TOMOYO Linux Cross Reference
Linux/arch/x86/Kconfig

   # 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_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
          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
          select EXECMEM if DYNAMIC_FTRACE
  
  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 ACPI_HOTPLUG_CPU                 if ACPI_PROCESSOR && HOTPLUG_CPU
          select ARCH_32BIT_OFF_T                 if X86_32
          select ARCH_CLOCKSOURCE_INIT
          select ARCH_CONFIGURES_CPU_MITIGATIONS
          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_CPU_PASID               if IOMMU_SVA
          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_DMA_OPS                 if GART_IOMMU || XEN
          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_KERNEL_FPU_SUPPORT
          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_HW_PTE_YOUNG
          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
         select ARCH_HAS_DEBUG_WX
         select ARCH_HAS_ZONE_DMA_SET if EXPERT
         select ARCH_HAVE_NMI_SAFE_CMPXCHG
         select ARCH_HAVE_EXTRA_ELF_NOTES
         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_SUPPORTS_RT
         select ARCH_USE_BUILTIN_BSWAP
         select ARCH_USE_CMPXCHG_LOCKREF         if X86_CMPXCHG64
         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_BROADCAST_IDLE       if GENERIC_CLOCKEVENTS_BROADCAST
         select GENERIC_CLOCKEVENTS_MIN_ADJUST
         select GENERIC_CMOS_UPDATE
         select GENERIC_CPU_AUTOPROBE
         select GENERIC_CPU_DEVICES
         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 GENERIC_VDSO_OVERFLOW_PROTECT
         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
         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_GUP_FAST
         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_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_PAGE_SIZE_4KB
         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 VDSO_GETRANDOM                   if X86_64
         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 NUMA_MEMBLKS                     if NUMA
         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_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_POSTED_MSI
         bool "Enable MSI and MSI-x delivery by posted interrupts"
         depends on X86_64 && IRQ_REMAP
         help
           This enables MSIs that are under interrupt remapping to be delivered as
           posted interrupts to the host kernel. Interrupt throughput can
           potentially be improved by coalescing CPU notifications during high
           frequency bursts.
 
           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 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.
 
 config X86_FRED
         bool "Flexible Return and Event Delivery"
         depends on X86_64
         help
           When enabled, try to use Flexible Return and Event Delivery
           instead of the legacy SYSCALL/SYSENTER/IDT architecture for
           ring transitions and exception/interrupt handling if the
           system supports it.
 
 config X86_BIGSMP
         bool "Support for big SMP systems with more than 8 CPUs"
         depends on SMP && X86_32
         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 x86 platforms, depending on the value of
           CONFIG_64BIT.
 
           32-bit platforms (CONFIG_64BIT=n):
                 Goldfish (Android emulator)
                 AMD Elan
                 RDC R-321x SoC
                 SGI 320/540 (Visual Workstation)
                 STA2X11-based (e.g. Northville)
                 Moorestown MID devices
 
           64-bit platforms (CONFIG_64BIT=y):
                 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.
 
 # 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 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
         select X86_INTEL_PSTATE if CPU_SUP_INTEL
         select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
         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 ACPI_MADT_WAKEUP
         def_bool y
         depends on X86_64
         depends on ACPI
         depends on SMP
         depends on X86_LOCAL_APIC
 
 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_INITRD32
         def_bool y
         depends on MICROCODE && X86_32 && BLK_DEV_INITRD
 
 config MICROCODE_LATE_LOADING
         bool "Late microcode loading (DANGEROUS)"
         default n
         depends on MICROCODE && SMP
         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 unless the
           microcode header indicates that it is safe for late loading via the
           minimal revision check. This minimal revision check can be enforced on
           the kernel command line with "microcode.minrev=Y".
 
 config MICROCODE_LATE_FORCE_MINREV
         bool "Enforce late microcode loading minimal revision check"
         default n
         depends on MICROCODE_LATE_LOADING
         help
           To prevent that users load microcode late which modifies already
           in use features, newer microcode patches have a minimum revision field
           in the microcode header, which tells the kernel which minimum
           revision must be active in the CPU to safely load that new microcode
           late into the running system. If disabled the check will not
           be enforced but the kernel will be tainted when the minimal
           revision check fails.
 
