStefan Assmann This option enables a workaround that fixes a source of 108841b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 108941b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 109041b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 109141b9eb26SStefan Assmann 109241b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 109341b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 109441b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 109541b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 109641b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 109741b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 109841b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 109941b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 110041b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 110141b9eb26SStefan Assmann down (vital) interrupt lines. 110241b9eb26SStefan Assmann 110341b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 110441b9eb26SStefan Assmann increased on these systems. 110541b9eb26SStefan Assmann 1106506f1d07SSam Ravnborgconfig X86_MCE 1107bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1108648ed940SChen, Gong select GENERIC_ALLOCATOR 1109e57dbaf7SBorislav Petkov default y 1110a7f7f624SMasahiro Yamada help 1111bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1112bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1113506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1114bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11154efc0670SAndi Kleen 11165de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11175de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11185de97c9fSTony Luck depends on X86_MCE 1119a7f7f624SMasahiro Yamada help 11205de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11215de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11225de97c9fSTony Luck rasdaemon solution. 11235de97c9fSTony Luck 1124506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11253c2362e6SHarvey Harrison def_bool y 11263c2362e6SHarvey Harrison prompt "Intel MCE features" 1127c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1128a7f7f624SMasahiro Yamada help 1129506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1130506f1d07SSam Ravnborg the thermal monitor. 1131506f1d07SSam Ravnborg 1132506f1d07SSam Ravnborgconfig X86_MCE_AMD 11333c2362e6SHarvey Harrison def_bool y 11343c2362e6SHarvey Harrison prompt "AMD MCE features" 1135f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1136a7f7f624SMasahiro Yamada help 1137506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1138506f1d07SSam Ravnborg the DRAM Error Threshold. 1139506f1d07SSam Ravnborg 11404efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11416fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1142c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1143a7f7f624SMasahiro Yamada help 11444efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11455065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11464efc0670SAndi Kleen line. 11474efc0670SAndi Kleen 1148b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1149b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11506fc108a0SJan Beulich def_bool y 1151b2762686SAndi Kleen 1152ea149b36SAndi Kleenconfig X86_MCE_INJECT 1153bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1154ea149b36SAndi Kleen tristate "Machine check injector support" 1155a7f7f624SMasahiro Yamada help 1156ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1157ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1158ea149b36SAndi Kleen QA it is safe to say n. 1159ea149b36SAndi Kleen 116007dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1161e633c65aSKan Liang 11625aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11631e642812SIngo Molnar bool "Legacy VM86 support" 1164506f1d07SSam Ravnborg depends on X86_32 1165a7f7f624SMasahiro Yamada help 11665aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11675aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11685aef51c3SAndy Lutomirski 11695aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11705aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11715aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11725aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11735aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 11741e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 11751e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 11761e642812SIngo Molnar mode might be faster than emulation and you might want to 11771e642812SIngo Molnar enable this option. 11785aef51c3SAndy Lutomirski 11791e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 11801e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 11811e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 11821e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 11835aef51c3SAndy Lutomirski 11841e642812SIngo Molnar Enabling this option increases the complexity of the kernel 11851e642812SIngo Molnar and slows down exception handling a tiny bit. 11865aef51c3SAndy Lutomirski 11871e642812SIngo Molnar If unsure, say N here. 11885aef51c3SAndy Lutomirski 11895aef51c3SAndy Lutomirskiconfig VM86 11905aef51c3SAndy Lutomirski bool 11915aef51c3SAndy Lutomirski default X86_LEGACY_VM86 119234273f41SH. Peter Anvin 119334273f41SH. Peter Anvinconfig X86_16BIT 119434273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 119534273f41SH. Peter Anvin default y 1196a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1197a7f7f624SMasahiro Yamada help 119834273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 119934273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 120034273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 120134273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 120234273f41SH. Peter Anvin 120334273f41SH. Peter Anvinconfig X86_ESPFIX32 120434273f41SH. Peter Anvin def_bool y 120534273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1206506f1d07SSam Ravnborg 1207197725deSH. Peter Anvinconfig X86_ESPFIX64 1208197725deSH. Peter Anvin def_bool y 120934273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1210506f1d07SSam Ravnborg 12111ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12121ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12131ad83c85SAndy Lutomirski default y 12141ad83c85SAndy Lutomirski depends on X86_64 1215a7f7f624SMasahiro Yamada help 12161ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12171ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12181ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12191ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12201ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12211ad83c85SAndy Lutomirski 0xffffffffff600?00. 12221ad83c85SAndy Lutomirski 12231ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12241ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12251ad83c85SAndy Lutomirski 12261ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12271ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12281ad83c85SAndy Lutomirski 1229111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1230111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1231a24ca997SThomas Gleixner default y 1232a7f7f624SMasahiro Yamada help 1233111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1234111e7b15SThomas Gleixner for legacy applications. 1235111e7b15SThomas Gleixner 1236c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1237c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1238c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1239c8137aceSThomas Gleixner capabilities and permission from potentially active security 1240c8137aceSThomas Gleixner modules. 1241c8137aceSThomas Gleixner 1242c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1243c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1244a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1245a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1246c8137aceSThomas Gleixner 1247506f1d07SSam Ravnborgconfig TOSHIBA 1248506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1249506f1d07SSam Ravnborg depends on X86_32 1250a7f7f624SMasahiro Yamada help 1251506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1252506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1253506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1254506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1255506f1d07SSam Ravnborg 1256506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1257506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1258506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1259506f1d07SSam Ravnborg 1260506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1261506f1d07SSam Ravnborg Say N otherwise. 1262506f1d07SSam Ravnborg 1263506f1d07SSam Ravnborgconfig I8K 1264039ae585SPali Rohár tristate "Dell i8k legacy laptop support" 1265949a9d70SJean Delvare select HWMON 1266039ae585SPali Rohár select SENSORS_DELL_SMM 1267a7f7f624SMasahiro Yamada help 1268039ae585SPali Rohár This option enables legacy /proc/i8k userspace interface in hwmon 1269039ae585SPali Rohár dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1270039ae585SPali Rohár temperature and allows controlling fan speeds of Dell laptops via 1271039ae585SPali Rohár System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1272039ae585SPali Rohár it reports also power and hotkey status. For fan speed control is 1273039ae585SPali Rohár needed userspace package i8kutils. 1274506f1d07SSam Ravnborg 1275039ae585SPali Rohár Say Y if you intend to run this kernel on old Dell laptops or want to 1276039ae585SPali Rohár use userspace package i8kutils. 1277506f1d07SSam Ravnborg Say N otherwise. 1278506f1d07SSam Ravnborg 1279506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12809ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12819ba16087SJan Beulich depends on X86_32 1282a7f7f624SMasahiro Yamada help 1283506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1284506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1285506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1286506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1287506f1d07SSam Ravnborg system. 1288506f1d07SSam Ravnborg 1289506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 12905e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1291506f1d07SSam Ravnborg 1292506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1293506f1d07SSam Ravnborg enable this option even if you don't need it. 1294506f1d07SSam Ravnborg Say N otherwise. 1295506f1d07SSam Ravnborg 1296506f1d07SSam Ravnborgconfig MICROCODE 12979a2bc335SBorislav Petkov bool "CPU microcode loading support" 12989a2bc335SBorislav Petkov default y 129980030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1300a7f7f624SMasahiro Yamada 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 1321a7f7f624SMasahiro Yamada help 13228d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13238d86f390SPeter Oruba processors. 13248d86f390SPeter Oruba 1325b8989db9SAlan For the current Intel microcode data package go to 1326b8989db9SAlan <https://downloadcenter.intel.com> and search for 1327b8989db9SAlan 'Linux Processor Microcode Data File'. 