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Diffstat (limited to 'arch/arm/mm/Kconfig')
| -rw-r--r-- | arch/arm/mm/Kconfig | 1143 |
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diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig new file mode 100644 index 000000000..c6bf34a33 --- /dev/null +++ b/arch/arm/mm/Kconfig @@ -0,0 +1,1143 @@ +# SPDX-License-Identifier: GPL-2.0 +comment "Processor Type" + +# Select CPU types depending on the architecture selected. This selects +# which CPUs we support in the kernel image, and the compiler instruction +# optimiser behaviour. + +# ARM7TDMI +config CPU_ARM7TDMI + bool + depends on !MMU + select CPU_32v4T + select CPU_ABRT_LV4T + select CPU_CACHE_V4 + select CPU_PABRT_LEGACY + help + A 32-bit RISC microprocessor based on the ARM7 processor core + which has no memory control unit and cache. + + Say Y if you want support for the ARM7TDMI processor. + Otherwise, say N. + +# ARM720T +config CPU_ARM720T + bool + select CPU_32v4T + select CPU_ABRT_LV4T + select CPU_CACHE_V4 + select CPU_CACHE_VIVT + select CPU_COPY_V4WT if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WT if MMU + help + A 32-bit RISC processor with 8kByte Cache, Write Buffer and + MMU built around an ARM7TDMI core. + + Say Y if you want support for the ARM720T processor. + Otherwise, say N. + +# ARM740T +config CPU_ARM740T + bool + depends on !MMU + select CPU_32v4T + select CPU_ABRT_LV4T + select CPU_CACHE_V4 + select CPU_CP15_MPU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + help + A 32-bit RISC processor with 8KB cache or 4KB variants, + write buffer and MPU(Protection Unit) built around + an ARM7TDMI core. + + Say Y if you want support for the ARM740T processor. + Otherwise, say N. + +# ARM9TDMI +config CPU_ARM9TDMI + bool + depends on !MMU + select CPU_32v4T + select CPU_ABRT_NOMMU + select CPU_CACHE_V4 + select CPU_PABRT_LEGACY + help + A 32-bit RISC microprocessor based on the ARM9 processor core + which has no memory control unit and cache. + + Say Y if you want support for the ARM9TDMI processor. + Otherwise, say N. + +# ARM920T +config CPU_ARM920T + bool + select CPU_32v4T + select CPU_ABRT_EV4T + select CPU_CACHE_V4WT + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + help + The ARM920T is licensed to be produced by numerous vendors, + and is used in the Cirrus EP93xx and the Samsung S3C2410. + + Say Y if you want support for the ARM920T processor. + Otherwise, say N. + +# ARM922T +config CPU_ARM922T + bool + select CPU_32v4T + select CPU_ABRT_EV4T + select CPU_CACHE_V4WT + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + help + The ARM922T is a version of the ARM920T, but with smaller + instruction and data caches. It is used in Altera's + Excalibur XA device family and the ARM Integrator. + + Say Y if you want support for the ARM922T processor. + Otherwise, say N. + +# ARM925T +config CPU_ARM925T + bool + select CPU_32v4T + select CPU_ABRT_EV4T + select CPU_CACHE_V4WT + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + help + The ARM925T is a mix between the ARM920T and ARM926T, but with + different instruction and data caches. It is used in TI's OMAP + device family. + + Say Y if you want support for the ARM925T processor. + Otherwise, say N. + +# ARM926T +config CPU_ARM926T + bool + select CPU_32v5 + select CPU_ABRT_EV5TJ + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + help + This is a variant of the ARM920. It has slightly different + instruction sequences for cache and TLB operations. Curiously, + there is no documentation on it at the ARM corporate website. + + Say Y if you want support