diff options
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 2993 |
1 files changed, 2993 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig new file mode 100644 index 0000000000..fe3292e310 --- /dev/null +++ b/arch/x86/Kconfig @@ -0,0 +1,2993 @@ +# SPDX-License-Identifier: GPL-2.0 +# Select 32 or 64 bit +config 64BIT + bool "64-bit kernel" if "$(ARCH)" = "x86" + default "$(ARCH)" != "i386" + help + Say yes to build a 64-bit kernel - formerly known as x86_64 + Say no to build a 32-bit kernel - formerly known as i386 + +config X86_32 + def_bool y + depends on !64BIT + # Options that are inherently 32-bit kernel only: + select ARCH_WANT_IPC_PARSE_VERSION + select CLKSRC_I8253 + select CLONE_BACKWARDS + select GENERIC_VDSO_32 + select HAVE_DEBUG_STACKOVERFLOW + select KMAP_LOCAL + select MODULES_USE_ELF_REL + select OLD_SIGACTION + select ARCH_SPLIT_ARG64 + +config X86_64 + def_bool y + depends on 64BIT + # Options that are inherently 64-bit kernel only: + select ARCH_HAS_GIGANTIC_PAGE + select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 + select ARCH_SUPPORTS_PER_VMA_LOCK + select ARCH_USE_CMPXCHG_LOCKREF + select HAVE_ARCH_SOFT_DIRTY + select MODULES_USE_ELF_RELA + select NEED_DMA_MAP_STATE + select SWIOTLB + select ARCH_HAS_ELFCORE_COMPAT + select ZONE_DMA32 + +config FORCE_DYNAMIC_FTRACE + def_bool y + depends on X86_32 + depends on FUNCTION_TRACER + select DYNAMIC_FTRACE + help + We keep the static function tracing (!DYNAMIC_FTRACE) around + in order to test the non static function tracing in the + generic code, as other architectures still use it. But we + only need to keep it around for x86_64. No need to keep it + for x86_32. For x86_32, force DYNAMIC_FTRACE. +# +# Arch settings +# +# ( Note that options that are marked 'if X86_64' could in principle be +# ported to 32-bit as well. ) +# +config X86 + def_bool y + # + # Note: keep this list sorted alphabetically + # + select ACPI_LEGACY_TABLES_LOOKUP if ACPI + select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI + select ARCH_32BIT_OFF_T if X86_32 + select ARCH_CLOCKSOURCE_INIT + select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE + select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION + select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 + select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG + select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) + select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE + select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI + select ARCH_HAS_CACHE_LINE_SIZE + select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION + select ARCH_HAS_CPU_FINALIZE_INIT + select ARCH_HAS_CURRENT_STACK_POINTER + select ARCH_HAS_DEBUG_VIRTUAL + select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE + select ARCH_HAS_DEVMEM_IS_ALLOWED + select ARCH_HAS_EARLY_DEBUG if KGDB + select ARCH_HAS_ELF_RANDOMIZE + select ARCH_HAS_FAST_MULTIPLIER + select ARCH_HAS_FORTIFY_SOURCE + select ARCH_HAS_GCOV_PROFILE_ALL + select ARCH_HAS_KCOV if X86_64 + select ARCH_HAS_MEM_ENCRYPT + select ARCH_HAS_MEMBARRIER_SYNC_CORE + select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS + select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE + select ARCH_HAS_PMEM_API if X86_64 + select ARCH_HAS_PTE_DEVMAP if X86_64 + select ARCH_HAS_PTE_SPECIAL + select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 + select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 + select ARCH_HAS_COPY_MC if X86_64 + select ARCH_HAS_SET_MEMORY + select ARCH_HAS_SET_DIRECT_MAP + select ARCH_HAS_STRICT_KERNEL_RWX + select ARCH_HAS_STRICT_MODULE_RWX + select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE + select ARCH_HAS_SYSCALL_WRAPPER + select ARCH_HAS_UBSAN_SANITIZE_ALL + select ARCH_HAS_DEBUG_WX + select ARCH_HAS_ZONE_DMA_SET if EXPERT + select ARCH_HAVE_NMI_SAFE_CMPXCHG + select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE + select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI + select ARCH_MIGHT_HAVE_PC_PARPORT + select ARCH_MIGHT_HAVE_PC_SERIO + select ARCH_STACKWALK + select ARCH_SUPPORTS_ACPI + select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_DEBUG_PAGEALLOC + select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 + select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 + select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 + select ARCH_SUPPORTS_CFI_CLANG if X86_64 + select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG + select ARCH_SUPPORTS_LTO_CLANG + select ARCH_SUPPORTS_LTO_CLANG_THIN + select ARCH_USE_BUILTIN_BSWAP + select ARCH_USE_MEMTEST + select ARCH_USE_QUEUED_RWLOCKS + select ARCH_USE_QUEUED_SPINLOCKS + select ARCH_USE_SYM_ANNOTATIONS + select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH + select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 + select ARCH_WANTS_DYNAMIC_TASK_STRUCT + select ARCH_WANTS_NO_INSTR + select ARCH_WANT_GENERAL_HUGETLB + select ARCH_WANT_HUGE_PMD_SHARE + select ARCH_WANT_LD_ORPHAN_WARN + select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 + select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 + select ARCH_WANTS_THP_SWAP if X86_64 + select ARCH_HAS_PARANOID_L1D_FLUSH + select BUILDTIME_TABLE_SORT + select CLKEVT_I8253 + select CLOCKSOURCE_VALIDATE_LAST_CYCLE + select CLOCKSOURCE_WATCHDOG + # Word-size accesses may read uninitialized data past the trailing \0 + # in strings and cause false KMSAN reports. + select DCACHE_WORD_ACCESS if !KMSAN + select DYNAMIC_SIGFRAME + select EDAC_ATOMIC_SCRUB + select EDAC_SUPPORT + select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) + select GENERIC_CLOCKEVENTS_MIN_ADJUST + select GENERIC_CMOS_UPDATE + select GENERIC_CPU_AUTOPROBE + select GENERIC_CPU_VULNERABILITIES + select GENERIC_EARLY_IOREMAP + select GENERIC_ENTRY + select GENERIC_IOMAP + select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP + select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC + select GENERIC_IRQ_MIGRATION if SMP + select GENERIC_IRQ_PROBE + select GENERIC_IRQ_RESERVATION_MODE + select GENERIC_IRQ_SHOW + select GENERIC_PENDING_IRQ if SMP + select GENERIC_PTDUMP + select GENERIC_SMP_IDLE_THREAD + select GENERIC_TIME_VSYSCALL + select GENERIC_GETTIMEOFDAY + select GENERIC_VDSO_TIME_NS + select GUP_GET_PXX_LOW_HIGH if X86_PAE + select HARDIRQS_SW_RESEND + select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 + select HAS_IOPORT + select HAVE_ACPI_APEI if ACPI + select HAVE_ACPI_APEI_NMI if ACPI + select HAVE_ALIGNED_STRUCT_PAGE if SLUB + select HAVE_ARCH_AUDITSYSCALL + select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE + select HAVE_ARCH_HUGE_VMALLOC if X86_64 + select HAVE_ARCH_JUMP_LABEL + select HAVE_ARCH_JUMP_LABEL_RELATIVE + select HAVE_ARCH_KASAN if X86_64 + select HAVE_ARCH_KASAN_VMALLOC if X86_64 + select HAVE_ARCH_KFENCE + select HAVE_ARCH_KMSAN if X86_64 + select HAVE_ARCH_KGDB + select HAVE_ARCH_MMAP_RND_BITS if MMU + select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT + select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT + select HAVE_ARCH_PREL32_RELOCATIONS + select HAVE_ARCH_SECCOMP_FILTER + select HAVE_ARCH_THREAD_STRUCT_WHITELIST + select HAVE_ARCH_STACKLEAK + select HAVE_ARCH_TRACEHOOK + select HAVE_ARCH_TRANSPARENT_HUGEPAGE + select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 + select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD + select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD + select HAVE_ARCH_VMAP_STACK if X86_64 + select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET + select HAVE_ARCH_WITHIN_STACK_FRAMES + select HAVE_ASM_MODVERSIONS + select HAVE_CMPXCHG_DOUBLE + select HAVE_CMPXCHG_LOCAL + select HAVE_CONTEXT_TRACKING_USER if X86_64 + select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER + select HAVE_C_RECORDMCOUNT + select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL + select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT + select HAVE_BUILDTIME_MCOUNT_SORT + select HAVE_DEBUG_KMEMLEAK + select HAVE_DMA_CONTIGUOUS + select HAVE_DYNAMIC_FTRACE + select HAVE_DYNAMIC_FTRACE_WITH_REGS + select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 + select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 + select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 + select HAVE_EBPF_JIT + select HAVE_EFFICIENT_UNALIGNED_ACCESS + select HAVE_EISA + select HAVE_EXIT_THREAD + select HAVE_FAST_GUP + select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE + select HAVE_FTRACE_MCOUNT_RECORD + select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER + select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) + select HAVE_FUNCTION_TRACER + select HAVE_GCC_PLUGINS + select HAVE_HW_BREAKPOINT + select HAVE_IOREMAP_PROT + select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 + select HAVE_IRQ_TIME_ACCOUNTING + select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL + select HAVE_KERNEL_BZIP2 + select HAVE_KERNEL_GZIP + select HAVE_KERNEL_LZ4 + select HAVE_KERNEL_LZMA + select HAVE_KERNEL_LZO + select HAVE_KERNEL_XZ + select HAVE_KERNEL_ZSTD + select HAVE_KPROBES + select HAVE_KPROBES_ON_FTRACE + select HAVE_FUNCTION_ERROR_INJECTION + select HAVE_KRETPROBES + select HAVE_RETHOOK + select HAVE_KVM + select HAVE_LIVEPATCH if X86_64 + select HAVE_MIXED_BREAKPOINTS_REGS + select HAVE_MOD_ARCH_SPECIFIC + select HAVE_MOVE_PMD + select HAVE_MOVE_PUD + select HAVE_NOINSTR_HACK if HAVE_OBJTOOL + select HAVE_NMI + select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL + select HAVE_OBJTOOL if X86_64 + select HAVE_OPTPROBES + select HAVE_PCSPKR_PLATFORM + select HAVE_PERF_EVENTS + select HAVE_PERF_EVENTS_NMI + select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI + select HAVE_PCI + select HAVE_PERF_REGS + select HAVE_PERF_USER_STACK_DUMP + select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT + select MMU_GATHER_MERGE_VMAS + select HAVE_POSIX_CPU_TIMERS_TASK_WORK + select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION + select HAVE_FUNCTION_ARG_ACCESS_API + select HAVE_SETUP_PER_CPU_AREA + select HAVE_SOFTIRQ_ON_OWN_STACK + select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR + select HAVE_STACK_VALIDATION if HAVE_OBJTOOL + select HAVE_STATIC_CALL + select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL + select HAVE_PREEMPT_DYNAMIC_CALL + select HAVE_RSEQ + select HAVE_RUST if X86_64 + select HAVE_SYSCALL_TRACEPOINTS + select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL + select HAVE_UNSTABLE_SCHED_CLOCK + select HAVE_USER_RETURN_NOTIFIER + select HAVE_GENERIC_VDSO + select HOTPLUG_PARALLEL if SMP && X86_64 + select HOTPLUG_SMT if SMP + select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 + select IRQ_FORCED_THREADING + select LOCK_MM_AND_FIND_VMA + select NEED_PER_CPU_EMBED_FIRST_CHUNK + select NEED_PER_CPU_PAGE_FIRST_CHUNK + select NEED_SG_DMA_LENGTH + select PCI_DOMAINS if PCI + select PCI_LOCKLESS_CONFIG if PCI + select PERF_EVENTS + select RTC_LIB + select RTC_MC146818_LIB + select SPARSE_IRQ + select SYSCTL_EXCEPTION_TRACE + select THREAD_INFO_IN_TASK + select TRACE_IRQFLAGS_SUPPORT + select TRACE_IRQFLAGS_NMI_SUPPORT + select USER_STACKTRACE_SUPPORT + select HAVE_ARCH_KCSAN if X86_64 + select PROC_PID_ARCH_STATUS if PROC_FS + select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX + select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 + select FUNCTION_ALIGNMENT_4B + imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI + select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE + +config INSTRUCTION_DECODER + def_bool y + depends on KPROBES || PERF_EVENTS || UPROBES + +config OUTPUT_FORMAT + string + default "elf32-i386" if X86_32 + default "elf64-x86-64" if X86_64 + +config LOCKDEP_SUPPORT + def_bool y + +config STACKTRACE_SUPPORT + def_bool y + +config MMU + def_bool y + +config ARCH_MMAP_RND_BITS_MIN + default 28 if 64BIT + default 8 + +config ARCH_MMAP_RND_BITS_MAX + default 32 if 64BIT + default 16 + +config ARCH_MMAP_RND_COMPAT_BITS_MIN + default 8 + +config ARCH_MMAP_RND_COMPAT_BITS_MAX + default 16 + +config SBUS + bool + +config GENERIC_ISA_DMA + def_bool y + depends on ISA_DMA_API + +config GENERIC_CSUM + bool + default y if KMSAN || KASAN + +config GENERIC_BUG + def_bool y + depends on BUG + select GENERIC_BUG_RELATIVE_POINTERS if X86_64 + +config GENERIC_BUG_RELATIVE_POINTERS + bool + +config ARCH_MAY_HAVE_PC_FDC + def_bool y + depends on ISA_DMA_API + +config GENERIC_CALIBRATE_DELAY + def_bool y + +config ARCH_HAS_CPU_RELAX + def_bool y + +config ARCH_HIBERNATION_POSSIBLE + def_bool y + +config ARCH_SUSPEND_POSSIBLE + def_bool y + +config AUDIT_ARCH + def_bool y if X86_64 + +config KASAN_SHADOW_OFFSET + hex + depends on KASAN + default 0xdffffc0000000000 + +config HAVE_INTEL_TXT + def_bool y + depends on INTEL_IOMMU && ACPI + +config X86_32_SMP + def_bool y + depends on X86_32 && SMP + +config X86_64_SMP + def_bool y + depends on X86_64 && SMP + +config ARCH_SUPPORTS_UPROBES + def_bool y + +config FIX_EARLYCON_MEM + def_bool y + +config DYNAMIC_PHYSICAL_MASK + bool + +config PGTABLE_LEVELS + int + default 5 if X86_5LEVEL + default 4 if X86_64 + default 3 if X86_PAE + default 2 + +config CC_HAS_SANE_STACKPROTECTOR + bool + default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT + default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) + help + We have to make sure stack protector is unconditionally disabled if + the compiler produces broken code or if it does not let us control + the segment on 32-bit kernels. + +menu "Processor type and features" + +config SMP + bool "Symmetric multi-processing support" + help + This enables support for systems with more than one CPU. If you have + a system with only one CPU, say N. If you have a system with more + than one CPU, say Y. + + If you say N here, the kernel will run on uni- and multiprocessor + machines, but will use only one CPU of a multiprocessor machine. If + you say Y here, the kernel will run on many, but not all, + uniprocessor machines. On a uniprocessor machine, the kernel + will run faster if you say N here. + + Note that if you say Y here and choose architecture "586" or + "Pentium" under "Processor family", the kernel will not work on 486 + architectures. Similarly, multiprocessor kernels for the "PPro" + architecture may not work on all Pentium based boards. + + People using multiprocessor machines who say Y here should also say + Y to "Enhanced Real Time Clock Support", below. The "Advanced Power + Management" code will be disabled if you say Y here. + + See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, + <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at + <http://www.tldp.org/docs.html#howto>. + + If you don't know what to do here, say N. + +config X86_X2APIC + bool "Support x2apic" + depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) + help + This enables x2apic support on CPUs that have this feature. + + This allows 32-bit apic IDs (so it can support very large systems), + and accesses the local apic via MSRs not via mmio. + + Some Intel systems circa 2022 and later are locked into x2APIC mode + and can not fall back to the legacy APIC modes if SGX or TDX are + enabled in the BIOS. They will boot with very reduced functionality + without enabling this option. + + If you don't know what to do here, say N. + +config X86_MPPARSE + bool "Enable MPS table" if ACPI + default y + depends on X86_LOCAL_APIC + help + For old smp systems that do not have proper acpi support. Newer systems + (esp with 64bit cpus) with acpi support, MADT and DSDT will override it + +config GOLDFISH + def_bool y + depends on X86_GOLDFISH + +config X86_CPU_RESCTRL + bool "x86 CPU resource control support" + depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) + select KERNFS + select PROC_CPU_RESCTRL if PROC_FS + help + Enable x86 CPU resource control support. + + Provide support for the allocation and monitoring of system resources + usage by the CPU. + + Intel calls this Intel Resource Director Technology + (Intel(R) RDT). More information about RDT can be found in the + Intel x86 Architecture Software Developer Manual. + + AMD calls this AMD Platform Quality of Service (AMD QoS). + More information about AMD QoS can be found in the AMD64 Technology + Platform Quality of Service Extensions manual. + + Say N if unsure. + +if X86_32 +config X86_BIGSMP + bool "Support for big SMP systems with more than 8 CPUs" + depends on SMP + help + This option is needed for the systems that have more than 8 CPUs. + +config X86_EXTENDED_PLATFORM + bool "Support for extended (non-PC) x86 platforms" + default y + help + If you disable this option then the kernel will only support + standard PC platforms. (which covers the vast majority of + systems out there.) + + If you enable this option then you'll be able to select support + for the following (non-PC) 32 bit x86 platforms: + Goldfish (Android emulator) + AMD Elan + RDC R-321x SoC + SGI 320/540 (Visual Workstation) + STA2X11-based (e.g. Northville) + Moorestown MID devices + + If you have one of these systems, or if you want to build a + generic distribution kernel, say Y here - otherwise say N. +endif # X86_32 + +if X86_64 +config X86_EXTENDED_PLATFORM + bool "Support for extended (non-PC) x86 platforms" + default y + help + If you disable this option then the kernel will only support + standard PC platforms. (which covers the vast majority of + systems out there.) + + If you enable this option then you'll be able to select support + for the following (non-PC) 64 bit x86 platforms: + Numascale NumaChip + ScaleMP vSMP + SGI Ultraviolet + + If you have one of these systems, or if you want to build a + generic distribution kernel, say Y here - otherwise say N. +endif # X86_64 +# This is an alphabetically sorted list of 64 bit extended platforms +# Please maintain the alphabetic order if and when there are additions +config X86_NUMACHIP + bool "Numascale NumaChip" + depends on X86_64 + depends on X86_EXTENDED_PLATFORM + depends on NUMA + depends on SMP + depends on X86_X2APIC + depends on PCI_MMCONFIG + help + Adds support for Numascale NumaChip large-SMP systems. Needed to + enable more than ~168 cores. + If you don't have one of these, you should say N here. + +config X86_VSMP + bool "ScaleMP vSMP" + select HYPERVISOR_GUEST + select PARAVIRT + depends on X86_64 && PCI + depends on X86_EXTENDED_PLATFORM + depends on SMP + help + Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is + supposed to run on these EM64T-based machines. Only choose this option + if you have one of these machines. + +config X86_UV + bool "SGI Ultraviolet" + depends on X86_64 + depends on X86_EXTENDED_PLATFORM + depends on NUMA + depends on EFI + depends on KEXEC_CORE + depends on X86_X2APIC + depends on PCI + help + This option is needed in order to support SGI Ultraviolet systems. + If you don't have one of these, you should say N here. + +# Following is an alphabetically sorted list of 32 bit extended platforms +# Please maintain the alphabetic order if and when there are additions + +config X86_GOLDFISH + bool "Goldfish (Virtual Platform)" + depends on X86_EXTENDED_PLATFORM + help + Enable support for the Goldfish virtual platform used primarily + for Android development. Unless you are building for the Android + Goldfish emulator say N here. + +config X86_INTEL_CE + bool "CE4100 TV platform" + depends on PCI + depends on PCI_GODIRECT + depends on X86_IO_APIC + depends on X86_32 + depends on X86_EXTENDED_PLATFORM + select X86_REBOOTFIXUPS + select OF + select OF_EARLY_FLATTREE + help + Select for the Intel CE media processor (CE4100) SOC. + This option compiles in support for the CE4100 SOC for settop + boxes and media devices. + +config X86_INTEL_MID + bool "Intel MID platform support" + depends on X86_EXTENDED_PLATFORM + depends on X86_PLATFORM_DEVICES + depends on PCI + depends on X86_64 || (PCI_GOANY && X86_32) + depends on X86_IO_APIC + select I2C + select DW_APB_TIMER + select INTEL_SCU_PCI + help + Select to build a kernel capable of supporting Intel MID (Mobile + Internet Device) platform systems which do not have the PCI legacy + interfaces. If you are building for a PC class system say N here. + + Intel MID platforms are based on an Intel processor and chipset which + consume less power than most of the x86 derivatives. + +config X86_INTEL_QUARK + bool "Intel Quark platform support" + depends on X86_32 + depends on X86_EXTENDED_PLATFORM + depends on X86_PLATFORM_DEVICES + depends on X86_TSC + depends on PCI + depends on PCI_GOANY + depends on X86_IO_APIC + select IOSF_MBI + select INTEL_IMR + select COMMON_CLK + help + Select to include support for Quark X1000 SoC. + Say Y here if you have a Quark based system such as the Arduino + compatible Intel Galileo. + +config X86_INTEL_LPSS + bool "Intel Low Power Subsystem Support" + depends on X86 && ACPI && PCI + select COMMON_CLK + select PINCTRL + select IOSF_MBI + help + Select to build support for Intel Low Power Subsystem such as + found on Intel Lynxpoint PCH. Selecting this option enables + things like clock tree (common clock framework) and pincontrol + which are needed by the LPSS peripheral drivers. + +config X86_AMD_PLATFORM_DEVICE + bool "AMD ACPI2Platform devices support" + depends on ACPI + select COMMON_CLK + select PINCTRL + help + Select to interpret AMD specific ACPI device to platform device + such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. + I2C and UART depend on COMMON_CLK to set clock. GPIO driver is + implemented under PINCTRL subsystem. + +config IOSF_MBI + tristate "Intel SoC IOSF Sideband support for SoC platforms" + depends on PCI + help + This option enables sideband register access support for Intel SoC + platforms. On these platforms the IOSF sideband is used in lieu of + MSR's for some register accesses, mostly but not limited to thermal + and power. Drivers may query the availability of this device to + determine if they need the sideband in order to work on these + platforms. The sideband is available on the following SoC products. + This list is not meant to be exclusive. + - BayTrail + - Braswell + - Quark + + You should say Y if you are running a kernel on one of these SoC's. + +config IOSF_MBI_DEBUG + bool "Enable IOSF sideband access through debugfs" + depends on IOSF_MBI && DEBUG_FS + help + Select this option to expose the IOSF sideband access registers (MCR, + MDR, MCRX) through debugfs to write and read register information from + different units on the SoC. This is most useful for obtaining device + state information for debug and analysis. As this is a general access + mechanism, users of this option would have specific knowledge of the + device they want to access. + + If you don't require the option or are in doubt, say N. + +config X86_RDC321X + bool "RDC R-321x SoC" + depends on X86_32 + depends on X86_EXTENDED_PLATFORM + select M486 + select X86_REBOOTFIXUPS + help + This option is needed for RDC R-321x system-on-chip, also known + as R-8610-(G). + If you don't have one of these chips, you should say N here. + +config X86_32_NON_STANDARD + bool "Support non-standard 32-bit SMP architectures" + depends on X86_32 && SMP + depends on X86_EXTENDED_PLATFORM + help + This option compiles in the bigsmp and STA2X11 default + subarchitectures. It is intended for a generic binary + kernel. If you select them all, kernel will probe it one by + one and will fallback to default. + +# Alphabetically sorted list of Non standard 32 bit platforms + +config X86_SUPPORTS_MEMORY_FAILURE + def_bool y + # MCE code calls memory_failure(): + depends on X86_MCE + # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: + # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: + depends on X86_64 || !SPARSEMEM + select ARCH_SUPPORTS_MEMORY_FAILURE + +config STA2X11 + bool "STA2X11 Companion Chip Support" + depends on X86_32_NON_STANDARD && PCI + select SWIOTLB + select MFD_STA2X11 + select GPIOLIB + help + This adds support for boards based on the STA2X11 IO-Hub, + a.k.a. "ConneXt". The chip is used in place of the standard + PC chipset, so all "standard" peripherals are missing. If this + option is selected the kernel will still be able to boot on + standard PC machines. + +config X86_32_IRIS + tristate "Eurobraille/Iris poweroff module" + depends on X86_32 + help + The Iris machines from EuroBraille do not have APM or ACPI support + to shut themselves down properly. A special I/O sequence is + needed to do so, which is what this module does at + kernel shutdown. + + This is only for Iris machines from EuroBraille. + + If unused, say N. + +config SCHED_OMIT_FRAME_POINTER + def_bool y + prompt "Single-depth WCHAN output" + depends on X86 + help + Calculate simpler /proc/<PID>/wchan values. If this option + is disabled then wchan values will recurse back to the + caller function. This provides more accurate wchan values, + at the expense of slightly more scheduling overhead. + + If in doubt, say "Y". + +menuconfig HYPERVISOR_GUEST + bool "Linux guest support" + help + Say