13288d86f390SPeter Oruba 132980cc9f10SPeter Orubaconfig MICROCODE_AMD 1330e43f6e67SBorislav Petkov bool "AMD microcode loading support" 133180cc9f10SPeter Oruba depends on MICROCODE 1332a7f7f624SMasahiro Yamada help 133380cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 133480cc9f10SPeter Oruba processors will be enabled. 133580cc9f10SPeter Oruba 1336506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1337c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1338c02f48e0SBorislav Petkov default n 1339506f1d07SSam Ravnborg depends on MICROCODE 1340a7f7f624SMasahiro Yamada help 1341c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1342c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1343c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1344c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1345c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1346cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1347506f1d07SSam Ravnborg 1348506f1d07SSam Ravnborgconfig X86_MSR 1349506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1350a7f7f624SMasahiro Yamada help 1351506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1352506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1353506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1354506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1355506f1d07SSam Ravnborg systems. 1356506f1d07SSam Ravnborg 1357506f1d07SSam Ravnborgconfig X86_CPUID 1358506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1359a7f7f624SMasahiro Yamada help 1360506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1361506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1362506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1363506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1364506f1d07SSam Ravnborg 1365506f1d07SSam Ravnborgchoice 1366506f1d07SSam Ravnborg prompt "High Memory Support" 13676fc108a0SJan Beulich default HIGHMEM4G 1368506f1d07SSam Ravnborg depends on X86_32 1369506f1d07SSam Ravnborg 1370506f1d07SSam Ravnborgconfig NOHIGHMEM 1371506f1d07SSam Ravnborg bool "off" 1372a7f7f624SMasahiro Yamada help 1373506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1374506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1375506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1376506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1377506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1378506f1d07SSam Ravnborg "high memory". 1379506f1d07SSam Ravnborg 1380506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1381506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1382506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1383506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1384506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1385506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1386506f1d07SSam Ravnborg possible. 1387506f1d07SSam Ravnborg 1388506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1389506f1d07SSam Ravnborg answer "4GB" here. 1390506f1d07SSam Ravnborg 1391506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1392506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1393506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1394506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1395506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1396506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1397506f1d07SSam Ravnborg 1398506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1399506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1400506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1401506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1402506f1d07SSam Ravnborg kernel at boot time.) 1403506f1d07SSam Ravnborg 1404506f1d07SSam Ravnborg If unsure, say "off". 1405506f1d07SSam Ravnborg 1406506f1d07SSam Ravnborgconfig HIGHMEM4G 1407506f1d07SSam Ravnborg bool "4GB" 1408a7f7f624SMasahiro Yamada help 1409506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1410506f1d07SSam Ravnborg gigabytes of physical RAM. 1411506f1d07SSam Ravnborg 1412506f1d07SSam Ravnborgconfig HIGHMEM64G 1413506f1d07SSam Ravnborg bool "64GB" 14140ef3439cSMaciej W. Rozycki depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1415506f1d07SSam Ravnborg select X86_PAE 1416a7f7f624SMasahiro Yamada help 1417506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1418506f1d07SSam Ravnborg gigabytes of physical RAM. 1419506f1d07SSam Ravnborg 1420506f1d07SSam Ravnborgendchoice 1421506f1d07SSam Ravnborg 1422506f1d07SSam Ravnborgchoice 14236a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1424506f1d07SSam Ravnborg default VMSPLIT_3G 1425506f1d07SSam Ravnborg depends on X86_32 1426a7f7f624SMasahiro Yamada help 1427506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1428506f1d07SSam Ravnborg 1429506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1430506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1431506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1432506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1433506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1434506f1d07SSam Ravnborg available to user programs, making the address space there 1435506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1436506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1437506f1d07SSam Ravnborg kernel modules. 1438506f1d07SSam Ravnborg 1439506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1440506f1d07SSam Ravnborg option alone! 1441506f1d07SSam Ravnborg 1442506f1d07SSam Ravnborg config VMSPLIT_3G 1443506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1444506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1445506f1d07SSam Ravnborg depends on !X86_PAE 1446506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1447506f1d07SSam Ravnborg config VMSPLIT_2G 1448506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1449506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1450506f1d07SSam Ravnborg depends on !X86_PAE 1451506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1452506f1d07SSam Ravnborg config VMSPLIT_1G 1453506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1454506f1d07SSam Ravnborgendchoice 1455506f1d07SSam Ravnborg 1456506f1d07SSam Ravnborgconfig PAGE_OFFSET 1457506f1d07SSam Ravnborg hex 1458506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1459506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1460506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1461506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1462506f1d07SSam Ravnborg default 0xC0000000 1463506f1d07SSam Ravnborg depends on X86_32 1464506f1d07SSam Ravnborg 1465506f1d07SSam Ravnborgconfig HIGHMEM 14663c2362e6SHarvey Harrison def_bool y 1467506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1468506f1d07SSam Ravnborg 1469506f1d07SSam Ravnborgconfig X86_PAE 14709ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1471506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1472d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14739d99c712SChristian Melki select SWIOTLB 1474a7f7f624SMasahiro Yamada help 1475506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1476506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1477506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1478506f1d07SSam Ravnborg consumes more pagetable space per process. 1479506f1d07SSam Ravnborg 148077ef56e4SKirill A. Shutemovconfig X86_5LEVEL 148177ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 148218ec1eafSKirill A. Shutemov default y 1483eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1484162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 148577ef56e4SKirill A. Shutemov depends on X86_64 1486a7f7f624SMasahiro Yamada help 148777ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 148877ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 148977ef56e4SKirill A. Shutemov physical address space. 149077ef56e4SKirill A. Shutemov 149177ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 149277ef56e4SKirill A. Shutemov 14936657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 14946657fca0SKirill A. Shutemov support 4- or 5-level paging. 149577ef56e4SKirill A. Shutemov 1496cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 149777ef56e4SKirill A. Shutemov information. 149877ef56e4SKirill A. Shutemov 149977ef56e4SKirill A. Shutemov Say N if unsure. 150077ef56e4SKirill A. Shutemov 150110971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1502e5008abeSLuis R. Rodriguez def_bool y 15032e1da13fSVlastimil Babka depends on X86_64 1504a7f7f624SMasahiro Yamada help 150510971ab2SIngo Molnar Certain kernel features effectively disable kernel 150610971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 150710971ab2SIngo Molnar supports them), so don't confuse the user by printing 150810971ab2SIngo Molnar that we have them enabled. 15099e899816SNick Piggin 15105c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15115c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15125c280cf6SThomas Gleixner depends on DEBUG_FS 1513a7f7f624SMasahiro Yamada help 1514b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1515a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15165c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15175c280cf6SThomas Gleixner 15187744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15197744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15207744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 152182fef0adSDavid Rientjes select DMA_COHERENT_POOL 152294d49eb3SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 1523ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 15249087c375STom Lendacky select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1525597cfe48SJoerg Roedel select INSTRUCTION_DECODER 152622916417STom Lendacky select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1527a7f7f624SMasahiro Yamada help 15287744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15297744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15307744ccdbSTom Lendacky Encryption (SME). 15317744ccdbSTom Lendacky 15327744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15337744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15347744ccdbSTom Lendacky default y 15357744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1536a7f7f624SMasahiro Yamada help 15377744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15387744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15397744ccdbSTom Lendacky 15407744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15417744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15427744ccdbSTom Lendacky 15437744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15447744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15457744ccdbSTom Lendacky 1546506f1d07SSam Ravnborg# Common NUMA Features 1547506f1d07SSam Ravnborgconfig NUMA 1548e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1549506f1d07SSam Ravnborg depends on SMP 1550b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1551b5660ba7SH. Peter Anvin default y if X86_BIGSMP 1552a7f7f624SMasahiro Yamada help 1553e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1554fd51b2d7SKOSAKI Motohiro 1555506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1556506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1557506f1d07SSam Ravnborg NUMA awareness to the kernel. 