1# SPDX-License-Identifier: GPL-2.0 2config ARM 3 bool 4 default y 5 select ARCH_32BIT_OFF_T 6 select ARCH_CLOCKSOURCE_DATA 7 select ARCH_HAS_BINFMT_FLAT 8 select ARCH_HAS_DEBUG_VIRTUAL if MMU 9 select ARCH_HAS_DEVMEM_IS_ALLOWED 10 select ARCH_HAS_DMA_WRITE_COMBINE if !ARM_DMA_MEM_BUFFERABLE 11 select ARCH_HAS_ELF_RANDOMIZE 12 select ARCH_HAS_FORTIFY_SOURCE 13 select ARCH_HAS_KEEPINITRD 14 select ARCH_HAS_KCOV 15 select ARCH_HAS_MEMBARRIER_SYNC_CORE 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 23 select ARCH_HAS_SYNC_DMA_FOR_CPU if SWIOTLB 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_HAS_GCOV_PROFILE_ALL 28 select ARCH_KEEP_MEMBLOCK if HAVE_ARCH_PFN_VALID || KEXEC 29 select ARCH_MIGHT_HAVE_PC_PARPORT 30 select ARCH_NO_SG_CHAIN if !ARM_HAS_SG_CHAIN 31 select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX 32 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 33 select ARCH_SUPPORTS_ATOMIC_RMW 34 select ARCH_USE_BUILTIN_BSWAP 35 select ARCH_USE_CMPXCHG_LOCKREF 36 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU 37 select ARCH_WANT_IPC_PARSE_VERSION 38 select BINFMT_FLAT_ARGVP_ENVP_ON_STACK 39 select BUILDTIME_EXTABLE_SORT if MMU 40 select CLONE_BACKWARDS 41 select CPU_PM if SUSPEND || CPU_IDLE 42 select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS 43 select DMA_DECLARE_COHERENT 44 select DMA_REMAP if MMU 45 select EDAC_SUPPORT 46 select EDAC_ATOMIC_SCRUB 47 select GENERIC_ALLOCATOR 48 select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY 49 select GENERIC_ATOMIC64 if CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI 50 select GENERIC_CLOCKEVENTS_BROADCAST if SMP 51 select GENERIC_CPU_AUTOPROBE 52 select GENERIC_EARLY_IOREMAP 53 select GENERIC_IDLE_POLL_SETUP 54 select GENERIC_IRQ_PROBE 55 select GENERIC_IRQ_SHOW 56 select GENERIC_IRQ_SHOW_LEVEL 57 select GENERIC_PCI_IOMAP 58 select GENERIC_SCHED_CLOCK 59 select GENERIC_SMP_IDLE_THREAD 60 select GENERIC_STRNCPY_FROM_USER 61 select GENERIC_STRNLEN_USER 62 select HANDLE_DOMAIN_IRQ 63 select HARDIRQS_SW_RESEND 64 select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT 65 select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 66 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU 67 select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU 68 select HAVE_ARCH_MMAP_RND_BITS if MMU 69 select HAVE_ARCH_SECCOMP_FILTER if AEABI && !OABI_COMPAT 70 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 71 select HAVE_ARCH_TRACEHOOK 72 select HAVE_ARM_SMCCC if CPU_V7 73 select HAVE_EBPF_JIT if !CPU_ENDIAN_BE32 74 select HAVE_CONTEXT_TRACKING 75 select HAVE_C_RECORDMCOUNT 76 select HAVE_DEBUG_KMEMLEAK 77 select HAVE_DMA_CONTIGUOUS if MMU 78 select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU 79 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE 80 select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU 81 select HAVE_EXIT_THREAD 82 select HAVE_FAST_GUP if ARM_LPAE 83 select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL 84 select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG 85 select HAVE_FUNCTION_TRACER if !XIP_KERNEL && (CC_IS_GCC || CLANG_VERSION >= 100000) 86 select HAVE_GCC_PLUGINS 87 select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7) 88 select HAVE_IDE if PCI || ISA || PCMCIA 89 select HAVE_IRQ_TIME_ACCOUNTING 90 select HAVE_KERNEL_GZIP 91 select HAVE_KERNEL_LZ4 92 select HAVE_KERNEL_LZMA 93 select HAVE_KERNEL_LZO 94 select HAVE_KERNEL_XZ 95 select HAVE_KPROBES if !XIP_KERNEL && !CPU_ENDIAN_BE32 && !CPU_V7M 96 select HAVE_KRETPROBES if HAVE_KPROBES 97 select HAVE_MOD_ARCH_SPECIFIC 98 select HAVE_NMI 99 select HAVE_OPROFILE if HAVE_PERF_EVENTS 100 select HAVE_OPTPROBES if !THUMB2_KERNEL 101 select HAVE_PERF_EVENTS 102 select HAVE_PERF_REGS 103 select HAVE_PERF_USER_STACK_DUMP 104 select HAVE_RCU_TABLE_FREE if SMP && ARM_LPAE 105 select HAVE_REGS_AND_STACK_ACCESS_API 106 select HAVE_RSEQ 107 select HAVE_STACKPROTECTOR 108 select HAVE_SYSCALL_TRACEPOINTS 109 select HAVE_UID16 110 select HAVE_VIRT_CPU_ACCOUNTING_GEN 111 select IRQ_FORCED_THREADING 112 select MODULES_USE_ELF_REL 113 select NEED_DMA_MAP_STATE 114 select OF_EARLY_FLATTREE if OF 115 select OLD_SIGACTION 116 select OLD_SIGSUSPEND3 117 select PCI_SYSCALL if PCI 118 select PERF_USE_VMALLOC 119 select RTC_LIB 120 select SYS_SUPPORTS_APM_EMULATION 121 # Above selects are sorted alphabetically; please add new ones 122 # according to that. Thanks. 123 help 124 The ARM series is a line of low-power-consumption RISC chip designs 125 licensed by ARM Ltd and targeted at embedded applications and 126 handhelds such as the Compaq IPAQ. ARM-based PCs are no longer 127 manufactured, but legacy ARM-based PC hardware remains popular in 128 Europe. There is an ARM Linux project with a web page at 129 <http://www.arm.linux.org.uk/>. 130 131config ARM_HAS_SG_CHAIN 132 bool 133 134config ARM_DMA_USE_IOMMU 135 bool 136 select ARM_HAS_SG_CHAIN 137 select NEED_SG_DMA_LENGTH 138 139if ARM_DMA_USE_IOMMU 140 141config ARM_DMA_IOMMU_ALIGNMENT 142 int "Maximum PAGE_SIZE order of alignment for DMA IOMMU buffers" 143 range 4 9 144 default 8 145 help 146 DMA mapping framework by default aligns all buffers to the smallest 147 PAGE_SIZE order which is greater than or equal to the requested buffer 148 size. This works well for buffers up to a few hundreds kilobytes, but 149 for larger buffers it just a waste of address space. Drivers which has 150 relatively small addressing window (like 64Mib) might run out of 151 virtual space with just a few allocations. 152 153 With this parameter you can specify the maximum PAGE_SIZE order for 154 DMA IOMMU buffers. Larger buffers will be aligned only to this 155 specified order. The order is expressed as a power of two multiplied 156 by the PAGE_SIZE. 157 158endif 159 160config SYS_SUPPORTS_APM_EMULATION 161 bool 162 163config HAVE_TCM 164 bool 165 select GENERIC_ALLOCATOR 166 167config HAVE_PROC_CPU 168 bool 169 170config NO_IOPORT_MAP 171 bool 172 173config SBUS 174 bool 175 176config STACKTRACE_SUPPORT 177 bool 178 default y 179 180config LOCKDEP_SUPPORT 181 bool 182 default y 183 184config TRACE_IRQFLAGS_SUPPORT 185 bool 186 default !CPU_V7M 187 188config ARCH_HAS_ILOG2_U32 189 bool 190 191config ARCH_HAS_ILOG2_U64 192 bool 193 194config ARCH_HAS_BANDGAP 195 bool 196 197config FIX_EARLYCON_MEM 198 def_bool y if MMU 199 200config GENERIC_HWEIGHT 201 bool 202 default y 203 204config GENERIC_CALIBRATE_DELAY 205 bool 206 default y 207 208config ARCH_MAY_HAVE_PC_FDC 209 bool 210 211config ZONE_DMA 212 bool 213 214config ARCH_SUPPORTS_UPROBES 215 def_bool y 216 217config ARCH_HAS_DMA_SET_COHERENT_MASK 218 bool 219 220config GENERIC_ISA_DMA 221 bool 222 223config FIQ 224 bool 225 226config NEED_RET_TO_USER 227 bool 228 229config ARCH_MTD_XIP 230 bool 231 232config ARM_PATCH_PHYS_VIRT 233 bool "Patch physical to virtual translations at runtime" if EMBEDDED 234 default y 235 depends on !XIP_KERNEL && MMU 236 help 237 Patch phys-to-virt and virt-to-phys translation functions at 238 boot and module load time according to the position of the 239 kernel in system memory. 240 241 This can only be used with non-XIP MMU kernels where the base 242 of physical memory is at a 16MB boundary. 243 244 Only disable this option if you know that you do not require 245 this feature (eg, building a kernel for a single machine) and 246 you need to shrink the kernel to the minimal size. 247 248config NEED_MACH_IO_H 249 bool 250 help 251 Select this when mach/io.h is required to provide special 252 definitions for this platform. The need for mach/io.h should 253 be avoided when possible. 254 255config NEED_MACH_MEMORY_H 256 bool 257 help 258 Select this when mach/memory.h is required to provide special 259 definitions for this platform. The need for mach/memory.h should 260 be avoided when possible. 261 262config PHYS_OFFSET 263 hex "Physical address of main memory" if MMU 264 depends on !ARM_PATCH_PHYS_VIRT 265 default DRAM_BASE if !MMU 266 default 0x00000000 if ARCH_EBSA110 || \ 267 ARCH_FOOTBRIDGE || \ 268 ARCH_INTEGRATOR || \ 269 ARCH_REALVIEW 270 default 0x10000000 if ARCH_OMAP1 || ARCH_RPC 271 default 0x20000000 if ARCH_S5PV210 272 default 0xc0000000 if ARCH_SA1100 273 help 274 Please provide the physical address corresponding to the 275 location of main memory in your system. 276 277config GENERIC_BUG 278 def_bool y 279 depends on BUG 280 281config PGTABLE_LEVELS 282 int 283 default 3 if ARM_LPAE 284 default 2 285 286menu "System Type" 287 288config MMU 289 bool "MMU-based Paged Memory Management Support" 290 default y 291 help 292 Select if you want MMU-based virtualised addressing space 293 support by paged memory management. If unsure, say 'Y'. 294 295config ARCH_MMAP_RND_BITS_MIN 296 default 8 297 298config ARCH_MMAP_RND_BITS_MAX 299 default 14 if PAGE_OFFSET=0x40000000 300 default 15 if PAGE_OFFSET=0x80000000 301 default 16 302 303# 304# The "ARM system type" choice list is ordered alphabetically by option 305# text. Please add new entries in the option alphabetic order. 