Y here to enable options for running Linux under various hyper- + visors. This option enables basic hypervisor detection and platform + setup. + + If you say N, all options in this submenu will be skipped and + disabled, and Linux guest support won't be built in. + +if HYPERVISOR_GUEST + +config PARAVIRT + bool "Enable paravirtualization code" + depends on HAVE_STATIC_CALL + help + This changes the kernel so it can modify itself when it is run + under a hypervisor, potentially improving performance significantly + over full virtualization. However, when run without a hypervisor + the kernel is theoretically slower and slightly larger. + +config PARAVIRT_XXL + bool + +config PARAVIRT_DEBUG + bool "paravirt-ops debugging" + depends on PARAVIRT && DEBUG_KERNEL + help + Enable to debug paravirt_ops internals. Specifically, BUG if + a paravirt_op is missing when it is called. + +config PARAVIRT_SPINLOCKS + bool "Paravirtualization layer for spinlocks" + depends on PARAVIRT && SMP + help + Paravirtualized spinlocks allow a pvops backend to replace the + spinlock implementation with something virtualization-friendly + (for example, block the virtual CPU rather than spinning). + + It has a minimal impact on native kernels and gives a nice performance + benefit on paravirtualized KVM / Xen kernels. + + If you are unsure how to answer this question, answer Y. + +config X86_HV_CALLBACK_VECTOR + def_bool n + +source "arch/x86/xen/Kconfig" + +config KVM_GUEST + bool "KVM Guest support (including kvmclock)" + depends on PARAVIRT + select PARAVIRT_CLOCK + select ARCH_CPUIDLE_HALTPOLL + select X86_HV_CALLBACK_VECTOR + default y + help + This option enables various optimizations for running under the KVM + hypervisor. It includes a paravirtualized clock, so that instead + of relying on a PIT (or probably other) emulation by the + underlying device model, the host provides the guest with + timing infrastructure such as time of day, and system time + +config ARCH_CPUIDLE_HALTPOLL + def_bool n + prompt "Disable host haltpoll when loading haltpoll driver" + help + If virtualized under KVM, disable host haltpoll. + +config PVH + bool "Support for running PVH guests" + help + This option enables the PVH entry point for guest virtual machines + as specified in the x86/HVM direct boot ABI. + +config PARAVIRT_TIME_ACCOUNTING + bool "Paravirtual steal time accounting" + depends on PARAVIRT + help + Select this option to enable fine granularity task steal time + accounting. Time spent executing other tasks in parallel with + the current vCPU is discounted from the vCPU power. To account for + that, there can be a small performance impact. + + If in doubt, say N here. + +config PARAVIRT_CLOCK + bool + +config JAILHOUSE_GUEST + bool "Jailhouse non-root cell support" + depends on X86_64 && PCI + select X86_PM_TIMER + help + This option allows to run Linux as guest in a Jailhouse non-root + cell. You can leave this option disabled if you only want to start + Jailhouse and run Linux afterwards in the root cell. + +config ACRN_GUEST + bool "ACRN Guest support" + depends on X86_64 + select X86_HV_CALLBACK_VECTOR + help + This option allows to run Linux as guest in the ACRN hypervisor. ACRN is + a flexible, lightweight reference open-source hypervisor, built with + real-time and safety-criticality in mind. It is built for embedded + IOT with small footprint and real-time features. More details can be + found in https://projectacrn.org/. + +config INTEL_TDX_GUEST + bool "Intel TDX (Trust Domain Extensions) - Guest Support" + depends on X86_64 && CPU_SUP_INTEL + depends on X86_X2APIC + depends on EFI_STUB + select ARCH_HAS_CC_PLATFORM + select X86_MEM_ENCRYPT + select X86_MCE + select UNACCEPTED_MEMORY + help + Support running as a guest under Intel TDX. Without this support, + the guest kernel can not boot or run under TDX. + TDX includes memory encryption and integrity capabilities + which protect the confidentiality and integrity of guest + memory contents and CPU state. TDX guests are protected from + some attacks from the VMM. + +endif # HYPERVISOR_GUEST + +source "arch/x86/Kconfig.cpu" + +config HPET_TIMER + def_bool X86_64 + prompt "HPET Timer Support" if X86_32 + help + Use the IA-PC HPET (High Precision Event Timer) to manage + time in preference to the PIT and RTC, if a HPET is + present. + HPET is the next generation timer replacing legacy 8254s. + The HPET provides a stable time base on SMP + systems, unlike the TSC, but it is more expensive to access, + as it is off-chip. The interface used is documented + in the HPET spec, revision 1. + + You can safely choose Y here. However, HPET will only be + activated if the platform and the BIOS support this feature. + Otherwise the 8254 will be used for timing services. + + Choose N to continue using the legacy 8254 timer. + +config HPET_EMULATE_RTC + def_bool y + depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) + +# Mark as expert because too many people got it wrong. +# The code disables itself when not needed. +config DMI + default y + select DMI_SCAN_MACHINE_NON_EFI_FALLBACK + bool "Enable DMI scanning" if EXPERT + help + Enabled scanning of DMI to identify machine quirks. Say Y + here unless you have verified that your setup is not + affected by entries in the DMI blacklist. Required by PNP + BIOS code. + +config GART_IOMMU + bool "Old AMD GART IOMMU support" + select DMA_OPS + select IOMMU_HELPER + select SWIOTLB + depends on X86_64 && PCI && AMD_NB + help + Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron + GART based hardware IOMMUs. + + The GART supports full DMA access for devices with 32-bit access + limitations, on systems with more than 3 GB. This is usually needed + for USB, sound, many IDE/SATA chipsets and some other devices. + + Newer systems typically have a modern AMD IOMMU, supported via + the CONFIG_AMD_IOMMU=y config option. + + In normal configurations this driver is only active when needed: + there's more than 3 GB of memory and the system contains a + 32-bit limited device. + + If unsure, say Y. + +config BOOT_VESA_SUPPORT + bool + help + If true, at least one selected framebuffer driver can take advantage + of VESA video modes set at an early boot stage via the vga= parameter. + +config MAXSMP + bool "Enable Maximum number of SMP Processors and NUMA Nodes" + depends on X86_64 && SMP && DEBUG_KERNEL + select CPUMASK_OFFSTACK + help + Enable maximum number of CPUS and NUMA Nodes for this architecture. + If unsure, say N. + +# +# The maximum number of CPUs supported: +# +# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, +# and which can be configured interactively in the +# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. +# +# The ranges are different on 32-bit and 64-bit kernels, depending on +# hardware capabilities and scalability features of the kernel. +# +# ( If MAXSMP is enabled we just use the highest possible value and disable +# interactive configuration. ) +# + +config NR_CPUS_RANGE_BEGIN + int + default NR_CPUS_RANGE_END if MAXSMP + default 1 if !SMP + default 2 + +config NR_CPUS_RANGE_END + int + depends on X86_32 + default 64 if SMP && X86_BIGSMP + default 8 if SMP && !X86_BIGSMP + default 1 if !SMP + +config NR_CPUS_RANGE_END + int + depends on X86_64 + default 8192 if SMP && CPUMASK_OFFSTACK + default 512 if SMP && !CPUMASK_OFFSTACK + default 1 if !SMP + +config NR_CPUS_DEFAULT + int + depends on X86_32 + default 32 if X86_BIGSMP + default 8 if SMP + default 1 if !SMP + +config NR_CPUS_DEFAULT + int + depends on X86_64 + default 8192 if MAXSMP + default 64 if SMP + default 1 if !SMP + +config NR_CPUS + int "Maximum number of CPUs" if SMP && !MAXSMP + range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END + default NR_CPUS_DEFAULT + help + This allows you to specify the maximum number of CPUs which this + kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum + supported value is 8192, otherwise the maximum value is 512. The + minimum value which makes sense is 2. + + This is purely to save memory: each supported CPU adds about 8KB + to the kernel image. + +config SCHED_CLUSTER + bool "Cluster scheduler support" + depends on SMP + default y + help + Cluster scheduler support improves the CPU scheduler's decision + making when dealing with machines that have clusters of CPUs. + Cluster usually means a couple of CPUs which are placed closely + by sharing mid-level caches, last-level cache tags or internal + busses. + +config SCHED_SMT + def_bool y if SMP + +config SCHED_MC + def_bool y + prompt "Multi-core scheduler support" + depends on SMP + help + Multi-core scheduler support improves the CPU scheduler's decision + making when dealing with multi-core CPU chips at a cost of slightly + increased overhead in some places. If unsure say N here. + +config SCHED_MC_PRIO + bool "CPU core priorities scheduler support" + depends on SCHED_MC && CPU_SUP_INTEL + select X86_INTEL_PSTATE + select CPU_FREQ + default y + help + Intel Turbo Boost Max Technology 3.0 enabled CPUs have a + core ordering determined at manufacturing time, which allows + certain cores to reach higher turbo frequencies (when running + single threaded workloads) than others. + + Enabling this kernel feature teaches the scheduler about + the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the + scheduler's CPU selection logic accordingly, so that higher + overall system performance can be achieved. + + This feature will have no effect on CPUs without this feature. + + If unsure say Y here. + +config UP_LATE_INIT + def_bool y + depends on !SMP && X86_LOCAL_APIC + +config X86_UP_APIC + bool "Local APIC support on uniprocessors" if !PCI_MSI + default PCI_MSI + depends on X86_32 && !SMP && !X86_32_NON_STANDARD + help + A local APIC (Advanced Programmable Interrupt Controller) is an + integrated interrupt controller in the CPU. If you have a single-CPU + system which has a processor with a local APIC, you can say Y here to + enable and use it. If you say Y here even though your machine doesn't + have a local APIC, then the kernel will still run with no slowdown at + all. The local APIC supports CPU-generated self-interrupts (timer, + performance counters), and the NMI watchdog which detects hard + lockups. + +config X86_UP_IOAPIC + bool "IO-APIC support on uniprocessors" + depends on X86_UP_APIC + help + An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an + SMP-capable replacement for PC-style interrupt controllers. Most + SMP systems and many recent uniprocessor systems have one. + + If you have a single-CPU system with an IO-APIC, you can say Y here + to use it. If you say Y here even though your machine doesn't have + an IO-APIC, then the kernel will still run with no slowdown at all. + +config X86_LOCAL_APIC + def_bool y + depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI + select IRQ_DOMAIN_HIERARCHY + +config X86_IO_APIC + def_bool y + depends on X86_LOCAL_APIC || X86_UP_IOAPIC + +config X86_REROUTE_FOR_BROKEN_BOOT_IRQS + bool "Reroute for broken boot IRQs" + depends on X86_IO_APIC + help + This option enables a workaround that fixes a source of + spurious interrupts. This is recommended when threaded + interrupt handling is used on systems where the generation of + superfluous "boot interrupts" cannot be disabled. + + Some chipsets generate a legacy INTx "boot IRQ" when the IRQ + entry in the chipset's IO-APIC is masked (as, e.g. the RT + kernel does during interrupt handling). On chipsets where this + boot IRQ generation cannot be disabled, this workaround keeps + the original IRQ line masked so that only the equivalent "boot + IRQ" is delivered to the CPUs. The workaround also tells the + kernel to set up the IRQ handler on the boot IRQ line. In this + way only one interrupt is delivered to the kernel. Otherwise + the spurious second interrupt may cause the kernel to bring + down (vital) interrupt lines. + + Only affects "broken" chipsets. Interrupt sharing may be + increased on these systems. + +config X86_MCE + bool "Machine Check / overheating reporting" + select GENERIC_ALLOCATOR + default y + help + Machine Check support allows the processor to notify the + kernel if it detects a problem (e.g. overheating, data corruption). + The action the kernel takes depends on the severity of the problem, + ranging from warning messages to halting the machine. + +config X86_MCELOG_LEGACY + bool "Support for deprecated /dev/mcelog character device" + depends on X86_MCE + help + Enable support for /dev/mcelog which is needed by the old mcelog + userspace logging