1 # SPDX-License-Identifier: GPL-2.0
2 comment "Processor Type"
4 # Select CPU types depending on the architecture selected. This selects
5 # which CPUs we support in the kernel image, and the compiler instruction
15 select CPU_PABRT_LEGACY
17 A 32-bit RISC microprocessor based on the ARM7 processor core
18 which has no memory control unit and cache.
20 Say Y if you want support for the ARM7TDMI processor.
30 select CPU_COPY_V4WT if MMU
32 select CPU_PABRT_LEGACY
33 select CPU_THUMB_CAPABLE
34 select CPU_TLB_V4WT if MMU
36 A 32-bit RISC processor with 8kByte Cache, Write Buffer and
37 MMU built around an ARM7TDMI core.
39 Say Y if you want support for the ARM720T processor.
50 select CPU_PABRT_LEGACY
51 select CPU_THUMB_CAPABLE
53 A 32-bit RISC processor with 8KB cache or 4KB variants,
54 write buffer and MPU(Protection Unit) built around
57 Say Y if you want support for the ARM740T processor.
67 select CPU_PABRT_LEGACY
69 A 32-bit RISC microprocessor based on the ARM9 processor core
70 which has no memory control unit and cache.
72 Say Y if you want support for the ARM9TDMI processor.
82 select CPU_COPY_V4WB if MMU
84 select CPU_PABRT_LEGACY
85 select CPU_THUMB_CAPABLE
86 select CPU_TLB_V4WBI if MMU
88 The ARM920T is licensed to be produced by numerous vendors,
89 and is used in the Cirrus EP93xx and the Samsung S3C2410.
91 Say Y if you want support for the ARM920T processor.
100 select CPU_CACHE_VIVT
101 select CPU_COPY_V4WB if MMU
103 select CPU_PABRT_LEGACY
104 select CPU_THUMB_CAPABLE
105 select CPU_TLB_V4WBI if MMU
107 The ARM922T is a version of the ARM920T, but with smaller
108 instruction and data caches. It is used in Altera's
109 Excalibur XA device family and Micrel's KS8695 Centaur.
111 Say Y if you want support for the ARM922T processor.
119 select CPU_CACHE_V4WT
120 select CPU_CACHE_VIVT
121 select CPU_COPY_V4WB if MMU
123 select CPU_PABRT_LEGACY
124 select CPU_THUMB_CAPABLE
125 select CPU_TLB_V4WBI if MMU
127 The ARM925T is a mix between the ARM920T and ARM926T, but with
128 different instruction and data caches. It is used in TI's OMAP
131 Say Y if you want support for the ARM925T processor.
138 select CPU_ABRT_EV5TJ
139 select CPU_CACHE_VIVT
140 select CPU_COPY_V4WB if MMU
142 select CPU_PABRT_LEGACY
143 select CPU_THUMB_CAPABLE
144 select CPU_TLB_V4WBI if MMU
146 This is a variant of the ARM920. It has slightly different
147 instruction sequences for cache and TLB operations. Curiously,
148 there is no documentation on it at the ARM corporate website.
150 Say Y if you want support for the ARM926T processor.
159 select CPU_CACHE_VIVT
160 select CPU_COPY_FA if MMU
162 select CPU_PABRT_LEGACY
163 select CPU_TLB_FA if MMU
165 The FA526 is a version of the ARMv4 compatible processor with
166 Branch Target Buffer, Unified TLB and cache line size 16.
168 Say Y if you want support for the FA526 processor.
176 select CPU_ABRT_NOMMU
177 select CPU_CACHE_VIVT
179 select CPU_PABRT_LEGACY
180 select CPU_THUMB_CAPABLE
182 ARM940T is a member of the ARM9TDMI family of general-
183 purpose microprocessors with MPU and separate 4KB
184 instruction and 4KB data cases, each with a 4-word line
187 Say Y if you want support for the ARM940T processor.
195 select CPU_ABRT_NOMMU
196 select CPU_CACHE_VIVT
198 select CPU_PABRT_LEGACY
199 select CPU_THUMB_CAPABLE
201 ARM946E-S is a member of the ARM9E-S family of high-
202 performance, 32-bit system-on-chip processor solutions.