306# 307choice 308 prompt "ARM system type" 309 default ARM_SINGLE_ARMV7M if !MMU 310 default ARCH_MULTIPLATFORM if MMU 311 312config ARCH_MULTIPLATFORM 313 bool "Allow multiple platforms to be selected" 314 depends on MMU 315 select ARM_HAS_SG_CHAIN 316 select ARM_PATCH_PHYS_VIRT 317 select AUTO_ZRELADDR 318 select TIMER_OF 319 select COMMON_CLK 320 select GENERIC_CLOCKEVENTS 321 select GENERIC_IRQ_MULTI_HANDLER 322 select HAVE_PCI 323 select PCI_DOMAINS_GENERIC if PCI 324 select SPARSE_IRQ 325 select USE_OF 326 327config ARM_SINGLE_ARMV7M 328 bool "ARMv7-M based platforms (Cortex-M0/M3/M4)" 329 depends on !MMU 330 select ARM_NVIC 331 select AUTO_ZRELADDR 332 select TIMER_OF 333 select COMMON_CLK 334 select CPU_V7M 335 select GENERIC_CLOCKEVENTS 336 select NO_IOPORT_MAP 337 select SPARSE_IRQ 338 select USE_OF 339 340config ARCH_EBSA110 341 bool "EBSA-110" 342 select ARCH_USES_GETTIMEOFFSET 343 select CPU_SA110 344 select ISA 345 select NEED_MACH_IO_H 346 select NEED_MACH_MEMORY_H 347 select NO_IOPORT_MAP 348 help 349 This is an evaluation board for the StrongARM processor available 350 from Digital. It has limited hardware on-board, including an 351 Ethernet interface, two PCMCIA sockets, two serial ports and a 352 parallel port. 353 354config ARCH_EP93XX 355 bool "EP93xx-based" 356 select ARCH_SPARSEMEM_ENABLE 357 select ARM_AMBA 358 imply ARM_PATCH_PHYS_VIRT 359 select ARM_VIC 360 select AUTO_ZRELADDR 361 select CLKDEV_LOOKUP 362 select CLKSRC_MMIO 363 select CPU_ARM920T 364 select GENERIC_CLOCKEVENTS 365 select GPIOLIB 366 help 367 This enables support for the Cirrus EP93xx series of CPUs. 368 369config ARCH_FOOTBRIDGE 370 bool "FootBridge" 371 select CPU_SA110 372 select FOOTBRIDGE 373 select GENERIC_CLOCKEVENTS 374 select HAVE_IDE 375 select NEED_MACH_IO_H if !MMU 376 select NEED_MACH_MEMORY_H 377 help 378 Support for systems based on the DC21285 companion chip 379 ("FootBridge"), such as the Simtec CATS and the Rebel NetWinder. 380 381config ARCH_IOP32X 382 bool "IOP32x-based" 383 depends on MMU 384 select CPU_XSCALE 385 select GPIO_IOP 386 select GPIOLIB 387 select NEED_RET_TO_USER 388 select FORCE_PCI 389 select PLAT_IOP 390 help 391 Support for Intel's 80219 and IOP32X (XScale) family of 392 processors. 393 394config ARCH_IXP4XX 395 bool "IXP4xx-based" 396 depends on MMU 397 select ARCH_HAS_DMA_SET_COHERENT_MASK 398 select ARCH_SUPPORTS_BIG_ENDIAN 399 select CPU_XSCALE 400 select DMABOUNCE if PCI 401 select GENERIC_CLOCKEVENTS 402 select GENERIC_IRQ_MULTI_HANDLER 403 select GPIO_IXP4XX 404 select GPIOLIB 405 select HAVE_PCI 406 select IXP4XX_IRQ 407 select IXP4XX_TIMER 408 select NEED_MACH_IO_H 409 select USB_EHCI_BIG_ENDIAN_DESC 410 select USB_EHCI_BIG_ENDIAN_MMIO 411 help 412 Support for Intel's IXP4XX (XScale) family of processors. 413 414config ARCH_DOVE 415 bool "Marvell Dove" 416 select CPU_PJ4 417 select GENERIC_CLOCKEVENTS 418 select GENERIC_IRQ_MULTI_HANDLER 419 select GPIOLIB 420 select HAVE_PCI 421 select MVEBU_MBUS 422 select PINCTRL 423 select PINCTRL_DOVE 424 select PLAT_ORION_LEGACY 425 select SPARSE_IRQ 426 select PM_GENERIC_DOMAINS if PM 427 help 428 Support for the Marvell Dove SoC 88AP510 429 430config ARCH_PXA 431 bool "PXA2xx/PXA3xx-based" 432 depends on MMU 433 select ARCH_MTD_XIP 434 select ARM_CPU_SUSPEND if PM 435 select AUTO_ZRELADDR 436 select COMMON_CLK 437 select CLKDEV_LOOKUP 438 select CLKSRC_PXA 439 select CLKSRC_MMIO 440 select TIMER_OF 441 select CPU_XSCALE if !CPU_XSC3 442 select GENERIC_CLOCKEVENTS 443 select GENERIC_IRQ_MULTI_HANDLER 444 select GPIO_PXA 445 select GPIOLIB 446 select HAVE_IDE 447 select IRQ_DOMAIN 448 select PLAT_PXA 449 select SPARSE_IRQ 450 help 451 Support for Intel/Marvell's PXA2xx/PXA3xx processor line. 452 453config ARCH_RPC 454 bool "RiscPC" 455 depends on MMU 456 select ARCH_ACORN 457 select ARCH_MAY_HAVE_PC_FDC 458 select ARCH_SPARSEMEM_ENABLE 459 select ARM_HAS_SG_CHAIN 460 select CPU_SA110 461 select FIQ 462 select HAVE_IDE 463 select HAVE_PATA_PLATFORM 464 select ISA_DMA_API 465 select NEED_MACH_IO_H 466 select NEED_MACH_MEMORY_H 467 select NO_IOPORT_MAP 468 help 469 On the Acorn Risc-PC, Linux can support the internal IDE disk and 470 CD-ROM interface, serial and parallel port, and the floppy drive. 471 472config ARCH_SA1100 473 bool "SA1100-based" 474 select ARCH_MTD_XIP 475 select ARCH_SPARSEMEM_ENABLE 476 select CLKDEV_LOOKUP 477 select CLKSRC_MMIO 478 select CLKSRC_PXA 479 select TIMER_OF if OF 480 select COMMON_CLK 481 select CPU_FREQ 482 select CPU_SA1100 483 select GENERIC_CLOCKEVENTS 484 select GENERIC_IRQ_MULTI_HANDLER 485 select GPIOLIB 486 select HAVE_IDE 487 select IRQ_DOMAIN 488 select ISA 489 select NEED_MACH_MEMORY_H 490 select SPARSE_IRQ 491 help 492 Support for StrongARM 11x0 based boards. 493 494config ARCH_S3C24XX 495 bool "Samsung S3C24XX SoCs" 496 select ATAGS 497 select CLKDEV_LOOKUP 498 select CLKSRC_SAMSUNG_PWM 499 select GENERIC_CLOCKEVENTS 500 select GPIO_SAMSUNG 501 select GPIOLIB 502 select GENERIC_IRQ_MULTI_HANDLER 503 select HAVE_S3C2410_I2C if I2C 504 select HAVE_S3C2410_WATCHDOG if WATCHDOG 505 select HAVE_S3C_RTC if RTC_CLASS 506 select NEED_MACH_IO_H 507 select SAMSUNG_ATAGS 508 select USE_OF 509 help 510 Samsung S3C2410, S3C2412, S3C2413, S3C2416, S3C2440, S3C2442, S3C2443 511 and S3C2450 SoCs based systems, such as the Simtec Electronics BAST 512 (<http://www.simtec.co.uk/products/EB110ITX/>), the IPAQ 1940 or the 513 Samsung SMDK2410 development board (and derivatives). 514 515config ARCH_OMAP1 516 bool "TI OMAP1" 517 depends on MMU 518 select ARCH_HAS_HOLES_MEMORYMODEL 519 select ARCH_OMAP 520 select CLKDEV_LOOKUP 521 select CLKSRC_MMIO 522 select GENERIC_CLOCKEVENTS 523 select GENERIC_IRQ_CHIP 524 select GENERIC_IRQ_MULTI_HANDLER 525 select GPIOLIB 526 select HAVE_IDE 527 select IRQ_DOMAIN 528 select NEED_MACH_IO_H if PCCARD 529 select NEED_MACH_MEMORY_H 530 select SPARSE_IRQ 531 help 532 Support for older TI OMAP1 (omap7xx, omap15xx or omap16xx) 533 534endchoice 535 536menu "Multiple platform selection" 537 depends on ARCH_MULTIPLATFORM 538 539comment "CPU Core family selection" 540 541config ARCH_MULTI_V4 542 bool "ARMv4 based platforms (FA526)" 543 depends on !ARCH_MULTI_V6_V7 544 select ARCH_MULTI_V4_V5 545 select CPU_FA526 546 547config ARCH_MULTI_V4T 548 bool "ARMv4T based platforms (ARM720T, ARM920T, ...)" 549 depends on !ARCH_MULTI_V6_V7 550 select ARCH_MULTI_V4_V5 551 select CPU_ARM920T if !(CPU_ARM7TDMI || CPU_ARM720T || \ 552 CPU_ARM740T || CPU_ARM9TDMI || CPU_ARM922T || \ 553 CPU_ARM925T || CPU_ARM940T) 554 555config ARCH_MULTI_V5 556 bool "ARMv5 based platforms (ARM926T, XSCALE, PJ1, ...)" 557 depends on !ARCH_MULTI_V6_V7 558 select ARCH_MULTI_V4_V5 559 select CPU_ARM926T if !(CPU_ARM946E || CPU_ARM1020 || \ 560 CPU_ARM1020E || CPU_ARM1022 || CPU_ARM1026 || \ 561 CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_FEROCEON) 562 563config ARCH_MULTI_V4_V5 564 bool 565 566config ARCH_MULTI_V6 567 bool "ARMv6 based platforms (ARM11)" 568 select ARCH_MULTI_V6_V7 569 select CPU_V6K 570 571config ARCH_MULTI_V7 572 bool "ARMv7 based platforms (Cortex-A, PJ4, Scorpion, Krait)" 573 default y 574 select ARCH_MULTI_V6_V7 575 select CPU_V7 576 select HAVE_SMP 577 578config ARCH_MULTI_V6_V7 579 bool 580 select MIGHT_HAVE_CACHE_L2X0 581 582config ARCH_MULTI_CPU_AUTO 583 def_bool !(ARCH_MULTI_V4 || ARCH_MULTI_V4T || ARCH_MULTI_V6_V7) 584 select ARCH_MULTI_V5 585 586endmenu 587 588config ARCH_VIRT 589 bool "Dummy Virtual Machine" 590 depends on ARCH_MULTI_V7 591 select ARM_AMBA 592 select ARM_GIC 593 select ARM_GIC_V2M if PCI 594 select ARM_GIC_V3 595 select ARM_GIC_V3_ITS if PCI 596 select ARM_PSCI 597 select HAVE_ARM_ARCH_TIMER 598 select ARCH_SUPPORTS_BIG_ENDIAN 599 600# 601# This is sorted alphabetically by mach-* pathname. However, plat-* 602# Kconfigs may be included either alphabetically (according to the 603# plat- suffix) or along side the corresponding mach-* source. 