daemon. Consider switching to the new generation + rasdaemon solution. + +config X86_MCE_INTEL + def_bool y + prompt "Intel MCE features" + depends on X86_MCE && X86_LOCAL_APIC + help + Additional support for intel specific MCE features such as + the thermal monitor. + +config X86_MCE_AMD + def_bool y + prompt "AMD MCE features" + depends on X86_MCE && X86_LOCAL_APIC && AMD_NB + help + Additional support for AMD specific MCE features such as + the DRAM Error Threshold. + +config X86_ANCIENT_MCE + bool "Support for old Pentium 5 / WinChip machine checks" + depends on X86_32 && X86_MCE + help + Include support for machine check handling on old Pentium 5 or WinChip + systems. These typically need to be enabled explicitly on the command + line. + +config X86_MCE_THRESHOLD + depends on X86_MCE_AMD || X86_MCE_INTEL + def_bool y + +config X86_MCE_INJECT + depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS + tristate "Machine check injector support" + help + Provide support for injecting machine checks for testing purposes. + If you don't know what a machine check is and you don't do kernel + QA it is safe to say n. + +source "arch/x86/events/Kconfig" + +config X86_LEGACY_VM86 + bool "Legacy VM86 support" + depends on X86_32 + help + This option allows user programs to put the CPU into V8086 + mode, which is an 80286-era approximation of 16-bit real mode. + + Some very old versions of X and/or vbetool require this option + for user mode setting. Similarly, DOSEMU will use it if + available to accelerate real mode DOS programs. However, any + recent version of DOSEMU, X, or vbetool should be fully + functional even without kernel VM86 support, as they will all + fall back to software emulation. Nevertheless, if you are using + a 16-bit DOS program where 16-bit performance matters, vm86 + mode might be faster than emulation and you might want to + enable this option. + + Note that any app that works on a 64-bit kernel is unlikely to + need this option, as 64-bit kernels don't, and can't, support + V8086 mode. This option is also unrelated to 16-bit protected + mode and is not needed to run most 16-bit programs under Wine. + + Enabling this option increases the complexity of the kernel + and slows down exception handling a tiny bit. + + If unsure, say N here. + +config VM86 + bool + default X86_LEGACY_VM86 + +config X86_16BIT + bool "Enable support for 16-bit segments" if EXPERT + default y + depends on MODIFY_LDT_SYSCALL + help + This option is required by programs like Wine to run 16-bit + protected mode legacy code on x86 processors. Disabling + this option saves about 300 bytes on i386, or around 6K text + plus 16K runtime memory on x86-64, + +config X86_ESPFIX32 + def_bool y + depends on X86_16BIT && X86_32 + +config X86_ESPFIX64 + def_bool y + depends on X86_16BIT && X86_64 + +config X86_VSYSCALL_EMULATION + bool "Enable vsyscall emulation" if EXPERT + default y + depends on X86_64 + help + This enables emulation of the legacy vsyscall page. Disabling + it is roughly equivalent to booting with vsyscall=none, except + that it will also disable the helpful warning if a program + tries to use a vsyscall. With this option set to N, offending + programs will just segfault, citing addresses of the form + 0xffffffffff600?00. + + This option is required by many programs built before 2013, and + care should be used even with newer programs if set to N. + + Disabling this option saves about 7K of kernel size and + possibly 4K of additional runtime pagetable memory. + +config X86_IOPL_IOPERM + bool "IOPERM and IOPL Emulation" + default y + help + This enables the ioperm() and iopl() syscalls which are necessary + for legacy applications. + + Legacy IOPL support is an overbroad mechanism which allows user + space aside of accessing all 65536 I/O ports also to disable + interrupts. To gain this access the caller needs CAP_SYS_RAWIO + capabilities and permission from potentially active security + modules. + + The emulation restricts the functionality of the syscall to + only allowing the full range I/O port access, but prevents the + ability to disable interrupts from user space which would be + granted if the hardware IOPL mechanism would be used. + +config TOSHIBA + tristate "Toshiba Laptop support" + depends on X86_32 + help + This adds a driver to safely access the System Management Mode of + the CPU on Toshiba portables with a genuine Toshiba BIOS. It does + not work on models with a Phoenix BIOS. The System Management Mode + is used to set the BIOS and power saving options on Toshiba portables. + + For information on utilities to make use of this driver see the + Toshiba Linux utilities web site at: + <http://www.buzzard.org.uk/toshiba/>. + + Say Y if you intend to run this kernel on a Toshiba portable. + Say N otherwise. + +config X86_REBOOTFIXUPS + bool "Enable X86 board specific fixups for reboot" + depends on X86_32 + help + This enables chipset and/or board specific fixups to be done + in order to get reboot to work correctly. This is only needed on + some combinations of hardware and BIOS. The symptom, for which + this config is intended, is when reboot ends with a stalled/hung + system. + + Currently, the only fixup is for the Geode machines using + CS5530A and CS5536 chipsets and the RDC R-321x SoC. + + Say Y if you want to enable the fixup. Currently, it's safe to + enable this option even if you don't need it. + Say N otherwise. + +config MICROCODE + def_bool y + depends on CPU_SUP_AMD || CPU_SUP_INTEL + +config MICROCODE_LATE_LOADING + bool "Late microcode loading (DANGEROUS)" + default n + depends on MICROCODE + help + Loading microcode late, when the system is up and executing instructions + is a tricky business and should be avoided if possible. Just the sequence + of synchronizing all cores and SMT threads is one fragile dance which does + not guarantee that cores might not softlock after the loading. Therefore, + use this at your own risk. Late loading taints the kernel too. + +config X86_MSR + tristate "/dev/cpu/*/msr - Model-specific register support" + help + This device gives privileged processes access to the x86 + Model-Specific Registers (MSRs). It is a character device with + major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. + MSR accesses are directed to a specific CPU on multi-processor + systems. + +config X86_CPUID + tristate "/dev/cpu/*/cpuid - CPU information support" + help + This device gives processes access to the x86 CPUID instruction to + be executed on a specific processor. It is a character device + with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to + /dev/cpu/31/cpuid. + +choice + prompt "High Memory Support" + default HIGHMEM4G + depends on X86_32 + +config NOHIGHMEM + bool "off" + help + Linux can use up to 64 Gigabytes of physical memory on x86 systems. + However, the address space of 32-bit x86 processors is only 4 + Gigabytes large. That means that, if you have a large amount of + physical memory, not all of it can be "permanently mapped" by the + kernel. The physical memory that's not permanently mapped is called + "high memory". + + If you are compiling a kernel which will never run on a machine with + more than 1 Gigabyte total physical RAM, answer "off" here (default + choice and suitable for most users). This will result in a "3GB/1GB" + split: 3GB are mapped so that each process sees a 3GB virtual memory + space and the remaining part of the 4GB virtual memory space is used + by the kernel to permanently map as much physical memory as + possible. + + If the machine has between 1 and 4 Gigabytes physical RAM, then + answer "4GB" here. + + If more than 4 Gigabytes is used then answer "64GB" here. This + selection turns Intel PAE (Physical Address Extension) mode on. + PAE implements 3-level paging on IA32 processors. PAE is fully + supported by Linux, PAE mode is implemented on all recent Intel + processors (Pentium Pro and better). NOTE: If you say "64GB" here, + then the kernel will not boot on CPUs that don't support PAE! + + The actual amount of total physical memory will either be + auto detected or can be forced by using a kernel command line option + such as "mem=256M". (Try "man bootparam" or see the documentation of + your boot loader (lilo or loadlin) about how to pass options to the + kernel at boot time.) + + If unsure, say "off". + +config HIGHMEM4G + bool "4GB" + help + Select this if you have a 32-bit processor and between 1 and 4 + gigabytes of physical RAM. + +config HIGHMEM64G + bool "64GB" + depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 + select X86_PAE + help + Select this if you have a 32-bit processor and more than 4 + gigabytes of physical RAM. + +endchoice + +choice + prompt "Memory split" if EXPERT + default VMSPLIT_3G + depends on X86_32 + help + Select the desired split between kernel and user memory. + + If the address range available to the kernel is less than the + physical memory installed, the remaining memory will be available + as "high memory". Accessing high memory is a little more costly + than low memory, as it needs to be mapped into the kernel first. + Note that increasing the kernel address space limits the range + available to user programs, making the address space there + tighter. Selecting anything other than the default 3G/1G split + will also likely make your kernel incompatible with binary-only + kernel modules. + + If you are not absolutely sure what you are doing, leave this + option alone! + + config VMSPLIT_3G + bool "3G/1G user/kernel split" + config VMSPLIT_3G_OPT + depends on !X86_PAE + bool "3G/1G user/kernel split (for full 1G low memory)" + config VMSPLIT_2G + bool "2G/2G user/kernel split" + config VMSPLIT_2G_OPT + depends on !X86_PAE + bool "2G/2G user/kernel split (for full 2G low memory)" + config VMSPLIT_1G + bool "1G/3G user/kernel split" +endchoice + +config PAGE_OFFSET + hex + default 0xB0000000 if VMSPLIT_3G_OPT + default 0x80000000 if VMSPLIT_2G + default 0x78000000 if VMSPLIT_2G_OPT + default 0x40000000 if VMSPLIT_1G + default 0xC0000000 + depends on X86_32 + +config HIGHMEM + def_bool y + depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) + +config X86_PAE + bool "PAE (Physical Address Extension) Support" + depends on X86_32 && !HIGHMEM4G + select PHYS_ADDR_T_64BIT + select SWIOTLB + help + PAE is required for NX support, and furthermore enables + larger swapspace support for non-overcommit purposes. It + has the cost of more pagetable lookup overhead, and also + consumes more pagetable space per process. + +config X86_5LEVEL + bool "Enable 5-level page tables support" + default y + select DYNAMIC_MEMORY_LAYOUT + select SPARSEMEM_VMEMMAP + depends on X86_64 + help + 5-level paging enables access to larger address space: + up to 128 PiB of virtual address space and 4 PiB of + physical address space. + + It will be supported by future Intel CPUs. + + A kernel with the option enabled can be booted on machines that + support 4- or 5-level paging. + + See Documentation/arch/x86/x86_64/5level-paging.rst for more + information. + + Say N if unsure. + +config X86_DIRECT_GBPAGES + def_bool y + depends on X86_64 + help + Certain kernel features effectively disable kernel + linear 1 GB mappings (even if the CPU otherwise + supports them), so don't confuse the user by printing + that we have them enabled. + +config X86_CPA_STATISTICS + bool "Enable statistic for Change Page Attribute" + depends on DEBUG_FS + help + Expose statistics about the Change Page Attribute mechanism, which + helps to determine the effectiveness of preserving large and huge + page mappings when mapping protections are changed. + +config X86_MEM_ENCRYPT + select ARCH_HAS_FORCE_DMA_UNENCRYPTED + select DYNAMIC_PHYSICAL_MASK + def_bool n + +config AMD_MEM_ENCRYPT + bool "AMD Secure Memory Encryption (SME) support" + depends on X86_64 && CPU_SUP_AMD + depends on EFI_STUB + select DMA_COHERENT_POOL + select ARCH_USE_MEMREMAP_PROT + select INSTRUCTION_DECODER + select ARCH_HAS_CC_PLATFORM + select X86_MEM_ENCRYPT + select UNACCEPTED_MEMORY + help + Say yes to enable support for the encryption of system memory. + This requires an AMD processor that supports Secure Memory + Encryption (SME). + +config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT + bool "Activate AMD Secure Memory Encryption (SME) by default" + depends on AMD_MEM_ENCRYPT + help + Say yes to have system memory encrypted by default if running on + an AMD processor that supports Secure Memory Encryption (SME). + + If set to Y, then the encryption of system memory can