4 select ARCH_CLOCKSOURCE_DATA
5 select ARCH_HAS_DEBUG_VIRTUAL
6 select ARCH_HAS_DEVMEM_IS_ALLOWED
7 select ARCH_HAS_ELF_RANDOMIZE
8 select ARCH_HAS_SET_MEMORY
9 select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
10 select ARCH_HAS_STRICT_MODULE_RWX if MMU
11 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
12 select ARCH_HAVE_CUSTOM_GPIO_H
13 select ARCH_HAS_GCOV_PROFILE_ALL
14 select ARCH_MIGHT_HAVE_PC_PARPORT
15 select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
16 select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
17 select ARCH_SUPPORTS_ATOMIC_RMW
18 select ARCH_USE_BUILTIN_BSWAP
19 select ARCH_USE_CMPXCHG_LOCKREF
20 select ARCH_WANT_IPC_PARSE_VERSION
21 select BUILDTIME_EXTABLE_SORT if MMU
22 select CLONE_BACKWARDS
23 select CPU_PM if (SUSPEND || CPU_IDLE)
24 select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS
26 select EDAC_ATOMIC_SCRUB
27 select GENERIC_ALLOCATOR
28 select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI)
29 select GENERIC_CLOCKEVENTS_BROADCAST if SMP
30 select GENERIC_CPU_AUTOPROBE
31 select GENERIC_EARLY_IOREMAP
32 select GENERIC_IDLE_POLL_SETUP
33 select GENERIC_IRQ_PROBE
34 select GENERIC_IRQ_SHOW
35 select GENERIC_IRQ_SHOW_LEVEL
36 select GENERIC_PCI_IOMAP
37 select GENERIC_SCHED_CLOCK
38 select GENERIC_SMP_IDLE_THREAD
39 select GENERIC_STRNCPY_FROM_USER
40 select GENERIC_STRNLEN_USER
41 select HANDLE_DOMAIN_IRQ
42 select HARDIRQS_SW_RESEND
43 select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT)
44 select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
45 select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
46 select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
47 select HAVE_ARCH_MMAP_RND_BITS if MMU
48 select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)
49 select HAVE_ARCH_TRACEHOOK
50 select HAVE_ARM_SMCCC if CPU_V7
52 select HAVE_CC_STACKPROTECTOR
53 select HAVE_CONTEXT_TRACKING
54 select HAVE_C_RECORDMCOUNT
55 select HAVE_DEBUG_KMEMLEAK
56 select HAVE_DMA_API_DEBUG
57 select HAVE_DMA_CONTIGUOUS if MMU
58 select HAVE_DYNAMIC_FTRACE if (!XIP_KERNEL) && !CPU_ENDIAN_BE32 && MMU
59 select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
60 select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
61 select HAVE_EXIT_THREAD
62 select HAVE_FTRACE_MCOUNT_RECORD if (!XIP_KERNEL)
63 select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL)
64 select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
65 select HAVE_GCC_PLUGINS
66 select HAVE_GENERIC_DMA_COHERENT
67 select HAVE_HW_BREAKPOINT if (PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7))
68 select HAVE_IDE if PCI || ISA || PCMCIA
69 select HAVE_IRQ_TIME_ACCOUNTING
70 select HAVE_KERNEL_GZIP
71 select HAVE_KERNEL_LZ4
72 select HAVE_KERNEL_LZMA
73 select HAVE_KERNEL_LZO
75 select HAVE_KPROBES if !XIP_KERNEL && !CPU_ENDIAN_BE32 && !CPU_V7M
76 select HAVE_KRETPROBES if (HAVE_KPROBES)
78 select HAVE_MOD_ARCH_SPECIFIC
80 select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
81 select HAVE_OPTPROBES if !THUMB2_KERNEL
82 select HAVE_PERF_EVENTS
84 select HAVE_PERF_USER_STACK_DUMP
85 select HAVE_RCU_TABLE_FREE if (SMP && ARM_LPAE)
86 select HAVE_REGS_AND_STACK_ACCESS_API
87 select HAVE_SYSCALL_TRACEPOINTS
89 select HAVE_VIRT_CPU_ACCOUNTING_GEN
90 select IRQ_FORCED_THREADING
91 select MODULES_USE_ELF_REL
93 select OF_EARLY_FLATTREE if OF
94 select OF_RESERVED_MEM if OF
96 select OLD_SIGSUSPEND3
97 select PERF_USE_VMALLOC
99 select SYS_SUPPORTS_APM_EMULATION
100 # Above selects are sorted alphabetically; please add new ones
101 # according to that. Thanks.
103 The ARM series is a line of low-power-consumption RISC chip designs
104 licensed by ARM Ltd and targeted at embedded applications and
105 handhelds such as the Compaq IPAQ. ARM-based PCs are no longer
106 manufactured, but legacy ARM-based PC hardware remains popular in
107 Europe. There is an ARM Linux project with a web page at
108 <http://www.arm.linux.org.uk/>.
110 config ARM_HAS_SG_CHAIN
111 select ARCH_HAS_SG_CHAIN
114 config NEED_SG_DMA_LENGTH
117 config ARM_DMA_USE_IOMMU
119 select ARM_HAS_SG_CHAIN
120 select NEED_SG_DMA_LENGTH
124 config ARM_DMA_IOMMU_ALIGNMENT
125 int "Maximum PAGE_SIZE order of alignment for DMA IOMMU buffers"
129 DMA mapping framework by default aligns all buffers to the smallest
130 PAGE_SIZE order which is greater than or equal to the requested buffer
131 size. This works well for buffers up to a few hundreds kilobytes, but
132 for larger buffers it just a waste of address space. Drivers which has
133 relatively small addressing window (like 64Mib) might run out of
134 virtual space with just a few allocations.
136 With this parameter you can specify the maximum PAGE_SIZE order for
137 DMA IOMMU buffers. Larger buffers will be aligned only to this
138 specified order. The order is expressed as a power of two multiplied
143 config MIGHT_HAVE_PCI
146 config SYS_SUPPORTS_APM_EMULATION
151 select GENERIC_ALLOCATOR
162 The Extended Industry Standard Architecture (EISA) bus was
163 developed as an open alternative to the IBM MicroChannel bus.
165 The EISA bus provided some of the features of the IBM MicroChannel
166 bus while maintaining backward compatibility with cards made for
167 the older ISA bus. The EISA bus saw limited use between 1988 and
168 1995 when it was made obsolete by the PCI bus.
170 Say Y here if you are building a kernel for an EISA-based machine.
177 config STACKTRACE_SUPPORT
181 config LOCKDEP_SUPPORT
185 config TRACE_IRQFLAGS_SUPPORT
189 config RWSEM_XCHGADD_ALGORITHM
193 config ARCH_HAS_ILOG2_U32
196 config ARCH_HAS_ILOG2_U64
199 config ARCH_HAS_BANDGAP
202 config FIX_EARLYCON_MEM
205 config GENERIC_HWEIGHT
209 config GENERIC_CALIBRATE_DELAY
213 config ARCH_MAY_HAVE_PC_FDC
219 config NEED_DMA_MAP_STATE
222 config ARCH_SUPPORTS_UPROBES
225 config ARCH_HAS_DMA_SET_COHERENT_MASK
228 config GENERIC_ISA_DMA
234 config NEED_RET_TO_USER
242 default 0xffff0000 if MMU || CPU_HIGH_VECTOR
243 default DRAM_BASE if REMAP_VECTORS_TO_RAM
246 The base address of exception vectors. This must be two pages
249 config ARM_PATCH_PHYS_VIRT
250 bool "Patch physical to virtual translations at runtime" if EMBEDDED
252 depends on !XIP_KERNEL && MMU
254 Patch phys-to-virt and virt-to-phys translation functions at
255 boot and module load time according to the position of the
256 kernel in system memory.
258 This can only be used with non-XIP MMU kernels where the base
259 of physical memory is at a 16MB boundary.
261 Only disable this option if you know that you do not require
262 this feature (eg, building a kernel for a single machine) and
263 you need to shrink the kernel to the minimal size.
265 config NEED_MACH_IO_H
268 Select this when mach/io.h is required to provide special
269 definitions for this platform. The need for mach/io.h should
270 be avoided when possible.
272 config NEED_MACH_MEMORY_H
275 Select this when mach/memory.h is required to provide special
276 definitions for this platform. The need for mach/memory.h should
277 be avoided when possible.