604# 605source "arch/arm/mach-actions/Kconfig" 606 607source "arch/arm/mach-alpine/Kconfig" 608 609source "arch/arm/mach-artpec/Kconfig" 610 611source "arch/arm/mach-asm9260/Kconfig" 612 613source "arch/arm/mach-aspeed/Kconfig" 614 615source "arch/arm/mach-at91/Kconfig" 616 617source "arch/arm/mach-axxia/Kconfig" 618 619source "arch/arm/mach-bcm/Kconfig" 620 621source "arch/arm/mach-berlin/Kconfig" 622 623source "arch/arm/mach-clps711x/Kconfig" 624 625source "arch/arm/mach-cns3xxx/Kconfig" 626 627source "arch/arm/mach-davinci/Kconfig" 628 629source "arch/arm/mach-digicolor/Kconfig" 630 631source "arch/arm/mach-dove/Kconfig" 632 633source "arch/arm/mach-ep93xx/Kconfig" 634 635source "arch/arm/mach-exynos/Kconfig" 636source "arch/arm/plat-samsung/Kconfig" 637 638source "arch/arm/mach-footbridge/Kconfig" 639 640source "arch/arm/mach-gemini/Kconfig" 641 642source "arch/arm/mach-highbank/Kconfig" 643 644source "arch/arm/mach-hisi/Kconfig" 645 646source "arch/arm/mach-imx/Kconfig" 647 648source "arch/arm/mach-integrator/Kconfig" 649 650source "arch/arm/mach-iop32x/Kconfig" 651 652source "arch/arm/mach-ixp4xx/Kconfig" 653 654source "arch/arm/mach-keystone/Kconfig" 655 656source "arch/arm/mach-lpc32xx/Kconfig" 657 658source "arch/arm/mach-mediatek/Kconfig" 659 660source "arch/arm/mach-meson/Kconfig" 661 662source "arch/arm/mach-milbeaut/Kconfig" 663 664source "arch/arm/mach-mmp/Kconfig" 665 666source "arch/arm/mach-moxart/Kconfig" 667 668source "arch/arm/mach-mv78xx0/Kconfig" 669 670source "arch/arm/mach-mvebu/Kconfig" 671 672source "arch/arm/mach-mxs/Kconfig" 673 674source "arch/arm/mach-nomadik/Kconfig" 675 676source "arch/arm/mach-npcm/Kconfig" 677 678source "arch/arm/mach-nspire/Kconfig" 679 680source "arch/arm/plat-omap/Kconfig" 681 682source "arch/arm/mach-omap1/Kconfig" 683 684source "arch/arm/mach-omap2/Kconfig" 685 686source "arch/arm/mach-orion5x/Kconfig" 687 688source "arch/arm/mach-oxnas/Kconfig" 689 690source "arch/arm/mach-picoxcell/Kconfig" 691 692source "arch/arm/mach-prima2/Kconfig" 693 694source "arch/arm/mach-pxa/Kconfig" 695source "arch/arm/plat-pxa/Kconfig" 696 697source "arch/arm/mach-qcom/Kconfig" 698 699source "arch/arm/mach-rda/Kconfig" 700 701source "arch/arm/mach-realview/Kconfig" 702 703source "arch/arm/mach-rockchip/Kconfig" 704 705source "arch/arm/mach-s3c24xx/Kconfig" 706 707source "arch/arm/mach-s3c64xx/Kconfig" 708 709source "arch/arm/mach-s5pv210/Kconfig" 710 711source "arch/arm/mach-sa1100/Kconfig" 712 713source "arch/arm/mach-shmobile/Kconfig" 714 715source "arch/arm/mach-socfpga/Kconfig" 716 717source "arch/arm/mach-spear/Kconfig" 718 719source "arch/arm/mach-sti/Kconfig" 720 721source "arch/arm/mach-stm32/Kconfig" 722 723source "arch/arm/mach-sunxi/Kconfig" 724 725source "arch/arm/mach-tango/Kconfig" 726 727source "arch/arm/mach-tegra/Kconfig" 728 729source "arch/arm/mach-u300/Kconfig" 730 731source "arch/arm/mach-uniphier/Kconfig" 732 733source "arch/arm/mach-ux500/Kconfig" 734 735source "arch/arm/mach-versatile/Kconfig" 736 737source "arch/arm/mach-vexpress/Kconfig" 738source "arch/arm/plat-versatile/Kconfig" 739 740source "arch/arm/mach-vt8500/Kconfig" 741 742source "arch/arm/mach-zx/Kconfig" 743 744source "arch/arm/mach-zynq/Kconfig" 745 746# ARMv7-M architecture 747config ARCH_EFM32 748 bool "Energy Micro efm32" 749 depends on ARM_SINGLE_ARMV7M 750 select GPIOLIB 751 help 752 Support for Energy Micro's (now Silicon Labs) efm32 Giant Gecko 753 processors. 754 755config ARCH_LPC18XX 756 bool "NXP LPC18xx/LPC43xx" 757 depends on ARM_SINGLE_ARMV7M 758 select ARCH_HAS_RESET_CONTROLLER 759 select ARM_AMBA 760 select CLKSRC_LPC32XX 761 select PINCTRL 762 help 763 Support for NXP's LPC18xx Cortex-M3 and LPC43xx Cortex-M4 764 high performance microcontrollers. 765 766config ARCH_MPS2 767 bool "ARM MPS2 platform" 768 depends on ARM_SINGLE_ARMV7M 769 select ARM_AMBA 770 select CLKSRC_MPS2 771 help 772 Support for Cortex-M Prototyping System (or V2M-MPS2) which comes 773 with a range of available cores like Cortex-M3/M4/M7. 774 775 Please, note that depends which Application Note is used memory map 776 for the platform may vary, so adjustment of RAM base might be needed. 777 778# Definitions to make life easier 779config ARCH_ACORN 780 bool 781 782config PLAT_IOP 783 bool 784 select GENERIC_CLOCKEVENTS 785 786config PLAT_ORION 787 bool 788 select CLKSRC_MMIO 789 select COMMON_CLK 790 select GENERIC_IRQ_CHIP 791 select IRQ_DOMAIN 792 793config PLAT_ORION_LEGACY 794 bool 795 select PLAT_ORION 796 797config PLAT_PXA 798 bool 799 800config PLAT_VERSATILE 801 bool 802 803source "arch/arm/mm/Kconfig" 804 805config IWMMXT 806 bool "Enable iWMMXt support" 807 depends on CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_PJ4 || CPU_PJ4B 808 default y if PXA27x || PXA3xx || ARCH_MMP || CPU_PJ4 || CPU_PJ4B 809 help 810 Enable support for iWMMXt context switching at run time if 811 running on a CPU that supports it. 812 813if !MMU 814source "arch/arm/Kconfig-nommu" 815endif 816 817config PJ4B_ERRATA_4742 818 bool "PJ4B Errata 4742: IDLE Wake Up Commands can Cause the CPU Core to Cease Operation" 819 depends on CPU_PJ4B && MACH_ARMADA_370 820 default y 821 help 822 When coming out of either a Wait for Interrupt (WFI) or a Wait for 823 Event (WFE) IDLE states, a specific timing sensitivity exists between 824 the retiring WFI/WFE instructions and the newly issued subsequent 825 instructions. This sensitivity can result in a CPU hang scenario. 826 Workaround: 827 The software must insert either a Data Synchronization Barrier (DSB) 828 or Data Memory Barrier (DMB) command immediately after the WFI/WFE 829 instruction 830 831config ARM_ERRATA_326103 832 bool "ARM errata: FSR write bit incorrect on a SWP to read-only memory" 833 depends on CPU_V6 834 help 835 Executing a SWP instruction to read-only memory does not set bit 11 836 of the FSR on the ARM 1136 prior to r1p0. This causes the kernel to 837 treat the access as a read, preventing a COW from occurring and 838 causing the faulting task to livelock. 839 840config ARM_ERRATA_411920 841 bool "ARM errata: Invalidation of the Instruction Cache operation can fail" 842 depends on CPU_V6 || CPU_V6K 843 help 844 Invalidation of the Instruction Cache operation can 845 fail. This erratum is present in 1136 (before r1p4), 1156 and 1176. 846 It does not affect the MPCore. This option enables the ARM Ltd. 847 recommended workaround. 848 849config ARM_ERRATA_430973 850 bool "ARM errata: Stale prediction on replaced interworking branch" 851 depends on CPU_V7 852 help 853 This option enables the workaround for the 430973 Cortex-A8 854 r1p* erratum. If a code sequence containing an ARM/Thumb 855 interworking branch is replaced with another code sequence at the 856 same virtual address, whether due to self-modifying code or virtual 857 to physical address re-mapping, Cortex-A8 does not recover from the 858 stale interworking branch prediction. This results in Cortex-A8 859 executing the new code sequence in the incorrect ARM or Thumb state. 860 The workaround enables the BTB/BTAC operations by setting ACTLR.IBE 861 and also flushes the branch target cache at every context switch. 862 Note that setting specific bits in the ACTLR register may not be 863 available in non-secure mode. 864 865config ARM_ERRATA_458693 866 bool "ARM errata: Processor deadlock when a false hazard is created" 867 depends on CPU_V7 868 depends on !ARCH_MULTIPLATFORM 869 help 870 This option enables the workaround for the 458693 Cortex-A8 (r2p0) 871 erratum. For very specific sequences of memory operations, it is 872 possible for a hazard condition intended for a cache line to instead 873 be incorrectly associated with a different cache line. This false 874 hazard might then cause a processor deadlock. The workaround enables 875 the L1 caching of the NEON accesses and disables the PLD instruction 876 in the ACTLR register. Note that setting specific bits in the ACTLR 877 register may not be available in non-secure mode. 878 879config ARM_ERRATA_460075 880 bool "ARM errata: Data written to the L2 cache can be overwritten with stale data" 881 depends on CPU_V7 882 depends on !ARCH_MULTIPLATFORM 883 help 884 This option enables the workaround for the 460075 Cortex-A8 (r2p0) 885 erratum. Any asynchronous access to the L2 cache may encounter a 886 situation in which recent store transactions to the L2 cache are lost 887 and overwritten with stale memory contents from external memory. The 888 workaround disables the write-allocate mode for the L2 cache via the 889 ACTLR register. Note that setting specific bits in the ACTLR register 890 may not be available in non-secure mode. 891 892config ARM_ERRATA_742230 893 bool "ARM errata: DMB operation may be faulty" 894 depends on CPU_V7 && SMP 895 depends on !ARCH_MULTIPLATFORM 896 help 897 This option enables the workaround for the 742230 Cortex-A9 898 (r1p0..r2p2) erratum. Under rare circumstances, a DMB instruction 899 between two write operations may not ensure the correct visibility 900 ordering of the two writes. This workaround sets a specific bit in 901 the diagnostic register of the Cortex-A9 which causes the DMB 902 instruction to behave as a DSB, ensuring the correct behaviour of 903 the two writes. 904 905config ARM_ERRATA_742231 906 bool "ARM errata: Incorrect hazard handling in the SCU may lead to data corruption" 907 depends on CPU_V7 && SMP 908 depends on !ARCH_MULTIPLATFORM 909 help 910 This option enables the workaround for the 742231 Cortex-A9 911 (r2p0..r2p2) erratum. Under certain conditions, specific to the 912 Cortex-A9 MPCore micro-architecture, two CPUs working in SMP mode, 913 accessing some data located in the same cache line, may get corrupted 914 data due to bad handling of the address hazard when the line gets 915 replaced from one of the CPUs at the same time as another CPU is 916 accessing it. This workaround sets specific bits in the diagnostic 917 register of the Cortex-A9 which reduces the linefill issuing 918 capabilities of the processor. 