CONFIG_ARM is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_ARM (not configurable)

configname: CONFIG_ARM

Linux Kernel Configuration
└─>ARM
In linux kernel since version 2.6.12  
The ARM series is a line of low-power-consumption RISC chip designs
licensed by ARM Ltd and targeted at embedded applications and
handhelds such as the Compaq IPAQ. ARM-based PCs are no longer
manufactured, but legacy ARM-based PC hardware remains popular in
Europe. There is an ARM Linux project with a web page at
<http://www.arm.linux.org.uk/>.

selects
CONFIG_ARCH_32BIT_OFF_T
CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
CONFIG_ARCH_HAS_BINFMT_FLAT
CONFIG_ARCH_HAS_CPU_CACHE_ALIASING
CONFIG_ARCH_HAS_CPU_FINALIZE_INIT
CONFIG_ARCH_HAS_CURRENT_STACK_POINTER
CONFIG_ARCH_HAS_DEBUG_VIRTUAL
CONFIG_ARCH_HAS_DMA_ALLOC
CONFIG_ARCH_HAS_DMA_WRITE_COMBINE
CONFIG_ARCH_HAS_ELF_RANDOMIZE
CONFIG_ARCH_HAS_FORTIFY_SOURCE
CONFIG_ARCH_HAS_KEEPINITRD
CONFIG_ARCH_HAS_KCOV
CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE
CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
CONFIG_ARCH_HAS_PTE_SPECIAL
CONFIG_ARCH_HAS_SETUP_DMA_OPS
CONFIG_ARCH_HAS_SET_MEMORY
CONFIG_ARCH_STACKWALK
CONFIG_ARCH_HAS_STRICT_KERNEL_RWX
CONFIG_ARCH_HAS_STRICT_MODULE_RWX
CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE
CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
CONFIG_ARCH_HAS_TEARDOWN_DMA_OPS
CONFIG_ARCH_HAS_TICK_BROADCAST
CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
CONFIG_ARCH_HAS_GCOV_PROFILE_ALL
CONFIG_ARCH_KEEP_MEMBLOCK
CONFIG_ARCH_HAS_UBSAN
CONFIG_ARCH_MIGHT_HAVE_PC_PARPORT
CONFIG_ARCH_OPTIONAL_KERNEL_RWX
CONFIG_ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
CONFIG_ARCH_SUPPORTS_ATOMIC_RMW
CONFIG_ARCH_SUPPORTS_CFI_CLANG
CONFIG_ARCH_SUPPORTS_HUGETLBFS
CONFIG_ARCH_SUPPORTS_PER_VMA_LOCK
CONFIG_ARCH_USE_BUILTIN_BSWAP
CONFIG_ARCH_USE_CMPXCHG_LOCKREF
CONFIG_ARCH_USE_MEMTEST
CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
CONFIG_ARCH_WANT_GENERAL_HUGETLB
CONFIG_ARCH_WANT_IPC_PARSE_VERSION
CONFIG_ARCH_WANT_LD_ORPHAN_WARN
CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK
CONFIG_BUILDTIME_TABLE_SORT
CONFIG_COMMON_CLK
CONFIG_CLONE_BACKWARDS
CONFIG_CPU_PM
CONFIG_DCACHE_WORD_ACCESS
CONFIG_DMA_DECLARE_COHERENT
CONFIG_DMA_GLOBAL_POOL
CONFIG_DMA_OPS
CONFIG_DMA_NONCOHERENT_MMAP
CONFIG_EDAC_SUPPORT
CONFIG_EDAC_ATOMIC_SCRUB
CONFIG_GENERIC_ALLOCATOR
CONFIG_GENERIC_ARCH_TOPOLOGY
CONFIG_GENERIC_ATOMIC64