203 The TCM and ARMv5TE 32-bit instruction set is supported.
205 Say Y if you want support for the ARM946E-S processor.
208 # ARM1020 - needs validating
213 select CPU_CACHE_V4WT
214 select CPU_CACHE_VIVT
215 select CPU_COPY_V4WB if MMU
217 select CPU_PABRT_LEGACY
218 select CPU_THUMB_CAPABLE
219 select CPU_TLB_V4WBI if MMU
221 The ARM1020 is the 32K cached version of the ARM10 processor,
222 with an addition of a floating-point unit.
224 Say Y if you want support for the ARM1020 processor.
227 # ARM1020E - needs validating
233 select CPU_CACHE_V4WT
234 select CPU_CACHE_VIVT
235 select CPU_COPY_V4WB if MMU
237 select CPU_PABRT_LEGACY
238 select CPU_THUMB_CAPABLE
239 select CPU_TLB_V4WBI if MMU
246 select CPU_CACHE_VIVT
247 select CPU_COPY_V4WB if MMU # can probably do better
249 select CPU_PABRT_LEGACY
250 select CPU_THUMB_CAPABLE
251 select CPU_TLB_V4WBI if MMU
253 The ARM1022E is an implementation of the ARMv5TE architecture
254 based upon the ARM10 integer core with a 16KiB L1 Harvard cache,
255 embedded trace macrocell, and a floating-point unit.
257 Say Y if you want support for the ARM1022E processor.
264 select CPU_ABRT_EV5T # But need Jazelle, but EV5TJ ignores bit 10
265 select CPU_CACHE_VIVT
266 select CPU_COPY_V4WB if MMU # can probably do better
268 select CPU_PABRT_LEGACY
269 select CPU_THUMB_CAPABLE
270 select CPU_TLB_V4WBI if MMU
272 The ARM1026EJ-S is an implementation of the ARMv5TEJ architecture
273 based upon the ARM10 integer core.
275 Say Y if you want support for the ARM1026EJ-S processor.
281 select CPU_32v3 if ARCH_RPC
282 select CPU_32v4 if !ARCH_RPC
284 select CPU_CACHE_V4WB
285 select CPU_CACHE_VIVT
286 select CPU_COPY_V4WB if MMU
288 select CPU_PABRT_LEGACY
289 select CPU_TLB_V4WB if MMU
291 The Intel StrongARM(R) SA-110 is a 32-bit microprocessor and
292 is available at five speeds ranging from 100 MHz to 233 MHz.
293 More information is available at
294 <http://developer.intel.com/design/strong/sa110.htm>.
296 Say Y if you want support for the SA-110 processor.
304 select CPU_CACHE_V4WB
305 select CPU_CACHE_VIVT
307 select CPU_PABRT_LEGACY
308 select CPU_TLB_V4WB if MMU
315 select CPU_CACHE_VIVT
317 select CPU_PABRT_LEGACY
318 select CPU_THUMB_CAPABLE
319 select CPU_TLB_V4WBI if MMU
321 # XScale Core Version 3
326 select CPU_CACHE_VIVT
328 select CPU_PABRT_LEGACY
329 select CPU_THUMB_CAPABLE
330 select CPU_TLB_V4WBI if MMU
333 # Marvell PJ1 (Mohawk)
338 select CPU_CACHE_VIVT
339 select CPU_COPY_V4WB if MMU
341 select CPU_PABRT_LEGACY
342 select CPU_THUMB_CAPABLE
343 select CPU_TLB_V4WBI if MMU
350 select CPU_CACHE_VIVT
351 select CPU_COPY_FEROCEON if MMU
353 select CPU_PABRT_LEGACY
354 select CPU_THUMB_CAPABLE
355 select CPU_TLB_FEROCEON if MMU
357 config CPU_FEROCEON_OLD_ID
358 bool "Accept early Feroceon cores with an ARM926 ID"
359 depends on CPU_FEROCEON && !CPU_ARM926T
362 This enables the usage of some old Feroceon cores
363 for which the CPU ID is equal to the ARM926 ID.