919 920config ARM_ERRATA_643719 921 bool "ARM errata: LoUIS bit field in CLIDR register is incorrect" 922 depends on CPU_V7 && SMP 923 default y 924 help 925 This option enables the workaround for the 643719 Cortex-A9 (prior to 926 r1p0) erratum. On affected cores the LoUIS bit field of the CLIDR 927 register returns zero when it should return one. The workaround 928 corrects this value, ensuring cache maintenance operations which use 929 it behave as intended and avoiding data corruption. 930 931config ARM_ERRATA_720789 932 bool "ARM errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID" 933 depends on CPU_V7 934 help 935 This option enables the workaround for the 720789 Cortex-A9 (prior to 936 r2p0) erratum. A faulty ASID can be sent to the other CPUs for the 937 broadcasted CP15 TLB maintenance operations TLBIASIDIS and TLBIMVAIS. 938 As a consequence of this erratum, some TLB entries which should be 939 invalidated are not, resulting in an incoherency in the system page 940 tables. The workaround changes the TLB flushing routines to invalidate 941 entries regardless of the ASID. 942 943config ARM_ERRATA_743622 944 bool "ARM errata: Faulty hazard checking in the Store Buffer may lead to data corruption" 945 depends on CPU_V7 946 depends on !ARCH_MULTIPLATFORM 947 help 948 This option enables the workaround for the 743622 Cortex-A9 949 (r2p*) erratum. Under very rare conditions, a faulty 950 optimisation in the Cortex-A9 Store Buffer may lead to data 951 corruption. This workaround sets a specific bit in the diagnostic 952 register of the Cortex-A9 which disables the Store Buffer 953 optimisation, preventing the defect from occurring. This has no 954 visible impact on the overall performance or power consumption of the 955 processor. 956 957config ARM_ERRATA_751472 958 bool "ARM errata: Interrupted ICIALLUIS may prevent completion of broadcasted operation" 959 depends on CPU_V7 960 depends on !ARCH_MULTIPLATFORM 961 help 962 This option enables the workaround for the 751472 Cortex-A9 (prior 963 to r3p0) erratum. An interrupted ICIALLUIS operation may prevent the 964 completion of a following broadcasted operation if the second 965 operation is received by a CPU before the ICIALLUIS has completed, 966 potentially leading to corrupted entries in the cache or TLB. 967 968config ARM_ERRATA_754322 969 bool "ARM errata: possible faulty MMU translations following an ASID switch" 970 depends on CPU_V7 971 help 972 This option enables the workaround for the 754322 Cortex-A9 (r2p*, 973 r3p*) erratum. A speculative memory access may cause a page table walk 974 which starts prior to an ASID switch but completes afterwards. This 975 can populate the micro-TLB with a stale entry which may be hit with 976 the new ASID. This workaround places two dsb instructions in the mm 977 switching code so that no page table walks can cross the ASID switch. 978 979config ARM_ERRATA_754327 980 bool "ARM errata: no automatic Store Buffer drain" 981 depends on CPU_V7 && SMP 982 help 983 This option enables the workaround for the 754327 Cortex-A9 (prior to 984 r2p0) erratum. The Store Buffer does not have any automatic draining 985 mechanism and therefore a livelock may occur if an external agent 986 continuously polls a memory location waiting to observe an update. 987 This workaround defines cpu_relax() as smp_mb(), preventing correctly 988 written polling loops from denying visibility of updates to memory. 989 990config ARM_ERRATA_364296 991 bool "ARM errata: Possible cache data corruption with hit-under-miss enabled" 992 depends on CPU_V6 993 help 994 This options enables the workaround for the 364296 ARM1136 995 r0p2 erratum (possible cache data corruption with 996 hit-under-miss enabled). It sets the undocumented bit 31 in 997 the auxiliary control register and the FI bit in the control 998 register, thus disabling hit-under-miss without putting the 999 processor into full low interrupt latency mode. ARM11MPCore 1000 is not affected. 1001 1002config ARM_ERRATA_764369 1003 bool "ARM errata: Data cache line maintenance operation by MVA may not succeed" 1004 depends on CPU_V7 && SMP 1005 help 1006 This option enables the workaround for erratum 764369 1007 affecting Cortex-A9 MPCore with two or more processors (all 1008 current revisions). Under certain timing circumstances, a data 1009 cache line maintenance operation by MVA targeting an Inner 1010 Shareable memory region may fail to proceed up to either the 1011 Point of Coherency or to the Point of Unification of the 1012 system. This workaround adds a DSB instruction before the 1013 relevant cache maintenance functions and sets a specific bit 1014 in the diagnostic control register of the SCU. 1015 1016config ARM_ERRATA_775420 1017 bool "ARM errata: A data cache maintenance operation which aborts, might lead to deadlock" 1018 depends on CPU_V7 1019 help 1020 This option enables the workaround for the 775420 Cortex-A9 (r2p2, 1021 r2p6,r2p8,r2p10,r3p0) erratum. In case a data cache maintenance 1022 operation aborts with MMU exception, it might cause the processor 1023 to deadlock. This workaround puts DSB before executing ISB if 1024 an abort may occur on cache maintenance. 1025 1026config ARM_ERRATA_798181 1027 bool "ARM errata: TLBI/DSB failure on Cortex-A15" 1028 depends on CPU_V7 && SMP 1029 help 1030 On Cortex-A15 (r0p0..r3p2) the TLBI*IS/DSB operations are not 1031 adequately shooting down all use of the old entries. This 1032 option enables the Linux kernel workaround for this erratum 1033 which sends an IPI to the CPUs that are running the same ASID 1034 as the one being invalidated. 1035 1036config ARM_ERRATA_773022 1037 bool "ARM errata: incorrect instructions may be executed from loop buffer" 1038 depends on CPU_V7 1039 help 1040 This option enables the workaround for the 773022 Cortex-A15 1041 (up to r0p4) erratum. In certain rare sequences of code, the 1042 loop buffer may deliver incorrect instructions. This 1043 workaround disables the loop buffer to avoid the erratum. 1044 1045config ARM_ERRATA_818325_852422 1046 bool "ARM errata: A12: some seqs of opposed cond code instrs => deadlock or corruption" 1047 depends on CPU_V7 1048 help 1049 This option enables the workaround for: 1050 - Cortex-A12 818325: Execution of an UNPREDICTABLE STR or STM 1051 instruction might deadlock. Fixed in r0p1. 1052 - Cortex-A12 852422: Execution of a sequence of instructions might 1053 lead to either a data corruption or a CPU deadlock. Not fixed in 1054 any Cortex-A12 cores yet. 1055 This workaround for all both errata involves setting bit[12] of the 1056 Feature Register. This bit disables an optimisation applied to a 1057 sequence of 2 instructions that use opposing condition codes. 1058 1059config ARM_ERRATA_821420 1060 bool "ARM errata: A12: sequence of VMOV to core registers might lead to a dead lock" 1061 depends on CPU_V7 1062 help 1063 This option enables the workaround for the 821420 Cortex-A12 1064 (all revs) erratum. In very rare timing conditions, a sequence 1065 of VMOV to Core registers instructions, for which the second 1066 one is in the shadow of a branch or abort, can lead to a 1067 deadlock when the VMOV instructions are issued out-of-order. 1068 1069config ARM_ERRATA_825619 1070 bool "ARM errata: A12: DMB NSHST/ISHST mixed ... might cause deadlock" 1071 depends on CPU_V7 1072 help 1073 This option enables the workaround for the 825619 Cortex-A12 1074 (all revs) erratum. Within rare timing constraints, executing a 1075 DMB NSHST or DMB ISHST instruction followed by a mix of Cacheable 1076 and Device/Strongly-Ordered loads and stores might cause deadlock 1077 1078config ARM_ERRATA_857271 1079 bool "ARM errata: A12: CPU might deadlock under some very rare internal conditions" 1080 depends on CPU_V7 1081 help 1082 This option enables the workaround for the 857271 Cortex-A12 1083 (all revs) erratum. Under very rare timing conditions, the CPU might 1084 hang. The workaround is expected to have a < 1% performance impact. 1085 1086config ARM_ERRATA_852421 1087 bool "ARM errata: A17: DMB ST might fail to create order between stores" 1088 depends on CPU_V7 1089 help 1090 This option enables the workaround for the 852421 Cortex-A17 1091 (r1p0, r1p1, r1p2) erratum. Under very rare timing conditions, 1092 execution of a DMB ST instruction might fail to properly order 1093 stores from GroupA and stores from GroupB. 1094 1095config ARM_ERRATA_852423 1096 bool "ARM errata: A17: some seqs of opposed cond code instrs => deadlock or corruption" 1097 depends on CPU_V7 1098 help 1099 This option enables the workaround for: 1100 - Cortex-A17 852423: Execution of a sequence of instructions might 1101 lead to either a data corruption or a CPU deadlock. Not fixed in 1102 any Cortex-A17 cores yet. 1103 This is identical to Cortex-A12 erratum 852422. It is a separate 1104 config option from the A12 erratum due to the way errata are checked 1105 for and handled. 