linux/arch/arm/Kconfig
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   1# SPDX-License-Identifier: GPL-2.0
   2config ARM
   3        bool
   4        default y
   5        select ARCH_32BIT_OFF_T
   6        select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE if HAVE_KRETPROBES && FRAME_POINTER && !ARM_UNWIND
   7        select ARCH_HAS_BINFMT_FLAT
   8        select ARCH_HAS_DEBUG_VIRTUAL if MMU
   9        select ARCH_HAS_DMA_WRITE_COMBINE if !ARM_DMA_MEM_BUFFERABLE
  10        select ARCH_HAS_ELF_RANDOMIZE
  11        select ARCH_HAS_FORTIFY_SOURCE
  12        select ARCH_HAS_KEEPINITRD
  13        select ARCH_HAS_KCOV
  14        select ARCH_HAS_MEMBARRIER_SYNC_CORE
  15        select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
  16        select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
  17        select ARCH_HAS_PHYS_TO_DMA
  18        select ARCH_HAS_SETUP_DMA_OPS
  19        select ARCH_HAS_SET_MEMORY
  20        select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
  21        select ARCH_HAS_STRICT_MODULE_RWX if MMU
  22        select ARCH_HAS_SYNC_DMA_FOR_DEVICE if SWIOTLB || !MMU
  23        select ARCH_HAS_SYNC_DMA_FOR_CPU if SWIOTLB || !MMU
  24        select ARCH_HAS_TEARDOWN_DMA_OPS if MMU
  25        select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
  26        select ARCH_HAVE_CUSTOM_GPIO_H
  27        select ARCH_HAVE_NMI_SAFE_CMPXCHG if CPU_V7 || CPU_V7M || CPU_V6K
  28        select ARCH_HAS_GCOV_PROFILE_ALL
  29        select ARCH_KEEP_MEMBLOCK
  30        select ARCH_MIGHT_HAVE_PC_PARPORT
  31        select ARCH_NO_SG_CHAIN if !ARM_HAS_SG_CHAIN
  32        select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
  33        select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
  34        select ARCH_SUPPORTS_ATOMIC_RMW
  35        select ARCH_SUPPORTS_HUGETLBFS if ARM_LPAE
  36        select ARCH_USE_BUILTIN_BSWAP
  37        select ARCH_USE_CMPXCHG_LOCKREF
  38        select ARCH_USE_MEMTEST
  39        select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
  40        select ARCH_WANT_IPC_PARSE_VERSION
  41        select ARCH_WANT_LD_ORPHAN_WARN
  42        select BINFMT_FLAT_ARGVP_ENVP_ON_STACK
  43        select BUILDTIME_TABLE_SORT if MMU
  44        select CLONE_BACKWARDS
  45        select CPU_PM if SUSPEND || CPU_IDLE
  46        select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS
  47        select DMA_DECLARE_COHERENT
  48        select DMA_GLOBAL_POOL if !MMU
  49        select DMA_OPS
  50        select DMA_REMAP if MMU
  51        select EDAC_SUPPORT
  52        select EDAC_ATOMIC_SCRUB
  53        select GENERIC_ALLOCATOR
  54        select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY
  55        select GENERIC_ATOMIC64 if CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI
  56        select GENERIC_CLOCKEVENTS_BROADCAST if SMP
  57        select GENERIC_IRQ_IPI if SMP
  58        select GENERIC_CPU_AUTOPROBE
  59        select GENERIC_EARLY_IOREMAP
  60        select GENERIC_IDLE_POLL_SETUP
  61        select GENERIC_IRQ_PROBE
  62        select GENERIC_IRQ_SHOW
  63        select GENERIC_IRQ_SHOW_LEVEL
  64        select GENERIC_LIB_DEVMEM_IS_ALLOWED
  65        select GENERIC_PCI_IOMAP
  66        select GENERIC_SCHED_CLOCK
  67        select GENERIC_SMP_IDLE_THREAD
  68        select HARDIRQS_SW_RESEND
  69        select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT
  70        select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
  71        select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
  72        select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
  73        select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
  74        select HAVE_ARCH_MMAP_RND_BITS if MMU
  75        select HAVE_ARCH_PFN_VALID
  76        select HAVE_ARCH_SECCOMP
  77        select HAVE_ARCH_SECCOMP_FILTER if AEABI && !OABI_COMPAT
  78        select HAVE_ARCH_THREAD_STRUCT_WHITELIST
  79        select HAVE_ARCH_TRACEHOOK
  80        select HAVE_ARCH_TRANSPARENT_HUGEPAGE if ARM_LPAE
  81        select HAVE_ARM_SMCCC if CPU_V7
  82        select HAVE_EBPF_JIT if !CPU_ENDIAN_BE32
  83        select HAVE_CONTEXT_TRACKING
  84        select HAVE_C_RECORDMCOUNT
  85        select HAVE_DEBUG_KMEMLEAK if !XIP_KERNEL
  86        select HAVE_DMA_CONTIGUOUS if MMU
  87        select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
  88        select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
  89        select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
  90        select HAVE_EXIT_THREAD
  91        select HAVE_FAST_GUP if ARM_LPAE
  92        select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
  93        select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG
  94        select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !(THUMB2_KERNEL && CC_IS_CLANG)
  95        select HAVE_FUTEX_CMPXCHG if FUTEX
  96        select HAVE_GCC_PLUGINS
  97        select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7)
  98        select HAVE_IRQ_TIME_ACCOUNTING
  99        select HAVE_KERNEL_GZIP
 100        select HAVE_KERNEL_LZ4
 101        select HAVE_KERNEL_LZMA
 102        select HAVE_KERNEL_LZO
 103        select HAVE_KERNEL_XZ
 104        select HAVE_KPROBES if !XIP_KERNEL && !CPU_ENDIAN_BE32 && !CPU_V7M
 105        select HAVE_KRETPROBES if HAVE_KPROBES
 106        select HAVE_MOD_ARCH_SPECIFIC
 107        select HAVE_NMI
 108        select HAVE_OPTPROBES if !THUMB2_KERNEL
 109        select HAVE_PERF_EVENTS
 110        select HAVE_PERF_REGS
 111        select HAVE_PERF_USER_STACK_DUMP
 112        select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
 113        select HAVE_REGS_AND_STACK_ACCESS_API
 114        select HAVE_RSEQ
 115        select HAVE_STACKPROTECTOR
 116        select HAVE_SYSCALL_TRACEPOINTS
 117        select HAVE_UID16
 118        select HAVE_VIRT_CPU_ACCOUNTING_GEN
 119        select IRQ_FORCED_THREADING
 120        select MODULES_USE_ELF_REL
 121        select NEED_DMA_MAP_STATE
 122        select OF_EARLY_FLATTREE if OF
 123        select OLD_SIGACTION
 124        select OLD_SIGSUSPEND3
 125        select PCI_SYSCALL if PCI
 126        select PERF_USE_VMALLOC
 127        select RTC_LIB
 128        select SYS_SUPPORTS_APM_EMULATION
 129        select THREAD_INFO_IN_TASK if CURRENT_POINTER_IN_TPIDRURO
 130        select TRACE_IRQFLAGS_SUPPORT if !CPU_V7M
 131        # Above selects are sorted alphabetically; please add new ones
 132        # according to that.  Thanks.
 133        help
 134          The ARM series is a line of low-power-consumption RISC chip designs
 135          licensed by ARM Ltd and targeted at embedded applications and
 136          handhelds such as the Compaq IPAQ.  ARM-based PCs are no longer
 137          manufactured, but legacy ARM-based PC hardware remains popular in
 138          Europe.  There is an ARM Linux project with a web page at
 139          <http://www.arm.linux.org.uk/>.
 140
 141config ARM_HAS_SG_CHAIN
 142        bool
 143
 144config ARM_DMA_USE_IOMMU
 145        bool
 146        select ARM_HAS_SG_CHAIN
 147        select NEED_SG_DMA_LENGTH
 148
 149if ARM_DMA_USE_IOMMU
 150
 151config ARM_DMA_IOMMU_ALIGNMENT
 152        int "Maximum PAGE_SIZE order of alignment for DMA IOMMU buffers"
 153        range 4 9
 154        default 8
 155        help
 156          DMA mapping framework by default aligns all buffers to the smallest
 157          PAGE_SIZE order which is greater than or equal to the requested buffer
 158          size. This works well for buffers up to a few hundreds kilobytes, but
 159          for larger buffers it just a waste of address space. Drivers which has
 160          relatively small addressing window (like 64Mib) might run out of
 161          virtual space with just a few allocations.
 162
 163          With this parameter you can specify the maximum PAGE_SIZE order for
 164          DMA IOMMU buffers. Larger buffers will be aligned only to this
 165          specified order. The order is expressed as a power of two multiplied
 166          by the PAGE_SIZE.
 167
 168endif
 169
 170config SYS_SUPPORTS_APM_EMULATION
 171        bool
 172
 173config HAVE_TCM
 174        bool
 175        select GENERIC_ALLOCATOR
 176
 177config HAVE_PROC_CPU
 178        bool
 179
 180config NO_IOPORT_MAP
 181        bool
 182
 183config SBUS
 184        bool
 185
 186config STACKTRACE_SUPPORT
 187        bool
 188        default y
 189
 190config LOCKDEP_SUPPORT
 191        bool
 192        default y
 193
 194config ARCH_HAS_ILOG2_U32
 195        bool
 196
 197config ARCH_HAS_ILOG2_U64
 198        bool
 199
 200config ARCH_HAS_BANDGAP
 201        bool
 202
 203config FIX_EARLYCON_MEM
 204        def_bool y if MMU
 205
 206config GENERIC_HWEIGHT
 207        bool
 208        default y
 209
 210config GENERIC_CALIBRATE_DELAY
 211        bool
 212        default y
 213
 214config ARCH_MAY_HAVE_PC_FDC
 215        bool
 216
 217config ARCH_SUPPORTS_UPROBES
 218        def_bool y
 219
 220config ARCH_HAS_DMA_SET_COHERENT_MASK
 221        bool
 222
 223config GENERIC_ISA_DMA
 224        bool
 225
 226config FIQ
 227        bool
 228
 229config NEED_RET_TO_USER
 230        bool
 231
 232config ARCH_MTD_XIP
 233        bool
 234
 235config ARM_PATCH_PHYS_VIRT
 236        bool "Patch physical to virtual translations at runtime" if EMBEDDED
 237        default y
 238        depends on !XIP_KERNEL && MMU
 239        help
 240          Patch phys-to-virt and virt-to-phys translation functions at
 241          boot and module load time according to the position of the
 242          kernel in system memory.