           This minimal revision check can also be controlled via the
           "microcode.minrev" parameter on the kernel command line.
 
           If unsure say Y.
 
 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 X86_HAVE_PAE
         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 && X86_HAVE_PAE
         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).
 
 # 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
         select OF_NUMA if OF
         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 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
         select ARCH_USES_PG_ARCH_2
         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 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.
 
 config ARCH_PKEY_BITS
         int
         default 4
 
 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 INTEL_TDX_HOST
         bool "Intel Trust Domain Extensions (TDX) host support"
         depends on CPU_SUP_INTEL
         depends on X86_64
         depends on KVM_INTEL
         depends on X86_X2APIC
         select ARCH_KEEP_MEMBLOCK
         depends on CONTIG_ALLOC
         depends on !KEXEC_CORE
         depends on X86_MCE
         help
           Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
           host and certain physical attacks.  This option enables necessary TDX
           support in the host kernel to run confidential VMs.
 
           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_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 ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
         def_bool CRASH_RESERVE
 
 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 the kernel is 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. The only exception is if it is loaded below the
           above physical address, in which case it will relocate itself there.
 
           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
         depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
         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.
 
 config CFI_AUTO_DEFAULT
         bool "Attempt to use FineIBT by default at boot time"
         depends on FINEIBT
         default y
         help
           Attempt to use FineIBT by default at boot time. If enabled,
           this is the same as booting with "cfi=auto". If disabled,
           this is the same as booting with "cfi=kcfi".
 
 source "kernel/livepatch/Kconfig"
 
 endmenu
 
 config CC_HAS_NAMED_AS
         def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
         depends on CC_IS_GCC
 
 config CC_HAS_NAMED_AS_FIXED_SANITIZERS
         def_bool CC_IS_GCC && GCC_VERSION >= 130300
 
 config USE_X86_SEG_SUPPORT
         def_bool y
         depends on CC_HAS_NAMED_AS
         #
         # -fsanitize=kernel-address (KASAN) and -fsanitize=thread
         # (KCSAN) are incompatible with named address spaces with
         # GCC < 13.3 - see GCC PR sanitizer/111736.
         #
         depends on !(KASAN || KCSAN) || CC_HAS_NAMED_AS_FIXED_SANITIZERS
 
 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 && MITIGATION_RETPOLINE
         select CALL_PADDING
 
 config HAVE_CALL_THUNKS
         def_bool y
         depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
 
 config CALL_THUNKS
         def_bool n
         select CALL_PADDING
 
 config PREFIX_SYMBOLS
         def_bool y
         depends on CALL_PADDING && !CFI_CLANG
 
 menuconfig CPU_MITIGATIONS
         bool "Mitigations for CPU vulnerabilities"
         default y
         help
           Say Y here to enable options which enable mitigations for hardware
           vulnerabilities (usually related to speculative execution).
           Mitigations can be disabled or restricted to SMT systems at runtime
           via the "mitigations" kernel parameter.
 
           If you say N, all mitigations will be disabled.  This CANNOT be
           overridden at runtime.
 
           Say 'Y', unless you really know what you are doing.
 
 if CPU_MITIGATIONS
 
 config MITIGATION_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 MITIGATION_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 MITIGATION_RETHUNK
         bool "Enable return-thunks"
         depends on MITIGATION_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 MITIGATION_UNRET_ENTRY
         bool "Enable UNRET on kernel entry"
         depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
         default y
         help
           Compile the kernel with support for the retbleed=unret mitigation.
 
 config MITIGATION_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 MITIGATION_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 MITIGATION_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 MITIGATION_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 MITIGATION_SRSO
         bool "Mitigate speculative RAS overflow on AMD"
         depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
         default y
         help
           Enable the SRSO mitigation needed on AMD Zen1-4 machines.
 
 config MITIGATION_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 MITIGATION_GDS
         bool "Mitigate Gather Data Sampling"
         depends on CPU_SUP_INTEL
         default y
         help
           Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
           vulnerability which allows unprivileged speculative access to data
           which was previously stored in vector registers. The attacker uses gather
           instructions to infer the stale vector register data.
 