1106 1107config ARM_ERRATA_857272 1108 bool "ARM errata: A17: CPU might deadlock under some very rare internal conditions" 1109 depends on CPU_V7 1110 help 1111 This option enables the workaround for the 857272 Cortex-A17 erratum. 1112 This erratum is not known to be fixed in any A17 revision. 1113 This is identical to Cortex-A12 erratum 857271. It is a separate 1114 config option from the A12 erratum due to the way errata are checked 1115 for and handled. 1116 1117endmenu 1118 1119source "arch/arm/common/Kconfig" 1120 1121menu "Bus support" 1122 1123config ISA 1124 bool 1125 help 1126 Find out whether you have ISA slots on your motherboard. ISA is the 1127 name of a bus system, i.e. the way the CPU talks to the other stuff 1128 inside your box. Other bus systems are PCI, EISA, MicroChannel 1129 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 1130 newer boards don't support it. If you have ISA, say Y, otherwise N. 1131 1132# Select ISA DMA controller support 1133config ISA_DMA 1134 bool 1135 select ISA_DMA_API 1136 1137# Select ISA DMA interface 1138config ISA_DMA_API 1139 bool 1140 1141config PCI_NANOENGINE 1142 bool "BSE nanoEngine PCI support" 1143 depends on SA1100_NANOENGINE 1144 help 1145 Enable PCI on the BSE nanoEngine board. 1146 1147config PCI_HOST_ITE8152 1148 bool 1149 depends on PCI && MACH_ARMCORE 1150 default y 1151 select DMABOUNCE 1152 1153config ARM_ERRATA_814220 1154 bool "ARM errata: Cache maintenance by set/way operations can execute out of order" 1155 depends on CPU_V7 1156 help 1157 The v7 ARM states that all cache and branch predictor maintenance 1158 operations that do not specify an address execute, relative to 1159 each other, in program order. 1160 However, because of this erratum, an L2 set/way cache maintenance 1161 operation can overtake an L1 set/way cache maintenance operation. 1162 This ERRATA only affected the Cortex-A7 and present in r0p2, r0p3, 1163 r0p4, r0p5. 1164 1165endmenu 1166 1167menu "Kernel Features" 1168 1169config HAVE_SMP 1170 bool 1171 help 1172 This option should be selected by machines which have an SMP- 1173 capable CPU. 1174 1175 The only effect of this option is to make the SMP-related 1176 options available to the user for configuration. 1177 1178config SMP 1179 bool "Symmetric Multi-Processing" 1180 depends on CPU_V6K || CPU_V7 1181 depends on GENERIC_CLOCKEVENTS 1182 depends on HAVE_SMP 1183 depends on MMU || ARM_MPU 1184 select IRQ_WORK 1185 help 1186 This enables support for systems with more than one CPU. If you have 1187 a system with only one CPU, say N. If you have a system with more 1188 than one CPU, say Y. 1189 1190 If you say N here, the kernel will run on uni- and multiprocessor 1191 machines, but will use only one CPU of a multiprocessor machine. If 1192 you say Y here, the kernel will run on many, but not all, 1193 uniprocessor machines. On a uniprocessor machine, the kernel 1194 will run faster if you say N here. 1195 1196 See also <file:Documentation/x86/i386/IO-APIC.rst>, 1197 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 1198 <http://tldp.org/HOWTO/SMP-HOWTO.html>. 1199 1200 If you don't know what to do here, say N. 1201 1202config SMP_ON_UP 1203 bool "Allow booting SMP kernel on uniprocessor systems" 1204 depends on SMP && !XIP_KERNEL && MMU 1205 default y 1206 help 1207 SMP kernels contain instructions which fail on non-SMP processors. 1208 Enabling this option allows the kernel to modify itself to make 1209 these instructions safe. Disabling it allows about 1K of space 1210 savings. 1211 1212 If you don't know what to do here, say Y. 1213 1214config ARM_CPU_TOPOLOGY 1215 bool "Support cpu topology definition" 1216 depends on SMP && CPU_V7 1217 default y 1218 help 1219 Support ARM cpu topology definition. The MPIDR register defines 1220 affinity between processors which is then used to describe the cpu 1221 topology of an ARM System. 1222 1223config SCHED_MC 1224 bool "Multi-core scheduler support" 1225 depends on ARM_CPU_TOPOLOGY 1226 help 1227 Multi-core scheduler support improves the CPU scheduler's decision 1228 making when dealing with multi-core CPU chips at a cost of slightly 1229 increased overhead in some places. If unsure say N here. 1230 1231config SCHED_SMT 1232 bool "SMT scheduler support" 1233 depends on ARM_CPU_TOPOLOGY 1234 help 1235 Improves the CPU scheduler's decision making when dealing with 1236 MultiThreading at a cost of slightly increased overhead in some 1237 places. If unsure say N here. 1238 1239config HAVE_ARM_SCU 1240 bool 1241 help 1242 This option enables support for the ARM snoop control unit 1243 1244config HAVE_ARM_ARCH_TIMER 1245 bool "Architected timer support" 1246 depends on CPU_V7 1247 select ARM_ARCH_TIMER 1248 select GENERIC_CLOCKEVENTS 1249 help 1250 This option enables support for the ARM architected timer 1251 1252config HAVE_ARM_TWD 1253 bool 1254 help 1255 This options enables support for the ARM timer and watchdog unit 1256 1257config MCPM 1258 bool "Multi-Cluster Power Management" 1259 depends on CPU_V7 && SMP 1260 help 1261 This option provides the common power management infrastructure 1262 for (multi-)cluster based systems, such as big.LITTLE based 1263 systems. 1264 1265config MCPM_QUAD_CLUSTER 1266 bool 1267 depends on MCPM 1268 help 1269 To avoid wasting resources unnecessarily, MCPM only supports up 1270 to 2 clusters by default. 1271 Platforms with 3 or 4 clusters that use MCPM must select this 1272 option to allow the additional clusters to be managed. 1273 1274config BIG_LITTLE 1275 bool "big.LITTLE support (Experimental)" 1276 depends on CPU_V7 && SMP 1277 select MCPM 1278 help 1279 This option enables support selections for the big.LITTLE 1280 system architecture. 1281 1282config BL_SWITCHER 1283 bool "big.LITTLE switcher support" 1284 depends on BIG_LITTLE && MCPM && HOTPLUG_CPU && ARM_GIC 1285 select CPU_PM 1286 help 1287 The big.LITTLE "switcher" provides the core functionality to 1288 transparently handle transition between a cluster of A15's 1289 and a cluster of A7's in a big.LITTLE system. 1290 1291config BL_SWITCHER_DUMMY_IF 1292 tristate "Simple big.LITTLE switcher user interface" 1293 depends on BL_SWITCHER && DEBUG_KERNEL 1294 help 1295 This is a simple and dummy char dev interface to control 1296 the big.LITTLE switcher core code. It is meant for 1297 debugging purposes only. 1298 1299choice 1300 prompt "Memory split" 1301 depends on MMU 1302 default VMSPLIT_3G 1303 help 1304 Select the desired split between kernel and user memory. 1305 1306 If you are not absolutely sure what you are doing, leave this 1307 option alone! 1308 1309 config VMSPLIT_3G 1310 bool "3G/1G user/kernel split" 1311 config VMSPLIT_3G_OPT 1312 depends on !ARM_LPAE 1313 bool "3G/1G user/kernel split (for full 1G low memory)" 1314 config VMSPLIT_2G 1315 bool "2G/2G user/kernel split" 1316 config VMSPLIT_1G 1317 bool "1G/3G user/kernel split" 1318endchoice 1319 1320config PAGE_OFFSET 1321 hex 1322 default PHYS_OFFSET if !MMU 1323 default 0x40000000 if VMSPLIT_1G 1324 default 0x80000000 if VMSPLIT_2G 1325 default 0xB0000000 if VMSPLIT_3G_OPT 1326 default 0xC0000000 1327 1328config NR_CPUS 1329 int "Maximum number of CPUs (2-32)" 1330 range 2 32 1331 depends on SMP 1332 default "4" 1333 1334config HOTPLUG_CPU 1335 bool "Support for hot-pluggable CPUs" 1336 depends on SMP 1337 select GENERIC_IRQ_MIGRATION 1338 help 1339 Say Y here to experiment with turning CPUs off and on. CPUs 1340 can be controlled through /sys/devices/system/cpu. 1341 1342config ARM_PSCI 1343 bool "Support for the ARM Power State Coordination Interface (PSCI)" 1344 depends on HAVE_ARM_SMCCC 1345 select ARM_PSCI_FW 1346 help 1347 Say Y here if you want Linux to communicate with system firmware 1348 implementing the PSCI specification for CPU-centric power 1349 management operations described in ARM document number ARM DEN 1350 0022A ("Power State Coordination Interface System Software on 1351 ARM processors"). 1352 1353# The GPIO number here must be sorted by descending number. In case of 1354# a multiplatform kernel, we just want the highest value required by the 1355# selected platforms. 1356config ARCH_NR_GPIO 1357 int 1358 default 2048 if ARCH_SOCFPGA 1359 default 1024 if ARCH_BRCMSTB || ARCH_RENESAS || ARCH_TEGRA || \ 1360 ARCH_ZYNQ || ARCH_ASPEED 1361 default 512 if ARCH_EXYNOS || ARCH_KEYSTONE || SOC_OMAP5 || \ 1362 SOC_DRA7XX || ARCH_S3C24XX || ARCH_S3C64XX || ARCH_S5PV210 1363 default 416 if ARCH_SUNXI 1364 default 392 if ARCH_U8500 1365 default 352 if ARCH_VT8500 1366 default 288 if ARCH_ROCKCHIP 1367 default 264 if MACH_H4700 1368 default 0 1369 help 1370 Maximum number of GPIOs in the system. 1371 1372 If unsure, leave the default value. 