 243
 244          This can only be used with non-XIP MMU kernels where the base
 245          of physical memory is at a 2 MiB boundary.
 246
 247          Only disable this option if you know that you do not require
 248          this feature (eg, building a kernel for a single machine) and
 249          you need to shrink the kernel to the minimal size.
 250
 251config NEED_MACH_IO_H
 252        bool
 253        help
 254          Select this when mach/io.h is required to provide special
 255          definitions for this platform.  The need for mach/io.h should
 256          be avoided when possible.
 257
 258config NEED_MACH_MEMORY_H
 259        bool
 260        help
 261          Select this when mach/memory.h is required to provide special
 262          definitions for this platform.  The need for mach/memory.h should
 263          be avoided when possible.
 264
 265config PHYS_OFFSET
 266        hex "Physical address of main memory" if MMU
 267        depends on !ARM_PATCH_PHYS_VIRT
 268        default DRAM_BASE if !MMU
 269        default 0x00000000 if ARCH_FOOTBRIDGE || ARCH_IXP4XX
 270        default 0x10000000 if ARCH_OMAP1 || ARCH_RPC
 271        default 0x30000000 if ARCH_S3C24XX
 272        default 0xa0000000 if ARCH_IOP32X || ARCH_PXA
 273        default 0xc0000000 if ARCH_EP93XX || ARCH_SA1100
 274        default 0
 275        help
 276          Please provide the physical address corresponding to the
 277          location of main memory in your system.
 278
 279config GENERIC_BUG
 280        def_bool y
 281        depends on BUG
 282
 283config PGTABLE_LEVELS
 284        int
 285        default 3 if ARM_LPAE
 286        default 2
 287
 288menu "System Type"
 289
 290config MMU
 291        bool "MMU-based Paged Memory Management Support"
 292        default y
 293        help
 294          Select if you want MMU-based virtualised addressing space
 295          support by paged memory management. If unsure, say 'Y'.
 296
 297config ARCH_MMAP_RND_BITS_MIN
 298        default 8
 299
 300config ARCH_MMAP_RND_BITS_MAX
 301        default 14 if PAGE_OFFSET=0x40000000
 302        default 15 if PAGE_OFFSET=0x80000000
 303        default 16
 304
 305#
 306# The "ARM system type" choice list is ordered alphabetically by option
 307# text.  Please add new entries in the option alphabetic order.
 308#
 309choice
 310        prompt "ARM system type"
 311        default ARM_SINGLE_ARMV7M if !MMU
 312        default ARCH_MULTIPLATFORM if MMU
 313
 314config ARCH_MULTIPLATFORM
 315        bool "Allow multiple platforms to be selected"
 316        depends on MMU
 317        select ARCH_FLATMEM_ENABLE
 318        select ARCH_SPARSEMEM_ENABLE
 319        select ARCH_SELECT_MEMORY_MODEL
 320        select ARM_HAS_SG_CHAIN
 321        select ARM_PATCH_PHYS_VIRT
 322        select AUTO_ZRELADDR
 323        select TIMER_OF
 324        select COMMON_CLK
 325        select GENERIC_IRQ_MULTI_HANDLER
 326        select HAVE_PCI
 327        select PCI_DOMAINS_GENERIC if PCI
 328        select SPARSE_IRQ
 329        select USE_OF
 330
 331config ARM_SINGLE_ARMV7M
 332        bool "ARMv7-M based platforms (Cortex-M0/M3/M4)"
 333        depends on !MMU
 334        select ARM_NVIC
 335        select AUTO_ZRELADDR
 336        select TIMER_OF
 337        select COMMON_CLK
 338        select CPU_V7M
 339        select NO_IOPORT_MAP
 340        select SPARSE_IRQ
 341        select USE_OF
 342
 343config ARCH_EP93XX
 344        bool "EP93xx-based"
 345        select ARCH_SPARSEMEM_ENABLE
 346        select ARM_AMBA
 347        imply ARM_PATCH_PHYS_VIRT
 348        select ARM_VIC
 349        select GENERIC_IRQ_MULTI_HANDLER
 350        select AUTO_ZRELADDR
 351        select CLKSRC_MMIO
 352        select CPU_ARM920T
 353        select GPIOLIB
 354        select COMMON_CLK
 355        help
 356          This enables support for the Cirrus EP93xx series of CPUs.
 357
 358config ARCH_FOOTBRIDGE
 359        bool "FootBridge"
 360        select CPU_SA110
 361        select FOOTBRIDGE
 362        select NEED_MACH_IO_H if !MMU
 363        select NEED_MACH_MEMORY_H
 364        help
 365          Support for systems based on the DC21285 companion chip
 366          ("FootBridge"), such as the Simtec CATS and the Rebel NetWinder.
 367
 368config ARCH_IOP32X
 369        bool "IOP32x-based"
 370        depends on MMU
 371        select CPU_XSCALE
 372        select GPIO_IOP
 373        select GPIOLIB
 374        select NEED_RET_TO_USER
 375        select FORCE_PCI
 376        select PLAT_IOP
 377        help
 378          Support for Intel's 80219 and IOP32X (XScale) family of
 379          processors.
 380
 381config ARCH_IXP4XX
 382        bool "IXP4xx-based"
 383        depends on MMU
 384        select ARCH_HAS_DMA_SET_COHERENT_MASK
 385        select ARCH_SUPPORTS_BIG_ENDIAN
 386        select CPU_XSCALE
 387        select DMABOUNCE if PCI
 388        select GENERIC_IRQ_MULTI_HANDLER
 389        select GPIO_IXP4XX
 390        select GPIOLIB
 391        select HAVE_PCI
 392        select IXP4XX_IRQ
 393        select IXP4XX_TIMER
 394        # With the new PCI driver this is not needed
 395        select NEED_MACH_IO_H if IXP4XX_PCI_LEGACY
 396        select USB_EHCI_BIG_ENDIAN_DESC
 397        select USB_EHCI_BIG_ENDIAN_MMIO
 398        help
 399          Support for Intel's IXP4XX (XScale) family of processors.
 400
 401config ARCH_DOVE
 402        bool "Marvell Dove"
 403        select CPU_PJ4
 404        select GENERIC_IRQ_MULTI_HANDLER
 405        select GPIOLIB
 406        select HAVE_PCI
 407        select MVEBU_MBUS
 408        select PINCTRL
 409        select PINCTRL_DOVE
 410        select PLAT_ORION_LEGACY
 411        select SPARSE_IRQ
 412        select PM_GENERIC_DOMAINS if PM
 413        help
 414          Support for the Marvell Dove SoC 88AP510
 415
 416config ARCH_PXA
 417        bool "PXA2xx/PXA3xx-based"
 418        depends on MMU
 419        select ARCH_MTD_XIP
 420        select ARM_CPU_SUSPEND if PM
 421        select AUTO_ZRELADDR
 422        select COMMON_CLK
 423        select CLKSRC_PXA
 424        select CLKSRC_MMIO
 425        select TIMER_OF
 426        select CPU_XSCALE if !CPU_XSC3
 427        select GENERIC_IRQ_MULTI_HANDLER
 428        select GPIO_PXA
 429        select GPIOLIB
 430        select IRQ_DOMAIN
 431        select PLAT_PXA
 432        select SPARSE_IRQ
 433        help
 434          Support for Intel/Marvell's PXA2xx/PXA3xx processor line.
 435
 436config ARCH_RPC
 437        bool "RiscPC"
 438        depends on MMU
 439        depends on !CC_IS_CLANG && GCC_VERSION < 90100 && GCC_VERSION >= 60000
 440        select ARCH_ACORN
 441        select ARCH_MAY_HAVE_PC_FDC
 442        select ARCH_SPARSEMEM_ENABLE
 443        select ARM_HAS_SG_CHAIN
 444        select CPU_SA110
 445        select FIQ
 446        select HAVE_PATA_PLATFORM
 447        select ISA_DMA_API
 448        select LEGACY_TIMER_TICK
 449        select NEED_MACH_IO_H
 450        select NEED_MACH_MEMORY_H
 451        select NO_IOPORT_MAP
 452        help
 453          On the Acorn Risc-PC, Linux can support the internal IDE disk and
 454          CD-ROM interface, serial and parallel port, and the floppy drive.
 455
 456config ARCH_SA1100
 457        bool "SA1100-based"
 458        select ARCH_MTD_XIP
 459        select ARCH_SPARSEMEM_ENABLE
 460        select CLKSRC_MMIO
 461        select CLKSRC_PXA
 462        select TIMER_OF if OF
 463        select COMMON_CLK
 464        select CPU_FREQ
 465        select CPU_SA1100
 466        select GENERIC_IRQ_MULTI_HANDLER
 467        select GPIOLIB
 468        select IRQ_DOMAIN
 469        select ISA
 470        select NEED_MACH_MEMORY_H
 471        select SPARSE_IRQ
 472        help
 473          Support for StrongARM 11x0 based boards.
 474
 475config ARCH_S3C24XX
 476        bool "Samsung S3C24XX SoCs"
 477        select ATAGS
 478        select CLKSRC_SAMSUNG_PWM
 479        select GPIO_SAMSUNG
 480        select GPIOLIB
 481        select GENERIC_IRQ_MULTI_HANDLER
 482        select HAVE_S3C2410_I2C if I2C
 483        select NEED_MACH_IO_H
 484        select S3C2410_WATCHDOG
 485        select SAMSUNG_ATAGS
 486        select USE_OF
 487        select WATCHDOG
 488        help
 489          Samsung S3C2410, S3C2412, S3C2413, S3C2416, S3C2440, S3C2442, S3C2443
 490          and S3C2450 SoCs based systems, such as the Simtec Electronics BAST
 491          (<http://www.simtec.co.uk/products/EB110ITX/>), the IPAQ 1940 or the
 492          Samsung SMDK2410 development board (and derivatives).
 493
 494config ARCH_OMAP1
 495        bool "TI OMAP1"
 496        depends on MMU
 497        select ARCH_OMAP
 498        select CLKSRC_MMIO
 499        select GENERIC_IRQ_CHIP
 500        select GENERIC_IRQ_MULTI_HANDLER
 501        select GPIOLIB
 502        select HAVE_LEGACY_CLK
 503        select IRQ_DOMAIN
 504        select NEED_MACH_IO_H if PCCARD
 505        select NEED_MACH_MEMORY_H
 506        select SPARSE_IRQ
 507        help
 508          Support for older TI OMAP1 (omap7xx, omap15xx or omap16xx)
 509
 510endchoice
 511
 512menu "Multiple platform selection"
 513        depends on ARCH_MULTIPLATFORM
 514
 515comment "CPU Core family selection"
 516
 517config ARCH_MULTI_V4
 518        bool "ARMv4 based platforms (FA526)"
 519        depends on !ARCH_MULTI_V6_V7
 520        select ARCH_MULTI_V4_V5
 521        select CPU_FA526
 522
 523config ARCH_MULTI_V4T
 524        bool "ARMv4T based platforms (ARM720T, ARM920T, ...)"