be + deactivated with the mem_encrypt=off command line option. + + If set to N, then the encryption of system memory can be + activated with the mem_encrypt=on command line option. + +# Common NUMA Features +config NUMA + bool "NUMA Memory Allocation and Scheduler Support" + depends on SMP + depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) + default y if X86_BIGSMP + select USE_PERCPU_NUMA_NODE_ID + help + Enable NUMA (Non-Uniform Memory Access) support. + + The kernel will try to allocate memory used by a CPU on the + local memory controller of the CPU and add some more + NUMA awareness to the kernel. + + For 64-bit this is recommended if the system is Intel Core i7 + (or later), AMD Opteron, or EM64T NUMA. + + For 32-bit this is only needed if you boot a 32-bit + kernel on a 64-bit NUMA platform. + + Otherwise, you should say N. + +config AMD_NUMA + def_bool y + prompt "Old style AMD Opteron NUMA detection" + depends on X86_64 && NUMA && PCI + help + Enable AMD NUMA node topology detection. You should say Y here if + you have a multi processor AMD system. This uses an old method to + read the NUMA configuration directly from the builtin Northbridge + of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, + which also takes priority if both are compiled in. + +config X86_64_ACPI_NUMA + def_bool y + prompt "ACPI NUMA detection" + depends on X86_64 && NUMA && ACPI && PCI + select ACPI_NUMA + help + Enable ACPI SRAT based node topology detection. + +config NUMA_EMU + bool "NUMA emulation" + depends on NUMA + help + Enable NUMA emulation. A flat machine will be split + into virtual nodes when booted with "numa=fake=N", where N is the + number of nodes. This is only useful for debugging. + +config NODES_SHIFT + int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP + range 1 10 + default "10" if MAXSMP + default "6" if X86_64 + default "3" + depends on NUMA + help + Specify the maximum number of NUMA Nodes available on the target + system. Increases memory reserved to accommodate various tables. + +config ARCH_FLATMEM_ENABLE + def_bool y + depends on X86_32 && !NUMA + +config ARCH_SPARSEMEM_ENABLE + def_bool y + depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD + select SPARSEMEM_STATIC if X86_32 + select SPARSEMEM_VMEMMAP_ENABLE if X86_64 + +config ARCH_SPARSEMEM_DEFAULT + def_bool X86_64 || (NUMA && X86_32) + +config ARCH_SELECT_MEMORY_MODEL + def_bool y + depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE + +config ARCH_MEMORY_PROBE + bool "Enable sysfs memory/probe interface" + depends on MEMORY_HOTPLUG + help + This option enables a sysfs memory/probe interface for testing. + See Documentation/admin-guide/mm/memory-hotplug.rst for more information. + If you are unsure how to answer this question, answer N. + +config ARCH_PROC_KCORE_TEXT + def_bool y + depends on X86_64 && PROC_KCORE + +config ILLEGAL_POINTER_VALUE + hex + default 0 if X86_32 + default 0xdead000000000000 if X86_64 + +config X86_PMEM_LEGACY_DEVICE + bool + +config X86_PMEM_LEGACY + tristate "Support non-standard NVDIMMs and ADR protected memory" + depends on PHYS_ADDR_T_64BIT + depends on BLK_DEV + select X86_PMEM_LEGACY_DEVICE + select NUMA_KEEP_MEMINFO if NUMA + select LIBNVDIMM + help + Treat memory marked using the non-standard e820 type of 12 as used + by the Intel Sandy Bridge-EP reference BIOS as protected memory. + The kernel will offer these regions to the 'pmem' driver so + they can be used for persistent storage. + + Say Y if unsure. + +config HIGHPTE + bool "Allocate 3rd-level pagetables from highmem" + depends on HIGHMEM + help + The VM uses one page table entry for each page of physical memory. + For systems with a lot of RAM, this can be wasteful of precious + low memory. Setting this option will put user-space page table + entries in high memory. + +config X86_CHECK_BIOS_CORRUPTION + bool "Check for low memory corruption" + help + Periodically check for memory corruption in low memory, which + is suspected to be caused by BIOS. Even when enabled in the + configuration, it is disabled at runtime. Enable it by + setting "memory_corruption_check=1" on the kernel command + line. By default it scans the low 64k of memory every 60 + seconds; see the memory_corruption_check_size and + memory_corruption_check_period parameters in + Documentation/admin-guide/kernel-parameters.rst to adjust this. + + When enabled with the default parameters, this option has + almost no overhead, as it reserves a relatively small amount + of memory and scans it infrequently. It both detects corruption + and prevents it from affecting the running system. + + It is, however, intended as a diagnostic tool; if repeatable + BIOS-originated corruption always affects the same memory, + you can use memmap= to prevent the kernel from using that + memory. + +config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK + bool "Set the default setting of memory_corruption_check" + depends on X86_CHECK_BIOS_CORRUPTION + default y + help + Set whether the default state of memory_corruption_check is + on or off. + +config MATH_EMULATION + bool + depends on MODIFY_LDT_SYSCALL + prompt "Math emulation" if X86_32 && (M486SX || MELAN) + help + Linux can emulate a math coprocessor (used for floating point + operations) if you don't have one. 486DX and Pentium processors have + a math coprocessor built in, 486SX and 386 do not, unless you added + a 487DX or 387, respectively. (The messages during boot time can + give you some hints here ["man dmesg"].) Everyone needs either a + coprocessor or this emulation. + + If you don't have a math coprocessor, you need to say Y here; if you + say Y here even though you have a coprocessor, the coprocessor will + be used nevertheless. (This behavior can be changed with the kernel + command line option "no387", which comes handy if your coprocessor + is broken. Try "man bootparam" or see the documentation of your boot + loader (lilo or loadlin) about how to pass options to the kernel at + boot time.) This means that it is a good idea to say Y here if you + intend to use this kernel on different machines. + + More information about the internals of the Linux math coprocessor + emulation can be found in <file:arch/x86/math-emu/README>. + + If you are not sure, say Y; apart from resulting in a 66 KB bigger + kernel, it won't hurt. + +config MTRR + def_bool y + prompt "MTRR (Memory Type Range Register) support" if EXPERT + help + On Intel P6 family processors (Pentium Pro, Pentium II and later) + the Memory Type Range Registers (MTRRs) may be used to control + processor access to memory ranges. This is most useful if you have + a video (VGA) card on a PCI or AGP bus. Enabling write-combining + allows bus write transfers to be combined into a larger transfer + before bursting over the PCI/AGP bus. This can increase performance + of image write operations 2.5 times or more. Saying Y here creates a + /proc/mtrr file which may be used to manipulate your processor's + MTRRs. Typically the X server should use this. + + This code has a reasonably generic interface so that similar + control registers on other processors can be easily supported + as well: + + The Cyrix 6x86, 6x86MX and M II processors have Address Range + Registers (ARRs) which provide a similar functionality to MTRRs. For + these, the ARRs are used to emulate the MTRRs. + The AMD K6-2 (stepping 8 and above) and K6-3 processors have two + MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing + write-combining. All of these processors are supported by this code + and it makes sense to say Y here if you have one of them. + + Saying Y here also fixes a problem with buggy SMP BIOSes which only + set the MTRRs for the boot CPU and not for the secondary CPUs. This + can lead to all sorts of problems, so it's good to say Y here. + + You can safely say Y even if your machine doesn't have MTRRs, you'll + just add about 9 KB to your kernel. + + See <file:Documentation/arch/x86/mtrr.rst> for more information. + +config MTRR_SANITIZER + def_bool y + prompt "MTRR cleanup support" + depends on MTRR + help + Convert MTRR layout from continuous to discrete, so X drivers can + add writeback entries. + + Can be disabled with disable_mtrr_cleanup on the kernel command line. + The largest mtrr entry size for a continuous block can be set with + mtrr_chunk_size. + + If unsure, say Y. + +config MTRR_SANITIZER_ENABLE_DEFAULT + int "MTRR cleanup enable value (0-1)" + range 0 1 + default "0" + depends on MTRR_SANITIZER + help + Enable mtrr cleanup default value + +config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT + int "MTRR cleanup spare reg num (0-7)" + range 0 7 + default "1" + depends on MTRR_SANITIZER + help + mtrr cleanup spare entries default, it can be changed via + mtrr_spare_reg_nr=N on the kernel command line. + +config X86_PAT + def_bool y + prompt "x86 PAT support" if EXPERT + depends on MTRR + help + Use PAT attributes to setup page level cache control. + + PATs are the modern equivalents of MTRRs and are much more + flexible than MTRRs. + + Say N here if you see bootup problems (boot crash, boot hang, + spontaneous reboots) or a non-working video driver. + + If unsure, say Y. + +config ARCH_USES_PG_UNCACHED + def_bool y + depends on X86_PAT + +config X86_UMIP + def_bool y + prompt "User Mode Instruction Prevention" if EXPERT + help + User Mode Instruction Prevention (UMIP) is a security feature in + some x86 processors. If enabled, a general protection fault is + issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are + executed in user mode. These instructions unnecessarily expose + information about the hardware state. + + The vast majority of applications do not use these instructions. + For the very few that do, software emulation is provided in + specific cases in protected and virtual-8086 modes. Emulated + results are dummy. + +config CC_HAS_IBT + # GCC >= 9 and binutils >= 2.29 + # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 + # Clang/LLVM >= 14 + # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f + # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 + def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ + (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ + $(as-instr,endbr64) + +config X86_CET + def_bool n + help + CET features configured (Shadow stack or IBT) + +config X86_KERNEL_IBT + prompt "Indirect Branch Tracking" + def_bool y + depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL + # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f + depends on !LD_IS_LLD || LLD_VERSION >= 140000 + select OBJTOOL + select X86_CET + help + Build the kernel with support for Indirect Branch Tracking, a + hardware support course-grain forward-edge Control Flow Integrity + protection. It enforces that all indirect calls must land on + an ENDBR instruction, as such, the compiler will instrument the + code with them to make this happen. + + In addition to building the kernel with IBT, seal all functions that + are not indirect call targets, avoiding them ever becoming one. + + This requires LTO like objtool runs and will slow down the build. It + does significantly reduce the number of ENDBR instructions in the + kernel image. + +config X86_INTEL_MEMORY_PROTECTION_KEYS + prompt "Memory Protection Keys" + def_bool y + # Note: only available in 64-bit mode + depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) + select ARCH_USES_HIGH_VMA_FLAGS + select ARCH_HAS_PKEYS + help + Memory Protection Keys provides a mechanism for enforcing + page-based protections, but without requiring modification of the + page tables when an application changes protection domains. + + For details, see Documentation/core-api/protection-keys.rst + + If unsure, say y. + +choice + prompt "TSX enable mode" + depends on CPU_SUP_INTEL + default X86_INTEL_TSX_MODE_OFF + help + Intel's TSX (Transactional Synchronization Extensions) feature + allows to optimize locking protocols through lock elision which + can lead to a noticeable performance boost. + + On the other hand it has been shown that TSX can be exploited + to form side channel attacks (e.g. TAA) and chances are there + will be more of those attacks discovered in the future. + + Therefore TSX is not enabled by default (aka tsx=off). An admin + might override this decision by tsx=on the command line parameter. + Even with TSX enabled, the kernel will attempt to enable the best + possible TAA mitigation setting depending on the microcode available + for the particular machine. + + This option allows to set the