1373 1374config HZ_FIXED 1375 int 1376 default 200 if ARCH_EBSA110 1377 default 128 if SOC_AT91RM9200 1378 default 0 1379 1380choice 1381 depends on HZ_FIXED = 0 1382 prompt "Timer frequency" 1383 1384config HZ_100 1385 bool "100 Hz" 1386 1387config HZ_200 1388 bool "200 Hz" 1389 1390config HZ_250 1391 bool "250 Hz" 1392 1393config HZ_300 1394 bool "300 Hz" 1395 1396config HZ_500 1397 bool "500 Hz" 1398 1399config HZ_1000 1400 bool "1000 Hz" 1401 1402endchoice 1403 1404config HZ 1405 int 1406 default HZ_FIXED if HZ_FIXED != 0 1407 default 100 if HZ_100 1408 default 200 if HZ_200 1409 default 250 if HZ_250 1410 default 300 if HZ_300 1411 default 500 if HZ_500 1412 default 1000 1413 1414config SCHED_HRTICK 1415 def_bool HIGH_RES_TIMERS 1416 1417config THUMB2_KERNEL 1418 bool "Compile the kernel in Thumb-2 mode" if !CPU_THUMBONLY 1419 depends on (CPU_V7 || CPU_V7M) && !CPU_V6 && !CPU_V6K 1420 default y if CPU_THUMBONLY 1421 select ARM_UNWIND 1422 help 1423 By enabling this option, the kernel will be compiled in 1424 Thumb-2 mode. 1425 1426 If unsure, say N. 1427 1428config THUMB2_AVOID_R_ARM_THM_JUMP11 1429 bool "Work around buggy Thumb-2 short branch relocations in gas" 1430 depends on THUMB2_KERNEL && MODULES 1431 default y 1432 help 1433 Various binutils versions can resolve Thumb-2 branches to 1434 locally-defined, preemptible global symbols as short-range "b.n" 1435 branch instructions. 1436 1437 This is a problem, because there's no guarantee the final 1438 destination of the symbol, or any candidate locations for a 1439 trampoline, are within range of the branch. For this reason, the 1440 kernel does not support fixing up the R_ARM_THM_JUMP11 (102) 1441 relocation in modules at all, and it makes little sense to add 1442 support. 1443 1444 The symptom is that the kernel fails with an "unsupported 1445 relocation" error when loading some modules. 1446 1447 Until fixed tools are available, passing 1448 -fno-optimize-sibling-calls to gcc should prevent gcc generating 1449 code which hits this problem, at the cost of a bit of extra runtime 1450 stack usage in some cases. 1451 1452 The problem is described in more detail at: 1453 https://bugs.launchpad.net/binutils-linaro/+bug/725126 1454 1455 Only Thumb-2 kernels are affected. 1456 1457 Unless you are sure your tools don't have this problem, say Y. 1458 1459config ARM_PATCH_IDIV 1460 bool "Runtime patch udiv/sdiv instructions into __aeabi_{u}idiv()" 1461 depends on CPU_32v7 && !XIP_KERNEL 1462 default y 1463 help 1464 The ARM compiler inserts calls to __aeabi_idiv() and 1465 __aeabi_uidiv() when it needs to perform division on signed 1466 and unsigned integers. Some v7 CPUs have support for the sdiv 1467 and udiv instructions that can be used to implement those 1468 functions. 1469 1470 Enabling this option allows the kernel to modify itself to 1471 replace the first two instructions of these library functions 1472 with the sdiv or udiv plus "bx lr" instructions when the CPU 1473 it is running on supports them. Typically this will be faster 1474 and less power intensive than running the original library 1475 code to do integer division. 1476 1477config AEABI 1478 bool "Use the ARM EABI to compile the kernel" if !CPU_V7 && \ 1479 !CPU_V7M && !CPU_V6 && !CPU_V6K && !CC_IS_CLANG 1480 default CPU_V7 || CPU_V7M || CPU_V6 || CPU_V6K || CC_IS_CLANG 1481 help 1482 This option allows for the kernel to be compiled using the latest 1483 ARM ABI (aka EABI). This is only useful if you are using a user 1484 space environment that is also compiled with EABI. 1485 1486 Since there are major incompatibilities between the legacy ABI and 1487 EABI, especially with regard to structure member alignment, this 1488 option also changes the kernel syscall calling convention to 1489 disambiguate both ABIs and allow for backward compatibility support 1490 (selected with CONFIG_OABI_COMPAT). 1491 1492 To use this you need GCC version 4.0.0 or later. 1493 1494config OABI_COMPAT 1495 bool "Allow old ABI binaries to run with this kernel (EXPERIMENTAL)" 1496 depends on AEABI && !THUMB2_KERNEL 1497 help 1498 This option preserves the old syscall interface along with the 1499 new (ARM EABI) one. It also provides a compatibility layer to 1500 intercept syscalls that have structure arguments which layout 1501 in memory differs between the legacy ABI and the new ARM EABI 1502 (only for non "thumb" binaries). This option adds a tiny 1503 overhead to all syscalls and produces a slightly larger kernel. 1504 1505 The seccomp filter system will not be available when this is 1506 selected, since there is no way yet to sensibly distinguish 1507 between calling conventions during filtering. 1508 1509 If you know you'll be using only pure EABI user space then you 1510 can say N here. If this option is not selected and you attempt 1511 to execute a legacy ABI binary then the result will be 1512 UNPREDICTABLE (in fact it can be predicted that it won't work 1513 at all). If in doubt say N. 1514 1515config ARCH_HAS_HOLES_MEMORYMODEL 1516 bool 1517 1518config ARCH_SPARSEMEM_ENABLE 1519 bool 1520 1521config ARCH_SPARSEMEM_DEFAULT 1522 def_bool ARCH_SPARSEMEM_ENABLE 1523 1524config HAVE_ARCH_PFN_VALID 1525 def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM 1526 1527config HIGHMEM 1528 bool "High Memory Support" 1529 depends on MMU 1530 help 1531 The address space of ARM processors is only 4 Gigabytes large 1532 and it has to accommodate user address space, kernel address 1533 space as well as some memory mapped IO. That means that, if you 1534 have a large amount of physical memory and/or IO, not all of the 1535 memory can be "permanently mapped" by the kernel. The physical 1536 memory that is not permanently mapped is called "high memory". 1537 1538 Depending on the selected kernel/user memory split, minimum 1539 vmalloc space and actual amount of RAM, you may not need this 1540 option which should result in a slightly faster kernel. 1541 1542 If unsure, say n. 1543 1544config HIGHPTE 1545 bool "Allocate 2nd-level pagetables from highmem" if EXPERT 1546 depends on HIGHMEM 1547 default y 1548 help 1549 The VM uses one page of physical memory for each page table. 1550 For systems with a lot of processes, this can use a lot of 1551 precious low memory, eventually leading to low memory being 1552 consumed by page tables. Setting this option will allow 1553 user-space 2nd level page tables to reside in high memory. 1554 1555config CPU_SW_DOMAIN_PAN 1556 bool "Enable use of CPU domains to implement privileged no-access" 1557 depends on MMU && !ARM_LPAE 1558 default y 1559 help 1560 Increase kernel security by ensuring that normal kernel accesses 1561 are unable to access userspace addresses. This can help prevent 1562 use-after-free bugs becoming an exploitable privilege escalation 1563 by ensuring that magic values (such as LIST_POISON) will always 1564 fault when dereferenced. 1565 1566 CPUs with low-vector mappings use a best-efforts implementation. 1567 Their lower 1MB needs to remain accessible for the vectors, but 1568 the remainder of userspace will become appropriately inaccessible. 1569 1570config HW_PERF_EVENTS 1571 def_bool y 1572 depends on ARM_PMU 1573 1574config SYS_SUPPORTS_HUGETLBFS 1575 def_bool y 1576 depends on ARM_LPAE 1577 1578config HAVE_ARCH_TRANSPARENT_HUGEPAGE 1579 def_bool y 1580 depends on ARM_LPAE 1581 1582config ARCH_WANT_GENERAL_HUGETLB 1583 def_bool y 1584 1585config ARM_MODULE_PLTS 1586 bool "Use PLTs to allow module memory to spill over into vmalloc area" 1587 depends on MODULES 1588 default y 1589 help 1590 Allocate PLTs when loading modules so that jumps and calls whose 1591 targets are too far away for their relative offsets to be encoded 1592 in the instructions themselves can be bounced via veneers in the 1593 module's PLT. This allows modules to be allocated in the generic 1594 vmalloc area after the dedicated module memory area has been 1595 exhausted. The modules will use slightly more memory, but after 1596 rounding up to page size, the actual memory footprint is usually 1597 the same. 1598 1599 Disabling this is usually safe for small single-platform 1600 configurations. If unsure, say y. 1601 1602config FORCE_MAX_ZONEORDER 1603 int "Maximum zone order" 1604 default "12" if SOC_AM33XX 1605 default "9" if SA1111 || ARCH_EFM32 1606 default "11" 1607 help 1608 The kernel memory allocator divides physically contiguous memory 1609 blocks into "zones", where each zone is a power of two number of 1610 pages. This option selects the largest power of two that the kernel 1611 keeps in the memory allocator. If you need to allocate very large 1612 blocks of physically contiguous memory, then you may need to 1613 increase this value. 1614 1615 This config option is actually maximum order plus one. For example, 1616 a value of 11 means that the largest free memory block is 2^10 pages. 