364 Relevant for Feroceon-1850 and early Feroceon-2850.
382 select CPU_CACHE_VIPT
383 select CPU_COPY_V6 if MMU
385 select CPU_HAS_ASID if MMU
387 select CPU_THUMB_CAPABLE
388 select CPU_TLB_V6 if MMU
397 select CPU_CACHE_VIPT
398 select CPU_COPY_V6 if MMU
400 select CPU_HAS_ASID if MMU
402 select CPU_THUMB_CAPABLE
403 select CPU_TLB_V6 if MMU
412 select CPU_CACHE_VIPT
413 select CPU_COPY_V6 if MMU
414 select CPU_CP15_MMU if MMU
415 select CPU_CP15_MPU if !MMU
416 select CPU_HAS_ASID if MMU
418 select CPU_THUMB_CAPABLE
419 select CPU_TLB_V7 if MMU
425 select CPU_ABRT_NOMMU
428 select CPU_PABRT_LEGACY
433 select CPU_THUMB_CAPABLE
434 # There are no CPUs available with MMU that don't implement an ARM ISA:
437 Select this if your CPU doesn't support the 32 bit ARM instructions.
439 config CPU_THUMB_CAPABLE
442 Select this if your CPU can support Thumb mode.
444 # Figure out what processor architecture version we should be using.
445 # This defines the compiler instruction set which depends on the machine type.
448 select CPU_USE_DOMAINS if MMU
449 select NEED_KUSER_HELPERS
450 select TLS_REG_EMUL if SMP || !MMU
451 select CPU_NO_EFFICIENT_FFS
455 select CPU_USE_DOMAINS if MMU
456 select NEED_KUSER_HELPERS
457 select TLS_REG_EMUL if SMP || !MMU
458 select CPU_NO_EFFICIENT_FFS
462 select CPU_USE_DOMAINS if MMU
463 select NEED_KUSER_HELPERS
464 select TLS_REG_EMUL if SMP || !MMU
465 select CPU_NO_EFFICIENT_FFS
469 select CPU_USE_DOMAINS if MMU
470 select NEED_KUSER_HELPERS
471 select TLS_REG_EMUL if SMP || !MMU
475 select TLS_REG_EMUL if !CPU_32v6K && !MMU
487 config CPU_ABRT_NOMMU
502 config CPU_ABRT_EV5TJ
511 config CPU_PABRT_LEGACY
524 config CPU_CACHE_V4WT
527 config CPU_CACHE_V4WB
539 config CPU_CACHE_VIVT
542 config CPU_CACHE_VIPT
552 # The copy-page model
559 config CPU_COPY_FEROCEON
568 # This selects the TLB model
572 ARM Architecture Version 4 TLB with writethrough cache.
577 ARM Architecture Version 4 TLB with writeback cache.
582 ARM Architecture Version 4 TLB with writeback cache and invalidate
583 instruction cache entry.
585 config CPU_TLB_FEROCEON
588 Feroceon TLB (v4wbi with non-outer-cachable page table walks).
593 Faraday ARM FA526 architecture, unified TLB with writeback cache
594 and invalidate instruction cache entry. Branch target buffer is
603 config VERIFY_PERMISSION_FAULT
610 This indicates whether the CPU has the ASID register; used to
611 tag TLB and possibly cache entries.
616 Processor has the CP15 register.
622 Processor has the CP15 register, which has MMU related registers.
628 Processor has the CP15 register, which has MPU related registers.
630 config CPU_USE_DOMAINS
633 This option enables or disables the use of domain switching
634 via the set_fs() function.
636 config CPU_V7M_NUM_IRQ
637 int "Number of external interrupts connected to the NVIC"
639 default 90 if ARCH_STM32
640 default 38 if ARCH_EFM32
641 default 112 if SOC_VF610
644 This option indicates the number of interrupts connected to the NVIC.
645 The value can be larger than the real number of interrupts supported
646 by the system, but must not be lower.