 525        depends on !ARCH_MULTI_V6_V7
 526        select ARCH_MULTI_V4_V5
 527        select CPU_ARM920T if !(CPU_ARM7TDMI || CPU_ARM720T || \
 528                CPU_ARM740T || CPU_ARM9TDMI || CPU_ARM922T || \
 529                CPU_ARM925T || CPU_ARM940T)
 530
 531config ARCH_MULTI_V5
 532        bool "ARMv5 based platforms (ARM926T, XSCALE, PJ1, ...)"
 533        depends on !ARCH_MULTI_V6_V7
 534        select ARCH_MULTI_V4_V5
 535        select CPU_ARM926T if !(CPU_ARM946E || CPU_ARM1020 || \
 536                CPU_ARM1020E || CPU_ARM1022 || CPU_ARM1026 || \
 537                CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_FEROCEON)
 538
 539config ARCH_MULTI_V4_V5
 540        bool
 541
 542config ARCH_MULTI_V6
 543        bool "ARMv6 based platforms (ARM11)"
 544        select ARCH_MULTI_V6_V7
 545        select CPU_V6K
 546
 547config ARCH_MULTI_V7
 548        bool "ARMv7 based platforms (Cortex-A, PJ4, Scorpion, Krait)"
 549        default y
 550        select ARCH_MULTI_V6_V7
 551        select CPU_V7
 552        select HAVE_SMP
 553
 554config ARCH_MULTI_V6_V7
 555        bool
 556        select MIGHT_HAVE_CACHE_L2X0
 557
 558config ARCH_MULTI_CPU_AUTO
 559        def_bool !(ARCH_MULTI_V4 || ARCH_MULTI_V4T || ARCH_MULTI_V6_V7)
 560        select ARCH_MULTI_V5
 561
 562endmenu
 563
 564config ARCH_VIRT
 565        bool "Dummy Virtual Machine"
 566        depends on ARCH_MULTI_V7
 567        select ARM_AMBA
 568        select ARM_GIC
 569        select ARM_GIC_V2M if PCI
 570        select ARM_GIC_V3
 571        select ARM_GIC_V3_ITS if PCI
 572        select ARM_PSCI
 573        select HAVE_ARM_ARCH_TIMER
 574        select ARCH_SUPPORTS_BIG_ENDIAN
 575
 576#
 577# This is sorted alphabetically by mach-* pathname.  However, plat-*
 578# Kconfigs may be included either alphabetically (according to the
 579# plat- suffix) or along side the corresponding mach-* source.
 580#
 581source "arch/arm/mach-actions/Kconfig"
 582
 583source "arch/arm/mach-alpine/Kconfig"
 584
 585source "arch/arm/mach-artpec/Kconfig"
 586
 587source "arch/arm/mach-asm9260/Kconfig"
 588
 589source "arch/arm/mach-aspeed/Kconfig"
 590
 591source "arch/arm/mach-at91/Kconfig"
 592
 593source "arch/arm/mach-axxia/Kconfig"
 594
 595source "arch/arm/mach-bcm/Kconfig"
 596
 597source "arch/arm/mach-berlin/Kconfig"
 598
 599source "arch/arm/mach-clps711x/Kconfig"
 600
 601source "arch/arm/mach-cns3xxx/Kconfig"
 602
 603source "arch/arm/mach-davinci/Kconfig"
 604
 605source "arch/arm/mach-digicolor/Kconfig"
 606
 607source "arch/arm/mach-dove/Kconfig"
 608
 609source "arch/arm/mach-ep93xx/Kconfig"
 610
 611source "arch/arm/mach-exynos/Kconfig"
 612
 613source "arch/arm/mach-footbridge/Kconfig"
 614
 615source "arch/arm/mach-gemini/Kconfig"
 616
 617source "arch/arm/mach-highbank/Kconfig"
 618
 619source "arch/arm/mach-hisi/Kconfig"
 620
 621source "arch/arm/mach-imx/Kconfig"
 622
 623source "arch/arm/mach-integrator/Kconfig"
 624
 625source "arch/arm/mach-iop32x/Kconfig"
 626
 627source "arch/arm/mach-ixp4xx/Kconfig"
 628
 629source "arch/arm/mach-keystone/Kconfig"
 630
 631source "arch/arm/mach-lpc32xx/Kconfig"
 632
 633source "arch/arm/mach-mediatek/Kconfig"
 634
 635source "arch/arm/mach-meson/Kconfig"
 636
 637source "arch/arm/mach-milbeaut/Kconfig"
 638
 639source "arch/arm/mach-mmp/Kconfig"
 640
 641source "arch/arm/mach-moxart/Kconfig"
 642
 643source "arch/arm/mach-mstar/Kconfig"
 644
 645source "arch/arm/mach-mv78xx0/Kconfig"
 646
 647source "arch/arm/mach-mvebu/Kconfig"
 648
 649source "arch/arm/mach-mxs/Kconfig"
 650
 651source "arch/arm/mach-nomadik/Kconfig"
 652
 653source "arch/arm/mach-npcm/Kconfig"
 654
 655source "arch/arm/mach-nspire/Kconfig"
 656
 657source "arch/arm/plat-omap/Kconfig"
 658
 659source "arch/arm/mach-omap1/Kconfig"
 660
 661source "arch/arm/mach-omap2/Kconfig"
 662
 663source "arch/arm/mach-orion5x/Kconfig"
 664
 665source "arch/arm/mach-oxnas/Kconfig"
 666
 667source "arch/arm/mach-pxa/Kconfig"
 668source "arch/arm/plat-pxa/Kconfig"
 669
 670source "arch/arm/mach-qcom/Kconfig"
 671
 672source "arch/arm/mach-rda/Kconfig"
 673
 674source "arch/arm/mach-realtek/Kconfig"
 675
 676source "arch/arm/mach-realview/Kconfig"
 677
 678source "arch/arm/mach-rockchip/Kconfig"
 679
 680source "arch/arm/mach-s3c/Kconfig"
 681
 682source "arch/arm/mach-s5pv210/Kconfig"
 683
 684source "arch/arm/mach-sa1100/Kconfig"
 685
 686source "arch/arm/mach-shmobile/Kconfig"
 687
 688source "arch/arm/mach-socfpga/Kconfig"
 689
 690source "arch/arm/mach-spear/Kconfig"
 691
 692source "arch/arm/mach-sti/Kconfig"
 693
 694source "arch/arm/mach-stm32/Kconfig"
 695
 696source "arch/arm/mach-sunxi/Kconfig"
 697
 698source "arch/arm/mach-tegra/Kconfig"
 699
 700source "arch/arm/mach-uniphier/Kconfig"
 701
 702source "arch/arm/mach-ux500/Kconfig"
 703
 704source "arch/arm/mach-versatile/Kconfig"
 705
 706source "arch/arm/mach-vexpress/Kconfig"
 707
 708source "arch/arm/mach-vt8500/Kconfig"
 709
 710source "arch/arm/mach-zynq/Kconfig"
 711
 712# ARMv7-M architecture
 713config ARCH_LPC18XX
 714        bool "NXP LPC18xx/LPC43xx"
 715        depends on ARM_SINGLE_ARMV7M
 716        select ARCH_HAS_RESET_CONTROLLER
 717        select ARM_AMBA
 718        select CLKSRC_LPC32XX
 719        select PINCTRL
 720        help
 721          Support for NXP's LPC18xx Cortex-M3 and LPC43xx Cortex-M4
 722          high performance microcontrollers.
 723
 724config ARCH_MPS2
 725        bool "ARM MPS2 platform"
 726        depends on ARM_SINGLE_ARMV7M
 727        select ARM_AMBA
 728        select CLKSRC_MPS2
 729        help
 730          Support for Cortex-M Prototyping System (or V2M-MPS2) which comes
 731          with a range of available cores like Cortex-M3/M4/M7.
 732
 733          Please, note that depends which Application Note is used memory map
 734          for the platform may vary, so adjustment of RAM base might be needed.
 735
 736# Definitions to make life easier
 737config ARCH_ACORN
 738        bool
 739
 740config PLAT_IOP
 741        bool
 742
 743config PLAT_ORION
 744        bool
 745        select CLKSRC_MMIO
 746        select COMMON_CLK
 747        select GENERIC_IRQ_CHIP
 748        select IRQ_DOMAIN
 749
 750config PLAT_ORION_LEGACY
 751        bool
 752        select PLAT_ORION
 753
 754config PLAT_PXA
 755        bool
 756
 757config PLAT_VERSATILE
 758        bool
 759
 760source "arch/arm/mm/Kconfig"
 761
 762config IWMMXT
 763        bool "Enable iWMMXt support"
 764        depends on CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_PJ4 || CPU_PJ4B
 765        default y if PXA27x || PXA3xx || ARCH_MMP || CPU_PJ4 || CPU_PJ4B
 766        help
 767          Enable support for iWMMXt context switching at run time if
 768          running on a CPU that supports it.