1558506f1d07SSam Ravnborg 1559c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1560fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1561fd51b2d7SKOSAKI Motohiro 1562b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15637cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1564fd51b2d7SKOSAKI Motohiro 1565fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1566506f1d07SSam Ravnborg 1567eec1d4faSHans Rosenfeldconfig AMD_NUMA 15683c2362e6SHarvey Harrison def_bool y 15693c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15705da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1571a7f7f624SMasahiro Yamada help 1572eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1573eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1574eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1575eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1576eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1577506f1d07SSam Ravnborg 1578506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15793c2362e6SHarvey Harrison def_bool y 15803c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1581506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1582506f1d07SSam Ravnborg select ACPI_NUMA 1583a7f7f624SMasahiro Yamada help 1584506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1585506f1d07SSam Ravnborg 1586506f1d07SSam Ravnborgconfig NUMA_EMU 1587506f1d07SSam Ravnborg bool "NUMA emulation" 15881b7e03efSTejun Heo depends on NUMA 1589a7f7f624SMasahiro Yamada help 1590506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1591506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1592506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1593506f1d07SSam Ravnborg 1594506f1d07SSam Ravnborgconfig NODES_SHIFT 1595d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 159651591e31SDavid Rientjes range 1 10 159751591e31SDavid Rientjes default "10" if MAXSMP 1598506f1d07SSam Ravnborg default "6" if X86_64 1599506f1d07SSam Ravnborg default "3" 1600*a9ee6cf5SMike Rapoport depends on NUMA 1601a7f7f624SMasahiro Yamada help 16021184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1603692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1604506f1d07SSam Ravnborg 1605506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1606506f1d07SSam Ravnborg def_bool y 16073b16651fSTejun Heo depends on X86_32 && !NUMA 1608506f1d07SSam Ravnborg 1609506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1610506f1d07SSam Ravnborg def_bool y 16116ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1612506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1613506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1614506f1d07SSam Ravnborg 16153b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16166ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16173b16651fSTejun Heo 1618506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1619506f1d07SSam Ravnborg def_bool y 1620b263295dSChristoph Lameter depends on ARCH_SPARSEMEM_ENABLE 1621506f1d07SSam Ravnborg 1622506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1623a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16243120e25eSJan Beulich depends on X86_64 && MEMORY_HOTPLUG 1625a0842b70SToshi Kani help 1626a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1627cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1628a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1629506f1d07SSam Ravnborg 16303b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16313b16651fSTejun Heo def_bool y 16323b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16333b16651fSTejun Heo 1634a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1635a29815a3SAvi Kivity hex 1636a29815a3SAvi Kivity default 0 if X86_32 1637a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1638a29815a3SAvi Kivity 16397a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16407a67832cSDan Williams bool 16417a67832cSDan Williams 1642ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16437a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16449f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16459f53f9faSDan Williams depends on BLK_DEV 16467a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16477b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16489f53f9faSDan Williams select LIBNVDIMM 1649ec776ef6SChristoph Hellwig help 1650ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1651ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1652ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1653ec776ef6SChristoph Hellwig they can be used for persistent storage. 1654ec776ef6SChristoph Hellwig 1655ec776ef6SChristoph Hellwig Say Y if unsure. 1656ec776ef6SChristoph Hellwig 1657506f1d07SSam Ravnborgconfig HIGHPTE 1658506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16596fc108a0SJan Beulich depends on HIGHMEM 1660a7f7f624SMasahiro Yamada help 1661506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1662506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1663506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1664506f1d07SSam Ravnborg entries in high memory. 1665506f1d07SSam Ravnborg 16669f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16679f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1668a7f7f624SMasahiro Yamada help 16699f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16709f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16719f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16729f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16739f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16749f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16759f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16768c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16779f077871SJeremy Fitzhardinge 16789f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16799f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16809f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16819f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16829f077871SJeremy Fitzhardinge 16839f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16849f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16859f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16869f077871SJeremy Fitzhardinge memory. 16879f077871SJeremy Fitzhardinge 1688c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1689c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1690c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1691c885df50SJeremy Fitzhardinge default y 1692a7f7f624SMasahiro Yamada help 1693c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1694c885df50SJeremy Fitzhardinge on or off. 1695c885df50SJeremy Fitzhardinge 16969ea77bdbSH. Peter Anvinconfig X86_RESERVE_LOW 1697d0cd7425SH. Peter Anvin int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1698d0cd7425SH. Peter Anvin default 64 1699d0cd7425SH. Peter Anvin range 4 640 1700a7f7f624SMasahiro Yamada help 1701d0cd7425SH. Peter Anvin Specify the amount of low memory to reserve for the BIOS. 1702fc381519SIngo Molnar 1703d0cd7425SH. Peter Anvin The first page contains BIOS data structures that the kernel 1704d0cd7425SH. Peter Anvin must not use, so that page must always be reserved. 1705fc381519SIngo Molnar 1706d0cd7425SH. Peter Anvin By default we reserve the first 64K of physical RAM, as a 1707d0cd7425SH. Peter Anvin number of BIOSes are known to corrupt that memory range 1708d0cd7425SH. Peter Anvin during events such as suspend/resume or monitor cable 1709d0cd7425SH. Peter Anvin insertion, so it must not be used by the kernel. 1710fc381519SIngo Molnar 1711d0cd7425SH. Peter Anvin You can set this to 4 if you are absolutely sure that you 1712d0cd7425SH. Peter Anvin trust the BIOS to get all its memory reservations and usages 1713d0cd7425SH. Peter Anvin right. If you know your BIOS have problems beyond the 1714d0cd7425SH. Peter Anvin default 64K area, you can set this to 640 to avoid using the 1715d0cd7425SH. Peter Anvin entire low memory range. 1716d0cd7425SH. Peter Anvin 1717d0cd7425SH. Peter Anvin If you have doubts about the BIOS (e.g. suspend/resume does 1718d0cd7425SH. Peter Anvin not work or there's kernel crashes after certain hardware 1719d0cd7425SH. Peter Anvin hotplug events) then you might want to enable 1720d0cd7425SH. Peter Anvin X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1721d0cd7425SH. Peter Anvin typical corruption patterns. 1722d0cd7425SH. Peter Anvin 1723d0cd7425SH. Peter Anvin Leave this to the default value of 64 if you are unsure. 1724fc381519SIngo Molnar 1725506f1d07SSam Ravnborgconfig MATH_EMULATION 1726506f1d07SSam Ravnborg bool 1727a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 172887d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1729a7f7f624SMasahiro Yamada help 1730506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1731506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1732506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1733506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1734506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1735506f1d07SSam Ravnborg coprocessor or this emulation. 1736506f1d07SSam Ravnborg 1737506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1738506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1739506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1740506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1741506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1742506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1743506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1744506f1d07SSam Ravnborg intend to use this kernel on different machines. 