647 The default value is 240, corresponding to the maximum number of
648 interrupts supported by the NVIC on Cortex-M family.
650 If unsure, keep default value.
653 # CPU supports 36-bit I/O
658 comment "Processor Features"
661 bool "Support for the Large Physical Address Extension"
662 depends on MMU && CPU_32v7 && !CPU_32v6 && !CPU_32v5 && \
663 !CPU_32v4 && !CPU_32v3
664 select PHYS_ADDR_T_64BIT
666 Say Y if you have an ARMv7 processor supporting the LPAE page
667 table format and you would like to access memory beyond the
668 4GB limit. The resulting kernel image will not run on
669 processors without the LPA extension.
675 depends on ARM_LPAE && ARM_PATCH_PHYS_VIRT && ARCH_KEYSTONE
677 config ARCH_DMA_ADDR_T_64BIT
681 bool "Support Thumb user binaries" if !CPU_THUMBONLY && EXPERT
682 depends on CPU_THUMB_CAPABLE
685 Say Y if you want to include kernel support for running user space
688 The Thumb instruction set is a compressed form of the standard ARM
689 instruction set resulting in smaller binaries at the expense of
690 slightly less efficient code.
692 If this option is disabled, and you run userspace that switches to
693 Thumb mode, signal handling will not work correctly, resulting in
694 segmentation faults or illegal instruction aborts.
696 If you don't know what this all is, saying Y is a safe choice.
699 bool "Enable ThumbEE CPU extension"
702 Say Y here if you have a CPU with the ThumbEE extension and code to
703 make use of it. Say N for code that can run on CPUs without ThumbEE.
710 Enable the kernel to make use of the ARM Virtualization
711 Extensions to install hypervisors without run-time firmware
714 A compliant bootloader is required in order to make maximum
715 use of this feature. Refer to Documentation/arm/Booting for
719 bool "Emulate SWP/SWPB instructions" if !SMP
722 select HAVE_PROC_CPU if PROC_FS
724 ARMv6 architecture deprecates use of the SWP/SWPB instructions.
725 ARMv7 multiprocessing extensions introduce the ability to disable
726 these instructions, triggering an undefined instruction exception
727 when executed. Say Y here to enable software emulation of these
728 instructions for userspace (not kernel) using LDREX/STREX.
729 Also creates /proc/cpu/swp_emulation for statistics.
731 In some older versions of glibc [<=2.8] SWP is used during futex
732 trylock() operations with the assumption that the code will not
733 be preempted. This invalid assumption may be more likely to fail
734 with SWP emulation enabled, leading to deadlock of the user
737 NOTE: when accessing uncached shared regions, LDREX/STREX rely
738 on an external transaction monitoring block called a global
739 monitor to maintain update atomicity. If your system does not
740 implement a global monitor, this option can cause programs that
741 perform SWP operations to uncached memory to deadlock.
745 config CPU_BIG_ENDIAN
746 bool "Build big-endian kernel"
747 depends on ARCH_SUPPORTS_BIG_ENDIAN
749 Say Y if you plan on running a kernel in big-endian mode.
750 Note that your board must be properly built and your board
751 port must properly enable any big-endian related features
752 of your chipset/board/processor.
754 config CPU_ENDIAN_BE8
756 depends on CPU_BIG_ENDIAN
757 default CPU_V6 || CPU_V6K || CPU_V7
759 Support for the BE-8 (big-endian) mode on ARMv6 and ARMv7 processors.
761 config CPU_ENDIAN_BE32
763 depends on CPU_BIG_ENDIAN
764 default !CPU_ENDIAN_BE8
766 Support for the BE-32 (big-endian) mode on pre-ARMv6 processors.
768 config CPU_HIGH_VECTOR
769 depends on !MMU && CPU_CP15 && !CPU_ARM740T
770 bool "Select the High exception vector"
772 Say Y here to select high exception vector(0xFFFF0000~).
773 The exception vector can vary depending on the platform
774 design in nommu mode. If your platform needs to select
775 high exception vector, say Y.