280 hex "Physical address of main memory" if MMU
281 depends on !ARM_PATCH_PHYS_VIRT
282 default DRAM_BASE if !MMU
283 default 0x00000000 if ARCH_EBSA110 || \
289 default 0x10000000 if ARCH_OMAP1 || ARCH_RPC
290 default 0x20000000 if ARCH_S5PV210
291 default 0xc0000000 if ARCH_SA1100
293 Please provide the physical address corresponding to the
294 location of main memory in your system.
300 config PGTABLE_LEVELS
302 default 3 if ARM_LPAE
305 source "init/Kconfig"
307 source "kernel/Kconfig.freezer"
312 bool "MMU-based Paged Memory Management Support"
315 Select if you want MMU-based virtualised addressing space
316 support by paged memory management. If unsure, say 'Y'.
318 config ARCH_MMAP_RND_BITS_MIN
321 config ARCH_MMAP_RND_BITS_MAX
322 default 14 if PAGE_OFFSET=0x40000000
323 default 15 if PAGE_OFFSET=0x80000000
327 # The "ARM system type" choice list is ordered alphabetically by option
328 # text. Please add new entries in the option alphabetic order.
331 prompt "ARM system type"
332 default ARM_SINGLE_ARMV7M if !MMU
333 default ARCH_MULTIPLATFORM if MMU
335 config ARCH_MULTIPLATFORM
336 bool "Allow multiple platforms to be selected"
338 select ARM_HAS_SG_CHAIN
339 select ARM_PATCH_PHYS_VIRT
343 select GENERIC_CLOCKEVENTS
344 select MIGHT_HAVE_PCI
345 select MULTI_IRQ_HANDLER
346 select PCI_DOMAINS if PCI
350 config ARM_SINGLE_ARMV7M
351 bool "ARMv7-M based platforms (Cortex-M0/M3/M4)"
358 select GENERIC_CLOCKEVENTS
365 select ARCH_USES_GETTIMEOFFSET
368 select NEED_MACH_IO_H
369 select NEED_MACH_MEMORY_H
372 This is an evaluation board for the StrongARM processor available
373 from Digital. It has limited hardware on-board, including an
374 Ethernet interface, two PCMCIA sockets, two serial ports and a
379 select ARCH_HAS_HOLES_MEMORYMODEL
381 select ARM_PATCH_PHYS_VIRT
387 select GENERIC_CLOCKEVENTS
390 This enables support for the Cirrus EP93xx series of CPUs.
392 config ARCH_FOOTBRIDGE
396 select GENERIC_CLOCKEVENTS
398 select NEED_MACH_IO_H if !MMU
399 select NEED_MACH_MEMORY_H
401 Support for systems based on the DC21285 companion chip
402 ("FootBridge"), such as the Simtec CATS and the Rebel NetWinder.
405 bool "Hilscher NetX based"
409 select GENERIC_CLOCKEVENTS
411 This enables support for systems based on the Hilscher NetX Soc
417 select NEED_MACH_MEMORY_H
418 select NEED_RET_TO_USER
424 Support for Intel's IOP13XX (XScale) family of processors.
432 select NEED_RET_TO_USER
436 Support for Intel's 80219 and IOP32X (XScale) family of
445 select NEED_RET_TO_USER
449 Support for Intel's IOP33X (XScale) family of processors.
454 select ARCH_HAS_DMA_SET_COHERENT_MASK
455 select ARCH_SUPPORTS_BIG_ENDIAN
458 select DMABOUNCE if PCI
459 select GENERIC_CLOCKEVENTS
461 select MIGHT_HAVE_PCI
462 select NEED_MACH_IO_H
463 select USB_EHCI_BIG_ENDIAN_DESC
464 select USB_EHCI_BIG_ENDIAN_MMIO
466 Support for Intel's IXP4XX (XScale) family of processors.
471 select GENERIC_CLOCKEVENTS
473 select MIGHT_HAVE_PCI
474 select MULTI_IRQ_HANDLER
478 select PLAT_ORION_LEGACY
480 select PM_GENERIC_DOMAINS if PM
482 Support for the Marvell Dove SoC 88AP510
485 bool "Micrel/Kendin KS8695"
488 select GENERIC_CLOCKEVENTS
490 select NEED_MACH_MEMORY_H
492 Support for Micrel/Kendin KS8695 "Centaur" (ARM922T) based
493 System-on-Chip devices.
496 bool "Nuvoton W90X900 CPU"
500 select GENERIC_CLOCKEVENTS
503 Support for Nuvoton (Winbond logic dept.) ARM9 processor,
504 At present, the w90x900 has been renamed nuc900, regarding
505 the ARM series product line, you can login the following
506 link address to know more.
508 <http://www.nuvoton.com/hq/enu/ProductAndSales/ProductLines/
509 ConsumerElectronicsIC/ARMMicrocontroller/ARMMicrocontroller>
515 select CLKSRC_LPC32XX
518 select GENERIC_CLOCKEVENTS
520 select MULTI_IRQ_HANDLER
524 Support for the NXP LPC32XX family of processors
527 bool "PXA2xx/PXA3xx-based"
530 select ARM_CPU_SUSPEND if PM
537 select CPU_XSCALE if !CPU_XSC3
538 select GENERIC_CLOCKEVENTS
543 select MULTI_IRQ_HANDLER
547 Support for Intel/Marvell's PXA2xx/PXA3xx processor line.
553 select ARCH_MAY_HAVE_PC_FDC
554 select ARCH_SPARSEMEM_ENABLE
555 select ARCH_USES_GETTIMEOFFSET
559 select HAVE_PATA_PLATFORM
561 select NEED_MACH_IO_H
562 select NEED_MACH_MEMORY_H
565 On the Acorn Risc-PC, Linux can support the internal IDE disk and
566 CD-ROM interface, serial and parallel port, and the floppy drive.
571 select ARCH_SPARSEMEM_ENABLE
575 select CLKSRC_OF if OF
578 select GENERIC_CLOCKEVENTS
583 select MULTI_IRQ_HANDLER
584 select NEED_MACH_MEMORY_H
587 Support for StrongARM 11x0 based boards.
590 bool "Samsung S3C24XX SoCs"
593 select CLKSRC_SAMSUNG_PWM
594 select GENERIC_CLOCKEVENTS
597 select HAVE_S3C2410_I2C if I2C
598 select HAVE_S3C2410_WATCHDOG if WATCHDOG
599 select HAVE_S3C_RTC if RTC_CLASS
600 select MULTI_IRQ_HANDLER
601 select NEED_MACH_IO_H
604 Samsung S3C2410, S3C2412, S3C2413, S3C2416, S3C2440, S3C2442, S3C2443
605 and S3C2450 SoCs based systems, such as the Simtec Electronics BAST
606 (<http://www.simtec.co.uk/products/EB110ITX/>), the IPAQ 1940 or the
607 Samsung SMDK2410 development board (and derivatives).
611 select ARCH_HAS_HOLES_MEMORYMODEL
614 select GENERIC_ALLOCATOR
615 select GENERIC_CLOCKEVENTS
616 select GENERIC_IRQ_CHIP
622 Support for TI's DaVinci platform.
627 select ARCH_HAS_HOLES_MEMORYMODEL
631 select GENERIC_CLOCKEVENTS
632 select GENERIC_IRQ_CHIP
636 select MULTI_IRQ_HANDLER
637 select NEED_MACH_IO_H if PCCARD
638 select NEED_MACH_MEMORY_H
641 Support for older TI OMAP1 (omap7xx, omap15xx or omap16xx)
645 menu "Multiple platform selection"
646 depends on ARCH_MULTIPLATFORM
648 comment "CPU Core family selection"
651 bool "ARMv4 based platforms (FA526)"
652 depends on !ARCH_MULTI_V6_V7
653 select ARCH_MULTI_V4_V5
656 config ARCH_MULTI_V4T
657 bool "ARMv4T based platforms (ARM720T, ARM920T, ...)"
658 depends on !ARCH_MULTI_V6_V7
659 select ARCH_MULTI_V4_V5
660 select CPU_ARM920T if !(CPU_ARM7TDMI || CPU_ARM720T || \
661 CPU_ARM740T || CPU_ARM9TDMI || CPU_ARM922T || \
662 CPU_ARM925T || CPU_ARM940T)
665 bool "ARMv5 based platforms (ARM926T, XSCALE, PJ1, ...)"