for the ARM926T processor. + Otherwise, say N. + +# FA526 +config CPU_FA526 + bool + select CPU_32v4 + select CPU_ABRT_EV4 + select CPU_CACHE_FA + select CPU_CACHE_VIVT + select CPU_COPY_FA if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_TLB_FA if MMU + help + The FA526 is a version of the ARMv4 compatible processor with + Branch Target Buffer, Unified TLB and cache line size 16. + + Say Y if you want support for the FA526 processor. + Otherwise, say N. + +# ARM940T +config CPU_ARM940T + bool + depends on !MMU + select CPU_32v4T + select CPU_ABRT_NOMMU + select CPU_CACHE_VIVT + select CPU_CP15_MPU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + help + ARM940T is a member of the ARM9TDMI family of general- + purpose microprocessors with MPU and separate 4KB + instruction and 4KB data cases, each with a 4-word line + length. + + Say Y if you want support for the ARM940T processor. + Otherwise, say N. + +# ARM946E-S +config CPU_ARM946E + bool + depends on !MMU + select CPU_32v5 + select CPU_ABRT_NOMMU + select CPU_CACHE_VIVT + select CPU_CP15_MPU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + help + ARM946E-S is a member of the ARM9E-S family of high- + performance, 32-bit system-on-chip processor solutions. + The TCM and ARMv5TE 32-bit instruction set is supported. + + Say Y if you want support for the ARM946E-S processor. + Otherwise, say N. + +# ARM1020 - needs validating +config CPU_ARM1020 + bool + select CPU_32v5 + select CPU_ABRT_EV4T + select CPU_CACHE_V4WT + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + help + The ARM1020 is the 32K cached version of the ARM10 processor, + with an addition of a floating-point unit. + + Say Y if you want support for the ARM1020 processor. + Otherwise, say N. + +# ARM1020E - needs validating +config CPU_ARM1020E + bool + depends on n + select CPU_32v5 + select CPU_ABRT_EV4T + select CPU_CACHE_V4WT + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + +# ARM1022E +config CPU_ARM1022 + bool + select CPU_32v5 + select CPU_ABRT_EV4T + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU # can probably do better + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + help + The ARM1022E is an implementation of the ARMv5TE architecture + based upon the ARM10 integer core with a 16KiB L1 Harvard cache, + embedded trace macrocell, and a floating-point unit. + + Say Y if you want support for the ARM1022E processor. + Otherwise, say N. + +# ARM1026EJ-S +config CPU_ARM1026 + bool + select CPU_32v5 + select CPU_ABRT_EV5T # But need Jazelle, but EV5TJ ignores bit 10 + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU # can probably do better + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + help + The ARM1026EJ-S is an implementation of the ARMv5TEJ architecture + based upon the ARM10 integer core. + + Say Y if you want support for the ARM1026EJ-S processor. + Otherwise, say N. + +# SA110 +config CPU_SA110 + bool + select CPU_32v3 if ARCH_RPC + select CPU_32v4 if !ARCH_RPC + select CPU_ABRT_EV4 + select CPU_CACHE_V4WB + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_TLB_V4WB if MMU + help + The Intel StrongARM(R) SA-110 is a 32-bit microprocessor and + is available at five speeds ranging from 100 MHz to 233 MHz. + More information is available at + <http://developer.intel.com/design/strong/sa110.htm>. + + Say Y if you want support for the SA-110 processor. + Otherwise, say N. + +# SA1100 +config CPU_SA1100 + bool + select CPU_32v4 + select CPU_ABRT_EV4 + select CPU_CACHE_V4WB + select CPU_CACHE_VIVT + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_TLB_V4WB if MMU + +# XScale +config