1617 1618config ALIGNMENT_TRAP 1619 bool 1620 depends on CPU_CP15_MMU 1621 default y if !ARCH_EBSA110 1622 select HAVE_PROC_CPU if PROC_FS 1623 help 1624 ARM processors cannot fetch/store information which is not 1625 naturally aligned on the bus, i.e., a 4 byte fetch must start at an 1626 address divisible by 4. On 32-bit ARM processors, these non-aligned 1627 fetch/store instructions will be emulated in software if you say 1628 here, which has a severe performance impact. This is necessary for 1629 correct operation of some network protocols. With an IP-only 1630 configuration it is safe to say N, otherwise say Y. 1631 1632config UACCESS_WITH_MEMCPY 1633 bool "Use kernel mem{cpy,set}() for {copy_to,clear}_user()" 1634 depends on MMU 1635 default y if CPU_FEROCEON 1636 help 1637 Implement faster copy_to_user and clear_user methods for CPU 1638 cores where a 8-word STM instruction give significantly higher 1639 memory write throughput than a sequence of individual 32bit stores. 1640 1641 A possible side effect is a slight increase in scheduling latency 1642 between threads sharing the same address space if they invoke 1643 such copy operations with large buffers. 1644 1645 However, if the CPU data cache is using a write-allocate mode, 1646 this option is unlikely to provide any performance gain. 1647 1648config SECCOMP 1649 bool 1650 prompt "Enable seccomp to safely compute untrusted bytecode" 1651 ---help--- 1652 This kernel feature is useful for number crunching applications 1653 that may need to compute untrusted bytecode during their 1654 execution. By using pipes or other transports made available to 1655 the process as file descriptors supporting the read/write 1656 syscalls, it's possible to isolate those applications in 1657 their own address space using seccomp. Once seccomp is 1658 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1659 and the task is only allowed to execute a few safe syscalls 1660 defined by each seccomp mode. 1661 1662config PARAVIRT 1663 bool "Enable paravirtualization code" 1664 help 1665 This changes the kernel so it can modify itself when it is run 1666 under a hypervisor, potentially improving performance significantly 1667 over full virtualization. 1668 1669config PARAVIRT_TIME_ACCOUNTING 1670 bool "Paravirtual steal time accounting" 1671 select PARAVIRT 1672 help 1673 Select this option to enable fine granularity task steal time 1674 accounting. Time spent executing other tasks in parallel with 1675 the current vCPU is discounted from the vCPU power. To account for 1676 that, there can be a small performance impact. 1677 1678 If in doubt, say N here. 1679 1680config XEN_DOM0 1681 def_bool y 1682 depends on XEN 1683 1684config XEN 1685 bool "Xen guest support on ARM" 1686 depends on ARM && AEABI && OF 1687 depends on CPU_V7 && !CPU_V6 1688 depends on !GENERIC_ATOMIC64 1689 depends on MMU 1690 select ARCH_DMA_ADDR_T_64BIT 1691 select ARM_PSCI 1692 select SWIOTLB 1693 select SWIOTLB_XEN 1694 select PARAVIRT 1695 help 1696 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. 1697 1698config STACKPROTECTOR_PER_TASK 1699 bool "Use a unique stack canary value for each task" 1700 depends on GCC_PLUGINS && STACKPROTECTOR && SMP && !XIP_DEFLATED_DATA 1701 select GCC_PLUGIN_ARM_SSP_PER_TASK 1702 default y 1703 help 1704 Due to the fact that GCC uses an ordinary symbol reference from 1705 which to load the value of the stack canary, this value can only 1706 change at reboot time on SMP systems, and all tasks running in the 1707 kernel's address space are forced to use the same canary value for 1708 the entire duration that the system is up. 1709 1710 Enable this option to switch to a different method that uses a 1711 different canary value for each task. 1712 1713endmenu 1714 1715menu "Boot options" 1716 1717config USE_OF 1718 bool "Flattened Device Tree support" 1719 select IRQ_DOMAIN 1720 select OF 1721 help 1722 Include support for flattened device tree machine descriptions. 1723 1724config ATAGS 1725 bool "Support for the traditional ATAGS boot data passing" if USE_OF 1726 default y 1727 help 1728 This is the traditional way of passing data to the kernel at boot 1729 time. If you are solely relying on the flattened device tree (or 1730 the ARM_ATAG_DTB_COMPAT option) then you may unselect this option 1731 to remove ATAGS support from your kernel binary. If unsure, 1732 leave this to y. 1733 1734config DEPRECATED_PARAM_STRUCT 1735 bool "Provide old way to pass kernel parameters" 1736 depends on ATAGS 1737 help 1738 This was deprecated in 2001 and announced to live on for 5 years. 1739 Some old boot loaders still use this way. 1740 1741# Compressed boot loader in ROM. Yes, we really want to ask about 1742# TEXT and BSS so we preserve their values in the config files. 1743config ZBOOT_ROM_TEXT 1744 hex "Compressed ROM boot loader base address" 1745 default "0" 1746 help 1747 The physical address at which the ROM-able zImage is to be 1748 placed in the target. Platforms which normally make use of 1749 ROM-able zImage formats normally set this to a suitable 1750 value in their defconfig file. 1751 1752 If ZBOOT_ROM is not enabled, this has no effect. 1753 1754config ZBOOT_ROM_BSS 1755 hex "Compressed ROM boot loader BSS address" 1756 default "0" 1757 help 1758 The base address of an area of read/write memory in the target 1759 for the ROM-able zImage which must be available while the 1760 decompressor is running. It must be large enough to hold the 1761 entire decompressed kernel plus an additional 128 KiB. 1762 Platforms which normally make use of ROM-able zImage formats 1763 normally set this to a suitable value in their defconfig file. 1764 1765 If ZBOOT_ROM is not enabled, this has no effect. 1766 1767config ZBOOT_ROM 1768 bool "Compressed boot loader in ROM/flash" 1769 depends on ZBOOT_ROM_TEXT != ZBOOT_ROM_BSS 1770 depends on !ARM_APPENDED_DTB && !XIP_KERNEL && !AUTO_ZRELADDR 1771 help 1772 Say Y here if you intend to execute your compressed kernel image 1773 (zImage) directly from ROM or flash. If unsure, say N. 1774 1775config ARM_APPENDED_DTB 1776 bool "Use appended device tree blob to zImage (EXPERIMENTAL)" 1777 depends on OF 1778 help 1779 With this option, the boot code will look for a device tree binary 1780 (DTB) appended to zImage 1781 (e.g. cat zImage <filename>.dtb > zImage_w_dtb). 1782 1783 This is meant as a backward compatibility convenience for those 1784 systems with a bootloader that can't be upgraded to accommodate 1785 the documented boot protocol using a device tree. 1786 1787 Beware that there is very little in terms of protection against 1788 this option being confused by leftover garbage in memory that might 1789 look like a DTB header after a reboot if no actual DTB is appended 1790 to zImage. Do not leave this option active in a production kernel 1791 if you don't intend to always append a DTB. Proper passing of the 1792 location into r2 of a bootloader provided DTB is always preferable 1793 to this option. 1794 1795config ARM_ATAG_DTB_COMPAT 1796 bool "Supplement the appended DTB with traditional ATAG information" 1797 depends on ARM_APPENDED_DTB 1798 help 1799 Some old bootloaders can't be updated to a DTB capable one, yet 1800 they provide ATAGs with memory configuration, the ramdisk address, 1801 the kernel cmdline string, etc. Such information is dynamically 1802 provided by the bootloader and can't always be stored in a static 1803 DTB. To allow a device tree enabled kernel to be used with such 1804 bootloaders, this option allows zImage to extract the information 1805 from the ATAG list and store it at run time into the appended DTB. 1806 1807choice 1808 prompt "Kernel command line type" if ARM_ATAG_DTB_COMPAT 1809 default ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER 1810 1811config ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER 1812 bool "Use bootloader kernel arguments if available" 1813 help 1814 Uses the command-line options passed by the boot loader instead of 1815 the device tree bootargs property. If the boot loader doesn't provide 1816 any, the device tree bootargs property will be used. 1817 1818config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND 1819 bool "Extend with bootloader kernel arguments" 1820 help 1821 The command-line arguments provided by the boot loader will be 1822 appended to the the device tree bootargs property. 1823 1824endchoice 1825 1826config CMDLINE 1827 string "Default kernel command string" 1828 default "" 1829 help 1830 On some architectures (EBSA110 and CATS), there is currently no way 1831 for the boot loader to pass arguments to the kernel. For these 1832 architectures, you should supply some command-line options at build 1833 time by entering them here. As a minimum, you should specify the 1834 memory size and the root device (e.g., mem=64M root=/dev/nfs). 1835 1836choice 1837 prompt "Kernel command line type" if CMDLINE != "" 1838 default CMDLINE_FROM_BOOTLOADER 1839 depends on ATAGS 1840 1841config CMDLINE_FROM_BOOTLOADER 1842 bool "Use bootloader kernel arguments if available" 1843 help 1844 Uses the command-line options passed by the boot loader. If 1845 the boot loader doesn't provide any, the default kernel command 1846 string provided in CMDLINE will be used. 1847 1848config CMDLINE_EXTEND 1849 bool "Extend bootloader kernel arguments" 1850 help 1851 The command-line arguments provided by the boot loader will be 1852 appended to the default kernel command string. 