666 depends on !ARCH_MULTI_V6_V7
667 select ARCH_MULTI_V4_V5
668 select CPU_ARM926T if !(CPU_ARM946E || CPU_ARM1020 || \
669 CPU_ARM1020E || CPU_ARM1022 || CPU_ARM1026 || \
670 CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_FEROCEON)
672 config ARCH_MULTI_V4_V5
676 bool "ARMv6 based platforms (ARM11)"
677 select ARCH_MULTI_V6_V7
681 bool "ARMv7 based platforms (Cortex-A, PJ4, Scorpion, Krait)"
683 select ARCH_MULTI_V6_V7
687 config ARCH_MULTI_V6_V7
689 select MIGHT_HAVE_CACHE_L2X0
691 config ARCH_MULTI_CPU_AUTO
692 def_bool !(ARCH_MULTI_V4 || ARCH_MULTI_V4T || ARCH_MULTI_V6_V7)
698 bool "Dummy Virtual Machine"
699 depends on ARCH_MULTI_V7
702 select ARM_GIC_V2M if PCI
704 select ARM_GIC_V3_ITS if PCI
706 select HAVE_ARM_ARCH_TIMER
709 # This is sorted alphabetically by mach-* pathname. However, plat-*
710 # Kconfigs may be included either alphabetically (according to the
711 # plat- suffix) or along side the corresponding mach-* source.
713 source "arch/arm/mach-mvebu/Kconfig"
715 source "arch/arm/mach-alpine/Kconfig"
717 source "arch/arm/mach-artpec/Kconfig"
719 source "arch/arm/mach-asm9260/Kconfig"
721 source "arch/arm/mach-at91/Kconfig"
723 source "arch/arm/mach-axxia/Kconfig"
725 source "arch/arm/mach-bcm/Kconfig"
727 source "arch/arm/mach-berlin/Kconfig"
729 source "arch/arm/mach-clps711x/Kconfig"
731 source "arch/arm/mach-cns3xxx/Kconfig"
733 source "arch/arm/mach-davinci/Kconfig"
735 source "arch/arm/mach-digicolor/Kconfig"
737 source "arch/arm/mach-dove/Kconfig"
739 source "arch/arm/mach-ep93xx/Kconfig"
741 source "arch/arm/mach-footbridge/Kconfig"
743 source "arch/arm/mach-gemini/Kconfig"
745 source "arch/arm/mach-highbank/Kconfig"
747 source "arch/arm/mach-hisi/Kconfig"
749 source "arch/arm/mach-integrator/Kconfig"
751 source "arch/arm/mach-iop32x/Kconfig"
753 source "arch/arm/mach-iop33x/Kconfig"
755 source "arch/arm/mach-iop13xx/Kconfig"
757 source "arch/arm/mach-ixp4xx/Kconfig"
759 source "arch/arm/mach-keystone/Kconfig"
761 source "arch/arm/mach-ks8695/Kconfig"
763 source "arch/arm/mach-meson/Kconfig"
765 source "arch/arm/mach-moxart/Kconfig"
767 source "arch/arm/mach-aspeed/Kconfig"
769 source "arch/arm/mach-mv78xx0/Kconfig"
771 source "arch/arm/mach-imx/Kconfig"
773 source "arch/arm/mach-mediatek/Kconfig"
775 source "arch/arm/mach-mxs/Kconfig"
777 source "arch/arm/mach-netx/Kconfig"
779 source "arch/arm/mach-nomadik/Kconfig"
781 source "arch/arm/mach-nspire/Kconfig"
783 source "arch/arm/plat-omap/Kconfig"
785 source "arch/arm/mach-omap1/Kconfig"
787 source "arch/arm/mach-omap2/Kconfig"
789 source "arch/arm/mach-orion5x/Kconfig"
791 source "arch/arm/mach-picoxcell/Kconfig"
793 source "arch/arm/mach-pxa/Kconfig"
794 source "arch/arm/plat-pxa/Kconfig"
796 source "arch/arm/mach-mmp/Kconfig"
798 source "arch/arm/mach-oxnas/Kconfig"
800 source "arch/arm/mach-qcom/Kconfig"
802 source "arch/arm/mach-realview/Kconfig"
804 source "arch/arm/mach-rockchip/Kconfig"
806 source "arch/arm/mach-sa1100/Kconfig"
808 source "arch/arm/mach-socfpga/Kconfig"
810 source "arch/arm/mach-spear/Kconfig"
812 source "arch/arm/mach-sti/Kconfig"
814 source "arch/arm/mach-stm32/Kconfig"
816 source "arch/arm/mach-s3c24xx/Kconfig"
818 source "arch/arm/mach-s3c64xx/Kconfig"
820 source "arch/arm/mach-s5pv210/Kconfig"
822 source "arch/arm/mach-exynos/Kconfig"
823 source "arch/arm/plat-samsung/Kconfig"
825 source "arch/arm/mach-shmobile/Kconfig"
827 source "arch/arm/mach-sunxi/Kconfig"
829 source "arch/arm/mach-prima2/Kconfig"
831 source "arch/arm/mach-tango/Kconfig"
833 source "arch/arm/mach-tegra/Kconfig"
835 source "arch/arm/mach-u300/Kconfig"
837 source "arch/arm/mach-uniphier/Kconfig"
839 source "arch/arm/mach-ux500/Kconfig"
841 source "arch/arm/mach-versatile/Kconfig"
843 source "arch/arm/mach-vexpress/Kconfig"
844 source "arch/arm/plat-versatile/Kconfig"
846 source "arch/arm/mach-vt8500/Kconfig"
848 source "arch/arm/mach-w90x900/Kconfig"
850 source "arch/arm/mach-zx/Kconfig"
852 source "arch/arm/mach-zynq/Kconfig"
854 # ARMv7-M architecture
856 bool "Energy Micro efm32"
857 depends on ARM_SINGLE_ARMV7M
860 Support for Energy Micro's (now Silicon Labs) efm32 Giant Gecko
864 bool "NXP LPC18xx/LPC43xx"
865 depends on ARM_SINGLE_ARMV7M
866 select ARCH_HAS_RESET_CONTROLLER
868 select CLKSRC_LPC32XX
871 Support for NXP's LPC18xx Cortex-M3 and LPC43xx Cortex-M4
872 high performance microcontrollers.
875 bool "ARM MPS2 platform"
876 depends on ARM_SINGLE_ARMV7M
880 Support for Cortex-M Prototyping System (or V2M-MPS2) which comes
881 with a range of available cores like Cortex-M3/M4/M7.
883 Please, note that depends which Application Note is used memory map
884 for the platform may vary, so adjustment of RAM base might be needed.
886 # Definitions to make life easier
892 select GENERIC_CLOCKEVENTS
898 select GENERIC_IRQ_CHIP
901 config PLAT_ORION_LEGACY
908 config PLAT_VERSATILE
911 source "arch/arm/firmware/Kconfig"
913 source arch/arm/mm/Kconfig
916 bool "Enable iWMMXt support"
917 depends on CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_PJ4 || CPU_PJ4B
918 default y if PXA27x || PXA3xx || ARCH_MMP || CPU_PJ4 || CPU_PJ4B
920 Enable support for iWMMXt context switching at run time if
921 running on a CPU that supports it.
923 config MULTI_IRQ_HANDLER
926 Allow each machine to specify it's own IRQ handler at run time.
929 source "arch/arm/Kconfig-nommu"
932 config PJ4B_ERRATA_4742
933 bool "PJ4B Errata 4742: IDLE Wake Up Commands can Cause the CPU Core to Cease Operation"
934 depends on CPU_PJ4B && MACH_ARMADA_370
937 When coming out of either a Wait for Interrupt (WFI) or a Wait for
938 Event (WFE) IDLE states, a specific timing sensitivity exists between
939 the retiring WFI/WFE instructions and the newly issued subsequent
940 instructions. This sensitivity can result in a CPU hang scenario.
942 The software must insert either a Data Synchronization Barrier (DSB)
943 or Data Memory Barrier (DMB) command immediately after the WFI/WFE
946 config ARM_ERRATA_326103
947 bool "ARM errata: FSR write bit incorrect on a SWP to read-only memory"
950 Executing a SWP instruction to read-only memory does not set bit 11
951 of the FSR on the ARM 1136 prior to r1p0. This causes the kernel to
952 treat the access as a read, preventing a COW from occurring and
953 causing the faulting task to livelock.