CPU_XSCALE + bool + select CPU_32v5 + select CPU_ABRT_EV5T + select CPU_CACHE_VIVT + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + +# XScale Core Version 3 +config CPU_XSC3 + bool + select CPU_32v5 + select CPU_ABRT_EV5T + select CPU_CACHE_VIVT + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + select IO_36 + +# Marvell PJ1 (Mohawk) +config CPU_MOHAWK + bool + select CPU_32v5 + select CPU_ABRT_EV5T + select CPU_CACHE_VIVT + select CPU_COPY_V4WB if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_V4WBI if MMU + +# Feroceon +config CPU_FEROCEON + bool + select CPU_32v5 + select CPU_ABRT_EV5T + select CPU_CACHE_VIVT + select CPU_COPY_FEROCEON if MMU + select CPU_CP15_MMU + select CPU_PABRT_LEGACY + select CPU_THUMB_CAPABLE + select CPU_TLB_FEROCEON if MMU + +config CPU_FEROCEON_OLD_ID + bool "Accept early Feroceon cores with an ARM926 ID" + depends on CPU_FEROCEON && !CPU_ARM926T + default y + help + This enables the usage of some old Feroceon cores + for which the CPU ID is equal to the ARM926 ID. + Relevant for Feroceon-1850 and early Feroceon-2850. + +# Marvell PJ4 +config CPU_PJ4 + bool + select ARM_THUMBEE + select CPU_V7 + +config CPU_PJ4B + bool + select CPU_V7 + +# ARMv6 +config CPU_V6 + bool + select CPU_32v6 + select CPU_ABRT_EV6 + select CPU_CACHE_V6 + select CPU_CACHE_VIPT + select CPU_COPY_V6 if MMU + select CPU_CP15_MMU + select CPU_HAS_ASID if MMU + select CPU_PABRT_V6 + select CPU_THUMB_CAPABLE + select CPU_TLB_V6 if MMU + +# ARMv6k +config CPU_V6K + bool + select CPU_32v6 + select CPU_32v6K + select CPU_ABRT_EV6 + select CPU_CACHE_V6 + select CPU_CACHE_VIPT + select CPU_COPY_V6 if MMU + select CPU_CP15_MMU + select CPU_HAS_ASID if MMU + select CPU_PABRT_V6 + select CPU_THUMB_CAPABLE + select CPU_TLB_V6 if MMU + +# ARMv7 +config CPU_V7 + bool + select CPU_32v6K + select CPU_32v7 + select CPU_ABRT_EV7 + select CPU_CACHE_V7 + select CPU_CACHE_VIPT + select CPU_COPY_V6 if MMU + select CPU_CP15_MMU if MMU + select CPU_CP15_MPU if !MMU + select CPU_HAS_ASID if MMU + select CPU_PABRT_V7 + select CPU_SPECTRE if MMU + select CPU_THUMB_CAPABLE + select CPU_TLB_V7 if MMU + +# ARMv7M +config CPU_V7M + bool + select CPU_32v7M + select CPU_ABRT_NOMMU + select CPU_CACHE_V7M + select CPU_CACHE_NOP + select CPU_PABRT_LEGACY + select CPU_THUMBONLY + +config CPU_THUMBONLY + bool + select CPU_THUMB_CAPABLE + # There are no CPUs available with MMU that don't implement an ARM ISA: + depends on !MMU + help + Select this if your CPU doesn't support the 32 bit ARM instructions. + +config CPU_THUMB_CAPABLE + bool + help + Select this if your CPU can support Thumb mode. + +# Figure out what processor architecture version we should be using. +# This defines the compiler instruction set which depends on the machine type. +config CPU_32v3 + bool + select CPU_USE_DOMAINS if MMU + select NEED_KUSER_HELPERS + select TLS_REG_EMUL if SMP || !MMU + select CPU_NO_EFFICIENT_FFS + +config CPU_32v4 + bool + select CPU_USE_DOMAINS if MMU + select NEED_KUSER_HELPERS + select TLS_REG_EMUL if SMP || !MMU + select CPU_NO_EFFICIENT_FFS + +config CPU_32v4T + bool + select CPU_USE_DOMAINS if MMU + select NEED_KUSER_HELPERS + select TLS_REG_EMUL if SMP || !MMU + select CPU_NO_EFFICIENT_FFS + +config CPU_32v5 + bool + select CPU_USE_DOMAINS if MMU + select NEED_KUSER_HELPERS + select TLS_REG_EMUL if SMP || !MMU + +config CPU_32v6 + bool + select TLS_REG_EMUL if !CPU_32v6K && !MMU + +config CPU_32v6K + bool + +config CPU_32v7 + bool + +config CPU_32v7M + bool + +# The abort model +config CPU_ABRT_NOMMU + bool + +config CPU_ABRT_EV4 + bool + +config CPU_ABRT_EV4T + bool + +config