 769
 770if !MMU
 771source "arch/arm/Kconfig-nommu"
 772endif
 773
 774config PJ4B_ERRATA_4742
 775        bool "PJ4B Errata 4742: IDLE Wake Up Commands can Cause the CPU Core to Cease Operation"
 776        depends on CPU_PJ4B && MACH_ARMADA_370
 777        default y
 778        help
 779          When coming out of either a Wait for Interrupt (WFI) or a Wait for
 780          Event (WFE) IDLE states, a specific timing sensitivity exists between
 781          the retiring WFI/WFE instructions and the newly issued subsequent
 782          instructions.  This sensitivity can result in a CPU hang scenario.
 783          Workaround:
 784          The software must insert either a Data Synchronization Barrier (DSB)
 785          or Data Memory Barrier (DMB) command immediately after the WFI/WFE
 786          instruction
 787
 788config ARM_ERRATA_326103
 789        bool "ARM errata: FSR write bit incorrect on a SWP to read-only memory"
 790        depends on CPU_V6
 791        help
 792          Executing a SWP instruction to read-only memory does not set bit 11
 793          of the FSR on the ARM 1136 prior to r1p0. This causes the kernel to
 794          treat the access as a read, preventing a COW from occurring and
 795          causing the faulting task to livelock.
 796
 797config ARM_ERRATA_411920
 798        bool "ARM errata: Invalidation of the Instruction Cache operation can fail"
 799        depends on CPU_V6 || CPU_V6K
 800        help
 801          Invalidation of the Instruction Cache operation can
 802          fail. This erratum is present in 1136 (before r1p4), 1156 and 1176.
 803          It does not affect the MPCore. This option enables the ARM Ltd.
 804          recommended workaround.
 805
 806config ARM_ERRATA_430973
 807        bool "ARM errata: Stale prediction on replaced interworking branch"
 808        depends on CPU_V7
 809        help
 810          This option enables the workaround for the 430973 Cortex-A8
 811          r1p* erratum. If a code sequence containing an ARM/Thumb
 812          interworking branch is replaced with another code sequence at the
 813          same virtual address, whether due to self-modifying code or virtual
 814          to physical address re-mapping, Cortex-A8 does not recover from the
 815          stale interworking branch prediction. This results in Cortex-A8
 816          executing the new code sequence in the incorrect ARM or Thumb state.
 817          The workaround enables the BTB/BTAC operations by setting ACTLR.IBE
 818          and also flushes the branch target cache at every context switch.
 819          Note that setting specific bits in the ACTLR register may not be
 820          available in non-secure mode.
 821
 822config ARM_ERRATA_458693
 823        bool "ARM errata: Processor deadlock when a false hazard is created"
 824        depends on CPU_V7
 825        depends on !ARCH_MULTIPLATFORM
 826        help
 827          This option enables the workaround for the 458693 Cortex-A8 (r2p0)
 828          erratum. For very specific sequences of memory operations, it is
 829          possible for a hazard condition intended for a cache line to instead
 830          be incorrectly associated with a different cache line. This false
 831          hazard might then cause a processor deadlock. The workaround enables
 832          the L1 caching of the NEON accesses and disables the PLD instruction
 833          in the ACTLR register. Note that setting specific bits in the ACTLR
 834          register may not be available in non-secure mode.
 835
 836config ARM_ERRATA_460075
 837        bool "ARM errata: Data written to the L2 cache can be overwritten with stale data"
 838        depends on CPU_V7
 839        depends on !ARCH_MULTIPLATFORM
 840        help
 841          This option enables the workaround for the 460075 Cortex-A8 (r2p0)
 842          erratum. Any asynchronous access to the L2 cache may encounter a
 843          situation in which recent store transactions to the L2 cache are lost
 844          and overwritten with stale memory contents from external memory. The
 845          workaround disables the write-allocate mode for the L2 cache via the
 846          ACTLR register. Note that setting specific bits in the ACTLR register
 847          may not be available in non-secure mode.
 848
 849config ARM_ERRATA_742230
 850        bool "ARM errata: DMB operation may be faulty"
 851        depends on CPU_V7 && SMP
 852        depends on !ARCH_MULTIPLATFORM
 853        help
 854          This option enables the workaround for the 742230 Cortex-A9
 855          (r1p0..r2p2) erratum. Under rare circumstances, a DMB instruction
 856          between two write operations may not ensure the correct visibility
 857          ordering of the two writes. This workaround sets a specific bit in
 858          the diagnostic register of the Cortex-A9 which causes the DMB
 859          instruction to behave as a DSB, ensuring the correct behaviour of
 860          the two writes.
 861
 862config ARM_ERRATA_742231
 863        bool "ARM errata: Incorrect hazard handling in the SCU may lead to data corruption"
 864        depends on CPU_V7 && SMP
 865        depends on !ARCH_MULTIPLATFORM
 866        help
 867          This option enables the workaround for the 742231 Cortex-A9
 868          (r2p0..r2p2) erratum. Under certain conditions, specific to the
 869          Cortex-A9 MPCore micro-architecture, two CPUs working in SMP mode,
 870          accessing some data located in the same cache line, may get corrupted
 871          data due to bad handling of the address hazard when the line gets
 872          replaced from one of the CPUs at the same time as another CPU is
 873          accessing it. This workaround sets specific bits in the diagnostic
 874          register of the Cortex-A9 which reduces the linefill issuing
 875          capabilities of the processor.
 876
 877config ARM_ERRATA_643719
 878        bool "ARM errata: LoUIS bit field in CLIDR register is incorrect"
 879        depends on CPU_V7 && SMP
 880        default y
 881        help
 882          This option enables the workaround for the 643719 Cortex-A9 (prior to
 883          r1p0) erratum. On affected cores the LoUIS bit field of the CLIDR
 884          register returns zero when it should return one. The workaround
 885          corrects this value, ensuring cache maintenance operations which use
 886          it behave as intended and avoiding data corruption.
 887
 888config ARM_ERRATA_720789
 889        bool "ARM errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID"
 890        depends on CPU_V7
 891        help
 892          This option enables the workaround for the 720789 Cortex-A9 (prior to
 893          r2p0) erratum. A faulty ASID can be sent to the other CPUs for the
 894          broadcasted CP15 TLB maintenance operations TLBIASIDIS and TLBIMVAIS.
 895          As a consequence of this erratum, some TLB entries which should be
 896          invalidated are not, resulting in an incoherency in the system page
 897          tables. The workaround changes the TLB flushing routines to invalidate
 898          entries regardless of the ASID.
 899
 900config ARM_ERRATA_743622
 901        bool "ARM errata: Faulty hazard checking in the Store Buffer may lead to data corruption"
 902        depends on CPU_V7
 903        depends on !ARCH_MULTIPLATFORM
 904        help
 905          This option enables the workaround for the 743622 Cortex-A9
 906          (r2p*) erratum. Under very rare conditions, a faulty
 907          optimisation in the Cortex-A9 Store Buffer may lead to data
 908          corruption. This workaround sets a specific bit in the diagnostic
 909          register of the Cortex-A9 which disables the Store Buffer
 910          optimisation, preventing the defect from occurring. This has no
 911          visible impact on the overall performance or power consumption of the
 912          processor.
 913
 914config ARM_ERRATA_751472
 915        bool "ARM errata: Interrupted ICIALLUIS may prevent completion of broadcasted operation"
 916        depends on CPU_V7
 917        depends on !ARCH_MULTIPLATFORM
 918        help
 919          This option enables the workaround for the 751472 Cortex-A9 (prior
 920          to r3p0) erratum. An interrupted ICIALLUIS operation may prevent the
 921          completion of a following broadcasted operation if the second
 922          operation is received by a CPU before the ICIALLUIS has completed,
 923          potentially leading to corrupted entries in the cache or TLB.
 924
 925config ARM_ERRATA_754322
 926        bool "ARM errata: possible faulty MMU translations following an ASID switch"
 927        depends on CPU_V7
 928        help
 929          This option enables the workaround for the 754322 Cortex-A9 (r2p*,
 930          r3p*) erratum. A speculative memory access may cause a page table walk
 931          which starts prior to an ASID switch but completes afterwards. This
 932          can populate the micro-TLB with a stale entry which may be hit with
 933          the new ASID. This workaround places two dsb instructions in the mm
 934          switching code so that no page table walks can cross the ASID switch.
 935
 936config ARM_ERRATA_754327
 937        bool "ARM errata: no automatic Store Buffer drain"
 938        depends on CPU_V7 && SMP
 939        help
 940          This option enables the workaround for the 754327 Cortex-A9 (prior to
 941          r2p0) erratum. The Store Buffer does not have any automatic draining
 942          mechanism and therefore a livelock may occur if an external agent
 943          continuously polls a memory location waiting to observe an update.
 944          This workaround defines cpu_relax() as smp_mb(), preventing correctly
 945          written polling loops from denying visibility of updates to memory.
 946
 947config ARM_ERRATA_364296
 948        bool "ARM errata: Possible cache data corruption with hit-under-miss enabled"
 949        depends on CPU_V6
 950        help
 951          This options enables the workaround for the 364296 ARM1136
 952          r0p2 erratum (possible cache data corruption with
 953          hit-under-miss enabled). It sets the undocumented bit 31 in
 954          the auxiliary control register and the FI bit in the control
 955          register, thus disabling hit-under-miss without putting the
 956          processor into full low interrupt latency mode. ARM11MPCore
 957          is not affected.
 958
 959config ARM_ERRATA_764369
 960        bool "ARM errata: Data cache line maintenance operation by MVA may not succeed"
 961        depends on CPU_V7 && SMP
 962        help
 963          This option enables the workaround for erratum 764369
 964          affecting Cortex-A9 MPCore with two or more processors (all
 965          current revisions). Under certain timing circumstances, a data
 966          cache line maintenance operation by MVA targeting an Inner
 967          Shareable memory region may fail to proceed up to either the
 968          Point of Coherency or to the Point of Unification of the
 969          system. This workaround adds a DSB instruction before the
 970          relevant cache maintenance functions and sets a specific bit
 971          in the diagnostic control register of the SCU.