955 config ARM_ERRATA_411920
956 bool "ARM errata: Invalidation of the Instruction Cache operation can fail"
957 depends on CPU_V6 || CPU_V6K
959 Invalidation of the Instruction Cache operation can
960 fail. This erratum is present in 1136 (before r1p4), 1156 and 1176.
961 It does not affect the MPCore. This option enables the ARM Ltd.
962 recommended workaround.
964 config ARM_ERRATA_430973
965 bool "ARM errata: Stale prediction on replaced interworking branch"
968 This option enables the workaround for the 430973 Cortex-A8
969 r1p* erratum. If a code sequence containing an ARM/Thumb
970 interworking branch is replaced with another code sequence at the
971 same virtual address, whether due to self-modifying code or virtual
972 to physical address re-mapping, Cortex-A8 does not recover from the
973 stale interworking branch prediction. This results in Cortex-A8
974 executing the new code sequence in the incorrect ARM or Thumb state.
975 The workaround enables the BTB/BTAC operations by setting ACTLR.IBE
976 and also flushes the branch target cache at every context switch.
977 Note that setting specific bits in the ACTLR register may not be
978 available in non-secure mode.
980 config ARM_ERRATA_458693
981 bool "ARM errata: Processor deadlock when a false hazard is created"
983 depends on !ARCH_MULTIPLATFORM
985 This option enables the workaround for the 458693 Cortex-A8 (r2p0)
986 erratum. For very specific sequences of memory operations, it is
987 possible for a hazard condition intended for a cache line to instead
988 be incorrectly associated with a different cache line. This false
989 hazard might then cause a processor deadlock. The workaround enables
990 the L1 caching of the NEON accesses and disables the PLD instruction
991 in the ACTLR register. Note that setting specific bits in the ACTLR
992 register may not be available in non-secure mode.
994 config ARM_ERRATA_460075
995 bool "ARM errata: Data written to the L2 cache can be overwritten with stale data"
997 depends on !ARCH_MULTIPLATFORM
999 This option enables the workaround for the 460075 Cortex-A8 (r2p0)
1000 erratum. Any asynchronous access to the L2 cache may encounter a
1001 situation in which recent store transactions to the L2 cache are lost
1002 and overwritten with stale memory contents from external memory. The
1003 workaround disables the write-allocate mode for the L2 cache via the
1004 ACTLR register. Note that setting specific bits in the ACTLR register
1005 may not be available in non-secure mode.
1007 config ARM_ERRATA_742230
1008 bool "ARM errata: DMB operation may be faulty"
1009 depends on CPU_V7 && SMP
1010 depends on !ARCH_MULTIPLATFORM
1012 This option enables the workaround for the 742230 Cortex-A9
1013 (r1p0..r2p2) erratum. Under rare circumstances, a DMB instruction
1014 between two write operations may not ensure the correct visibility
1015 ordering of the two writes. This workaround sets a specific bit in
1016 the diagnostic register of the Cortex-A9 which causes the DMB
1017 instruction to behave as a DSB, ensuring the correct behaviour of
1020 config ARM_ERRATA_742231
1021 bool "ARM errata: Incorrect hazard handling in the SCU may lead to data corruption"
1022 depends on CPU_V7 && SMP
1023 depends on !ARCH_MULTIPLATFORM
1025 This option enables the workaround for the 742231 Cortex-A9
1026 (r2p0..r2p2) erratum. Under certain conditions, specific to the
1027 Cortex-A9 MPCore micro-architecture, two CPUs working in SMP mode,
1028 accessing some data located in the same cache line, may get corrupted
1029 data due to bad handling of the address hazard when the line gets
1030 replaced from one of the CPUs at the same time as another CPU is
1031 accessing it. This workaround sets specific bits in the diagnostic
1032 register of the Cortex-A9 which reduces the linefill issuing
1033 capabilities of the processor.
1035 config ARM_ERRATA_643719
1036 bool "ARM errata: LoUIS bit field in CLIDR register is incorrect"
1037 depends on CPU_V7 && SMP
1040 This option enables the workaround for the 643719 Cortex-A9 (prior to
1041 r1p0) erratum. On affected cores the LoUIS bit field of the CLIDR
1042 register returns zero when it should return one. The workaround
1043 corrects this value, ensuring cache maintenance operations which use
1044 it behave as intended and avoiding data corruption.
1046 config ARM_ERRATA_720789
1047 bool "ARM errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID"
1050 This option enables the workaround for the 720789 Cortex-A9 (prior to
1051 r2p0) erratum. A faulty ASID can be sent to the other CPUs for the
1052 broadcasted CP15 TLB maintenance operations TLBIASIDIS and TLBIMVAIS.
1053 As a consequence of this erratum, some TLB entries which should be
1054 invalidated are not, resulting in an incoherency in the system page
1055 tables. The workaround changes the TLB flushing routines to invalidate
1056 entries regardless of the ASID.
1058 config ARM_ERRATA_743622
1059 bool "ARM errata: Faulty hazard checking in the Store Buffer may lead to data corruption"
1061 depends on !ARCH_MULTIPLATFORM
1063 This option enables the workaround for the 743622 Cortex-A9
1064 (r2p*) erratum. Under very rare conditions, a faulty
1065 optimisation in the Cortex-A9 Store Buffer may lead to data
1066 corruption. This workaround sets a specific bit in the diagnostic
1067 register of the Cortex-A9 which disables the Store Buffer
1068 optimisation, preventing the defect from occurring. This has no
1069 visible impact on the overall performance or power consumption of the
1072 config ARM_ERRATA_751472
1073 bool "ARM errata: Interrupted ICIALLUIS may prevent completion of broadcasted operation"
1075 depends on !ARCH_MULTIPLATFORM
1077 This option enables the workaround for the 751472 Cortex-A9 (prior
1078 to r3p0) erratum. An interrupted ICIALLUIS operation may prevent the
1079 completion of a following broadcasted operation if the second
1080 operation is received by a CPU before the ICIALLUIS has completed,
1081 potentially leading to corrupted entries in the cache or TLB.
1083 config ARM_ERRATA_754322
1084 bool "ARM errata: possible faulty MMU translations following an ASID switch"
1087 This option enables the workaround for the 754322 Cortex-A9 (r2p*,
1088 r3p*) erratum. A speculative memory access may cause a page table walk
1089 which starts prior to an ASID switch but completes afterwards. This
1090 can populate the micro-TLB with a stale entry which may be hit with
1091 the new ASID. This workaround places two dsb instructions in the mm
1092 switching code so that no page table walks can cross the ASID switch.
1094 config ARM_ERRATA_754327
1095 bool "ARM errata: no automatic Store Buffer drain"
1096 depends on CPU_V7 && SMP
1098 This option enables the workaround for the 754327 Cortex-A9 (prior to
1099 r2p0) erratum. The Store Buffer does not have any automatic draining
1100 mechanism and therefore a livelock may occur if an external agent
1101 continuously polls a memory location waiting to observe an update.
1102 This workaround defines cpu_relax() as smp_mb(), preventing correctly
1103 written polling loops from denying visibility of updates to memory.
1105 config ARM_ERRATA_364296
1106 bool "ARM errata: Possible cache data corruption with hit-under-miss enabled"
1109 This options enables the workaround for the 364296 ARM1136
1110 r0p2 erratum (possible cache data corruption with
1111 hit-under-miss enabled). It sets the undocumented bit 31 in
1112 the auxiliary control register and the FI bit in the control
1113 register, thus disabling hit-under-miss without putting the
1114 processor into full low interrupt latency mode. ARM11MPCore
1117 config ARM_ERRATA_764369
1118 bool "ARM errata: Data cache line maintenance operation by MVA may not succeed"
1119 depends on CPU_V7 && SMP
1121 This option enables the workaround for erratum 764369
1122 affecting Cortex-A9 MPCore with two or more processors (all
1123 current revisions). Under certain timing circumstances, a data
1124 cache line maintenance operation by MVA targeting an Inner
1125 Shareable memory region may fail to proceed up to either the
1126 Point of Coherency or to the Point of Unification of the
1127 system. This workaround adds a DSB instruction before the
1128 relevant cache maintenance functions and sets a specific bit
1129 in the diagnostic control register of the SCU.