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
CONFIG_GENERIC_IRQ_IPI
CONFIG_GENERIC_CPU_AUTOPROBE
CONFIG_GENERIC_EARLY_IOREMAP
CONFIG_GENERIC_IDLE_POLL_SETUP
CONFIG_GENERIC_IRQ_MULTI_HANDLER
CONFIG_GENERIC_IRQ_PROBE
CONFIG_GENERIC_IRQ_SHOW
CONFIG_GENERIC_IRQ_SHOW_LEVEL
CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED
CONFIG_GENERIC_PCI_IOMAP
CONFIG_GENERIC_SCHED_CLOCK
CONFIG_GENERIC_SMP_IDLE_THREAD
CONFIG_HARDIRQS_SW_RESEND
CONFIG_HAS_IOPORT
CONFIG_HAVE_ARCH_AUDITSYSCALL
CONFIG_HAVE_ARCH_BITREVERSE
CONFIG_HAVE_ARCH_JUMP_LABEL
CONFIG_HAVE_ARCH_KFENCE
CONFIG_HAVE_ARCH_KGDB
CONFIG_HAVE_ARCH_KASAN
CONFIG_HAVE_ARCH_KASAN_VMALLOC
CONFIG_HAVE_ARCH_MMAP_RND_BITS
CONFIG_HAVE_ARCH_PFN_VALID
CONFIG_HAVE_ARCH_SECCOMP
CONFIG_HAVE_ARCH_SECCOMP_FILTER
CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
CONFIG_HAVE_ARCH_TRACEHOOK
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE
CONFIG_HAVE_ARM_SMCCC
CONFIG_HAVE_EBPF_JIT
CONFIG_HAVE_CONTEXT_TRACKING_USER
CONFIG_HAVE_C_RECORDMCOUNT
CONFIG_HAVE_BUILDTIME_MCOUNT_SORT
CONFIG_HAVE_DEBUG_KMEMLEAK
CONFIG_HAVE_DMA_CONTIGUOUS
CONFIG_HAVE_DYNAMIC_FTRACE
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
CONFIG_HAVE_EXIT_THREAD
CONFIG_HAVE_GUP_FAST
CONFIG_HAVE_FTRACE_MCOUNT_RECORD
CONFIG_HAVE_FUNCTION_ERROR_INJECTION
CONFIG_HAVE_FUNCTION_GRAPH_TRACER
CONFIG_HAVE_FUNCTION_TRACER
CONFIG_HAVE_GCC_PLUGINS
CONFIG_HAVE_HW_BREAKPOINT
CONFIG_HAVE_IRQ_TIME_ACCOUNTING
CONFIG_HAVE_KERNEL_GZIP
CONFIG_HAVE_KERNEL_LZ4
CONFIG_HAVE_KERNEL_LZMA
CONFIG_HAVE_KERNEL_LZO
CONFIG_HAVE_KERNEL_XZ
CONFIG_HAVE_KPROBES
CONFIG_HAVE_KRETPROBES
CONFIG_HAVE_MOD_ARCH_SPECIFIC
CONFIG_HAVE_NMI
CONFIG_HAVE_OPTPROBES
CONFIG_HAVE_PAGE_SIZE_4KB
CONFIG_HAVE_PCI
CONFIG_HAVE_PERF_EVENTS
CONFIG_HAVE_PERF_REGS
CONFIG_HAVE_PERF_USER_STACK_DUMP
CONFIG_MMU_GATHER_RCU_TABLE_FREE
CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
CONFIG_HAVE_RSEQ
CONFIG_HAVE_STACKPROTECTOR
CONFIG_HAVE_SYSCALL_TRACEPOINTS
CONFIG_HAVE_UID16
CONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN
CONFIG_HOTPLUG_CORE_SYNC_DEAD
CONFIG_IRQ_FORCED_THREADING
CONFIG_LOCK_MM_AND_FIND_VMA
CONFIG_MODULES_USE_ELF_REL
CONFIG_NEED_DMA_MAP_STATE
CONFIG_OF_EARLY_FLATTREE
CONFIG_OLD_SIGACTION
CONFIG_OLD_SIGSUSPEND3
CONFIG_PCI_DOMAINS_GENERIC
CONFIG_PCI_SYSCALL
CONFIG_PERF_USE_VMALLOC
CONFIG_RTC_LIB
CONFIG_SPARSE_IRQ
CONFIG_SYS_SUPPORTS_APM_EMULATION
CONFIG_THREAD_INFO_IN_TASK
CONFIG_TIMER_OF
CONFIG_HAVE_ARCH_VMAP_STACK
CONFIG_TRACE_IRQFLAGS_SUPPORT
CONFIG_USE_OF