default tsx mode between tsx=on, =off + and =auto. See Documentation/admin-guide/kernel-parameters.txt for more + details. + + Say off if not sure, auto if TSX is in use but it should be used on safe + platforms or on if TSX is in use and the security aspect of tsx is not + relevant. + +config X86_INTEL_TSX_MODE_OFF + bool "off" + help + TSX is disabled if possible - equals to tsx=off command line parameter. + +config X86_INTEL_TSX_MODE_ON + bool "on" + help + TSX is always enabled on TSX capable HW - equals the tsx=on command + line parameter. + +config X86_INTEL_TSX_MODE_AUTO + bool "auto" + help + TSX is enabled on TSX capable HW that is believed to be safe against + side channel attacks- equals the tsx=auto command line parameter. +endchoice + +config X86_SGX + bool "Software Guard eXtensions (SGX)" + depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC + depends on CRYPTO=y + depends on CRYPTO_SHA256=y + select MMU_NOTIFIER + select NUMA_KEEP_MEMINFO if NUMA + select XARRAY_MULTI + help + Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions + that can be used by applications to set aside private regions of code + and data, referred to as enclaves. An enclave's private memory can + only be accessed by code running within the enclave. Accesses from + outside the enclave, including other enclaves, are disallowed by + hardware. + + If unsure, say N. + +config X86_USER_SHADOW_STACK + bool "X86 userspace shadow stack" + depends on AS_WRUSS + depends on X86_64 + select ARCH_USES_HIGH_VMA_FLAGS + select X86_CET + help + Shadow stack protection is a hardware feature that detects function + return address corruption. This helps mitigate ROP attacks. + Applications must be enabled to use it, and old userspace does not + get protection "for free". + + CPUs supporting shadow stacks were first released in 2020. + + See Documentation/arch/x86/shstk.rst for more information. + + If unsure, say N. + +config EFI + bool "EFI runtime service support" + depends on ACPI + select UCS2_STRING + select EFI_RUNTIME_WRAPPERS + select ARCH_USE_MEMREMAP_PROT + select EFI_RUNTIME_MAP if KEXEC_CORE + help + This enables the kernel to use EFI runtime services that are + available (such as the EFI variable services). + + This option is only useful on systems that have EFI firmware. + In addition, you should use the latest ELILO loader available + at <http://elilo.sourceforge.net> in order to take advantage + of EFI runtime services. However, even with this option, the + resultant kernel should continue to boot on existing non-EFI + platforms. + +config EFI_STUB + bool "EFI stub support" + depends on EFI + select RELOCATABLE + help + This kernel feature allows a bzImage to be loaded directly + by EFI firmware without the use of a bootloader. + + See Documentation/admin-guide/efi-stub.rst for more information. + +config EFI_HANDOVER_PROTOCOL + bool "EFI handover protocol (DEPRECATED)" + depends on EFI_STUB + default y + help + Select this in order to include support for the deprecated EFI + handover protocol, which defines alternative entry points into the + EFI stub. This is a practice that has no basis in the UEFI + specification, and requires a priori knowledge on the part of the + bootloader about Linux/x86 specific ways of passing the command line + and initrd, and where in memory those assets may be loaded. + + If in doubt, say Y. Even though the corresponding support is not + present in upstream GRUB or other bootloaders, most distros build + GRUB with numerous downstream patches applied, and may rely on the + handover protocol as as result. + +config EFI_MIXED + bool "EFI mixed-mode support" + depends on EFI_STUB && X86_64 + help + Enabling this feature allows a 64-bit kernel to be booted + on a 32-bit firmware, provided that your CPU supports 64-bit + mode. + + Note that it is not possible to boot a mixed-mode enabled + kernel via the EFI boot stub - a bootloader that supports + the EFI handover protocol must be used. + + If unsure, say N. + +config EFI_FAKE_MEMMAP + bool "Enable EFI fake memory map" + depends on EFI + help + Saying Y here will enable "efi_fake_mem" boot option. By specifying + this parameter, you can add arbitrary attribute to specific memory + range by updating original (firmware provided) EFI memmap. This is + useful for debugging of EFI memmap related feature, e.g., Address + Range Mirroring feature. + +config EFI_MAX_FAKE_MEM + int "maximum allowable number of ranges in efi_fake_mem boot option" + depends on EFI_FAKE_MEMMAP + range 1 128 + default 8 + help + Maximum allowable number of ranges in efi_fake_mem boot option. + Ranges can be set up to this value using comma-separated list. + The default value is 8. + +config EFI_RUNTIME_MAP + bool "Export EFI runtime maps to sysfs" if EXPERT + depends on EFI + help + Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. + That memory map is required by the 2nd kernel to set up EFI virtual + mappings after kexec, but can also be used for debugging purposes. + + See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. + +source "kernel/Kconfig.hz" + +config ARCH_SUPPORTS_KEXEC + def_bool y + +config ARCH_SUPPORTS_KEXEC_FILE + def_bool X86_64 + +config ARCH_SELECTS_KEXEC_FILE + def_bool y + depends on KEXEC_FILE + select HAVE_IMA_KEXEC if IMA + +config ARCH_SUPPORTS_KEXEC_PURGATORY + def_bool y + +config ARCH_SUPPORTS_KEXEC_SIG + def_bool y + +config ARCH_SUPPORTS_KEXEC_SIG_FORCE + def_bool y + +config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG + def_bool y + +config ARCH_SUPPORTS_KEXEC_JUMP + def_bool y + +config ARCH_SUPPORTS_CRASH_DUMP + def_bool X86_64 || (X86_32 && HIGHMEM) + +config ARCH_SUPPORTS_CRASH_HOTPLUG + def_bool y + +config PHYSICAL_START + hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) + default "0x1000000" + help + This gives the physical address where the kernel is loaded. + + If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then + bzImage will decompress itself to above physical address and + run from there. Otherwise, bzImage will run from the address where + it has been loaded by the boot loader and will ignore above physical + address. + + In normal kdump cases one does not have to set/change this option + as now bzImage can be compiled as a completely relocatable image + (CONFIG_RELOCATABLE=y) and be used to load and run from a different + address. This option is mainly useful for the folks who don't want + to use a bzImage for capturing the crash dump and want to use a + vmlinux instead. vmlinux is not relocatable hence a kernel needs + to be specifically compiled to run from a specific memory area + (normally a reserved region) and this option comes handy. + + So if you are using bzImage for capturing the crash dump, + leave the value here unchanged to 0x1000000 and set + CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux + for capturing the crash dump change this value to start of + the reserved region. In other words, it can be set based on + the "X" value as specified in the "crashkernel=YM@XM" + command line boot parameter passed to the panic-ed + kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst + for more details about crash dumps. + + Usage of bzImage for capturing the crash dump is recommended as + one does not have to build two kernels. Same kernel can be used + as production kernel and capture kernel. Above option should have + gone away after relocatable bzImage support is introduced. But it + is present because there are users out there who continue to use + vmlinux for dump capture. This option should go away down the + line. + + Don't change this unless you know what you are doing. + +config RELOCATABLE + bool "Build a relocatable kernel" + default y + help + This builds a kernel image that retains relocation information + so it can be loaded someplace besides the default 1MB. + The relocations tend to make the kernel binary about 10% larger, + but are discarded at runtime. + + One use is for the kexec on panic case where the recovery kernel + must live at a different physical address than the primary + kernel. + + Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address + it has been loaded at and the compile time physical address + (CONFIG_PHYSICAL_START) is used as the minimum location. + +config RANDOMIZE_BASE + bool "Randomize the address of the kernel image (KASLR)" + depends on RELOCATABLE + default y + help + In support of Kernel Address Space Layout Randomization (KASLR), + this randomizes the physical address at which the kernel image + is decompressed and the virtual address where the kernel + image is mapped, as a security feature that deters exploit + attempts relying on knowledge of the location of kernel + code internals. + + On 64-bit, the kernel physical and virtual addresses are + randomized separately. The physical address will be anywhere + between 16MB and the top of physical memory (up to 64TB). The + virtual address will be randomized from 16MB up to 1GB (9 bits + of entropy). Note that this also reduces the memory space + available to kernel modules from 1.5GB to 1GB. + + On 32-bit, the kernel physical and virtual addresses are + randomized together. They will be randomized from 16MB up to + 512MB (8 bits of entropy). + + Entropy is generated using the RDRAND instruction if it is + supported. If RDTSC is supported, its value is mixed into + the entropy pool as well. If neither RDRAND nor RDTSC are + supported, then entropy is read from the i8254 timer. The + usable entropy is limited by the kernel being built using + 2GB addressing, and that PHYSICAL_ALIGN must be at a + minimum of 2MB. As a result, only 10 bits of entropy are + theoretically possible, but the implementations are further + limited due to memory layouts. + + If unsure, say Y. + +# Relocation on x86 needs some additional build support +config X86_NEED_RELOCS + def_bool y + depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) + +config PHYSICAL_ALIGN + hex "Alignment value to which kernel should be aligned" + default "0x200000" + range 0x2000 0x1000000 if X86_32 + range 0x200000 0x1000000 if X86_64 + help + This value puts the alignment restrictions on physical address + where kernel is loaded and run from. Kernel is compiled for an + address which meets above alignment restriction. + + If bootloader loads the kernel at a non-aligned address and + CONFIG_RELOCATABLE is set, kernel will move itself to nearest + address aligned to above value and run from there. + + If bootloader loads the kernel at a non-aligned address and + CONFIG_RELOCATABLE is not set, kernel will ignore the run time + load address and decompress itself to the address it has been + compiled for and run from there. The address for which kernel is + compiled already meets above alignment restrictions. Hence the + end result is that kernel runs from a physical address meeting + above alignment restrictions. + + On 32-bit this value must be a multiple of 0x2000. On 64-bit + this value must be a multiple of 0x200000. + + Don't change this unless you know what you are doing. + +config DYNAMIC_MEMORY_LAYOUT + bool + help + This option makes base addresses of vmalloc and vmemmap as well as + __PAGE_OFFSET movable during boot. + +config RANDOMIZE_MEMORY + bool "Randomize the kernel memory sections" + depends on X86_64 + depends on RANDOMIZE_BASE + select DYNAMIC_MEMORY_LAYOUT + default RANDOMIZE_BASE + help + Randomizes the base virtual address of kernel memory sections + (physical memory mapping, vmalloc & vmemmap). This security feature + makes exploits relying on predictable memory locations less reliable. + + The order of allocations remains unchanged. Entropy is generated in + the same way as RANDOMIZE_BASE. Current implementation in the optimal + configuration have in average 30,000 different possible virtual + addresses for each memory section. + + If unsure, say Y. + +config RANDOMIZE_MEMORY_PHYSICAL_PADDING + hex "Physical memory mapping padding" if EXPERT + depends on RANDOMIZE_MEMORY + default "0xa" if MEMORY_HOTPLUG + default "0x0" + range 0x1 0x40 if MEMORY_HOTPLUG + range 0x0 0x40 + help + Define the padding in terabytes added to the existing physical + memory size during kernel memory randomization. It is useful + for memory hotplug support but reduces the entropy available for + address randomization. + + If unsure, leave at the default value. + +config ADDRESS_MASKING + bool "Linear Address Masking support" + depends on X86_64 + help + Linear Address Masking (LAM) modifies the checking that is applied + to 64-bit linear