1131 config ARM_ERRATA_775420
1132 bool "ARM errata: A data cache maintenance operation which aborts, might lead to deadlock"
1135 This option enables the workaround for the 775420 Cortex-A9 (r2p2,
1136 r2p6,r2p8,r2p10,r3p0) erratum. In case a date cache maintenance
1137 operation aborts with MMU exception, it might cause the processor
1138 to deadlock. This workaround puts DSB before executing ISB if
1139 an abort may occur on cache maintenance.
1141 config ARM_ERRATA_798181
1142 bool "ARM errata: TLBI/DSB failure on Cortex-A15"
1143 depends on CPU_V7 && SMP
1145 On Cortex-A15 (r0p0..r3p2) the TLBI*IS/DSB operations are not
1146 adequately shooting down all use of the old entries. This
1147 option enables the Linux kernel workaround for this erratum
1148 which sends an IPI to the CPUs that are running the same ASID
1149 as the one being invalidated.
1151 config ARM_ERRATA_773022
1152 bool "ARM errata: incorrect instructions may be executed from loop buffer"
1155 This option enables the workaround for the 773022 Cortex-A15
1156 (up to r0p4) erratum. In certain rare sequences of code, the
1157 loop buffer may deliver incorrect instructions. This
1158 workaround disables the loop buffer to avoid the erratum.
1160 config ARM_ERRATA_818325_852422
1161 bool "ARM errata: A12: some seqs of opposed cond code instrs => deadlock or corruption"
1164 This option enables the workaround for:
1165 - Cortex-A12 818325: Execution of an UNPREDICTABLE STR or STM
1166 instruction might deadlock. Fixed in r0p1.
1167 - Cortex-A12 852422: Execution of a sequence of instructions might
1168 lead to either a data corruption or a CPU deadlock. Not fixed in
1169 any Cortex-A12 cores yet.
1170 This workaround for all both errata involves setting bit[12] of the
1171 Feature Register. This bit disables an optimisation applied to a
1172 sequence of 2 instructions that use opposing condition codes.
1174 config ARM_ERRATA_821420
1175 bool "ARM errata: A12: sequence of VMOV to core registers might lead to a dead lock"
1178 This option enables the workaround for the 821420 Cortex-A12
1179 (all revs) erratum. In very rare timing conditions, a sequence
1180 of VMOV to Core registers instructions, for which the second
1181 one is in the shadow of a branch or abort, can lead to a
1182 deadlock when the VMOV instructions are issued out-of-order.
1184 config ARM_ERRATA_825619
1185 bool "ARM errata: A12: DMB NSHST/ISHST mixed ... might cause deadlock"
1188 This option enables the workaround for the 825619 Cortex-A12
1189 (all revs) erratum. Within rare timing constraints, executing a
1190 DMB NSHST or DMB ISHST instruction followed by a mix of Cacheable
1191 and Device/Strongly-Ordered loads and stores might cause deadlock
1193 config ARM_ERRATA_852421
1194 bool "ARM errata: A17: DMB ST might fail to create order between stores"
1197 This option enables the workaround for the 852421 Cortex-A17
1198 (r1p0, r1p1, r1p2) erratum. Under very rare timing conditions,
1199 execution of a DMB ST instruction might fail to properly order
1200 stores from GroupA and stores from GroupB.
1202 config ARM_ERRATA_852423
1203 bool "ARM errata: A17: some seqs of opposed cond code instrs => deadlock or corruption"
1206 This option enables the workaround for:
1207 - Cortex-A17 852423: Execution of a sequence of instructions might
1208 lead to either a data corruption or a CPU deadlock. Not fixed in
1209 any Cortex-A17 cores yet.
1210 This is identical to Cortex-A12 erratum 852422. It is a separate
1211 config option from the A12 erratum due to the way errata are checked
1216 source "arch/arm/common/Kconfig"
1223 Find out whether you have ISA slots on your motherboard. ISA is the
1224 name of a bus system, i.e. the way the CPU talks to the other stuff
1225 inside your box. Other bus systems are PCI, EISA, MicroChannel
1226 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1227 newer boards don't support it. If you have ISA, say Y, otherwise N.
1229 # Select ISA DMA controller support
1234 # Select ISA DMA interface
1239 bool "PCI support" if MIGHT_HAVE_PCI
1241 Find out whether you have a PCI motherboard. PCI is the name of a
1242 bus system, i.e. the way the CPU talks to the other stuff inside
1243 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1244 VESA. If you have PCI, say Y, otherwise N.
1250 config PCI_DOMAINS_GENERIC
1251 def_bool PCI_DOMAINS
1253 config PCI_NANOENGINE
1254 bool "BSE nanoEngine PCI support"
1255 depends on SA1100_NANOENGINE
1257 Enable PCI on the BSE nanoEngine board.
1262 config PCI_HOST_ITE8152
1264 depends on PCI && MACH_ARMCORE
1268 source "drivers/pci/Kconfig"
1270 source "drivers/pcmcia/Kconfig"
1274 menu "Kernel Features"
1279 This option should be selected by machines which have an SMP-
1282 The only effect of this option is to make the SMP-related
1283 options available to the user for configuration.
1286 bool "Symmetric Multi-Processing"
1287 depends on CPU_V6K || CPU_V7
1288 depends on GENERIC_CLOCKEVENTS
1290 depends on MMU || ARM_MPU
1293 This enables support for systems with more than one CPU. If you have
1294 a system with only one CPU, say N. If you have a system with more
1295 than one CPU, say Y.
1297 If you say N here, the kernel will run on uni- and multiprocessor
1298 machines, but will use only one CPU of a multiprocessor machine. If
1299 you say Y here, the kernel will run on many, but not all,
1300 uniprocessor machines. On a uniprocessor machine, the kernel
1301 will run faster if you say N here.
1303 See also <file:Documentation/x86/i386/IO-APIC.txt>,
1304 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
1305 <http://tldp.org/HOWTO/SMP-HOWTO.html>.
1307 If you don't know what to do here, say N.
1310 bool "Allow booting SMP kernel on uniprocessor systems"
1311 depends on SMP && !XIP_KERNEL && MMU
1314 SMP kernels contain instructions which fail on non-SMP processors.
1315 Enabling this option allows the kernel to modify itself to make
1316 these instructions safe. Disabling it allows about 1K of space
1319 If you don't know what to do here, say Y.
1321 config ARM_CPU_TOPOLOGY
1322 bool "Support cpu topology definition"
1323 depends on SMP && CPU_V7
1326 Support ARM cpu topology definition. The MPIDR register defines
1327 affinity between processors which is then used to describe the cpu
1328 topology of an ARM System.
1331 bool "Multi-core scheduler support"
1332 depends on ARM_CPU_TOPOLOGY
1334 Multi-core scheduler support improves the CPU scheduler's decision
1335 making when dealing with multi-core CPU chips at a cost of slightly
1336 increased overhead in some places. If unsure say N here.
1339 bool "SMT scheduler support"
1340 depends on ARM_CPU_TOPOLOGY
1342 Improves the CPU scheduler's decision making when dealing with
1343 MultiThreading at a cost of slightly increased overhead in some
1344 places. If unsure say N here.
1349 This option enables support for the ARM system coherency unit
1351 config HAVE_ARM_ARCH_TIMER
1352 bool "Architected timer support"
1354 select ARM_ARCH_TIMER
1355 select GENERIC_CLOCKEVENTS
1357 This option enables support for the ARM architected timer
1361 select CLKSRC_OF if OF
1363 This options enables support for the ARM timer and watchdog unit
1366 bool "Multi-Cluster Power Management"
1367 depends on CPU_V7 && SMP
1369 This option provides the common power management infrastructure
1370 for (multi-)cluster based systems, such as big.LITTLE based
1373 config MCPM_QUAD_CLUSTER
1377 To avoid wasting resources unnecessarily, MCPM only supports up
1378 to 2 clusters by default.
1379 Platforms with 3 or 4 clusters that use MCPM must select this
1380 option to allow the additional clusters to be managed.
1383 bool "big.LITTLE support (Experimental)"
1384 depends on CPU_V7 && SMP
1387 This option enables support selections for the big.LITTLE
1388 system architecture.
1391 bool "big.LITTLE switcher support"
1392 depends on BIG_LITTLE && MCPM && HOTPLUG_CPU && ARM_GIC
1395 The big.LITTLE "switcher" provides the core functionality to
1396 transparently handle transition between a cluster of A15's
1397 and a cluster of A7's in a big.LITTLE system.