1745506f1d07SSam Ravnborg 1746506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1747506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1748506f1d07SSam Ravnborg 1749506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1750506f1d07SSam Ravnborg kernel, it won't hurt. 1751506f1d07SSam Ravnborg 1752506f1d07SSam Ravnborgconfig MTRR 17536fc108a0SJan Beulich def_bool y 17546a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1755a7f7f624SMasahiro Yamada help 1756506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1757506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1758506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1759506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1760506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1761506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1762506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1763506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1764506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1765506f1d07SSam Ravnborg 1766506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1767506f1d07SSam Ravnborg control registers on other processors can be easily supported 1768506f1d07SSam Ravnborg as well: 1769506f1d07SSam Ravnborg 1770506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1771506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1772506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1773506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1774506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1775506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1776506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1777506f1d07SSam Ravnborg 1778506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1779506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1780506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1781506f1d07SSam Ravnborg 1782506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1783506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1784506f1d07SSam Ravnborg 1785cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1786506f1d07SSam Ravnborg 178795ffa243SYinghai Luconfig MTRR_SANITIZER 17882ffb3501SYinghai Lu def_bool y 178995ffa243SYinghai Lu prompt "MTRR cleanup support" 179095ffa243SYinghai Lu depends on MTRR 1791a7f7f624SMasahiro Yamada help 1792aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1793aba3728cSThomas Gleixner add writeback entries. 179495ffa243SYinghai Lu 1795aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1796692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1797aba3728cSThomas Gleixner mtrr_chunk_size. 179895ffa243SYinghai Lu 17992ffb3501SYinghai Lu If unsure, say Y. 180095ffa243SYinghai Lu 180195ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1802f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1803f5098d62SYinghai Lu range 0 1 1804f5098d62SYinghai Lu default "0" 180595ffa243SYinghai Lu depends on MTRR_SANITIZER 1806a7f7f624SMasahiro Yamada help 1807f5098d62SYinghai Lu Enable mtrr cleanup default value 180895ffa243SYinghai Lu 180912031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 181012031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 181112031a62SYinghai Lu range 0 7 181212031a62SYinghai Lu default "1" 181312031a62SYinghai Lu depends on MTRR_SANITIZER 1814a7f7f624SMasahiro Yamada help 181512031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1816aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 181712031a62SYinghai Lu 18182e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18196fc108a0SJan Beulich def_bool y 18206a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18212a8a2719SIngo Molnar depends on MTRR 1822a7f7f624SMasahiro Yamada help 18232e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1824042b78e4SVenki Pallipadi 18252e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18262e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18272e5d9c85Svenkatesh.pallipadi@intel.com 18282e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1829042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18302e5d9c85Svenkatesh.pallipadi@intel.com 18312e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18322e5d9c85Svenkatesh.pallipadi@intel.com 183346cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 183446cf98cdSVenkatesh Pallipadi def_bool y 183546cf98cdSVenkatesh Pallipadi depends on X86_PAT 183646cf98cdSVenkatesh Pallipadi 1837628c6246SH. Peter Anvinconfig ARCH_RANDOM 1838628c6246SH. Peter Anvin def_bool y 1839628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1840a7f7f624SMasahiro Yamada help 1841628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1842628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1843628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1844628c6246SH. Peter Anvin secure hardware random number generator. 1845628c6246SH. Peter Anvin 184651ae4a2dSH. Peter Anvinconfig X86_SMAP 184751ae4a2dSH. Peter Anvin def_bool y 184851ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 1849a7f7f624SMasahiro Yamada help 185051ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 185151ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 185251ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 185351ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 185451ae4a2dSH. Peter Anvin 185551ae4a2dSH. Peter Anvin If unsure, say Y. 185651ae4a2dSH. Peter Anvin 1857b971880fSBabu Mogerconfig X86_UMIP 1858796ebc81SRicardo Neri def_bool y 1859b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1860a7f7f624SMasahiro Yamada help 1861b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1862b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1863b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1864b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1865b971880fSBabu Moger information about the hardware state. 1866796ebc81SRicardo Neri 1867796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1868796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1869796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1870796ebc81SRicardo Neri results are dummy. 1871aa35f896SRicardo Neri 187235e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 187338f3e775SBabu Moger prompt "Memory Protection Keys" 187435e97790SDave Hansen def_bool y 1875284244a9SDave Hansen # Note: only available in 64-bit mode 187638f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 187752c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 187852c8e601SIngo Molnar select ARCH_HAS_PKEYS 1879a7f7f624SMasahiro Yamada help 1880284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1881284244a9SDave Hansen page-based protections, but without requiring modification of the 1882284244a9SDave Hansen page tables when an application changes protection domains. 1883284244a9SDave Hansen 18841eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1885284244a9SDave Hansen 1886284244a9SDave Hansen If unsure, say y. 188735e97790SDave Hansen 1888db616173SMichal Hockochoice 1889db616173SMichal Hocko prompt "TSX enable mode" 1890db616173SMichal Hocko depends on CPU_SUP_INTEL 1891db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1892db616173SMichal Hocko help 1893db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1894db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1895db616173SMichal Hocko can lead to a noticeable performance boost. 1896db616173SMichal Hocko 1897db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1898db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1899db616173SMichal Hocko will be more of those attacks discovered in the future. 1900db616173SMichal Hocko 1901db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1902db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1903db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1904db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1905db616173SMichal Hocko for the particular machine. 1906db616173SMichal Hocko 1907db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1908db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1909db616173SMichal Hocko details. 1910db616173SMichal Hocko 1911db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1912db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1913db616173SMichal Hocko relevant. 1914db616173SMichal Hocko 1915db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1916db616173SMichal Hocko bool "off" 1917db616173SMichal Hocko help 1918db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1919db616173SMichal Hocko 1920db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1921db616173SMichal Hocko bool "on" 1922db616173SMichal Hocko help 1923db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1924db616173SMichal Hocko line parameter. 1925db616173SMichal Hocko 1926db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1927db616173SMichal Hocko bool "auto" 1928db616173SMichal Hocko help 1929db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1930db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1931db616173SMichal Hockoendchoice 1932db616173SMichal Hocko 1933e7e05452SSean Christophersonconfig X86_SGX 1934e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1935e7e05452SSean Christopherson depends on X86_64 && CPU_SUP_INTEL 1936e7e05452SSean Christopherson depends on CRYPTO=y 1937e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1938e7e05452SSean Christopherson select SRCU 1939e7e05452SSean Christopherson select MMU_NOTIFIER 1940901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 1941e7e05452SSean Christopherson help 1942e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1943e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1944e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1945e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1946e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1947e7e05452SSean Christopherson hardware. 1948e7e05452SSean Christopherson 1949e7e05452SSean Christopherson If unsure, say N. 1950e7e05452SSean Christopherson 1951506f1d07SSam Ravnborgconfig EFI 19529ba16087SJan Beulich bool "EFI runtime service support" 19535b83683fSHuang, Ying depends on ACPI 1954f6ce5002SSergey Vlasov select UCS2_STRING 1955022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 1956a7f7f624SMasahiro Yamada help 19578b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1958506f1d07SSam Ravnborg available (such as the EFI variable services). 1959506f1d07SSam Ravnborg 19608b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19618b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19628b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19638b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19648b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19658b2cb7a8SHuang, Ying platforms. 