addresses, allowing software to use of the + untranslated address bits for metadata. + + The capability can be used for efficient address sanitizers (ASAN) + implementation and for optimizations in JITs. + +config HOTPLUG_CPU + def_bool y + depends on SMP + +config COMPAT_VDSO + def_bool n + prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" + depends on COMPAT_32 + help + Certain buggy versions of glibc will crash if they are + presented with a 32-bit vDSO that is not mapped at the address + indicated in its segment table. + + The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a + and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and + 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is + the only released version with the bug, but OpenSUSE 9 + contains a buggy "glibc 2.3.2". + + The symptom of the bug is that everything crashes on startup, saying: + dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! + + Saying Y here changes the default value of the vdso32 boot + option from 1 to 0, which turns off the 32-bit vDSO entirely. + This works around the glibc bug but hurts performance. + + If unsure, say N: if you are compiling your own kernel, you + are unlikely to be using a buggy version of glibc. + +choice + prompt "vsyscall table for legacy applications" + depends on X86_64 + default LEGACY_VSYSCALL_XONLY + help + Legacy user code that does not know how to find the vDSO expects + to be able to issue three syscalls by calling fixed addresses in + kernel space. Since this location is not randomized with ASLR, + it can be used to assist security vulnerability exploitation. + + This setting can be changed at boot time via the kernel command + line parameter vsyscall=[emulate|xonly|none]. Emulate mode + is deprecated and can only be enabled using the kernel command + line. + + On a system with recent enough glibc (2.14 or newer) and no + static binaries, you can say None without a performance penalty + to improve security. + + If unsure, select "Emulate execution only". + + config LEGACY_VSYSCALL_XONLY + bool "Emulate execution only" + help + The kernel traps and emulates calls into the fixed vsyscall + address mapping and does not allow reads. This + configuration is recommended when userspace might use the + legacy vsyscall area but support for legacy binary + instrumentation of legacy code is not needed. It mitigates + certain uses of the vsyscall area as an ASLR-bypassing + buffer. + + config LEGACY_VSYSCALL_NONE + bool "None" + help + There will be no vsyscall mapping at all. This will + eliminate any risk of ASLR bypass due to the vsyscall + fixed address mapping. Attempts to use the vsyscalls + will be reported to dmesg, so that either old or + malicious userspace programs can be identified. + +endchoice + +config CMDLINE_BOOL + bool "Built-in kernel command line" + help + Allow for specifying boot arguments to the kernel at + build time. On some systems (e.g. embedded ones), it is + necessary or convenient to provide some or all of the + kernel boot arguments with the kernel itself (that is, + to not rely on the boot loader to provide them.) + + To compile command line arguments into the kernel, + set this option to 'Y', then fill in the + boot arguments in CONFIG_CMDLINE. + + Systems with fully functional boot loaders (i.e. non-embedded) + should leave this option set to 'N'. + +config CMDLINE + string "Built-in kernel command string" + depends on CMDLINE_BOOL + default "" + help + Enter arguments here that should be compiled into the kernel + image and used at boot time. If the boot loader provides a + command line at boot time, it is appended to this string to + form the full kernel command line, when the system boots. + + However, you can use the CONFIG_CMDLINE_OVERRIDE option to + change this behavior. + + In most cases, the command line (whether built-in or provided + by the boot loader) should specify the device for the root + file system. + +config CMDLINE_OVERRIDE + bool "Built-in command line overrides boot loader arguments" + depends on CMDLINE_BOOL && CMDLINE != "" + help + Set this option to 'Y' to have the kernel ignore the boot loader + command line, and use ONLY the built-in command line. + + This is used to work around broken boot loaders. This should + be set to 'N' under normal conditions. + +config MODIFY_LDT_SYSCALL + bool "Enable the LDT (local descriptor table)" if EXPERT + default y + help + Linux can allow user programs to install a per-process x86 + Local Descriptor Table (LDT) using the modify_ldt(2) system + call. This is required to run 16-bit or segmented code such as + DOSEMU or some Wine programs. It is also used by some very old + threading libraries. + + Enabling this feature adds a small amount of overhead to + context switches and increases the low-level kernel attack + surface. Disabling it removes the modify_ldt(2) system call. + + Saying 'N' here may make sense for embedded or server kernels. + +config STRICT_SIGALTSTACK_SIZE + bool "Enforce strict size checking for sigaltstack" + depends on DYNAMIC_SIGFRAME + help + For historical reasons MINSIGSTKSZ is a constant which became + already too small with AVX512 support. Add a mechanism to + enforce strict checking of the sigaltstack size against the + real size of the FPU frame. This option enables the check + by default. It can also be controlled via the kernel command + line option 'strict_sas_size' independent of this config + switch. Enabling it might break existing applications which + allocate a too small sigaltstack but 'work' because they + never get a signal delivered. + + Say 'N' unless you want to really enforce this check. + +source "kernel/livepatch/Kconfig" + +endmenu + +config CC_HAS_SLS + def_bool $(cc-option,-mharden-sls=all) + +config CC_HAS_RETURN_THUNK + def_bool $(cc-option,-mfunction-return=thunk-extern) + +config CC_HAS_ENTRY_PADDING + def_bool $(cc-option,-fpatchable-function-entry=16,16) + +config FUNCTION_PADDING_CFI + int + default 59 if FUNCTION_ALIGNMENT_64B + default 27 if FUNCTION_ALIGNMENT_32B + default 11 if FUNCTION_ALIGNMENT_16B + default 3 if FUNCTION_ALIGNMENT_8B + default 0 + +# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG +# except Kconfig can't do arithmetic :/ +config FUNCTION_PADDING_BYTES + int + default FUNCTION_PADDING_CFI if CFI_CLANG + default FUNCTION_ALIGNMENT + +config CALL_PADDING + def_bool n + depends on CC_HAS_ENTRY_PADDING && OBJTOOL + select FUNCTION_ALIGNMENT_16B + +config FINEIBT + def_bool y + depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE + select CALL_PADDING + +config HAVE_CALL_THUNKS + def_bool y + depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL + +config CALL_THUNKS + def_bool n + select CALL_PADDING + +config PREFIX_SYMBOLS + def_bool y + depends on CALL_PADDING && !CFI_CLANG + +menuconfig SPECULATION_MITIGATIONS + bool "Mitigations for speculative execution vulnerabilities" + default y + help + Say Y here to enable options which enable mitigations for + speculative execution hardware vulnerabilities. + + If you say N, all mitigations will be disabled. You really + should know what you are doing to say so. + +if SPECULATION_MITIGATIONS + +config PAGE_TABLE_ISOLATION + bool "Remove the kernel mapping in user mode" + default y + depends on (X86_64 || X86_PAE) + help + This feature reduces the number of hardware side channels by + ensuring that the majority of kernel addresses are not mapped + into userspace. + + See Documentation/arch/x86/pti.rst for more details. + +config RETPOLINE + bool "Avoid speculative indirect branches in kernel" + select OBJTOOL if HAVE_OBJTOOL + default y + help + Compile kernel with the retpoline compiler options to guard against + kernel-to-user data leaks by avoiding speculative indirect + branches. Requires a compiler with -mindirect-branch=thunk-extern + support for full protection. The kernel may run slower. + +config RETHUNK + bool "Enable return-thunks" + depends on RETPOLINE && CC_HAS_RETURN_THUNK + select OBJTOOL if HAVE_OBJTOOL + default y if X86_64 + help + Compile the kernel with the return-thunks compiler option to guard + against kernel-to-user data leaks by avoiding return speculation. + Requires a compiler with -mfunction-return=thunk-extern + support for full protection. The kernel may run slower. + +config CPU_UNRET_ENTRY + bool "Enable UNRET on kernel entry" + depends on CPU_SUP_AMD && RETHUNK && X86_64 + default y + help + Compile the kernel with support for the retbleed=unret mitigation. + +config CALL_DEPTH_TRACKING + bool "Mitigate RSB underflow with call depth tracking" + depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS + select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE + select CALL_THUNKS + default y + help + Compile the kernel with call depth tracking to mitigate the Intel + SKL Return-Speculation-Buffer (RSB) underflow issue. The + mitigation is off by default and needs to be enabled on the + kernel command line via the retbleed=stuff option. For + non-affected systems the overhead of this option is marginal as + the call depth tracking is using run-time generated call thunks + in a compiler generated padding area and call patching. This + increases text size by ~5%. For non affected systems this space + is unused. On affected SKL systems this results in a significant + performance gain over the IBRS mitigation. + +config CALL_THUNKS_DEBUG + bool "Enable call thunks and call depth tracking debugging" + depends on CALL_DEPTH_TRACKING + select FUNCTION_ALIGNMENT_32B + default n + help + Enable call/ret counters for imbalance detection and build in + a noisy dmesg about callthunks generation and call patching for + trouble shooting. The debug prints need to be enabled on the + kernel command line with 'debug-callthunks'. + Only enable this when you are debugging call thunks as this + creates a noticeable runtime overhead. If unsure say N. + +config CPU_IBPB_ENTRY + bool "Enable IBPB on kernel entry" + depends on CPU_SUP_AMD && X86_64 + default y + help + Compile the kernel with support for the retbleed=ibpb mitigation. + +config CPU_IBRS_ENTRY + bool "Enable IBRS on kernel entry" + depends on CPU_SUP_INTEL && X86_64 + default y + help + Compile the kernel with support for the spectre_v2=ibrs mitigation. + This mitigates both spectre_v2 and retbleed at great cost to + performance. + +config CPU_SRSO + bool "Mitigate speculative RAS overflow on AMD" + depends on CPU_SUP_AMD && X86_64 && RETHUNK + default y + help + Enable the SRSO mitigation needed on AMD Zen1-4 machines. + +config SLS + bool "Mitigate Straight-Line-Speculation" + depends on CC_HAS_SLS && X86_64 + select OBJTOOL if HAVE_OBJTOOL + default n + help + Compile the kernel with straight-line-speculation options to guard + against straight line speculation. The kernel image might be slightly + larger. + +config GDS_FORCE_MITIGATION + bool "Force GDS Mitigation" + depends on CPU_SUP_INTEL + default n + help + Gather Data Sampling (GDS) is a hardware vulnerability which allows + unprivileged speculative access to data which was previously stored in + vector registers. + + This option is equivalent to setting gather_data_sampling=force on the + command line. The microcode mitigation is used if present, otherwise + AVX is disabled as a mitigation. On affected systems that are missing + the microcode any userspace code that unconditionally uses AVX will + break with this option set. + + Setting this option on systems not vulnerable to GDS has no effect. + + If in doubt, say N. + +endif + +config ARCH_HAS_ADD_PAGES + def_bool y + depends on ARCH_ENABLE_MEMORY_HOTPLUG + +menu "Power management and ACPI options" + +config ARCH_HIBERNATION_HEADER + def_bool y + depends on HIBERNATION + +source "kernel/power/Kconfig" + +source "drivers/acpi/Kconfig" + +config X86_APM_BOOT + def_bool y + depends on APM + +menuconfig APM + tristate "APM (Advanced Power Management) BIOS support" + depends on X86_32 && PM_SLEEP + help + APM is a BIOS specification for saving power using several different + techniques. This is mostly useful for battery powered laptops with + APM compliant BIOSes. If you say Y here, the system time will be + reset after a RESUME operation, the /proc/apm device will provide + battery status information, and user-space programs will receive + notification of APM "events" (e.g. battery status change). + + If you select "Y" here, you can disable actual use of the APM + BIOS by passing the "apm=off" option to the kernel at boot time. + + Note that the APM support is almost completely disabled for + machines