CPU_ABRT_LV4T + bool + +config CPU_ABRT_EV5T + bool + +config CPU_ABRT_EV5TJ + bool + +config CPU_ABRT_EV6 + bool + +config CPU_ABRT_EV7 + bool + +config CPU_PABRT_LEGACY + bool + +config CPU_PABRT_V6 + bool + +config CPU_PABRT_V7 + bool + +# The cache model +config CPU_CACHE_V4 + bool + +config CPU_CACHE_V4WT + bool + +config CPU_CACHE_V4WB + bool + +config CPU_CACHE_V6 + bool + +config CPU_CACHE_V7 + bool + +config CPU_CACHE_NOP + bool + +config CPU_CACHE_VIVT + bool + +config CPU_CACHE_VIPT + bool + +config CPU_CACHE_FA + bool + +config CPU_CACHE_V7M + bool + +if MMU +# The copy-page model +config CPU_COPY_V4WT + bool + +config CPU_COPY_V4WB + bool + +config CPU_COPY_FEROCEON + bool + +config CPU_COPY_FA + bool + +config CPU_COPY_V6 + bool + +# This selects the TLB model +config CPU_TLB_V4WT + bool + help + ARM Architecture Version 4 TLB with writethrough cache. + +config CPU_TLB_V4WB + bool + help + ARM Architecture Version 4 TLB with writeback cache. + +config CPU_TLB_V4WBI + bool + help + ARM Architecture Version 4 TLB with writeback cache and invalidate + instruction cache entry. + +config CPU_TLB_FEROCEON + bool + help + Feroceon TLB (v4wbi with non-outer-cachable page table walks). + +config CPU_TLB_FA + bool + help + Faraday ARM FA526 architecture, unified TLB with writeback cache + and invalidate instruction cache entry. Branch target buffer is + also supported. + +config CPU_TLB_V6 + bool + +config CPU_TLB_V7 + bool + +config VERIFY_PERMISSION_FAULT + bool +endif + +config CPU_HAS_ASID + bool + help + This indicates whether the CPU has the ASID register; used to + tag TLB and possibly cache entries. + +config CPU_CP15 + bool + help + Processor has the CP15 register. + +config CPU_CP15_MMU + bool + select CPU_CP15 + help + Processor has the CP15 register, which has MMU related registers. + +config CPU_CP15_MPU + bool + select CPU_CP15 + help + Processor has the CP15 register, which has MPU related registers. + +config CPU_USE_DOMAINS + bool + help + This option enables or disables the use of domain switching + via the set_fs() function. + +config CPU_V7M_NUM_IRQ + int "Number of external interrupts connected to the NVIC" + depends on CPU_V7M + default 90 if ARCH_STM32 + default 38 if ARCH_EFM32 + default 112 if SOC_VF610 + default 240 + help + This option indicates the number of interrupts connected to the NVIC. + The value can be larger than the real number of interrupts supported + by the system, but must not be lower. + The default value is 240, corresponding to the maximum number of + interrupts supported by the NVIC on Cortex-M family. + + If unsure, keep default value. + +# +# CPU supports 36-bit I/O +# +config IO_36 + bool + +comment "Processor Features" + +config ARM_LPAE + bool "Support for the Large Physical Address Extension" + depends on MMU && CPU_32v7 && !CPU_32v6 && !CPU_32v5 && \ + !CPU_32v4 && !CPU_32v3 + select PHYS_ADDR_T_64BIT + select SWIOTLB + help + Say Y if you have an ARMv7 processor supporting the LPAE page + table format and you would like to access memory beyond the + 4GB limit. The resulting kernel image will not run on + processors without the LPA extension. + + If unsure, say N. + +config ARM_PV_FIXUP + def_bool y + depends on ARM_LPAE && ARM_PATCH_PHYS_VIRT && ARCH_KEYSTONE + +config ARM_THUMB + bool "Support Thumb user binaries" if !CPU_THUMBONLY && EXPERT + depends on CPU_THUMB_CAPABLE + default y + help + Say Y if you want to include kernel support for running user space + Thumb binaries. + + The Thumb instruction set is a compressed form of the standard ARM + instruction set resulting in smaller binaries at the