1399 config BL_SWITCHER_DUMMY_IF
1400 tristate "Simple big.LITTLE switcher user interface"
1401 depends on BL_SWITCHER && DEBUG_KERNEL
1403 This is a simple and dummy char dev interface to control
1404 the big.LITTLE switcher core code. It is meant for
1405 debugging purposes only.
1408 prompt "Memory split"
1412 Select the desired split between kernel and user memory.
1414 If you are not absolutely sure what you are doing, leave this
1418 bool "3G/1G user/kernel split"
1419 config VMSPLIT_3G_OPT
1420 depends on !ARM_LPAE
1421 bool "3G/1G user/kernel split (for full 1G low memory)"
1423 bool "2G/2G user/kernel split"
1425 bool "1G/3G user/kernel split"
1430 default PHYS_OFFSET if !MMU
1431 default 0x40000000 if VMSPLIT_1G
1432 default 0x80000000 if VMSPLIT_2G
1433 default 0xB0000000 if VMSPLIT_3G_OPT
1437 int "Maximum number of CPUs (2-32)"
1443 bool "Support for hot-pluggable CPUs"
1446 Say Y here to experiment with turning CPUs off and on. CPUs
1447 can be controlled through /sys/devices/system/cpu.
1450 bool "Support for the ARM Power State Coordination Interface (PSCI)"
1451 depends on HAVE_ARM_SMCCC
1454 Say Y here if you want Linux to communicate with system firmware
1455 implementing the PSCI specification for CPU-centric power
1456 management operations described in ARM document number ARM DEN
1457 0022A ("Power State Coordination Interface System Software on
1460 # The GPIO number here must be sorted by descending number. In case of
1461 # a multiplatform kernel, we just want the highest value required by the
1462 # selected platforms.
1465 default 1024 if ARCH_BRCMSTB || ARCH_SHMOBILE || ARCH_TEGRA || \
1467 default 512 if ARCH_EXYNOS || ARCH_KEYSTONE || SOC_OMAP5 || \
1468 SOC_DRA7XX || ARCH_S3C24XX || ARCH_S3C64XX || ARCH_S5PV210
1469 default 416 if ARCH_SUNXI
1470 default 392 if ARCH_U8500
1471 default 352 if ARCH_VT8500
1472 default 288 if ARCH_ROCKCHIP
1473 default 264 if MACH_H4700
1476 Maximum number of GPIOs in the system.
1478 If unsure, leave the default value.
1480 source kernel/Kconfig.preempt
1484 default 200 if ARCH_EBSA110
1485 default 128 if SOC_AT91RM9200
1489 depends on HZ_FIXED = 0
1490 prompt "Timer frequency"
1514 default HZ_FIXED if HZ_FIXED != 0
1515 default 100 if HZ_100
1516 default 200 if HZ_200
1517 default 250 if HZ_250
1518 default 300 if HZ_300
1519 default 500 if HZ_500
1523 def_bool HIGH_RES_TIMERS
1525 config THUMB2_KERNEL
1526 bool "Compile the kernel in Thumb-2 mode" if !CPU_THUMBONLY
1527 depends on (CPU_V7 || CPU_V7M) && !CPU_V6 && !CPU_V6K
1528 default y if CPU_THUMBONLY
1530 select ARM_ASM_UNIFIED
1533 By enabling this option, the kernel will be compiled in
1534 Thumb-2 mode. A compiler/assembler that understand the unified
1535 ARM-Thumb syntax is needed.
1539 config THUMB2_AVOID_R_ARM_THM_JUMP11
1540 bool "Work around buggy Thumb-2 short branch relocations in gas"
1541 depends on THUMB2_KERNEL && MODULES
1544 Various binutils versions can resolve Thumb-2 branches to
1545 locally-defined, preemptible global symbols as short-range "b.n"
1546 branch instructions.
1548 This is a problem, because there's no guarantee the final
1549 destination of the symbol, or any candidate locations for a
1550 trampoline, are within range of the branch. For this reason, the
1551 kernel does not support fixing up the R_ARM_THM_JUMP11 (102)
1552 relocation in modules at all, and it makes little sense to add
1555 The symptom is that the kernel fails with an "unsupported
1556 relocation" error when loading some modules.
1558 Until fixed tools are available, passing
1559 -fno-optimize-sibling-calls to gcc should prevent gcc generating
1560 code which hits this problem, at the cost of a bit of extra runtime
1561 stack usage in some cases.
1563 The problem is described in more detail at:
1564 https://bugs.launchpad.net/binutils-linaro/+bug/725126
1566 Only Thumb-2 kernels are affected.
1568 Unless you are sure your tools don't have this problem, say Y.
1570 config ARM_ASM_UNIFIED
1573 config ARM_PATCH_IDIV
1574 bool "Runtime patch udiv/sdiv instructions into __aeabi_{u}idiv()"
1575 depends on CPU_32v7 && !XIP_KERNEL
1578 The ARM compiler inserts calls to __aeabi_idiv() and
1579 __aeabi_uidiv() when it needs to perform division on signed
1580 and unsigned integers. Some v7 CPUs have support for the sdiv
1581 and udiv instructions that can be used to implement those
1584 Enabling this option allows the kernel to modify itself to
1585 replace the first two instructions of these library functions
1586 with the sdiv or udiv plus "bx lr" instructions when the CPU
1587 it is running on supports them. Typically this will be faster
1588 and less power intensive than running the original library
1589 code to do integer division.
1592 bool "Use the ARM EABI to compile the kernel"
1594 This option allows for the kernel to be compiled using the latest
1595 ARM ABI (aka EABI). This is only useful if you are using a user
1596 space environment that is also compiled with EABI.
1598 Since there are major incompatibilities between the legacy ABI and
1599 EABI, especially with regard to structure member alignment, this
1600 option also changes the kernel syscall calling convention to
1601 disambiguate both ABIs and allow for backward compatibility support
1602 (selected with CONFIG_OABI_COMPAT).
1604 To use this you need GCC version 4.0.0 or later.
1607 bool "Allow old ABI binaries to run with this kernel (EXPERIMENTAL)"
1608 depends on AEABI && !THUMB2_KERNEL
1610 This option preserves the old syscall interface along with the
1611 new (ARM EABI) one. It also provides a compatibility layer to
1612 intercept syscalls that have structure arguments which layout
1613 in memory differs between the legacy ABI and the new ARM EABI
1614 (only for non "thumb" binaries). This option adds a tiny
1615 overhead to all syscalls and produces a slightly larger kernel.
1617 The seccomp filter system will not be available when this is
1618 selected, since there is no way yet to sensibly distinguish
1619 between calling conventions during filtering.
1621 If you know you'll be using only pure EABI user space then you
1622 can say N here. If this option is not selected and you attempt
1623 to execute a legacy ABI binary then the result will be
1624 UNPREDICTABLE (in fact it can be predicted that it won't work
1625 at all). If in doubt say N.
1627 config ARCH_HAS_HOLES_MEMORYMODEL
1630 config ARCH_SPARSEMEM_ENABLE
1633 config ARCH_SPARSEMEM_DEFAULT
1634 def_bool ARCH_SPARSEMEM_ENABLE
1636 config ARCH_SELECT_MEMORY_MODEL
1637 def_bool ARCH_SPARSEMEM_ENABLE
1639 config HAVE_ARCH_PFN_VALID
1640 def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM
1642 config HAVE_GENERIC_RCU_GUP
1647 bool "High Memory Support"
1650 The address space of ARM processors is only 4 Gigabytes large
1651 and it has to accommodate user address space, kernel address
1652 space as well as some memory mapped IO. That means that, if you
1653 have a large amount of physical memory and/or IO, not all of the
1654 memory can be "permanently mapped" by the kernel. The physical
1655 memory that is not permanently mapped is called "high memory".
1657 Depending on the selected kernel/user memory split, minimum
1658 vmalloc space and actual amount of RAM, you may not need this
1659 option which should result in a slightly faster kernel.
1664 bool "Allocate 2nd-level pagetables from highmem" if EXPERT
1668 The VM uses one page of physical memory for each page table.
1669 For systems with a lot of processes, this can use a lot of
1670 precious low memory, eventually leading to low memory being
1671 consumed by page tables. Setting this option will allow
1672 user-space 2nd level page tables to reside in high memory.