776 Otherwise or if you are unsure, say N, and the low exception
777 vector (0x00000000~) will be used.
779 config CPU_ICACHE_DISABLE
780 bool "Disable I-Cache (I-bit)"
781 depends on (CPU_CP15 && !(CPU_ARM720T || CPU_ARM740T || CPU_XSCALE || CPU_XSC3)) || CPU_V7M
783 Say Y here to disable the processor instruction cache. Unless
784 you have a reason not to or are unsure, say N.
786 config CPU_DCACHE_DISABLE
787 bool "Disable D-Cache (C-bit)"
788 depends on (CPU_CP15 && !SMP) || CPU_V7M
790 Say Y here to disable the processor data cache. Unless
791 you have a reason not to or are unsure, say N.
793 config CPU_DCACHE_SIZE
795 depends on CPU_ARM740T || CPU_ARM946E
796 default 0x00001000 if CPU_ARM740T
797 default 0x00002000 # default size for ARM946E-S
799 Some cores are synthesizable to have various sized cache. For
800 ARM946E-S case, it can vary from 0KB to 1MB.
801 To support such cache operations, it is efficient to know the size
803 If your SoC is configured to have a different size, define the value
804 here with proper conditions.
806 config CPU_DCACHE_WRITETHROUGH
807 bool "Force write through D-cache"
808 depends on (CPU_ARM740T || CPU_ARM920T || CPU_ARM922T || CPU_ARM925T || CPU_ARM926T || CPU_ARM940T || CPU_ARM946E || CPU_ARM1020 || CPU_FA526) && !CPU_DCACHE_DISABLE
809 default y if CPU_ARM925T
811 Say Y here to use the data cache in writethrough mode. Unless you
812 specifically require this or are unsure, say N.
814 config CPU_CACHE_ROUND_ROBIN
815 bool "Round robin I and D cache replacement algorithm"
816 depends on (CPU_ARM926T || CPU_ARM946E || CPU_ARM1020) && (!CPU_ICACHE_DISABLE || !CPU_DCACHE_DISABLE)
818 Say Y here to use the predictable round-robin cache replacement
819 policy. Unless you specifically require this or are unsure, say N.
821 config CPU_BPREDICT_DISABLE
822 bool "Disable branch prediction"
823 depends on CPU_ARM1020 || CPU_V6 || CPU_V6K || CPU_MOHAWK || CPU_XSC3 || CPU_V7 || CPU_FA526 || CPU_V7M
825 Say Y here to disable branch prediction. If unsure, say N.
829 select NEED_KUSER_HELPERS
831 An SMP system using a pre-ARMv6 processor (there are apparently
832 a few prototypes like that in existence) and therefore access to
833 that required register must be emulated.
835 config NEED_KUSER_HELPERS
839 bool "Enable kuser helpers in vector page" if !NEED_KUSER_HELPERS
843 Warning: disabling this option may break user programs.
845 Provide kuser helpers in the vector page. The kernel provides
846 helper code to userspace in read only form at a fixed location
847 in the high vector page to allow userspace to be independent of
848 the CPU type fitted to the system. This permits binaries to be
849 run on ARMv4 through to ARMv7 without modification.
851 See Documentation/arm/kernel_user_helpers.txt for details.
853 However, the fixed address nature of these helpers can be used
854 by ROP (return orientated programming) authors when creating
857 If all of the binaries and libraries which run on your platform
858 are built specifically for your platform, and make no use of
859 these helpers, then you can turn this option off to hinder
860 such exploits. However, in that case, if a binary or library
861 relying on those helpers is run, it will receive a SIGILL signal,
862 which will terminate the program.
864 Say N here only if you are absolutely certain that you do not
865 need these helpers; otherwise, the safe option is to say Y.
868 bool "Enable VDSO for acceleration of some system calls"
869 depends on AEABI && MMU && CPU_V7
870 default y if ARM_ARCH_TIMER
871 select GENERIC_TIME_VSYSCALL
873 Place in the process address space an ELF shared object
874 providing fast implementations of gettimeofday and
875 clock_gettime. Systems that implement the ARM architected
876 timer will receive maximum benefit.