 config MITIGATION_RFDS
         bool "RFDS Mitigation"
         depends on CPU_SUP_INTEL
         default y
         help
           Enable mitigation for Register File Data Sampling (RFDS) by default.
           RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
           allows unprivileged speculative access to stale data previously
           stored in floating point, vector and integer registers.
           See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
 
 config MITIGATION_SPECTRE_BHI
         bool "Mitigate Spectre-BHB (Branch History Injection)"
         depends on CPU_SUP_INTEL
         default y
         help
           Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
           where the branch history buffer is poisoned to speculatively steer
           indirect branches.
           See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
 
 config MITIGATION_MDS
         bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
         depends on CPU_SUP_INTEL
         default y
         help
           Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
           a hardware vulnerability which allows unprivileged speculative access
           to data which is available in various CPU internal buffers.
           See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
 
 config MITIGATION_TAA
         bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
         depends on CPU_SUP_INTEL
         default y
         help
           Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
           vulnerability that allows unprivileged speculative access to data
           which is available in various CPU internal buffers by using
           asynchronous aborts within an Intel TSX transactional region.
           See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
 
 config MITIGATION_MMIO_STALE_DATA
         bool "Mitigate MMIO Stale Data hardware bug"
         depends on CPU_SUP_INTEL
         default y
         help
           Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
           Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
           vulnerabilities that can expose data. The vulnerabilities require the
           attacker to have access to MMIO.
           See also
           <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
 
 config MITIGATION_L1TF
         bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
         depends on CPU_SUP_INTEL
         default y
         help
           Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
           hardware vulnerability which allows unprivileged speculative access to data
           available in the Level 1 Data Cache.
           See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
 
 config MITIGATION_RETBLEED
         bool "Mitigate RETBleed hardware bug"
         depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
         default y
         help
           Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
           with Return Instructions) vulnerability.  RETBleed is a speculative
           execution attack which takes advantage of microarchitectural behavior
           in many modern microprocessors, similar to Spectre v2. An
           unprivileged attacker can use these flaws to bypass conventional
           memory security restrictions to gain read access to privileged memory
           that would otherwise be inaccessible.
 
 config MITIGATION_SPECTRE_V1
         bool "Mitigate SPECTRE V1 hardware bug"
         default y
         help
           Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
           class of side channel attacks that takes advantage of speculative
           execution that bypasses conditional branch instructions used for
           memory access bounds check.
           See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
 
 config MITIGATION_SPECTRE_V2
         bool "Mitigate SPECTRE V2 hardware bug"
         default y
         help
           Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
           V2 is a class of side channel attacks that takes advantage of
           indirect branch predictors inside the processor. In Spectre variant 2
           attacks, the attacker can steer speculative indirect branches in the
           victim to gadget code by poisoning the branch target buffer of a CPU
           used for predicting indirect branch addresses.
           See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
 
 config MITIGATION_SRBDS
         bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
         depends on CPU_SUP_INTEL
         default y
         help
           Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
           SRBDS is a hardware vulnerability that allows Microarchitectural Data
           Sampling (MDS) techniques to infer values returned from special
           register accesses. An unprivileged user can extract values returned
           from RDRAND and RDSEED executed on another core or sibling thread
           using MDS techniques.
           See also
           <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
 
 config MITIGATION_SSB
         bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
         default y
         help
           Enable mitigation for Speculative Store Bypass (SSB). SSB is a
           hardware security vulnerability and its exploitation takes advantage
           of speculative execution in a similar way to the Meltdown and Spectre
           security vulnerabilities.
 
 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 GEODE_COMMON
         bool
 
 config ALIX
         bool "PCEngines ALIX System Support (LED setup)"
         select GPIOLIB
         select GEODE_COMMON
         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
         select GEODE_COMMON
         help
           This option enables system support for the Soekris Engineering net5501.
 
 config GEOS
         bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
         select GPIOLIB
         select GEODE_COMMON
         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 IA32_EMULATION_DEFAULT_DISABLED
         bool "IA32 emulation disabled by default"
         default n
         depends on IA32_EMULATION
         help
           Make IA32 emulation disabled by default. This prevents loading 32-bit
           processes and access to 32-bit syscalls. If unsure, leave it to its
           default value.
 
 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"

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.