1966506f1d07SSam Ravnborg 1967291f3632SMatt Flemingconfig EFI_STUB 1968291f3632SMatt Fleming bool "EFI stub support" 1969b16d8c23SMatt Fleming depends on EFI && !X86_USE_3DNOW 19708f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19717b2a583aSMatt Fleming select RELOCATABLE 1972a7f7f624SMasahiro Yamada help 1973291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1974291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1975291f3632SMatt Fleming 19764f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19770c759662SMatt Fleming 19787d453eeeSMatt Flemingconfig EFI_MIXED 19797d453eeeSMatt Fleming bool "EFI mixed-mode support" 19807d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1981a7f7f624SMasahiro Yamada help 19827d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19837d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19847d453eeeSMatt Fleming mode. 19857d453eeeSMatt Fleming 19867d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19877d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19887d453eeeSMatt Fleming the EFI handover protocol must be used. 19897d453eeeSMatt Fleming 19907d453eeeSMatt Fleming If unsure, say N. 19917d453eeeSMatt Fleming 19928636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 1993506f1d07SSam Ravnborg 1994506f1d07SSam Ravnborgconfig KEXEC 1995506f1d07SSam Ravnborg bool "kexec system call" 19962965faa5SDave Young select KEXEC_CORE 1997a7f7f624SMasahiro Yamada help 1998506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 1999506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2000506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2001506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2002506f1d07SSam Ravnborg 2003506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2004506f1d07SSam Ravnborg 2005506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2006506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2007bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2008bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2009bf220695SGeert Uytterhoeven made. 2010506f1d07SSam Ravnborg 201174ca317cSVivek Goyalconfig KEXEC_FILE 201274ca317cSVivek Goyal bool "kexec file based system call" 20132965faa5SDave Young select KEXEC_CORE 201474ca317cSVivek Goyal select BUILD_BIN2C 201574ca317cSVivek Goyal depends on X86_64 201674ca317cSVivek Goyal depends on CRYPTO=y 201774ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2018a7f7f624SMasahiro Yamada help 201974ca317cSVivek Goyal This is new version of kexec system call. This system call is 202074ca317cSVivek Goyal file based and takes file descriptors as system call argument 202174ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 202274ca317cSVivek Goyal accepted by previous system call. 202374ca317cSVivek Goyal 2024b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2025b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2026b799a09fSAKASHI Takahiro 202799d5cadfSJiri Bohacconfig KEXEC_SIG 20288e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 202974ca317cSVivek Goyal depends on KEXEC_FILE 2030a7f7f624SMasahiro Yamada help 203199d5cadfSJiri Bohac 203299d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 203399d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 203499d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 203599d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 203699d5cadfSJiri Bohac 203799d5cadfSJiri Bohac In addition to this option, you need to enable signature 203899d5cadfSJiri Bohac verification for the corresponding kernel image type being 203999d5cadfSJiri Bohac loaded in order for this to work. 204099d5cadfSJiri Bohac 204199d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 204299d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 204399d5cadfSJiri Bohac depends on KEXEC_SIG 2044a7f7f624SMasahiro Yamada help 20458e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2046d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20478e7d8381SVivek Goyal 20488e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20498e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 205099d5cadfSJiri Bohac depends on KEXEC_SIG 20518e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20528e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2053a7f7f624SMasahiro Yamada help 20548e7d8381SVivek Goyal Enable bzImage signature verification support. 20558e7d8381SVivek Goyal 2056506f1d07SSam Ravnborgconfig CRASH_DUMP 205704b69447SPavel Machek bool "kernel crash dumps" 2058506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2059a7f7f624SMasahiro Yamada help 2060506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2061506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2062506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2063506f1d07SSam Ravnborg a specially reserved region and then later executed after 2064506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2065506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2066506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2067506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2068330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2069506f1d07SSam Ravnborg 20703ab83521SHuang Yingconfig KEXEC_JUMP 20716ea30386SKees Cook bool "kexec jump" 2072fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2073a7f7f624SMasahiro Yamada help 207489081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 207589081d17SHuang Ying code in physical address mode via KEXEC 20763ab83521SHuang Ying 2077506f1d07SSam Ravnborgconfig PHYSICAL_START 20786a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2079ceefccc9SH. Peter Anvin default "0x1000000" 2080a7f7f624SMasahiro Yamada help 2081506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2082506f1d07SSam Ravnborg 2083506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2084506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2085506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2086506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2087506f1d07SSam Ravnborg address. 2088506f1d07SSam Ravnborg 2089506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2090506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2091506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2092506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2093506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2094506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2095506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2096506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2097506f1d07SSam Ravnborg 2098ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2099ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2100ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2101ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2102ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2103ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2104ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2105330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2106ceefccc9SH. Peter Anvin for more details about crash dumps. 2107506f1d07SSam Ravnborg 2108506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2109506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2110506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2111506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2112506f1d07SSam Ravnborg is present because there are users out there who continue to use 2113506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2114506f1d07SSam Ravnborg line. 2115506f1d07SSam Ravnborg 2116506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2117506f1d07SSam Ravnborg 2118506f1d07SSam Ravnborgconfig RELOCATABLE 211926717808SH. Peter Anvin bool "Build a relocatable kernel" 212026717808SH. Peter Anvin default y 2121a7f7f624SMasahiro Yamada help 2122506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2123506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2124506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2125506f1d07SSam Ravnborg but are discarded at runtime. 2126506f1d07SSam Ravnborg 2127506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2128506f1d07SSam Ravnborg must live at a different physical address than the primary 2129506f1d07SSam Ravnborg kernel. 2130506f1d07SSam Ravnborg 2131506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2132506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21338ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2134506f1d07SSam Ravnborg 21358ab3820fSKees Cookconfig RANDOMIZE_BASE 2136e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21378ab3820fSKees Cook depends on RELOCATABLE 21386807c846SIngo Molnar default y 2139a7f7f624SMasahiro Yamada help 2140e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2141e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2142e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2143e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2144e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2145e8581e3dSBaoquan He code internals. 2146e8581e3dSBaoquan He 2147ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2148ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2149ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2150ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2151ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2152ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2153ed9f007eSKees Cook 2154ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2155ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2156ed9f007eSKees Cook 512MB (8 bits of entropy). 21578ab3820fSKees Cook 2158a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2159e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2160e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2161ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2162ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2163ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2164ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2165ed9f007eSKees Cook theoretically possible, but the implementations are further 2166ed9f007eSKees Cook limited due to memory layouts. 2167e8581e3dSBaoquan He 21686807c846SIngo Molnar If unsure, say Y. 2169da2b6fb9SKees Cook 21708ab3820fSKees Cook# Relocation on x86 needs some additional build support 2171845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2172845adf72SH. Peter Anvin def_bool y 21738ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2174845adf72SH. Peter Anvin 2175506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2176a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21778ab3820fSKees Cook default "0x200000" 2178a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2179a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2180a7f7f624SMasahiro Yamada help 2181506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2182506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2183506f1d07SSam Ravnborg address which meets above alignment restriction. 2184506f1d07SSam Ravnborg 2185506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2186506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2187506f1d07SSam Ravnborg address aligned to above value and run from there. 2188506f1d07SSam Ravnborg 2189506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2190506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2191506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2192506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2193506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2194506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2195506f1d07SSam Ravnborg above alignment restrictions. 2196506f1d07SSam Ravnborg 2197a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2198a0215061SKees Cook this value must be a multiple of 0x200000. 2199a0215061SKees Cook 2200506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2201506f1d07SSam Ravnborg 2202eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2203eedb92abSKirill A. Shutemov bool 2204a7f7f624SMasahiro Yamada help 2205eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2206eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2207eedb92abSKirill A. Shutemov 22080483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22090483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22100483e1faSThomas Garnier depends on X86_64 22110483e1faSThomas Garnier depends on RANDOMIZE_BASE 2212eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22130483e1faSThomas Garnier default RANDOMIZE_BASE 2214a7f7f624SMasahiro Yamada help 22150483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22160483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22170483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22180483e1faSThomas Garnier 22190483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22200483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22210483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22220483e1faSThomas Garnier addresses for each memory section. 