with more than one CPU. + + In order to use APM, you will need supporting software. For location + and more information, read <file:Documentation/power/apm-acpi.rst> + and the Battery Powered Linux mini-HOWTO, available from + <http://www.tldp.org/docs.html#howto>. + + This driver does not spin down disk drives (see the hdparm(8) + manpage ("man 8 hdparm") for that), and it doesn't turn off + VESA-compliant "green" monitors. + + This driver does not support the TI 4000M TravelMate and the ACER + 486/DX4/75 because they don't have compliant BIOSes. Many "green" + desktop machines also don't have compliant BIOSes, and this driver + may cause those machines to panic during the boot phase. + + Generally, if you don't have a battery in your machine, there isn't + much point in using this driver and you should say N. If you get + random kernel OOPSes or reboots that don't seem to be related to + anything, try disabling/enabling this option (or disabling/enabling + APM in your BIOS). + + Some other things you should try when experiencing seemingly random, + "weird" problems: + + 1) make sure that you have enough swap space and that it is + enabled. + 2) pass the "idle=poll" option to the kernel + 3) switch on floating point emulation in the kernel and pass + the "no387" option to the kernel + 4) pass the "floppy=nodma" option to the kernel + 5) pass the "mem=4M" option to the kernel (thereby disabling + all but the first 4 MB of RAM) + 6) make sure that the CPU is not over clocked. + 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> + 8) disable the cache from your BIOS settings + 9) install a fan for the video card or exchange video RAM + 10) install a better fan for the CPU + 11) exchange RAM chips + 12) exchange the motherboard. + + To compile this driver as a module, choose M here: the + module will be called apm. + +if APM + +config APM_IGNORE_USER_SUSPEND + bool "Ignore USER SUSPEND" + help + This option will ignore USER SUSPEND requests. On machines with a + compliant APM BIOS, you want to say N. However, on the NEC Versa M + series notebooks, it is necessary to say Y because of a BIOS bug. + +config APM_DO_ENABLE + bool "Enable PM at boot time" + help + Enable APM features at boot time. From page 36 of the APM BIOS + specification: "When disabled, the APM BIOS does not automatically + power manage devices, enter the Standby State, enter the Suspend + State, or take power saving steps in response to CPU Idle calls." + This driver will make CPU Idle calls when Linux is idle (unless this + feature is turned off -- see "Do CPU IDLE calls", below). This + should always save battery power, but more complicated APM features + will be dependent on your BIOS implementation. You may need to turn + this option off if your computer hangs at boot time when using APM + support, or if it beeps continuously instead of suspending. Turn + this off if you have a NEC UltraLite Versa 33/C or a Toshiba + T400CDT. This is off by default since most machines do fine without + this feature. + +config APM_CPU_IDLE + depends on CPU_IDLE + bool "Make CPU Idle calls when idle" + help + Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. + On some machines, this can activate improved power savings, such as + a slowed CPU clock rate, when the machine is idle. These idle calls + are made after the idle loop has run for some length of time (e.g., + 333 mS). On some machines, this will cause a hang at boot time or + whenever the CPU becomes idle. (On machines with more than one CPU, + this option does nothing.) + +config APM_DISPLAY_BLANK + bool "Enable console blanking using APM" + help + Enable console blanking using the APM. Some laptops can use this to + turn off the LCD backlight when the screen blanker of the Linux + virtual console blanks the screen. Note that this is only used by + the virtual console screen blanker, and won't turn off the backlight + when using the X Window system. This also doesn't have anything to + do with your VESA-compliant power-saving monitor. Further, this + option doesn't work for all laptops -- it might not turn off your + backlight at all, or it might print a lot of errors to the console, + especially if you are using gpm. + +config APM_ALLOW_INTS + bool "Allow interrupts during APM BIOS calls" + help + Normally we disable external interrupts while we are making calls to + the APM BIOS as a measure to lessen the effects of a badly behaving + BIOS implementation. The BIOS should reenable interrupts if it + needs to. Unfortunately, some BIOSes do not -- especially those in + many of the newer IBM Thinkpads. If you experience hangs when you + suspend, try setting this to Y. Otherwise, say N. + +endif # APM + +source "drivers/cpufreq/Kconfig" + +source "drivers/cpuidle/Kconfig" + +source "drivers/idle/Kconfig" + +endmenu + +menu "Bus options (PCI etc.)" + +choice + prompt "PCI access mode" + depends on X86_32 && PCI + default PCI_GOANY + help + On PCI systems, the BIOS can be used to detect the PCI devices and + determine their configuration. However, some old PCI motherboards + have BIOS bugs and may crash if this is done. Also, some embedded + PCI-based systems don't have any BIOS at all. Linux can also try to + detect the PCI hardware directly without using the BIOS. + + With this option, you can specify how Linux should detect the + PCI devices. If you choose "BIOS", the BIOS will be used, + if you choose "Direct", the BIOS won't be used, and if you + choose "MMConfig", then PCI Express MMCONFIG will be used. + If you choose "Any", the kernel will try MMCONFIG, then the + direct access method and falls back to the BIOS if that doesn't + work. If unsure, go with the default, which is "Any". + +config PCI_GOBIOS + bool "BIOS" + +config PCI_GOMMCONFIG + bool "MMConfig" + +config PCI_GODIRECT + bool "Direct" + +config PCI_GOOLPC + bool "OLPC XO-1" + depends on OLPC + +config PCI_GOANY + bool "Any" + +endchoice + +config PCI_BIOS + def_bool y + depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) + +# x86-64 doesn't support PCI BIOS access from long mode so always go direct. +config PCI_DIRECT + def_bool y + depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) + +config PCI_MMCONFIG + bool "Support mmconfig PCI config space access" if X86_64 + default y + depends on PCI && (ACPI || JAILHOUSE_GUEST) + depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) + +config PCI_OLPC + def_bool y + depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) + +config PCI_XEN + def_bool y + depends on PCI && XEN + +config MMCONF_FAM10H + def_bool y + depends on X86_64 && PCI_MMCONFIG && ACPI + +config PCI_CNB20LE_QUIRK + bool "Read CNB20LE Host Bridge Windows" if EXPERT + depends on PCI + help + Read the PCI windows out of the CNB20LE host bridge. This allows + PCI hotplug to work on systems with the CNB20LE chipset which do + not have ACPI. + + There's no public spec for this chipset, and this functionality + is known to be incomplete. + + You should say N unless you know you need this. + +config ISA_BUS + bool "ISA bus support on modern systems" if EXPERT + help + Expose ISA bus device drivers and options available for selection and + configuration. Enable this option if your target machine has an ISA + bus. ISA is an older system, displaced by PCI and newer bus + architectures -- if your target machine is modern, it probably does + not have an ISA bus. + + If unsure, say N. + +# x86_64 have no ISA slots, but can have ISA-style DMA. +config ISA_DMA_API + bool "ISA-style DMA support" if (X86_64 && EXPERT) + default y + help + Enables ISA-style DMA support for devices requiring such controllers. + If unsure, say Y. + +if X86_32 + +config ISA + bool "ISA support" + help + Find out whether you have ISA slots on your motherboard. ISA is the + name of a bus system, i.e. the way the CPU talks to the other stuff + inside your box. Other bus systems are PCI, EISA, MicroChannel + (MCA) or VESA. ISA is an older system, now being displaced by PCI; + newer boards don't support it. If you have ISA, say Y, otherwise N. + +config SCx200 + tristate "NatSemi SCx200 support" + help + This provides basic support for National Semiconductor's + (now AMD's) Geode processors. The driver probes for the + PCI-IDs of several on-chip devices, so its a good dependency + for other scx200_* drivers. + + If compiled as a module, the driver is named scx200. + +config SCx200HR_TIMER + tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" + depends on SCx200 + default y + help + This driver provides a clocksource built upon the on-chip + 27MHz high-resolution timer. Its also a workaround for + NSC Geode SC-1100's buggy TSC, which loses time when the + processor goes idle (as is done by the scheduler). The + other workaround is idle=poll boot option. + +config OLPC + bool "One Laptop Per Child support" + depends on !X86_PAE + select GPIOLIB + select OF + select OF_PROMTREE + select IRQ_DOMAIN + select OLPC_EC + help + Add support for detecting the unique features of the OLPC + XO hardware. + +config OLPC_XO1_PM + bool "OLPC XO-1 Power Management" + depends on OLPC && MFD_CS5535=y && PM_SLEEP + help + Add support for poweroff and suspend of the OLPC XO-1 laptop. + +config OLPC_XO1_RTC + bool "OLPC XO-1 Real Time Clock" + depends on OLPC_XO1_PM && RTC_DRV_CMOS + help + Add support for the XO-1 real time clock, which can be used as a + programmable wakeup source. + +config OLPC_XO1_SCI + bool "OLPC XO-1 SCI extras" + depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y + depends on INPUT=y + select POWER_SUPPLY + help + Add support for SCI-based features of the OLPC XO-1 laptop: + - EC-driven system wakeups + - Power button + - Ebook switch + - Lid switch + - AC adapter status updates + - Battery status updates + +config OLPC_XO15_SCI + bool "OLPC XO-1.5 SCI extras" + depends on OLPC && ACPI + select POWER_SUPPLY + help + Add support for SCI-based features of the OLPC XO-1.5 laptop: + - EC-driven system wakeups + - AC adapter status updates + - Battery status updates + +config ALIX + bool "PCEngines ALIX System Support (LED setup)" + select GPIOLIB + help + This option enables system support for the PCEngines ALIX. + At present this just sets up LEDs for GPIO control on + ALIX2/3/6 boards. However, other system specific setup should + get added here. + + Note: You must still enable the drivers for GPIO and LED support + (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs + + Note: You have to set alix.force=1 for boards with Award BIOS. + +config NET5501 + bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" + select GPIOLIB + help + This option enables system support for the Soekris Engineering net5501. + +config GEOS + bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" + select GPIOLIB + depends on DMI + help + This option enables system support for the Traverse Technologies GEOS. + +config TS5500 + bool "Technologic Systems TS-5500 platform support" + depends on MELAN + select CHECK_SIGNATURE + select NEW_LEDS + select LEDS_CLASS + help + This option enables system support for the Technologic Systems TS-5500. + +endif # X86_32 + +config AMD_NB + def_bool y + depends on CPU_SUP_AMD && PCI + +endmenu + +menu "Binary Emulations" + +config IA32_EMULATION + bool "IA32 Emulation" + depends on X86_64 + select ARCH_WANT_OLD_COMPAT_IPC + select BINFMT_ELF + select COMPAT_OLD_SIGACTION + help + Include code to run legacy 32-bit programs under a + 64-bit kernel. You should likely turn this on, unless you're + 100% sure that you don't have any 32-bit programs left. + +config X86_X32_ABI + bool "x32 ABI for 64-bit mode" + depends on X86_64 + # llvm-objcopy does not convert x86_64 .note.gnu.property or + # compressed debug sections to x86_x32 properly: + # https://github.com/ClangBuiltLinux/linux/issues/514 + # https://github.com/ClangBuiltLinux/linux/issues/1141 + depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) + help + Include code to run binaries for the x32 native 32-bit ABI + for 64-bit processors. An x32 process gets access to the + full 64-bit register file and wide data path while leaving + pointers at 32 bits for smaller memory footprint. + +config COMPAT_32 + def_bool y + depends on IA32_EMULATION || X86_32 + select HAVE_UID16 + select OLD_SIGSUSPEND3 + +config COMPAT + def_bool y + depends on IA32_EMULATION || X86_X32_ABI + +config COMPAT_FOR_U64_ALIGNMENT + def_bool y + depends on COMPAT + +endmenu + +config HAVE_ATOMIC_IOMAP + def_bool y + depends on X86_32 + +source "arch/x86/kvm/Kconfig" + +source "arch/x86/Kconfig.assembler" |