1674 config CPU_SW_DOMAIN_PAN
1675 bool "Enable use of CPU domains to implement privileged no-access"
1676 depends on MMU && !ARM_LPAE
1679 Increase kernel security by ensuring that normal kernel accesses
1680 are unable to access userspace addresses. This can help prevent
1681 use-after-free bugs becoming an exploitable privilege escalation
1682 by ensuring that magic values (such as LIST_POISON) will always
1683 fault when dereferenced.
1685 CPUs with low-vector mappings use a best-efforts implementation.
1686 Their lower 1MB needs to remain accessible for the vectors, but
1687 the remainder of userspace will become appropriately inaccessible.
1689 config HW_PERF_EVENTS
1693 config SYS_SUPPORTS_HUGETLBFS
1697 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
1701 config ARCH_WANT_GENERAL_HUGETLB
1704 config ARM_MODULE_PLTS
1705 bool "Use PLTs to allow module memory to spill over into vmalloc area"
1708 Allocate PLTs when loading modules so that jumps and calls whose
1709 targets are too far away for their relative offsets to be encoded
1710 in the instructions themselves can be bounced via veneers in the
1711 module's PLT. This allows modules to be allocated in the generic
1712 vmalloc area after the dedicated module memory area has been
1713 exhausted. The modules will use slightly more memory, but after
1714 rounding up to page size, the actual memory footprint is usually
1717 Say y if you are getting out of memory errors while loading modules
1721 config FORCE_MAX_ZONEORDER
1722 int "Maximum zone order"
1723 default "12" if SOC_AM33XX
1724 default "9" if SA1111 || ARCH_EFM32
1727 The kernel memory allocator divides physically contiguous memory
1728 blocks into "zones", where each zone is a power of two number of
1729 pages. This option selects the largest power of two that the kernel
1730 keeps in the memory allocator. If you need to allocate very large
1731 blocks of physically contiguous memory, then you may need to
1732 increase this value.
1734 This config option is actually maximum order plus one. For example,
1735 a value of 11 means that the largest free memory block is 2^10 pages.
1737 config ALIGNMENT_TRAP
1739 depends on CPU_CP15_MMU
1740 default y if !ARCH_EBSA110
1741 select HAVE_PROC_CPU if PROC_FS
1743 ARM processors cannot fetch/store information which is not
1744 naturally aligned on the bus, i.e., a 4 byte fetch must start at an
1745 address divisible by 4. On 32-bit ARM processors, these non-aligned
1746 fetch/store instructions will be emulated in software if you say
1747 here, which has a severe performance impact. This is necessary for
1748 correct operation of some network protocols. With an IP-only
1749 configuration it is safe to say N, otherwise say Y.
1751 config UACCESS_WITH_MEMCPY
1752 bool "Use kernel mem{cpy,set}() for {copy_to,clear}_user()"
1754 default y if CPU_FEROCEON
1756 Implement faster copy_to_user and clear_user methods for CPU
1757 cores where a 8-word STM instruction give significantly higher
1758 memory write throughput than a sequence of individual 32bit stores.
1760 A possible side effect is a slight increase in scheduling latency
1761 between threads sharing the same address space if they invoke
1762 such copy operations with large buffers.
1764 However, if the CPU data cache is using a write-allocate mode,
1765 this option is unlikely to provide any performance gain.
1769 prompt "Enable seccomp to safely compute untrusted bytecode"
1771 This kernel feature is useful for number crunching applications
1772 that may need to compute untrusted bytecode during their
1773 execution. By using pipes or other transports made available to
1774 the process as file descriptors supporting the read/write
1775 syscalls, it's possible to isolate those applications in
1776 their own address space using seccomp. Once seccomp is
1777 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1778 and the task is only allowed to execute a few safe syscalls
1779 defined by each seccomp mode.
1788 bool "Enable paravirtualization code"
1790 This changes the kernel so it can modify itself when it is run
1791 under a hypervisor, potentially improving performance significantly
1792 over full virtualization.
1794 config PARAVIRT_TIME_ACCOUNTING
1795 bool "Paravirtual steal time accounting"
1799 Select this option to enable fine granularity task steal time
1800 accounting. Time spent executing other tasks in parallel with
1801 the current vCPU is discounted from the vCPU power. To account for
1802 that, there can be a small performance impact.
1804 If in doubt, say N here.
1811 bool "Xen guest support on ARM"
1812 depends on ARM && AEABI && OF
1813 depends on CPU_V7 && !CPU_V6
1814 depends on !GENERIC_ATOMIC64
1816 select ARCH_DMA_ADDR_T_64BIT
1821 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
1828 bool "Flattened Device Tree support"
1832 Include support for flattened device tree machine descriptions.
1835 bool "Support for the traditional ATAGS boot data passing" if USE_OF
1838 This is the traditional way of passing data to the kernel at boot
1839 time. If you are solely relying on the flattened device tree (or
1840 the ARM_ATAG_DTB_COMPAT option) then you may unselect this option
1841 to remove ATAGS support from your kernel binary. If unsure,
1844 config DEPRECATED_PARAM_STRUCT
1845 bool "Provide old way to pass kernel parameters"
1848 This was deprecated in 2001 and announced to live on for 5 years.
1849 Some old boot loaders still use this way.
1851 # Compressed boot loader in ROM. Yes, we really want to ask about
1852 # TEXT and BSS so we preserve their values in the config files.
1853 config ZBOOT_ROM_TEXT
1854 hex "Compressed ROM boot loader base address"
1857 The physical address at which the ROM-able zImage is to be
1858 placed in the target. Platforms which normally make use of
1859 ROM-able zImage formats normally set this to a suitable
1860 value in their defconfig file.
1862 If ZBOOT_ROM is not enabled, this has no effect.
1864 config ZBOOT_ROM_BSS
1865 hex "Compressed ROM boot loader BSS address"
1868 The base address of an area of read/write memory in the target
1869 for the ROM-able zImage which must be available while the
1870 decompressor is running. It must be large enough to hold the
1871 entire decompressed kernel plus an additional 128 KiB.
1872 Platforms which normally make use of ROM-able zImage formats
1873 normally set this to a suitable value in their defconfig file.
1875 If ZBOOT_ROM is not enabled, this has no effect.
1878 bool "Compressed boot loader in ROM/flash"
1879 depends on ZBOOT_ROM_TEXT != ZBOOT_ROM_BSS
1880 depends on !ARM_APPENDED_DTB && !XIP_KERNEL && !AUTO_ZRELADDR
1882 Say Y here if you intend to execute your compressed kernel image
1883 (zImage) directly from ROM or flash. If unsure, say N.
1885 config ARM_APPENDED_DTB
1886 bool "Use appended device tree blob to zImage (EXPERIMENTAL)"
1889 With this option, the boot code will look for a device tree binary
1890 (DTB) appended to zImage
1891 (e.g. cat zImage <filename>.dtb > zImage_w_dtb).
1893 This is meant as a backward compatibility convenience for those
1894 systems with a bootloader that can't be upgraded to accommodate
1895 the documented boot protocol using a device tree.
1897 Beware that there is very little in terms of protection against
1898 this option being confused by leftover garbage in memory that might
1899 look like a DTB header after a reboot if no actual DTB is appended
1900 to zImage. Do not leave this option active in a production kernel
1901 if you don't intend to always append a DTB. Proper passing of the
1902 location into r2 of a bootloader provided DTB is always preferable
1905 config ARM_ATAG_DTB_COMPAT
1906 bool "Supplement the appended DTB with traditional ATAG information"
1907 depends on ARM_APPENDED_DTB
1909 Some old bootloaders can't be updated to a DTB capable one, yet
1910 they provide ATAGs with memory configuration, the ramdisk address,
1911 the kernel cmdline string, etc. Such information is dynamically
1912 provided by the bootloader and can't always be stored in a static
1913 DTB. To allow a device tree enabled kernel to be used with such
1914 bootloaders, this option allows zImage to extract the information
1915 from the ATAG list and store it at run time into the appended DTB.
1918 prompt "Kernel command line type" if ARM_ATAG_DTB_COMPAT
1919 default ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER
1921 config ARM_ATAG_DTB_COMPAT_CMDLINE_FROM_BOOTLOADER
1922 bool "Use bootloader kernel arguments if available"
1924 Uses the command-line options passed by the boot loader instead of
1925 the device tree bootargs property. If the boot loader doesn't provide
1926 any, the device tree bootargs property will be used.