22230483e1faSThomas Garnier 22246807c846SIngo Molnar If unsure, say Y. 22250483e1faSThomas Garnier 222690397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 222790397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 222890397a41SThomas Garnier depends on RANDOMIZE_MEMORY 222990397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 223090397a41SThomas Garnier default "0x0" 223190397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 223290397a41SThomas Garnier range 0x0 0x40 2233a7f7f624SMasahiro Yamada help 223490397a41SThomas Garnier Define the padding in terabytes added to the existing physical 223590397a41SThomas Garnier memory size during kernel memory randomization. It is useful 223690397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 223790397a41SThomas Garnier address randomization. 223890397a41SThomas Garnier 223990397a41SThomas Garnier If unsure, leave at the default value. 224090397a41SThomas Garnier 2241506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2242bebd024eSThomas Gleixner def_bool y 224340b31360SStephen Rothwell depends on SMP 2244506f1d07SSam Ravnborg 224580aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 224680aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22472c922cd0SKees Cook depends on HOTPLUG_CPU 2248a7f7f624SMasahiro Yamada help 224980aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 225080aa1dffSFenghua Yu 225180aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 225280aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 225380aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 225480aa1dffSFenghua Yu 225580aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 225680aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 225780aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 225880aa1dffSFenghua Yu 225980aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 226080aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 226180aa1dffSFenghua Yu 226280aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 226380aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 226480aa1dffSFenghua Yu be other CPU0 dependencies. 226580aa1dffSFenghua Yu 226680aa1dffSFenghua Yu Please make sure the dependencies are under your control before 226780aa1dffSFenghua Yu you enable this feature. 226880aa1dffSFenghua Yu 226980aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 227080aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 227180aa1dffSFenghua Yu parameter cpu0_hotplug. 227280aa1dffSFenghua Yu 2273a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2274a71c8bc5SFenghua Yu def_bool n 2275a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22762c922cd0SKees Cook depends on HOTPLUG_CPU 2277a7f7f624SMasahiro Yamada help 2278a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2279a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2280a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2281a71c8bc5SFenghua Yu 2282a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2283a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2284a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2285a71c8bc5SFenghua Yu 2286a71c8bc5SFenghua Yu If unsure, say N. 2287a71c8bc5SFenghua Yu 2288506f1d07SSam Ravnborgconfig COMPAT_VDSO 2289b0b49f26SAndy Lutomirski def_bool n 2290b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2291953fee1dSIngo Molnar depends on COMPAT_32 2292a7f7f624SMasahiro Yamada help 2293b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2294b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2295b0b49f26SAndy Lutomirski indicated in its segment table. 2296e84446deSRandy Dunlap 2297b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2298b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2299b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2300b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2301b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2302506f1d07SSam Ravnborg 2303b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2304b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2305b0b49f26SAndy Lutomirski 2306b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2307b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2308b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2309b0b49f26SAndy Lutomirski 2310b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2311b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2312506f1d07SSam Ravnborg 23133dc33bd3SKees Cookchoice 23143dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23153dc33bd3SKees Cook depends on X86_64 2316625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23173dc33bd3SKees Cook help 23183dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23193dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23203dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23213dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23223dc33bd3SKees Cook 23233dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2324bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23253dc33bd3SKees Cook 23263dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23273dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23283dc33bd3SKees Cook to improve security. 23293dc33bd3SKees Cook 2330bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23313dc33bd3SKees Cook 23323dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2333bd49e16eSAndy Lutomirski bool "Full emulation" 23343dc33bd3SKees Cook help 2335bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2336bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2337bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2338bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2339bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2340bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2341bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2342bd49e16eSAndy Lutomirski 2343bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2344bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2345bd49e16eSAndy Lutomirski 2346bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2347bd49e16eSAndy Lutomirski bool "Emulate execution only" 2348bd49e16eSAndy Lutomirski help 2349bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2350bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2351bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2352bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2353bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2354bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2355bd49e16eSAndy Lutomirski buffer. 23563dc33bd3SKees Cook 23573dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23583dc33bd3SKees Cook bool "None" 23593dc33bd3SKees Cook help 23603dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23613dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23623dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23633dc33bd3SKees Cook will be reported to dmesg, so that either old or 23643dc33bd3SKees Cook malicious userspace programs can be identified. 23653dc33bd3SKees Cook 23663dc33bd3SKees Cookendchoice 23673dc33bd3SKees Cook 2368516cbf37STim Birdconfig CMDLINE_BOOL 2369516cbf37STim Bird bool "Built-in kernel command line" 2370a7f7f624SMasahiro Yamada help 2371516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2372516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2373516cbf37STim Bird necessary or convenient to provide some or all of the 2374516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2375516cbf37STim Bird to not rely on the boot loader to provide them.) 2376516cbf37STim Bird 2377516cbf37STim Bird To compile command line arguments into the kernel, 2378516cbf37STim Bird set this option to 'Y', then fill in the 237969711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2380516cbf37STim Bird 2381516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2382516cbf37STim Bird should leave this option set to 'N'. 2383516cbf37STim Bird 2384516cbf37STim Birdconfig CMDLINE 2385516cbf37STim Bird string "Built-in kernel command string" 2386516cbf37STim Bird depends on CMDLINE_BOOL 2387516cbf37STim Bird default "" 2388a7f7f624SMasahiro Yamada help 2389516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2390516cbf37STim Bird image and used at boot time. If the boot loader provides a 2391516cbf37STim Bird command line at boot time, it is appended to this string to 2392516cbf37STim Bird form the full kernel command line, when the system boots. 2393516cbf37STim Bird 2394516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2395516cbf37STim Bird change this behavior. 2396516cbf37STim Bird 2397516cbf37STim Bird In most cases, the command line (whether built-in or provided 2398516cbf37STim Bird by the boot loader) should specify the device for the root 2399516cbf37STim Bird file system. 2400516cbf37STim Bird 2401516cbf37STim Birdconfig CMDLINE_OVERRIDE 2402516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2403645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2404a7f7f624SMasahiro Yamada help 2405516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2406516cbf37STim Bird command line, and use ONLY the built-in command line. 2407516cbf37STim Bird 2408516cbf37STim Bird This is used to work around broken boot loaders. This should 2409516cbf37STim Bird be set to 'N' under normal conditions. 2410516cbf37STim Bird 2411a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2412a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2413a5b9e5a2SAndy Lutomirski default y 2414a7f7f624SMasahiro Yamada help 2415a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2416a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2417a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2418a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2419a5b9e5a2SAndy Lutomirski threading libraries. 