 972
 973config ARM_ERRATA_775420
 974       bool "ARM errata: A data cache maintenance operation which aborts, might lead to deadlock"
 975       depends on CPU_V7
 976       help
 977         This option enables the workaround for the 775420 Cortex-A9 (r2p2,
 978         r2p6,r2p8,r2p10,r3p0) erratum. In case a data cache maintenance
 979         operation aborts with MMU exception, it might cause the processor
 980         to deadlock. This workaround puts DSB before executing ISB if
 981         an abort may occur on cache maintenance.
 982
 983config ARM_ERRATA_798181
 984        bool "ARM errata: TLBI/DSB failure on Cortex-A15"
 985        depends on CPU_V7 && SMP
 986        help
 987          On Cortex-A15 (r0p0..r3p2) the TLBI*IS/DSB operations are not
 988          adequately shooting down all use of the old entries. This
 989          option enables the Linux kernel workaround for this erratum
 990          which sends an IPI to the CPUs that are running the same ASID
 991          as the one being invalidated.
 992
 993config ARM_ERRATA_773022
 994        bool "ARM errata: incorrect instructions may be executed from loop buffer"
 995        depends on CPU_V7
 996        help
 997          This option enables the workaround for the 773022 Cortex-A15
 998          (up to r0p4) erratum. In certain rare sequences of code, the
 999          loop buffer may deliver incorrect instructions. This
1000          workaround disables the loop buffer to avoid the erratum.
1001
1002config ARM_ERRATA_818325_852422
1003        bool "ARM errata: A12: some seqs of opposed cond code instrs => deadlock or corruption"
1004        depends on CPU_V7
1005        help
1006          This option enables the workaround for:
1007          - Cortex-A12 818325: Execution of an UNPREDICTABLE STR or STM
1008            instruction might deadlock.  Fixed in r0p1.
1009          - Cortex-A12 852422: Execution of a sequence of instructions might
1010            lead to either a data corruption or a CPU deadlock.  Not fixed in
1011            any Cortex-A12 cores yet.
1012          This workaround for all both errata involves setting bit[12] of the
1013          Feature Register. This bit disables an optimisation applied to a
1014          sequence of 2 instructions that use opposing condition codes.
1015
1016config ARM_ERRATA_821420
1017        bool "ARM errata: A12: sequence of VMOV to core registers might lead to a dead lock"
1018        depends on CPU_V7
1019        help
1020          This option enables the workaround for the 821420 Cortex-A12
1021          (all revs) erratum. In very rare timing conditions, a sequence
1022          of VMOV to Core registers instructions, for which the second
1023          one is in the shadow of a branch or abort, can lead to a
1024          deadlock when the VMOV instructions are issued out-of-order.
1025
1026config ARM_ERRATA_825619
1027        bool "ARM errata: A12: DMB NSHST/ISHST mixed ... might cause deadlock"
1028        depends on CPU_V7
1029        help
1030          This option enables the workaround for the 825619 Cortex-A12
1031          (all revs) erratum. Within rare timing constraints, executing a
1032          DMB NSHST or DMB ISHST instruction followed by a mix of Cacheable
1033          and Device/Strongly-Ordered loads and stores might cause deadlock
1034
1035config ARM_ERRATA_857271
1036        bool "ARM errata: A12: CPU might deadlock under some very rare internal conditions"
1037        depends on CPU_V7
1038        help
1039          This option enables the workaround for the 857271 Cortex-A12
1040          (all revs) erratum. Under very rare timing conditions, the CPU might
1041          hang. The workaround is expected to have a < 1% performance impact.
1042
1043config ARM_ERRATA_852421
1044        bool "ARM errata: A17: DMB ST might fail to create order between stores"
1045        depends on CPU_V7
1046        help
1047          This option enables the workaround for the 852421 Cortex-A17
1048          (r1p0, r1p1, r1p2) erratum. Under very rare timing conditions,
1049          execution of a DMB ST instruction might fail to properly order
1050          stores from GroupA and stores from GroupB.
1051
1052config ARM_ERRATA_852423
1053        bool "ARM errata: A17: some seqs of opposed cond code instrs => deadlock or corruption"
1054        depends on CPU_V7
1055        help
1056          This option enables the workaround for:
1057          - Cortex-A17 852423: Execution of a sequence of instructions might
1058            lead to either a data corruption or a CPU deadlock.  Not fixed in
1059            any Cortex-A17 cores yet.
1060          This is identical to Cortex-A12 erratum 852422.  It is a separate
1061          config option from the A12 erratum due to the way errata are checked
1062          for and handled.
1063
1064config ARM_ERRATA_857272
1065        bool "ARM errata: A17: CPU might deadlock under some very rare internal conditions"
1066        depends on CPU_V7
1067        help
1068          This option enables the workaround for the 857272 Cortex-A17 erratum.
1069          This erratum is not known to be fixed in any A17 revision.
1070          This is identical to Cortex-A12 erratum 857271.  It is a separate
1071          config option from the A12 erratum due to the way errata are checked
1072          for and handled.
1073
1074endmenu
1075
1076source "arch/arm/common/Kconfig"
1077
1078menu "Bus support"
1079
1080config ISA
1081        bool
1082        help
1083          Find out whether you have ISA slots on your motherboard.  ISA is the
1084          name of a bus system, i.e. the way the CPU talks to the other stuff
1085          inside your box.  Other bus systems are PCI, EISA, MicroChannel
1086          (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
1087          newer boards don't support it.  If you have ISA, say Y, otherwise N.
1088
1089# Select ISA DMA controller support
1090config ISA_DMA
1091        bool
1092        select ISA_DMA_API
1093
1094# Select ISA DMA interface
1095config ISA_DMA_API
1096        bool
1097
1098config PCI_NANOENGINE
1099        bool "BSE nanoEngine PCI support"
1100        depends on SA1100_NANOENGINE
1101        help
1102          Enable PCI on the BSE nanoEngine board.
1103
1104config ARM_ERRATA_814220
1105        bool "ARM errata: Cache maintenance by set/way operations can execute out of order"
1106        depends on CPU_V7
1107        help
1108          The v7 ARM states that all cache and branch predictor maintenance
1109          operations that do not specify an address execute, relative to
1110          each other, in program order.
1111          However, because of this erratum, an L2 set/way cache maintenance
1112          operation can overtake an L1 set/way cache maintenance operation.
1113          This ERRATA only affected the Cortex-A7 and present in r0p2, r0p3,
1114          r0p4, r0p5.
1115
1116endmenu
1117
1118menu "Kernel Features"
1119
1120config HAVE_SMP
1121        bool
1122        help
1123          This option should be selected by machines which have an SMP-
1124          capable CPU.
1125
1126          The only effect of this option is to make the SMP-related
1127          options available to the user for configuration.
1128
1129config SMP
1130        bool "Symmetric Multi-Processing"
1131        depends on CPU_V6K || CPU_V7
1132        depends on HAVE_SMP
1133        depends on MMU || ARM_MPU
1134        select IRQ_WORK
1135        help
1136          This enables support for systems with more than one CPU. If you have
1137          a system with only one CPU, say N. If you have a system with more
1138          than one CPU, say Y.
1139
1140          If you say N here, the kernel will run on uni- and multiprocessor
1141          machines, but will use only one CPU of a multiprocessor machine. If
1142          you say Y here, the kernel will run on many, but not all,
1143          uniprocessor machines. On a uniprocessor machine, the kernel
1144          will run faster if you say N here.
1145
1146          See also <file:Documentation/x86/i386/IO-APIC.rst>,
1147          <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
1148          <http://tldp.org/HOWTO/SMP-HOWTO.html>.
1149
1150          If you don't know what to do here, say N.
1151
1152config SMP_ON_UP
1153        bool "Allow booting SMP kernel on uniprocessor systems"
1154        depends on SMP && !XIP_KERNEL && MMU
1155        default y
1156        help
1157          SMP kernels contain instructions which fail on non-SMP processors.
1158          Enabling this option allows the kernel to modify itself to make
1159          these instructions safe.  Disabling it allows about 1K of space
1160          savings.
1161
1162          If you don't know what to do here, say Y.
1163
1164
1165config CURRENT_POINTER_IN_TPIDRURO
1166        def_bool y
1167        depends on SMP && CPU_32v6K && !CPU_V6
1168
1169config ARM_CPU_TOPOLOGY
1170        bool "Support cpu topology definition"
1171        depends on SMP && CPU_V7
1172        default y
1173        help
1174          Support ARM cpu topology definition. The MPIDR register defines
1175          affinity between processors which is then used to describe the cpu
1176          topology of an ARM System.
1177
1178config SCHED_MC
1179        bool "Multi-core scheduler support"
1180        depends on ARM_CPU_TOPOLOGY
1181        help
1182          Multi-core scheduler support improves the CPU scheduler's decision
1183          making when dealing with multi-core CPU chips at a cost of slightly
1184          increased overhead in some places. If unsure say N here.
1185
1186config SCHED_SMT
1187        bool "SMT scheduler support"
1188        depends on ARM_CPU_TOPOLOGY
1189        help
1190          Improves the CPU scheduler's decision making when dealing with
1191          MultiThreading at a cost of slightly increased overhead in some
1192          places. If unsure say N here.
1193
1194config HAVE_ARM_SCU
1195        bool
1196        help
1197          This option enables support for the ARM snoop control unit
1198
1199config HAVE_ARM_ARCH_TIMER
1200        bool "Architected timer support"
1201        depends on CPU_V7
1202        select ARM_ARCH_TIMER
1203        help
1204          This option enables support for the ARM architected timer
1205
1206config HAVE_ARM_TWD
1207        bool
1208        help
1209          This options enables support for the ARM timer and watchdog unit
1210
1211config MCPM
1212        bool "Multi-Cluster Power Management"
1213        depends on CPU_V7 && SMP
1214        help
1215          This option provides the common power management infrastructure
1216          for (multi-)cluster based systems, such as big.LITTLE based
1217          systems.
1218
1219config MCPM_QUAD_CLUSTER
1220        bool
1221        depends on MCPM
1222        help
1223          To avoid wasting resources unnecessarily, MCPM only supports up
1224          to 2 clusters by default.
1225          Platforms with 3 or 4 clusters that use MCPM must select this
1226          option to allow the additional clusters to be managed.
1227
1228config BIG_LITTLE
1229        bool "big.LITTLE support (Experimental)"
1230        depends on CPU_V7 && SMP
1231        select MCPM
1232        help
1233          This option enables support selections for the big.LITTLE
1234          system architecture.