1928 config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND
1929 bool "Extend with bootloader kernel arguments"
1931 The command-line arguments provided by the boot loader will be
1932 appended to the the device tree bootargs property.
1937 string "Default kernel command string"
1940 On some architectures (EBSA110 and CATS), there is currently no way
1941 for the boot loader to pass arguments to the kernel. For these
1942 architectures, you should supply some command-line options at build
1943 time by entering them here. As a minimum, you should specify the
1944 memory size and the root device (e.g., mem=64M root=/dev/nfs).
1947 prompt "Kernel command line type" if CMDLINE != ""
1948 default CMDLINE_FROM_BOOTLOADER
1951 config CMDLINE_FROM_BOOTLOADER
1952 bool "Use bootloader kernel arguments if available"
1954 Uses the command-line options passed by the boot loader. If
1955 the boot loader doesn't provide any, the default kernel command
1956 string provided in CMDLINE will be used.
1958 config CMDLINE_EXTEND
1959 bool "Extend bootloader kernel arguments"
1961 The command-line arguments provided by the boot loader will be
1962 appended to the default kernel command string.
1964 config CMDLINE_FORCE
1965 bool "Always use the default kernel command string"
1967 Always use the default kernel command string, even if the boot
1968 loader passes other arguments to the kernel.
1969 This is useful if you cannot or don't want to change the
1970 command-line options your boot loader passes to the kernel.
1974 bool "Kernel Execute-In-Place from ROM"
1975 depends on !ARM_LPAE && !ARCH_MULTIPLATFORM
1977 Execute-In-Place allows the kernel to run from non-volatile storage
1978 directly addressable by the CPU, such as NOR flash. This saves RAM
1979 space since the text section of the kernel is not loaded from flash
1980 to RAM. Read-write sections, such as the data section and stack,
1981 are still copied to RAM. The XIP kernel is not compressed since
1982 it has to run directly from flash, so it will take more space to
1983 store it. The flash address used to link the kernel object files,
1984 and for storing it, is configuration dependent. Therefore, if you
1985 say Y here, you must know the proper physical address where to
1986 store the kernel image depending on your own flash memory usage.
1988 Also note that the make target becomes "make xipImage" rather than
1989 "make zImage" or "make Image". The final kernel binary to put in
1990 ROM memory will be arch/arm/boot/xipImage.
1994 config XIP_PHYS_ADDR
1995 hex "XIP Kernel Physical Location"
1996 depends on XIP_KERNEL
1997 default "0x00080000"
1999 This is the physical address in your flash memory the kernel will
2000 be linked for and stored to. This address is dependent on your
2004 bool "Kexec system call (EXPERIMENTAL)"
2005 depends on (!SMP || PM_SLEEP_SMP)
2009 kexec is a system call that implements the ability to shutdown your
2010 current kernel, and to start another kernel. It is like a reboot
2011 but it is independent of the system firmware. And like a reboot
2012 you can start any kernel with it, not just Linux.
2014 It is an ongoing process to be certain the hardware in a machine
2015 is properly shutdown, so do not be surprised if this code does not
2016 initially work for you.
2019 bool "Export atags in procfs"
2020 depends on ATAGS && KEXEC
2023 Should the atags used to boot the kernel be exported in an "atags"
2024 file in procfs. Useful with kexec.
2027 bool "Build kdump crash kernel (EXPERIMENTAL)"
2029 Generate crash dump after being started by kexec. This should
2030 be normally only set in special crash dump kernels which are
2031 loaded in the main kernel with kexec-tools into a specially
2032 reserved region and then later executed after a crash by
2033 kdump/kexec. The crash dump kernel must be compiled to a
2034 memory address not used by the main kernel
2036 For more details see Documentation/kdump/kdump.txt
2038 config AUTO_ZRELADDR
2039 bool "Auto calculation of the decompressed kernel image address"
2041 ZRELADDR is the physical address where the decompressed kernel
2042 image will be placed. If AUTO_ZRELADDR is selected, the address
2043 will be determined at run-time by masking the current IP with
2044 0xf8000000. This assumes the zImage being placed in the first 128MB
2045 from start of memory.
2051 bool "UEFI runtime support"
2052 depends on OF && !CPU_BIG_ENDIAN && MMU && AUTO_ZRELADDR && !XIP_KERNEL
2054 select EFI_PARAMS_FROM_FDT
2057 select EFI_RUNTIME_WRAPPERS
2059 This option provides support for runtime services provided
2060 by UEFI firmware (such as non-volatile variables, realtime
2061 clock, and platform reset). A UEFI stub is also provided to
2062 allow the kernel to be booted as an EFI application. This
2063 is only useful for kernels that may run on systems that have
2068 menu "CPU Power Management"
2070 source "drivers/cpufreq/Kconfig"
2072 source "drivers/cpuidle/Kconfig"
2076 menu "Floating point emulation"
2078 comment "At least one emulation must be selected"
2081 bool "NWFPE math emulation"
2082 depends on (!AEABI || OABI_COMPAT) && !THUMB2_KERNEL
2084 Say Y to include the NWFPE floating point emulator in the kernel.
2085 This is necessary to run most binaries. Linux does not currently
2086 support floating point hardware so you need to say Y here even if
2087 your machine has an FPA or floating point co-processor podule.
2089 You may say N here if you are going to load the Acorn FPEmulator
2090 early in the bootup.
2093 bool "Support extended precision"
2094 depends on FPE_NWFPE
2096 Say Y to include 80-bit support in the kernel floating-point
2097 emulator. Otherwise, only 32 and 64-bit support is compiled in.
2098 Note that gcc does not generate 80-bit operations by default,
2099 so in most cases this option only enlarges the size of the
2100 floating point emulator without any good reason.
2102 You almost surely want to say N here.
2105 bool "FastFPE math emulation (EXPERIMENTAL)"
2106 depends on (!AEABI || OABI_COMPAT) && !CPU_32v3
2108 Say Y here to include the FAST floating point emulator in the kernel.
2109 This is an experimental much faster emulator which now also has full
2110 precision for the mantissa. It does not support any exceptions.
2111 It is very simple, and approximately 3-6 times faster than NWFPE.
2113 It should be sufficient for most programs. It may be not suitable
2114 for scientific calculations, but you have to check this for yourself.
2115 If you do not feel you need a faster FP emulation you should better
2119 bool "VFP-format floating point maths"
2120 depends on CPU_V6 || CPU_V6K || CPU_ARM926T || CPU_V7 || CPU_FEROCEON
2122 Say Y to include VFP support code in the kernel. This is needed
2123 if your hardware includes a VFP unit.
2125 Please see <file:Documentation/arm/VFP/release-notes.txt> for
2126 release notes and additional status information.
2128 Say N if your target does not have VFP hardware.
2136 bool "Advanced SIMD (NEON) Extension support"
2137 depends on VFPv3 && CPU_V7
2139 Say Y to include support code for NEON, the ARMv7 Advanced SIMD
2142 config KERNEL_MODE_NEON
2143 bool "Support for NEON in kernel mode"
2144 depends on NEON && AEABI
2146 Say Y to include support for NEON in kernel mode.
2150 menu "Userspace binary formats"
2152 source "fs/Kconfig.binfmt"
2156 menu "Power management options"
2158 source "kernel/power/Kconfig"
2160 config ARCH_SUSPEND_POSSIBLE
2161 depends on CPU_ARM920T || CPU_ARM926T || CPU_FEROCEON || CPU_SA1100 || \
2162 CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M || CPU_XSC3 || CPU_XSCALE || CPU_MOHAWK
2165 config ARM_CPU_SUSPEND
2166 def_bool PM_SLEEP || BL_SWITCHER || ARM_PSCI_FW
2167 depends on ARCH_SUSPEND_POSSIBLE
2169 config ARCH_HIBERNATION_POSSIBLE
2172 default y if ARCH_SUSPEND_POSSIBLE
2176 source "net/Kconfig"
2178 source "drivers/Kconfig"
2180 source "drivers/firmware/Kconfig"
2184 source "arch/arm/Kconfig.debug"
2186 source "security/Kconfig"
2188 source "crypto/Kconfig"
2190 source "arch/arm/crypto/Kconfig"
2193 source "lib/Kconfig"
2195 source "arch/arm/kvm/Kconfig"