2420a5b9e5a2SAndy Lutomirski 2421a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2422a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2423a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2424a5b9e5a2SAndy Lutomirski 2425a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2426a5b9e5a2SAndy Lutomirski 2427b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2428b700e7f0SSeth Jennings 2429506f1d07SSam Ravnborgendmenu 2430506f1d07SSam Ravnborg 24313072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24323072e413SMichal Hocko def_bool y 24333072e413SMichal Hocko depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 24343072e413SMichal Hocko 2435f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2436f91ef222SOscar Salvador def_bool y 2437f91ef222SOscar Salvador 2438e534c7c5SLee Schermerhornconfig USE_PERCPU_NUMA_NODE_ID 2439645a7919STejun Heo def_bool y 2440e534c7c5SLee Schermerhorn depends on NUMA 2441e534c7c5SLee Schermerhorn 2442da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2443e279b6c1SSam Ravnborg 2444e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 24453c2362e6SHarvey Harrison def_bool y 244644556530SZhimin Gu depends on HIBERNATION 2447e279b6c1SSam Ravnborg 2448e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2449e279b6c1SSam Ravnborg 2450e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2451e279b6c1SSam Ravnborg 2452a6b68076SAndi Kleenconfig X86_APM_BOOT 24536fc108a0SJan Beulich def_bool y 2454282e5aabSPaul Bolle depends on APM 2455a6b68076SAndi Kleen 2456e279b6c1SSam Ravnborgmenuconfig APM 2457e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2458efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2459a7f7f624SMasahiro Yamada help 2460e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2461e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2462e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2463e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2464e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2465e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2466e279b6c1SSam Ravnborg 2467e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2468e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2469e279b6c1SSam Ravnborg 2470e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2471e279b6c1SSam Ravnborg machines with more than one CPU. 2472e279b6c1SSam Ravnborg 2473e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2474151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 24752dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2476e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2477e279b6c1SSam Ravnborg 2478e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2479e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2480e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2481e279b6c1SSam Ravnborg 2482e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2483e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2484e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2485e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2486e279b6c1SSam Ravnborg 2487e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2488e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2489e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2490e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2491e279b6c1SSam Ravnborg APM in your BIOS). 2492e279b6c1SSam Ravnborg 2493e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2494e279b6c1SSam Ravnborg "weird" problems: 2495e279b6c1SSam Ravnborg 2496e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2497e279b6c1SSam Ravnborg enabled. 2498e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2499e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2500e279b6c1SSam Ravnborg the "no387" option to the kernel 2501e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2502e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2503e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2504e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2505e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2506e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2507e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2508e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2509e279b6c1SSam Ravnborg 11) exchange RAM chips 2510e279b6c1SSam Ravnborg 12) exchange the motherboard. 2511e279b6c1SSam Ravnborg 2512e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2513e279b6c1SSam Ravnborg module will be called apm. 2514e279b6c1SSam Ravnborg 2515e279b6c1SSam Ravnborgif APM 2516e279b6c1SSam Ravnborg 2517e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2518e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2519a7f7f624SMasahiro Yamada help 2520e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2521e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2522e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2523e279b6c1SSam Ravnborg 2524e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2525e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2526a7f7f624SMasahiro Yamada help 2527e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2528e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2529e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2530e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2531e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2532e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2533e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2534e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2535e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2536e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2537e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2538e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2539e279b6c1SSam Ravnborg this feature. 2540e279b6c1SSam Ravnborg 2541e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2542dd8af076SLen Brown depends on CPU_IDLE 2543e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2544a7f7f624SMasahiro Yamada help 2545e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2546e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2547e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2548e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2549e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2550e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2551e279b6c1SSam Ravnborg this option does nothing.) 2552e279b6c1SSam Ravnborg 2553e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2554e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2555a7f7f624SMasahiro Yamada help 2556e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2557e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2558e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2559e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2560e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2561e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2562e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2563e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2564e279b6c1SSam Ravnborg especially if you are using gpm. 2565e279b6c1SSam Ravnborg 2566e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2567e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2568a7f7f624SMasahiro Yamada help 2569e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2570e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2571e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2572e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2573e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2574e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2575e279b6c1SSam Ravnborg 2576e279b6c1SSam Ravnborgendif # APM 2577e279b6c1SSam Ravnborg 2578bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2579e279b6c1SSam Ravnborg 2580e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2581e279b6c1SSam Ravnborg 258227471fdbSAndy Henroidsource "drivers/idle/Kconfig" 258327471fdbSAndy Henroid 2584e279b6c1SSam Ravnborgendmenu 2585e279b6c1SSam Ravnborg 2586e279b6c1SSam Ravnborg 2587e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2588e279b6c1SSam Ravnborg 2589e279b6c1SSam Ravnborgchoice 2590e279b6c1SSam Ravnborg prompt "PCI access mode" 2591efefa6f6SIngo Molnar depends on X86_32 && PCI 2592e279b6c1SSam Ravnborg default PCI_GOANY 2593a7f7f624SMasahiro Yamada help 2594e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2595e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2596e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2597e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2598e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2599e279b6c1SSam Ravnborg 2600e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2601e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2602e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2603e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2604e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2605e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2606e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2607e279b6c1SSam Ravnborg 2608e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2609e279b6c1SSam Ravnborg bool "BIOS" 2610e279b6c1SSam Ravnborg 2611e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2612e279b6c1SSam Ravnborg bool "MMConfig" 2613e279b6c1SSam Ravnborg 2614e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2615e279b6c1SSam Ravnborg bool "Direct" 2616e279b6c1SSam Ravnborg 26173ef0e1f8SAndres Salomonconfig PCI_GOOLPC 261876fb6570SDaniel Drake bool "OLPC XO-1" 26193ef0e1f8SAndres Salomon depends on OLPC 26203ef0e1f8SAndres Salomon 26212bdd1b03SAndres Salomonconfig PCI_GOANY 26222bdd1b03SAndres Salomon bool "Any" 26232bdd1b03SAndres Salomon 2624e279b6c1SSam Ravnborgendchoice 2625e279b6c1SSam Ravnborg 2626e279b6c1SSam Ravnborgconfig PCI_BIOS 26273c2362e6SHarvey Harrison def_bool y 2628efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2629e279b6c1SSam Ravnborg 2630e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2631e279b6c1SSam Ravnborgconfig PCI_DIRECT 26323c2362e6SHarvey Harrison def_bool y 26330aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2634e279b6c1SSam Ravnborg 2635e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2636b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2637b45c9f36SJan Kiszka default y 26384590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2639b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2640e279b6c1SSam Ravnborg 26413ef0e1f8SAndres Salomonconfig PCI_OLPC 26422bdd1b03SAndres Salomon def_bool y 26432bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 26443ef0e1f8SAndres Salomon 2645b5401a96SAlex Nixonconfig PCI_XEN 2646b5401a96SAlex Nixon def_bool y 2647b5401a96SAlex Nixon depends on PCI && XEN 2648b5401a96SAlex Nixon select SWIOTLB_XEN 2649b5401a96SAlex Nixon 26508364e1f8SJan Kiszkaconfig MMCONF_FAM10H 26518364e1f8SJan Kiszka def_bool y 26528364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2653e279b6c1SSam Ravnborg 26543f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 26556a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 26566ea30386SKees Cook depends on PCI 26573f6ea84aSIra W. Snyder help 26583f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 26593f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 26603f6ea84aSIra W. Snyder not have ACPI. 26613f6ea84aSIra W. Snyder 266264a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 266364a5fed6SBjorn Helgaas is known to be incomplete. 