1235
1236config BL_SWITCHER
1237        bool "big.LITTLE switcher support"
1238        depends on BIG_LITTLE && MCPM && HOTPLUG_CPU && ARM_GIC
1239        select CPU_PM
1240        help
1241          The big.LITTLE "switcher" provides the core functionality to
1242          transparently handle transition between a cluster of A15's
1243          and a cluster of A7's in a big.LITTLE system.
1244
1245config BL_SWITCHER_DUMMY_IF
1246        tristate "Simple big.LITTLE switcher user interface"
1247        depends on BL_SWITCHER && DEBUG_KERNEL
1248        help
1249          This is a simple and dummy char dev interface to control
1250          the big.LITTLE switcher core code.  It is meant for
1251          debugging purposes only.
1252
1253choice
1254        prompt "Memory split"
1255        depends on MMU
1256        default VMSPLIT_3G
1257        help
1258          Select the desired split between kernel and user memory.
1259
1260          If you are not absolutely sure what you are doing, leave this
1261          option alone!
1262
1263        config VMSPLIT_3G
1264                bool "3G/1G user/kernel split"
1265        config VMSPLIT_3G_OPT
1266                depends on !ARM_LPAE
1267                bool "3G/1G user/kernel split (for full 1G low memory)"
1268        config VMSPLIT_2G
1269                bool "2G/2G user/kernel split"
1270        config VMSPLIT_1G
1271                bool "1G/3G user/kernel split"
1272endchoice
1273
1274config PAGE_OFFSET
1275        hex
1276        default PHYS_OFFSET if !MMU
1277        default 0x40000000 if VMSPLIT_1G
1278        default 0x80000000 if VMSPLIT_2G
1279        default 0xB0000000 if VMSPLIT_3G_OPT
1280        default 0xC0000000
1281
1282config KASAN_SHADOW_OFFSET
1283        hex
1284        depends on KASAN
1285        default 0x1f000000 if PAGE_OFFSET=0x40000000
1286        default 0x5f000000 if PAGE_OFFSET=0x80000000
1287        default 0x9f000000 if PAGE_OFFSET=0xC0000000
1288        default 0x8f000000 if PAGE_OFFSET=0xB0000000
1289        default 0xffffffff
1290
1291config NR_CPUS
1292        int "Maximum number of CPUs (2-32)"
1293        range 2 16 if DEBUG_KMAP_LOCAL
1294        range 2 32 if !DEBUG_KMAP_LOCAL
1295        depends on SMP
1296        default "4"
1297        help
1298          The maximum number of CPUs that the kernel can support.
1299          Up to 32 CPUs can be supported, or up to 16 if kmap_local()
1300          debugging is enabled, which uses half of the per-CPU fixmap
1301          slots as guard regions.
1302
1303config HOTPLUG_CPU
1304        bool "Support for hot-pluggable CPUs"
1305        depends on SMP
1306        select GENERIC_IRQ_MIGRATION
1307        help
1308          Say Y here to experiment with turning CPUs off and on.  CPUs
1309          can be controlled through /sys/devices/system/cpu.
1310
1311config ARM_PSCI
1312        bool "Support for the ARM Power State Coordination Interface (PSCI)"
1313        depends on HAVE_ARM_SMCCC
1314        select ARM_PSCI_FW
1315        help
1316          Say Y here if you want Linux to communicate with system firmware
1317          implementing the PSCI specification for CPU-centric power
1318          management operations described in ARM document number ARM DEN
1319          0022A ("Power State Coordination Interface System Software on
1320          ARM processors").
1321
1322# The GPIO number here must be sorted by descending number. In case of
1323# a multiplatform kernel, we just want the highest value required by the
1324# selected platforms.
1325config ARCH_NR_GPIO
1326        int
1327        default 2048 if ARCH_INTEL_SOCFPGA
1328        default 1024 if ARCH_BRCMSTB || ARCH_RENESAS || ARCH_TEGRA || \
1329                ARCH_ZYNQ || ARCH_ASPEED
1330        default 512 if ARCH_EXYNOS || ARCH_KEYSTONE || SOC_OMAP5 || \
1331                SOC_DRA7XX || ARCH_S3C24XX || ARCH_S3C64XX || ARCH_S5PV210
1332        default 416 if ARCH_SUNXI
1333        default 392 if ARCH_U8500
1334        default 352 if ARCH_VT8500
1335        default 288 if ARCH_ROCKCHIP
1336        default 264 if MACH_H4700
1337        default 0
1338        help
1339          Maximum number of GPIOs in the system.
1340
1341          If unsure, leave the default value.
1342
1343config HZ_FIXED
1344        int
1345        default 128 if SOC_AT91RM9200
1346        default 0
1347
1348choice
1349        depends on HZ_FIXED = 0
1350        prompt "Timer frequency"
1351
1352config HZ_100
1353        bool "100 Hz"
1354
1355config HZ_200
1356        bool "200 Hz"
1357
1358config HZ_250
1359        bool "250 Hz"
1360
1361config HZ_300
1362        bool "300 Hz"
1363
1364config HZ_500
1365        bool "500 Hz"
1366
1367config HZ_1000
1368        bool "1000 Hz"
1369
1370endchoice
1371
1372config HZ
1373        int
1374        default HZ_FIXED if HZ_FIXED != 0
1375        default 100 if HZ_100
1376        default 200 if HZ_200
1377        default 250 if HZ_250
1378        default 300 if HZ_300
1379        default 500 if HZ_500
1380        default 1000
1381
1382config SCHED_HRTICK
1383        def_bool HIGH_RES_TIMERS
1384
1385config THUMB2_KERNEL
1386        bool "Compile the kernel in Thumb-2 mode" if !CPU_THUMBONLY
1387        depends on (CPU_V7 || CPU_V7M) && !CPU_V6 && !CPU_V6K
1388        default y if CPU_THUMBONLY
1389        select ARM_UNWIND
1390        help
1391          By enabling this option, the kernel will be compiled in
1392          Thumb-2 mode.
1393
1394          If unsure, say N.
1395
1396config ARM_PATCH_IDIV
1397        bool "Runtime patch udiv/sdiv instructions into __aeabi_{u}idiv()"
1398        depends on CPU_32v7 && !XIP_KERNEL
1399        default y
1400        help
1401          The ARM compiler inserts calls to __aeabi_idiv() and
1402          __aeabi_uidiv() when it needs to perform division on signed
1403          and unsigned integers. Some v7 CPUs have support for the sdiv
1404          and udiv instructions that can be used to implement those
1405          functions.
1406
1407          Enabling this option allows the kernel to modify itself to
1408          replace the first two instructions of these library functions
1409          with the sdiv or udiv plus "bx lr" instructions when the CPU
1410          it is running on supports them. Typically this will be faster
1411          and less power intensive than running the original library
1412          code to do integer division.
1413
1414config AEABI
1415        bool "Use the ARM EABI to compile the kernel" if !CPU_V7 && \
1416                !CPU_V7M && !CPU_V6 && !CPU_V6K && !CC_IS_CLANG
1417        default CPU_V7 || CPU_V7M || CPU_V6 || CPU_V6K || CC_IS_CLANG
1418        help
1419          This option allows for the kernel to be compiled using the latest
1420          ARM ABI (aka EABI).  This is only useful if you are using a user
1421          space environment that is also compiled with EABI.
1422
1423          Since there are major incompatibilities between the legacy ABI and
1424          EABI, especially with regard to structure member alignment, this
1425          option also changes the kernel syscall calling convention to
1426          disambiguate both ABIs and allow for backward compatibility support
1427          (selected with CONFIG_OABI_COMPAT).
1428
1429          To use this you need GCC version 4.0.0 or later.
1430
1431config OABI_COMPAT
1432        bool "Allow old ABI binaries to run with this kernel (EXPERIMENTAL)"
1433        depends on AEABI && !THUMB2_KERNEL
1434        help
1435          This option preserves the old syscall interface along with the
1436          new (ARM EABI) one. It also provides a compatibility layer to
1437          intercept syscalls that have structure arguments which layout
1438          in memory differs between the legacy ABI and the new ARM EABI
1439          (only for non "thumb" binaries). This option adds a tiny
1440          overhead to all syscalls and produces a slightly larger kernel.
1441
1442          The seccomp filter system will not be available when this is
1443          selected, since there is no way yet to sensibly distinguish
1444          between calling conventions during filtering.
1445
1446          If you know you'll be using only pure EABI user space then you
1447          can say N here. If this option is not selected and you attempt
1448          to execute a legacy ABI binary then the result will be
1449          UNPREDICTABLE (in fact it can be predicted that it won't work
1450          at all). If in doubt say N.
1451
1452config ARCH_SELECT_MEMORY_MODEL
1453        bool
1454
1455config ARCH_FLATMEM_ENABLE
1456        bool
1457
1458config ARCH_SPARSEMEM_ENABLE
1459        bool
1460        select SPARSEMEM_STATIC if SPARSEMEM
1461
1462config HIGHMEM
1463        bool "High Memory Support"
1464        depends on MMU
1465        select KMAP_LOCAL
1466        select KMAP_LOCAL_NON_LINEAR_PTE_ARRAY
1467        help
1468          The address space of ARM processors is only 4 Gigabytes large
1469          and it has to accommodate user address space, kernel address
1470          space as well as some memory mapped IO. That means that, if you
1471          have a large amount of physical memory and/or IO, not all of the
1472          memory can be "permanently mapped" by the kernel. The physical
1473          memory that is not permanently mapped is called "high memory".
1474
1475          Depending on the selected kernel/user memory split, minimum
1476          vmalloc space and actual amount of RAM, you may not need this
1477          option which should result in a slightly faster kernel.
1478
1479          If unsure, say n.
1480
1481config HIGHPTE
1482        bool "Allocate 2nd-level pagetables from highmem" if EXPERT
1483        depends on HIGHMEM
1484        default y
1485        help
1486          The VM uses one page of physical memory for each page table.
1487          For systems with a lot of processes, this can use a lot of
1488          precious low memory, eventually leading to low memory being
1489          consumed by page tables.  Setting this option will allow
1490          user-space 2nd level page tables to reside in high memory.