878 You must have glibc 2.22 or later for programs to seamlessly
879 take advantage of this.
881 config DMA_CACHE_RWFO
882 bool "Enable read/write for ownership DMA cache maintenance"
883 depends on CPU_V6K && SMP
886 The Snoop Control Unit on ARM11MPCore does not detect the
887 cache maintenance operations and the dma_{map,unmap}_area()
888 functions may leave stale cache entries on other CPUs. By
889 enabling this option, Read or Write For Ownership in the ARMv6
890 DMA cache maintenance functions is performed. These LDR/STR
891 instructions change the cache line state to shared or modified
892 so that the cache operation has the desired effect.
894 Note that the workaround is only valid on processors that do
895 not perform speculative loads into the D-cache. For such
896 processors, if cache maintenance operations are not broadcast
897 in hardware, other workarounds are needed (e.g. cache
898 maintenance broadcasting in software via FIQ).
903 config OUTER_CACHE_SYNC
907 The outer cache has a outer_cache_fns.sync function pointer
908 that can be used to drain the write buffer of the outer cache.
911 bool "Enable the Broadcom Brahma-B15 read-ahead cache controller"
912 depends on ARCH_BRCMSTB
915 This option enables the Broadcom Brahma-B15 read-ahead cache
916 controller. If disabled, the read-ahead cache remains off.
918 config CACHE_FEROCEON_L2
919 bool "Enable the Feroceon L2 cache controller"
920 depends on ARCH_MV78XX0 || ARCH_MVEBU
924 This option enables the Feroceon L2 cache controller.
926 config CACHE_FEROCEON_L2_WRITETHROUGH
927 bool "Force Feroceon L2 cache write through"
928 depends on CACHE_FEROCEON_L2
930 Say Y here to use the Feroceon L2 cache in writethrough mode.
931 Unless you specifically require this, say N for writeback mode.
933 config MIGHT_HAVE_CACHE_L2X0
936 This option should be selected by machines which have a L2x0
937 or PL310 cache controller, but where its use is optional.
939 The only effect of this option is to make CACHE_L2X0 and
940 related options available to the user for configuration.
942 Boards or SoCs which always require the cache controller
943 support to be present should select CACHE_L2X0 directly
944 instead of this option, thus preventing the user from
945 inadvertently configuring a broken kernel.
948 bool "Enable the L2x0 outer cache controller" if MIGHT_HAVE_CACHE_L2X0
949 default MIGHT_HAVE_CACHE_L2X0
951 select OUTER_CACHE_SYNC
953 This option enables the L2x0 PrimeCell.
955 config CACHE_L2X0_PMU
956 bool "L2x0 performance monitor support" if CACHE_L2X0
957 depends on PERF_EVENTS
959 This option enables support for the performance monitoring features
960 of the L220 and PL310 outer cache controllers.
964 config PL310_ERRATA_588369
965 bool "PL310 errata: Clean & Invalidate maintenance operations do not invalidate clean lines"
967 The PL310 L2 cache controller implements three types of Clean &
968 Invalidate maintenance operations: by Physical Address
969 (offset 0x7F0), by Index/Way (0x7F8) and by Way (0x7FC).
970 They are architecturally defined to behave as the execution of a
971 clean operation followed immediately by an invalidate operation,
972 both performing to the same memory location. This functionality
973 is not correctly implemented in PL310 prior to r2p0 (fixed in r2p0)
974 as clean lines are not invalidated as a result of these operations.
976 config PL310_ERRATA_727915
977 bool "PL310 errata: Background Clean & Invalidate by Way operation can cause data corruption"
979 PL310 implements the Clean & Invalidate by Way L2 cache maintenance
980 operation (offset 0x7FC). This operation runs in background so that
981 PL310 can handle normal accesses while it is in progress. Under very
982 rare circumstances, due to this erratum, write data can be lost when
983 PL310 treats a cacheable write transaction during a Clean &
984 Invalidate by Way operation. Revisions prior to r3p1 are affected by
985 this errata (fixed in r3p1).