266464a5fed6SBjorn Helgaas 266564a5fed6SBjorn Helgaas You should say N unless you know you need this. 266664a5fed6SBjorn Helgaas 26673a495511SWilliam Breathitt Grayconfig ISA_BUS 266817a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 26693a495511SWilliam Breathitt Gray help 267017a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 267117a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 267217a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 267317a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 267417a2a129SWilliam Breathitt Gray not have an ISA bus. 26753a495511SWilliam Breathitt Gray 26763a495511SWilliam Breathitt Gray If unsure, say N. 26773a495511SWilliam Breathitt Gray 26781c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2679e279b6c1SSam Ravnborgconfig ISA_DMA_API 26801c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 26811c00f016SDavid Rientjes default y 26821c00f016SDavid Rientjes help 26831c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 26841c00f016SDavid Rientjes If unsure, say Y. 2685e279b6c1SSam Ravnborg 268651e68d05SLinus Torvaldsif X86_32 268751e68d05SLinus Torvalds 2688e279b6c1SSam Ravnborgconfig ISA 2689e279b6c1SSam Ravnborg bool "ISA support" 2690a7f7f624SMasahiro Yamada help 2691e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2692e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2693e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2694e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2695e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2696e279b6c1SSam Ravnborg 2697e279b6c1SSam Ravnborgconfig SCx200 2698e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2699a7f7f624SMasahiro Yamada help 2700e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2701e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2702e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2703e279b6c1SSam Ravnborg for other scx200_* drivers. 2704e279b6c1SSam Ravnborg 2705e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2706e279b6c1SSam Ravnborg 2707e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2708e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2709592913ecSJohn Stultz depends on SCx200 2710e279b6c1SSam Ravnborg default y 2711a7f7f624SMasahiro Yamada help 2712e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2713e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2714e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2715e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2716e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2717e279b6c1SSam Ravnborg 27183ef0e1f8SAndres Salomonconfig OLPC 27193ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 272054008979SThomas Gleixner depends on !X86_PAE 27213c554946SAndres Salomon select GPIOLIB 2722dc3119e7SThomas Gleixner select OF 272345bb1674SDaniel Drake select OF_PROMTREE 2724b4e51854SGrant Likely select IRQ_DOMAIN 27250c3d931bSLubomir Rintel select OLPC_EC 2726a7f7f624SMasahiro Yamada help 27273ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27283ef0e1f8SAndres Salomon XO hardware. 27293ef0e1f8SAndres Salomon 2730a3128588SDaniel Drakeconfig OLPC_XO1_PM 2731a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2732fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2733a7f7f624SMasahiro Yamada help 273497c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2735bf1ebf00SDaniel Drake 2736cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2737cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2738cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2739a7f7f624SMasahiro Yamada help 2740cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2741cfee9597SDaniel Drake programmable wakeup source. 2742cfee9597SDaniel Drake 27437feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 27447feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 274592e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2746ed8e47feSRandy Dunlap depends on INPUT=y 2747d8d01a63SDaniel Drake select POWER_SUPPLY 2748a7f7f624SMasahiro Yamada help 27497feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 27507bc74b3dSDaniel Drake - EC-driven system wakeups 27517feda8e9SDaniel Drake - Power button 27527bc74b3dSDaniel Drake - Ebook switch 27532cf2baeaSDaniel Drake - Lid switch 2754e1040ac6SDaniel Drake - AC adapter status updates 2755e1040ac6SDaniel Drake - Battery status updates 27567feda8e9SDaniel Drake 2757a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2758a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2759d8d01a63SDaniel Drake depends on OLPC && ACPI 2760d8d01a63SDaniel Drake select POWER_SUPPLY 2761a7f7f624SMasahiro Yamada help 2762a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2763a0f30f59SDaniel Drake - EC-driven system wakeups 2764a0f30f59SDaniel Drake - AC adapter status updates 2765a0f30f59SDaniel Drake - Battery status updates 2766e279b6c1SSam Ravnborg 2767d4f3e350SEd Wildgooseconfig ALIX 2768d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2769d4f3e350SEd Wildgoose select GPIOLIB 2770a7f7f624SMasahiro Yamada help 2771d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2772d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2773d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2774d4f3e350SEd Wildgoose get added here. 2775d4f3e350SEd Wildgoose 2776d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2777d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2778d4f3e350SEd Wildgoose 2779d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2780d4f3e350SEd Wildgoose 2781da4e3302SPhilip Prindevilleconfig NET5501 2782da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2783da4e3302SPhilip Prindeville select GPIOLIB 2784a7f7f624SMasahiro Yamada help 2785da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2786da4e3302SPhilip Prindeville 27873197059aSPhilip A. Prindevilleconfig GEOS 27883197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 27893197059aSPhilip A. Prindeville select GPIOLIB 27903197059aSPhilip A. Prindeville depends on DMI 2791a7f7f624SMasahiro Yamada help 27923197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 27933197059aSPhilip A. Prindeville 27947d029125SVivien Didelotconfig TS5500 27957d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 27967d029125SVivien Didelot depends on MELAN 27977d029125SVivien Didelot select CHECK_SIGNATURE 27987d029125SVivien Didelot select NEW_LEDS 27997d029125SVivien Didelot select LEDS_CLASS 2800a7f7f624SMasahiro Yamada help 28017d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28027d029125SVivien Didelot 2803e279b6c1SSam Ravnborgendif # X86_32 2804e279b6c1SSam Ravnborg 280523ac4ae8SAndreas Herrmannconfig AMD_NB 2806e279b6c1SSam Ravnborg def_bool y 28070e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2808e279b6c1SSam Ravnborg 2809e3263ab3SDavid Herrmannconfig X86_SYSFB 2810e3263ab3SDavid Herrmann bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2811e3263ab3SDavid Herrmann help 2812e3263ab3SDavid Herrmann Firmwares often provide initial graphics framebuffers so the BIOS, 2813e3263ab3SDavid Herrmann bootloader or kernel can show basic video-output during boot for 2814e3263ab3SDavid Herrmann user-guidance and debugging. Historically, x86 used the VESA BIOS 2815e3263ab3SDavid Herrmann Extensions and EFI-framebuffers for this, which are mostly limited 2816e3263ab3SDavid Herrmann to x86. 2817e3263ab3SDavid Herrmann This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2818e3263ab3SDavid Herrmann framebuffers so the new generic system-framebuffer drivers can be 2819e3263ab3SDavid Herrmann used on x86. If the framebuffer is not compatible with the generic 2820e3a5dc08SNikolas Nyby modes, it is advertised as fallback platform framebuffer so legacy 2821e3263ab3SDavid Herrmann drivers like efifb, vesafb and uvesafb can pick it up. 2822e3263ab3SDavid Herrmann If this option is not selected, all system framebuffers are always 2823e3263ab3SDavid Herrmann marked as fallback platform framebuffers as usual. 2824e3263ab3SDavid Herrmann 2825e3263ab3SDavid Herrmann Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2826e3263ab3SDavid Herrmann not be able to pick up generic system framebuffers if this option 2827e3263ab3SDavid Herrmann is selected. You are highly encouraged to enable simplefb as 2828e3263ab3SDavid Herrmann replacement if you select this option. simplefb can correctly deal 2829e3263ab3SDavid Herrmann with generic system framebuffers. But you should still keep vesafb 2830e3263ab3SDavid Herrmann and others enabled as fallback if a system framebuffer is 2831e3263ab3SDavid Herrmann incompatible with simplefb. 2832e3263ab3SDavid Herrmann 2833e3263ab3SDavid Herrmann If unsure, say Y. 2834e3263ab3SDavid Herrmann 2835e279b6c1SSam Ravnborgendmenu 2836e279b6c1SSam Ravnborg 2837e279b6c1SSam Ravnborg 28381572497cSChristoph Hellwigmenu "Binary Emulations" 2839e279b6c1SSam Ravnborg 2840e279b6c1SSam Ravnborgconfig IA32_EMULATION 2841e279b6c1SSam Ravnborg bool "IA32 Emulation" 2842e279b6c1SSam Ravnborg depends on X86_64 284339f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2844d1603990SRandy Dunlap select BINFMT_ELF 284539f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2846a7f7f624SMasahiro Yamada help 28475fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 28485fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 28495fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2850e279b6c1SSam Ravnborg 2851e279b6c1SSam Ravnborgconfig IA32_AOUT 2852e279b6c1SSam Ravnborg tristate "IA32 a.out support" 28536b213e1bSDavid Woodhouse depends on IA32_EMULATION 2854eac61655SBorislav Petkov depends on BROKEN 2855a7f7f624SMasahiro Yamada help 2856e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2857e279b6c1SSam Ravnborg 28580bf62763SH. Peter Anvinconfig X86_X32 28596ea30386SKees Cook bool "x32 ABI for 64-bit mode" 28609b54050bSBrian Gerst depends on X86_64 2861a7f7f624SMasahiro Yamada help 28625fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 28635fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 28645fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 28655fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 28665fd92e65SH. J. Lu 28675fd92e65SH. J. Lu You will need a recent binutils (2.22 or later) with 28685fd92e65SH. J. Lu elf32_x86_64 support enabled to compile a kernel with this 28695fd92e65SH. J. Lu option set. 28705fd92e65SH. J. Lu 2871953fee1dSIngo Molnarconfig COMPAT_32 2872953fee1dSIngo Molnar def_bool y 2873953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2874953fee1dSIngo Molnar select HAVE_UID16 2875953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2876953fee1dSIngo Molnar 2877e279b6c1SSam Ravnborgconfig COMPAT 28783c2362e6SHarvey Harrison def_bool y 28790bf62763SH. Peter Anvin depends on IA32_EMULATION || X86_X32 2880e279b6c1SSam Ravnborg 28813120e25eSJan Beulichif COMPAT 2882e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 28833120e25eSJan Beulich def_bool y 2884e279b6c1SSam Ravnborg 2885e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 28863c2362e6SHarvey Harrison def_bool y 28873120e25eSJan Beulich depends on SYSVIPC 28883120e25eSJan Beulichendif 2889ee009e4aSDavid Howells 2890e279b6c1SSam Ravnborgendmenu 2891e279b6c1SSam Ravnborg 2892e279b6c1SSam Ravnborg 2893e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2894e5beae16SKeith Packard def_bool y 2895e5beae16SKeith Packard depends on X86_32 2896e5beae16SKeith Packard 2897e279b6c1SSam Ravnborgsource "drivers/firmware/Kconfig" 2898e279b6c1SSam Ravnborg 2899edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 29005e8ebd84SJason A. Donenfeld 29015e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2902