1491
1492config CPU_SW_DOMAIN_PAN
1493        bool "Enable use of CPU domains to implement privileged no-access"
1494        depends on MMU && !ARM_LPAE
1495        default y
1496        help
1497          Increase kernel security by ensuring that normal kernel accesses
1498          are unable to access userspace addresses.  This can help prevent
1499          use-after-free bugs becoming an exploitable privilege escalation
1500          by ensuring that magic values (such as LIST_POISON) will always
1501          fault when dereferenced.
1502
1503          CPUs with low-vector mappings use a best-efforts implementation.
1504          Their lower 1MB needs to remain accessible for the vectors, but
1505          the remainder of userspace will become appropriately inaccessible.
1506
1507config HW_PERF_EVENTS
1508        def_bool y
1509        depends on ARM_PMU
1510
1511config ARCH_WANT_GENERAL_HUGETLB
1512        def_bool y
1513
1514config ARM_MODULE_PLTS
1515        bool "Use PLTs to allow module memory to spill over into vmalloc area"
1516        depends on MODULES
1517        default y
1518        help
1519          Allocate PLTs when loading modules so that jumps and calls whose
1520          targets are too far away for their relative offsets to be encoded
1521          in the instructions themselves can be bounced via veneers in the
1522          module's PLT. This allows modules to be allocated in the generic
1523          vmalloc area after the dedicated module memory area has been
1524          exhausted. The modules will use slightly more memory, but after
1525          rounding up to page size, the actual memory footprint is usually
1526          the same.
1527
1528          Disabling this is usually safe for small single-platform
1529          configurations. If unsure, say y.
1530
1531config FORCE_MAX_ZONEORDER
1532        int "Maximum zone order"
1533        default "12" if SOC_AM33XX
1534        default "9" if SA1111
1535        default "11"
1536        help
1537          The kernel memory allocator divides physically contiguous memory
1538          blocks into "zones", where each zone is a power of two number of
1539          pages.  This option selects the largest power of two that the kernel
1540          keeps in the memory allocator.  If you need to allocate very large
1541          blocks of physically contiguous memory, then you may need to
1542          increase this value.
1543
1544          This config option is actually maximum order plus one. For example,
1545          a value of 11 means that the largest free memory block is 2^10 pages.
1546
1547config ALIGNMENT_TRAP
1548        def_bool CPU_CP15_MMU
1549        select HAVE_PROC_CPU if PROC_FS
1550        help
1551          ARM processors cannot fetch/store information which is not
1552          naturally aligned on the bus, i.e., a 4 byte fetch must start at an
1553          address divisible by 4. On 32-bit ARM processors, these non-aligned
1554          fetch/store instructions will be emulated in software if you say
1555          here, which has a severe performance impact. This is necessary for
1556          correct operation of some network protocols. With an IP-only
1557          configuration it is safe to say N, otherwise say Y.
1558
1559config UACCESS_WITH_MEMCPY
1560        bool "Use kernel mem{cpy,set}() for {copy_to,clear}_user()"
1561        depends on MMU
1562        default y if CPU_FEROCEON
1563        help
1564          Implement faster copy_to_user and clear_user methods for CPU
1565          cores where a 8-word STM instruction give significantly higher
1566          memory write throughput than a sequence of individual 32bit stores.
1567
1568          A possible side effect is a slight increase in scheduling latency
1569          between threads sharing the same address space if they invoke
1570          such copy operations with large buffers.
1571
1572          However, if the CPU data cache is using a write-allocate mode,
1573          this option is unlikely to provide any performance gain.
1574
1575config PARAVIRT
1576        bool "Enable paravirtualization code"
1577        help
1578          This changes the kernel so it can modify itself when it is run
1579          under a hypervisor, potentially improving performance significantly
1580          over full virtualization.
1581
1582config PARAVIRT_TIME_ACCOUNTING
1583        bool "Paravirtual steal time accounting"
1584        select PARAVIRT
1585        help
1586          Select this option to enable fine granularity task steal time
1587          accounting. Time spent executing other tasks in parallel with
1588          the current vCPU is discounted from the vCPU power. To account for
1589          that, there can be a small performance impact.
1590
1591          If in doubt, say N here.
1592
1593config XEN_DOM0
1594        def_bool y
1595        depends on XEN
1596
1597config XEN
1598        bool "Xen guest support on ARM"
1599        depends on ARM && AEABI && OF
1600        depends on CPU_V7 && !CPU_V6
1601        depends on !GENERIC_ATOMIC64
1602        depends on MMU
1603        select ARCH_DMA_ADDR_T_64BIT
1604        select ARM_PSCI
1605        select SWIOTLB
1606        select SWIOTLB_XEN
1607        select PARAVIRT
1608        help
1609          Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
1610
1611config STACKPROTECTOR_PER_TASK
1612        bool "Use a unique stack canary value for each task"
1613        depends on GCC_PLUGINS && STACKPROTECTOR && THREAD_INFO_IN_TASK && !XIP_DEFLATED_DATA
1614        select GCC_PLUGIN_ARM_SSP_PER_TASK
1615        default y
1616        help
1617          Due to the fact that GCC uses an ordinary symbol reference from
1618          which to load the value of the stack canary, this value can only
1619          change at reboot time on SMP systems, and all tasks running in the
1620          kernel's address space are forced to use the same canary value for
1621          the entire duration that the system is up.
1622
1623          Enable this option to switch to a different method that uses a
1624          different canary value for each task.
1625
1626endmenu
1627
1628menu "Boot options"
1629
1630config USE_OF
1631        bool "Flattened Device Tree support"
1632        select IRQ_DOMAIN
1633        select OF
1634        help
1635          Include support for flattened device tree machine descriptions.
1636
1637config ATAGS
1638        bool "Support for the traditional ATAGS boot data passing" if USE_OF
1639        default y
1640        help
1641          This is the traditional way of passing data to the kernel at boot
1642          time. If you are solely relying on the flattened device tree (or
1643          the ARM_ATAG_DTB_COMPAT option) then you may unselect this option
1644          to remove ATAGS support from your kernel binary.  If unsure,
1645          leave this to y.
1646
1647config DEPRECATED_PARAM_STRUCT
1648        bool "Provide old way to pass kernel parameters"
1649        depends on ATAGS
1650        help
1651          This was deprecated in 2001 and announced to live on for 5 years.
1652          Some old boot loaders still use this way.
1653
1654# Compressed boot loader in ROM.  Yes, we really want to ask about
1655# TEXT and BSS so we preserve their values in the config files.
1656config ZBOOT_ROM_TEXT
1657        hex "Compressed ROM boot loader base address"
1658        default 0x0
1659        help
1660          The physical address at which the ROM-able zImage is to be
1661          placed in the target.  Platforms which normally make use of
1662          ROM-able zImage formats normally set this to a suitable
1663          value in their defconfig file.
1664
1665          If ZBOOT_ROM is not enabled, this has no effect.
1666
1667config ZBOOT_ROM_BSS
1668        hex "Compressed ROM boot loader BSS address"
1669        default 0x0
1670        help
1671          The base address of an area of read/write memory in the target
1672          for the ROM-able zImage which must be available while the
1673          decompressor is running. It must be large enough to hold the
1674          entire decompressed kernel plus an additional 128 KiB.
1675          Platforms which normally make use of ROM-able zImage formats
1676          normally set this to a suitable value in their defconfig file.
1677
1678          If ZBOOT_ROM is not enabled, this has no effect.
1679
1680config ZBOOT_ROM
1681        bool "Compressed boot loader in ROM/flash"
1682        depends on ZBOOT_ROM_TEXT != ZBOOT_ROM_BSS
1683        depends on !ARM_APPENDED_DTB && !XIP_KERNEL && !AUTO_ZRELADDR
1684        help
1685          Say Y here if you intend to execute your compressed kernel image
1686          (zImage) directly from ROM or flash.  If unsure, say N.
1687
1688config ARM_APPENDED_DTB
1689        bool "Use appended device tree blob to zImage (EXPERIMENTAL)"
1690        depends on OF
1691        help
1692          With this option, the boot code will look for a device tree binary
1693          (DTB) appended to zImage
1694          (e.g. cat zImage <filename>.dtb > zImage_w_dtb).
1695
1696          This is meant as a backward compatibility convenience for those
1697          systems with a bootloader that can't be upgraded to accommodate
1698          the documented boot protocol using a device tree.
1699
1700          Beware that there is very little in terms of protection against
1701          this option being confused by leftover garbage in memory that might
1702          look like a DTB header after a reboot if no actual DTB is appended
1703          to zImage.  Do not leave this option active in a production kernel
1704          if you don't intend to always append a DTB.  Proper passing of the
1705          location into r2 of a bootloader provided DTB is always preferable
1706          to this option.
1707
1708config ARM_ATAG_DTB_COMPAT
1709        bool "Supplement the appended DTB with traditional ATAG information"
1710        depends on ARM_APPENDED_DTB
1711        help
1712          Some old bootloaders can't be updated to a DTB capable one, yet
1713          they provide ATAGs with memory configuration, the ramdisk address,
1714          the kernel cmdline string, etc.  Such information is dynamically
1715          provided by the bootloader and can't always be stored in a static
1716          DTB.  To allow a device tree enabled kernel to be used with such
1717          bootloaders, this option allows zImage to extract the information
1718          from the ATAG list and store it at run time into the appended DTB.
1719
1720choice
1721        prompt "Kernel command line type" if ARM_ATAG_DTB_COMPAT
1722        default ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER
1723
1724config ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER
1725        bool "Use bootloader kernel arguments if available"
1726        help
1727          Uses the command-line options passed by the boot loader instead of
1728          the device tree bootargs property. If the boot loader doesn't provide
1729          any, the device tree bootargs property will be used.
1730
1731config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND
1732        bool "Extend with bootloader kernel arguments"
1733        help
1734          The command-line arguments provided by the boot loader will be
1735          appended to the the device tree bootargs property.
1736
1737endchoice
1738
1739config CMDLINE
1740        string "Default kernel command string"
1741        default ""
1742        help
1743          On some architectures (e.g. CATS), there is currently no way
1744          for the boot loader to pass arguments to the kernel. For these
1745          architectures, you should supply some command-line options at build
1746          time by entering them here. As a minimum, you should specify the
1747          memory size and the root device (e.g., mem=64M root=/dev/nfs).