1853 1854config CMDLINE_FORCE 1855 bool "Always use the default kernel command string" 1856 help 1857 Always use the default kernel command string, even if the boot 1858 loader passes other arguments to the kernel. 1859 This is useful if you cannot or don't want to change the 1860 command-line options your boot loader passes to the kernel. 1861endchoice 1862 1863config XIP_KERNEL 1864 bool "Kernel Execute-In-Place from ROM" 1865 depends on !ARM_LPAE && !ARCH_MULTIPLATFORM 1866 help 1867 Execute-In-Place allows the kernel to run from non-volatile storage 1868 directly addressable by the CPU, such as NOR flash. This saves RAM 1869 space since the text section of the kernel is not loaded from flash 1870 to RAM. Read-write sections, such as the data section and stack, 1871 are still copied to RAM. The XIP kernel is not compressed since 1872 it has to run directly from flash, so it will take more space to 1873 store it. The flash address used to link the kernel object files, 1874 and for storing it, is configuration dependent. Therefore, if you 1875 say Y here, you must know the proper physical address where to 1876 store the kernel image depending on your own flash memory usage. 1877 1878 Also note that the make target becomes "make xipImage" rather than 1879 "make zImage" or "make Image". The final kernel binary to put in 1880 ROM memory will be arch/arm/boot/xipImage. 1881 1882 If unsure, say N. 1883 1884config XIP_PHYS_ADDR 1885 hex "XIP Kernel Physical Location" 1886 depends on XIP_KERNEL 1887 default "0x00080000" 1888 help 1889 This is the physical address in your flash memory the kernel will 1890 be linked for and stored to. This address is dependent on your 1891 own flash usage. 1892 1893config XIP_DEFLATED_DATA 1894 bool "Store kernel .data section compressed in ROM" 1895 depends on XIP_KERNEL 1896 select ZLIB_INFLATE 1897 help 1898 Before the kernel is actually executed, its .data section has to be 1899 copied to RAM from ROM. This option allows for storing that data 1900 in compressed form and decompressed to RAM rather than merely being 1901 copied, saving some precious ROM space. A possible drawback is a 1902 slightly longer boot delay. 1903 1904config KEXEC 1905 bool "Kexec system call (EXPERIMENTAL)" 1906 depends on (!SMP || PM_SLEEP_SMP) 1907 depends on !CPU_V7M 1908 select KEXEC_CORE 1909 help 1910 kexec is a system call that implements the ability to shutdown your 1911 current kernel, and to start another kernel. It is like a reboot 1912 but it is independent of the system firmware. And like a reboot 1913 you can start any kernel with it, not just Linux. 1914 1915 It is an ongoing process to be certain the hardware in a machine 1916 is properly shutdown, so do not be surprised if this code does not 1917 initially work for you. 1918 1919config ATAGS_PROC 1920 bool "Export atags in procfs" 1921 depends on ATAGS && KEXEC 1922 default y 1923 help 1924 Should the atags used to boot the kernel be exported in an "atags" 1925 file in procfs. Useful with kexec. 1926 1927config CRASH_DUMP 1928 bool "Build kdump crash kernel (EXPERIMENTAL)" 1929 help 1930 Generate crash dump after being started by kexec. This should 1931 be normally only set in special crash dump kernels which are 1932 loaded in the main kernel with kexec-tools into a specially 1933 reserved region and then later executed after a crash by 1934 kdump/kexec. The crash dump kernel must be compiled to a 1935 memory address not used by the main kernel 1936 1937 For more details see Documentation/admin-guide/kdump/kdump.rst 1938 1939config AUTO_ZRELADDR 1940 bool "Auto calculation of the decompressed kernel image address" 1941 help 1942 ZRELADDR is the physical address where the decompressed kernel 1943 image will be placed. If AUTO_ZRELADDR is selected, the address 1944 will be determined at run-time by masking the current IP with 1945 0xf8000000. This assumes the zImage being placed in the first 128MB 1946 from start of memory. 1947 1948config EFI_STUB 1949 bool 1950 1951config EFI 1952 bool "UEFI runtime support" 1953 depends on OF && !CPU_BIG_ENDIAN && MMU && AUTO_ZRELADDR && !XIP_KERNEL 1954 select UCS2_STRING 1955 select EFI_PARAMS_FROM_FDT 1956 select EFI_STUB 1957 select EFI_ARMSTUB 1958 select EFI_RUNTIME_WRAPPERS 1959 ---help--- 1960 This option provides support for runtime services provided 1961 by UEFI firmware (such as non-volatile variables, realtime 1962 clock, and platform reset). A UEFI stub is also provided to 1963 allow the kernel to be booted as an EFI application. This 1964 is only useful for kernels that may run on systems that have 1965 UEFI firmware. 1966 1967config DMI 1968 bool "Enable support for SMBIOS (DMI) tables" 1969 depends on EFI 1970 default y 1971 help 1972 This enables SMBIOS/DMI feature for systems. 1973 1974 This option is only useful on systems that have UEFI firmware. 1975 However, even with this option, the resultant kernel should 1976 continue to boot on existing non-UEFI platforms. 1977 1978 NOTE: This does *NOT* enable or encourage the use of DMI quirks, 1979 i.e., the the practice of identifying the platform via DMI to 1980 decide whether certain workarounds for buggy hardware and/or 1981 firmware need to be enabled. This would require the DMI subsystem 1982 to be enabled much earlier than we do on ARM, which is non-trivial. 1983 1984endmenu 1985 1986menu "CPU Power Management" 1987 1988source "drivers/cpufreq/Kconfig" 1989 1990source "drivers/cpuidle/Kconfig" 1991 1992endmenu 1993 1994menu "Floating point emulation" 1995 1996comment "At least one emulation must be selected" 1997 1998config FPE_NWFPE 1999 bool "NWFPE math emulation" 2000 depends on (!AEABI || OABI_COMPAT) && !THUMB2_KERNEL 2001 ---help--- 2002 Say Y to include the NWFPE floating point emulator in the kernel. 2003 This is necessary to run most binaries. Linux does not currently 2004 support floating point hardware so you need to say Y here even if 2005 your machine has an FPA or floating point co-processor podule. 2006 2007 You may say N here if you are going to load the Acorn FPEmulator 2008 early in the bootup. 2009 2010config FPE_NWFPE_XP 2011 bool "Support extended precision" 2012 depends on FPE_NWFPE 2013 help 2014 Say Y to include 80-bit support in the kernel floating-point 2015 emulator. Otherwise, only 32 and 64-bit support is compiled in. 2016 Note that gcc does not generate 80-bit operations by default, 2017 so in most cases this option only enlarges the size of the 2018 floating point emulator without any good reason. 2019 2020 You almost surely want to say N here. 2021 2022config FPE_FASTFPE 2023 bool "FastFPE math emulation (EXPERIMENTAL)" 2024 depends on (!AEABI || OABI_COMPAT) && !CPU_32v3 2025 ---help--- 2026 Say Y here to include the FAST floating point emulator in the kernel. 2027 This is an experimental much faster emulator which now also has full 2028 precision for the mantissa. It does not support any exceptions. 2029 It is very simple, and approximately 3-6 times faster than NWFPE. 2030 2031 It should be sufficient for most programs. It may be not suitable 2032 for scientific calculations, but you have to check this for yourself. 2033 If you do not feel you need a faster FP emulation you should better 2034 choose NWFPE. 2035 2036config VFP 2037 bool "VFP-format floating point maths" 2038 depends on CPU_V6 || CPU_V6K || CPU_ARM926T || CPU_V7 || CPU_FEROCEON 2039 help 2040 Say Y to include VFP support code in the kernel. This is needed 2041 if your hardware includes a VFP unit. 2042 2043 Please see <file:Documentation/arm/vfp/release-notes.rst> for 2044 release notes and additional status information. 2045 2046 Say N if your target does not have VFP hardware. 2047 2048config VFPv3 2049 bool 2050 depends on VFP 2051 default y if CPU_V7 2052 2053config NEON 2054 bool "Advanced SIMD (NEON) Extension support" 2055 depends on VFPv3 && CPU_V7 2056 help 2057 Say Y to include support code for NEON, the ARMv7 Advanced SIMD 2058 Extension. 2059 2060config KERNEL_MODE_NEON 2061 bool "Support for NEON in kernel mode" 2062 depends on NEON && AEABI 2063 help 2064 Say Y to include support for NEON in kernel mode. 2065 2066endmenu 2067 2068menu "Power management options" 2069 2070source "kernel/power/Kconfig" 2071 2072config ARCH_SUSPEND_POSSIBLE 2073 depends on CPU_ARM920T || CPU_ARM926T || CPU_FEROCEON || CPU_SA1100 || \ 2074 CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M || CPU_XSC3 || CPU_XSCALE || CPU_MOHAWK 2075 def_bool y 2076 2077config ARM_CPU_SUSPEND 2078 def_bool PM_SLEEP || BL_SWITCHER || ARM_PSCI_FW 2079 depends on ARCH_SUSPEND_POSSIBLE 2080 2081config ARCH_HIBERNATION_POSSIBLE 2082 bool 2083 depends on MMU 2084 default y if ARCH_SUSPEND_POSSIBLE 2085 2086endmenu 2087 2088source "drivers/firmware/Kconfig" 2089 2090if CRYPTO 2091source "arch/arm/crypto/Kconfig" 2092endif 2093 2094source "arch/arm/kvm/Kconfig" 2095