987 config PL310_ERRATA_753970
988 bool "PL310 errata: cache sync operation may be faulty"
990 This option enables the workaround for the 753970 PL310 (r3p0) erratum.
992 Under some condition the effect of cache sync operation on
993 the store buffer still remains when the operation completes.
994 This means that the store buffer is always asked to drain and
995 this prevents it from merging any further writes. The workaround
996 is to replace the normal offset of cache sync operation (0x730)
997 by another offset targeting an unmapped PL310 register 0x740.
998 This has the same effect as the cache sync operation: store buffer
999 drain and waiting for all buffers empty.
1001 config PL310_ERRATA_769419
1002 bool "PL310 errata: no automatic Store Buffer drain"
1004 On revisions of the PL310 prior to r3p2, the Store Buffer does
1005 not automatically drain. This can cause normal, non-cacheable
1006 writes to be retained when the memory system is idle, leading
1007 to suboptimal I/O performance for drivers using coherent DMA.
1008 This option adds a write barrier to the cpu_idle loop so that,
1009 on systems with an outer cache, the store buffer is drained
1014 config CACHE_TAUROS2
1015 bool "Enable the Tauros2 L2 cache controller"
1016 depends on (ARCH_DOVE || ARCH_MMP || CPU_PJ4)
1020 This option enables the Tauros2 L2 cache controller (as
1023 config CACHE_UNIPHIER
1024 bool "Enable the UniPhier outer cache controller"
1025 depends on ARCH_UNIPHIER
1026 select ARM_L1_CACHE_SHIFT_7
1028 select OUTER_CACHE_SYNC
1030 This option enables the UniPhier outer cache (system cache)
1034 bool "Enable the L2 cache on XScale3"
1039 This option enables the L2 cache on XScale3.
1041 config ARM_L1_CACHE_SHIFT_6
1045 Setting ARM L1 cache line size to 64 Bytes.
1047 config ARM_L1_CACHE_SHIFT_7
1050 Setting ARM L1 cache line size to 128 Bytes.
1052 config ARM_L1_CACHE_SHIFT
1054 default 7 if ARM_L1_CACHE_SHIFT_7
1055 default 6 if ARM_L1_CACHE_SHIFT_6
1058 config ARM_DMA_MEM_BUFFERABLE
1059 bool "Use non-cacheable memory for DMA" if (CPU_V6 || CPU_V6K || CPU_V7M) && !CPU_V7
1060 default y if CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M
1062 Historically, the kernel has used strongly ordered mappings to
1063 provide DMA coherent memory. With the advent of ARMv7, mapping
1064 memory with differing types results in unpredictable behaviour,
1065 so on these CPUs, this option is forced on.
1067 Multiple mappings with differing attributes is also unpredictable
1068 on ARMv6 CPUs, but since they do not have aggressive speculative
1069 prefetch, no harm appears to occur.
1071 However, drivers may be missing the necessary barriers for ARMv6,
1072 and therefore turning this on may result in unpredictable driver
1073 behaviour. Therefore, we offer this as an option.
1075 On some of the beefier ARMv7-M machines (with DMA and write
1076 buffers) you likely want this enabled, while those that
1077 didn't need it until now also won't need it in the future.
1079 You are recommended say 'Y' here and debug any affected drivers.
1084 config ARCH_SUPPORTS_BIG_ENDIAN
1087 This option specifies the architecture can support big endian
1090 config DEBUG_ALIGN_RODATA
1091 bool "Make rodata strictly non-executable"
1092 depends on STRICT_KERNEL_RWX
1095 If this is set, rodata will be made explicitly non-executable. This
1096 provides protection on the rare chance that attackers might find and
1097 use ROP gadgets that exist in the rodata section. This adds an
1098 additional section-aligned split of rodata from kernel text so it
1099 can be made explicitly non-executable. This padding may waste memory
1100 space to gain the additional protection.