1748
1749choice
1750        prompt "Kernel command line type" if CMDLINE != ""
1751        default CMDLINE_FROM_BOOTLOADER
1752        depends on ATAGS
1753
1754config CMDLINE_FROM_BOOTLOADER
1755        bool "Use bootloader kernel arguments if available"
1756        help
1757          Uses the command-line options passed by the boot loader. If
1758          the boot loader doesn't provide any, the default kernel command
1759          string provided in CMDLINE will be used.
1760
1761config CMDLINE_EXTEND
1762        bool "Extend bootloader kernel arguments"
1763        help
1764          The command-line arguments provided by the boot loader will be
1765          appended to the default kernel command string.
1766
1767config CMDLINE_FORCE
1768        bool "Always use the default kernel command string"
1769        help
1770          Always use the default kernel command string, even if the boot
1771          loader passes other arguments to the kernel.
1772          This is useful if you cannot or don't want to change the
1773          command-line options your boot loader passes to the kernel.
1774endchoice
1775
1776config XIP_KERNEL
1777        bool "Kernel Execute-In-Place from ROM"
1778        depends on !ARM_LPAE && !ARCH_MULTIPLATFORM
1779        help
1780          Execute-In-Place allows the kernel to run from non-volatile storage
1781          directly addressable by the CPU, such as NOR flash. This saves RAM
1782          space since the text section of the kernel is not loaded from flash
1783          to RAM.  Read-write sections, such as the data section and stack,
1784          are still copied to RAM.  The XIP kernel is not compressed since
1785          it has to run directly from flash, so it will take more space to
1786          store it.  The flash address used to link the kernel object files,
1787          and for storing it, is configuration dependent. Therefore, if you
1788          say Y here, you must know the proper physical address where to
1789          store the kernel image depending on your own flash memory usage.
1790
1791          Also note that the make target becomes "make xipImage" rather than
1792          "make zImage" or "make Image".  The final kernel binary to put in
1793          ROM memory will be arch/arm/boot/xipImage.
1794
1795          If unsure, say N.
1796
1797config XIP_PHYS_ADDR
1798        hex "XIP Kernel Physical Location"
1799        depends on XIP_KERNEL
1800        default "0x00080000"
1801        help
1802          This is the physical address in your flash memory the kernel will
1803          be linked for and stored to.  This address is dependent on your
1804          own flash usage.
1805
1806config XIP_DEFLATED_DATA
1807        bool "Store kernel .data section compressed in ROM"
1808        depends on XIP_KERNEL
1809        select ZLIB_INFLATE
1810        help
1811          Before the kernel is actually executed, its .data section has to be
1812          copied to RAM from ROM. This option allows for storing that data
1813          in compressed form and decompressed to RAM rather than merely being
1814          copied, saving some precious ROM space. A possible drawback is a
1815          slightly longer boot delay.
1816
1817config KEXEC
1818        bool "Kexec system call (EXPERIMENTAL)"
1819        depends on (!SMP || PM_SLEEP_SMP)
1820        depends on MMU
1821        select KEXEC_CORE
1822        help
1823          kexec is a system call that implements the ability to shutdown your
1824          current kernel, and to start another kernel.  It is like a reboot
1825          but it is independent of the system firmware.   And like a reboot
1826          you can start any kernel with it, not just Linux.
1827
1828          It is an ongoing process to be certain the hardware in a machine
1829          is properly shutdown, so do not be surprised if this code does not
1830          initially work for you.
1831
1832config ATAGS_PROC
1833        bool "Export atags in procfs"
1834        depends on ATAGS && KEXEC
1835        default y
1836        help
1837          Should the atags used to boot the kernel be exported in an "atags"
1838          file in procfs. Useful with kexec.
1839
1840config CRASH_DUMP
1841        bool "Build kdump crash kernel (EXPERIMENTAL)"
1842        help
1843          Generate crash dump after being started by kexec. This should
1844          be normally only set in special crash dump kernels which are
1845          loaded in the main kernel with kexec-tools into a specially
1846          reserved region and then later executed after a crash by
1847          kdump/kexec. The crash dump kernel must be compiled to a
1848          memory address not used by the main kernel
1849
1850          For more details see Documentation/admin-guide/kdump/kdump.rst
1851
1852config AUTO_ZRELADDR
1853        bool "Auto calculation of the decompressed kernel image address"
1854        help
1855          ZRELADDR is the physical address where the decompressed kernel
1856          image will be placed. If AUTO_ZRELADDR is selected, the address
1857          will be determined at run-time, either by masking the current IP
1858          with 0xf8000000, or, if invalid, from the DTB passed in r2.
1859          This assumes the zImage being placed in the first 128MB from
1860          start of memory.
1861
1862config EFI_STUB
1863        bool
1864
1865config EFI
1866        bool "UEFI runtime support"
1867        depends on OF && !CPU_BIG_ENDIAN && MMU && AUTO_ZRELADDR && !XIP_KERNEL
1868        select UCS2_STRING
1869        select EFI_PARAMS_FROM_FDT
1870        select EFI_STUB
1871        select EFI_GENERIC_STUB
1872        select EFI_RUNTIME_WRAPPERS
1873        help
1874          This option provides support for runtime services provided
1875          by UEFI firmware (such as non-volatile variables, realtime
1876          clock, and platform reset). A UEFI stub is also provided to
1877          allow the kernel to be booted as an EFI application. This
1878          is only useful for kernels that may run on systems that have
1879          UEFI firmware.
1880
1881config DMI
1882        bool "Enable support for SMBIOS (DMI) tables"
1883        depends on EFI
1884        default y
1885        help
1886          This enables SMBIOS/DMI feature for systems.
1887
1888          This option is only useful on systems that have UEFI firmware.
1889          However, even with this option, the resultant kernel should
1890          continue to boot on existing non-UEFI platforms.
1891
1892          NOTE: This does *NOT* enable or encourage the use of DMI quirks,
1893          i.e., the the practice of identifying the platform via DMI to
1894          decide whether certain workarounds for buggy hardware and/or
1895          firmware need to be enabled. This would require the DMI subsystem
1896          to be enabled much earlier than we do on ARM, which is non-trivial.
1897
1898endmenu
1899
1900menu "CPU Power Management"
1901
1902source "drivers/cpufreq/Kconfig"
1903
1904source "drivers/cpuidle/Kconfig"
1905
1906endmenu
1907
1908menu "Floating point emulation"
1909
1910comment "At least one emulation must be selected"
1911
1912config FPE_NWFPE
1913        bool "NWFPE math emulation"
1914        depends on (!AEABI || OABI_COMPAT) && !THUMB2_KERNEL
1915        help
1916          Say Y to include the NWFPE floating point emulator in the kernel.
1917          This is necessary to run most binaries. Linux does not currently
1918          support floating point hardware so you need to say Y here even if
1919          your machine has an FPA or floating point co-processor podule.
1920
1921          You may say N here if you are going to load the Acorn FPEmulator
1922          early in the bootup.
1923
1924config FPE_NWFPE_XP
1925        bool "Support extended precision"
1926        depends on FPE_NWFPE
1927        help
1928          Say Y to include 80-bit support in the kernel floating-point
1929          emulator.  Otherwise, only 32 and 64-bit support is compiled in.
1930          Note that gcc does not generate 80-bit operations by default,
1931          so in most cases this option only enlarges the size of the
1932          floating point emulator without any good reason.
1933
1934          You almost surely want to say N here.
1935
1936config FPE_FASTFPE
1937        bool "FastFPE math emulation (EXPERIMENTAL)"
1938        depends on (!AEABI || OABI_COMPAT) && !CPU_32v3
1939        help
1940          Say Y here to include the FAST floating point emulator in the kernel.
1941          This is an experimental much faster emulator which now also has full
1942          precision for the mantissa.  It does not support any exceptions.
1943          It is very simple, and approximately 3-6 times faster than NWFPE.
1944
1945          It should be sufficient for most programs.  It may be not suitable
1946          for scientific calculations, but you have to check this for yourself.
1947          If you do not feel you need a faster FP emulation you should better
1948          choose NWFPE.
1949
1950config VFP
1951        bool "VFP-format floating point maths"
1952        depends on CPU_V6 || CPU_V6K || CPU_ARM926T || CPU_V7 || CPU_FEROCEON
1953        help
1954          Say Y to include VFP support code in the kernel. This is needed
1955          if your hardware includes a VFP unit.
1956
1957          Please see <file:Documentation/arm/vfp/release-notes.rst> for
1958          release notes and additional status information.
1959
1960          Say N if your target does not have VFP hardware.
1961
1962config VFPv3
1963        bool
1964        depends on VFP
1965        default y if CPU_V7
1966
1967config NEON
1968        bool "Advanced SIMD (NEON) Extension support"
1969        depends on VFPv3 && CPU_V7
1970        help
1971          Say Y to include support code for NEON, the ARMv7 Advanced SIMD
1972          Extension.
1973
1974config KERNEL_MODE_NEON
1975        bool "Support for NEON in kernel mode"
1976        depends on NEON && AEABI
1977        help
1978          Say Y to include support for NEON in kernel mode.
1979
1980endmenu
1981
1982menu "Power management options"
1983
1984source "kernel/power/Kconfig"
1985
1986config ARCH_SUSPEND_POSSIBLE
1987        depends on CPU_ARM920T || CPU_ARM926T || CPU_FEROCEON || CPU_SA1100 || \
1988                CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M || CPU_XSC3 || CPU_XSCALE || CPU_MOHAWK
1989        def_bool y
1990
1991config ARM_CPU_SUSPEND
1992        def_bool PM_SLEEP || BL_SWITCHER || ARM_PSCI_FW
1993        depends on ARCH_SUSPEND_POSSIBLE
1994
1995config ARCH_HIBERNATION_POSSIBLE
1996        bool
1997        depends on MMU
1998        default y if ARCH_SUSPEND_POSSIBLE
1999
2000endmenu
2001
2002if CRYPTO
2003source "arch/arm/crypto/Kconfig"
2004endif
2005
2006source "arch/arm/Kconfig.assembler"
2007