expense of + slightly less efficient code. + + If this option is disabled, and you run userspace that switches to + Thumb mode, signal handling will not work correctly, resulting in + segmentation faults or illegal instruction aborts. + + If you don't know what this all is, saying Y is a safe choice. + +config ARM_THUMBEE + bool "Enable ThumbEE CPU extension" + depends on CPU_V7 + help + Say Y here if you have a CPU with the ThumbEE extension and code to + make use of it. Say N for code that can run on CPUs without ThumbEE. + +config ARM_VIRT_EXT + bool + default y if CPU_V7 + help + Enable the kernel to make use of the ARM Virtualization + Extensions to install hypervisors without run-time firmware + assistance. + + A compliant bootloader is required in order to make maximum + use of this feature. Refer to Documentation/arm/booting.rst for + details. + +config SWP_EMULATE + bool "Emulate SWP/SWPB instructions" if !SMP + depends on CPU_V7 + default y if SMP + select HAVE_PROC_CPU if PROC_FS + help + ARMv6 architecture deprecates use of the SWP/SWPB instructions. + ARMv7 multiprocessing extensions introduce the ability to disable + these instructions, triggering an undefined instruction exception + when executed. Say Y here to enable software emulation of these + instructions for userspace (not kernel) using LDREX/STREX. + Also creates /proc/cpu/swp_emulation for statistics. + + In some older versions of glibc [<=2.8] SWP is used during futex + trylock() operations with the assumption that the code will not + be preempted. This invalid assumption may be more likely to fail + with SWP emulation enabled, leading to deadlock of the user + application. + + NOTE: when accessing uncached shared regions, LDREX/STREX rely + on an external transaction monitoring block called a global + monitor to maintain update atomicity. If your system does not + implement a global monitor, this option can cause programs that + perform SWP operations to uncached memory to deadlock. + + If unsure, say Y. + +config CPU_BIG_ENDIAN + bool "Build big-endian kernel" + depends on ARCH_SUPPORTS_BIG_ENDIAN + depends on !LD_IS_LLD + help + Say Y if you plan on running a kernel in big-endian mode. + Note that your board must be properly built and your board + port must properly enable any big-endian related features + of your chipset/board/processor. + +config CPU_ENDIAN_BE8 + bool + depends on CPU_BIG_ENDIAN + default CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M + help + Support for the BE-8 (big-endian) mode on ARMv6 and ARMv7 processors. + +config CPU_ENDIAN_BE32 + bool + depends on CPU_BIG_ENDIAN + default !CPU_ENDIAN_BE8 + help + Support for the BE-32 (big-endian) mode on pre-ARMv6 processors. + +config CPU_HIGH_VECTOR + depends on !MMU && CPU_CP15 && !CPU_ARM740T + bool "Select the High exception vector" + help + Say Y here to select high exception vector(0xFFFF0000~). + The exception vector can vary depending on the platform + design in nommu mode. If your platform needs to select + high exception vector, say Y. + Otherwise or if you are unsure, say N, and the low exception + vector (0x00000000~) will be used. + +config CPU_ICACHE_DISABLE + bool "Disable I-Cache (I-bit)" + depends on (CPU_CP15 && !(CPU_ARM720T || CPU_ARM740T || CPU_XSCALE || CPU_XSC3)) || CPU_V7M + help + Say Y here to disable the processor instruction cache. Unless + you have a reason not to or are unsure, say N. + +config CPU_ICACHE_MISMATCH_WORKAROUND + bool "Workaround for I-Cache line size mismatch between CPU cores" + depends on SMP && CPU_V7 + help + Some big.LITTLE systems have I-Cache line size mismatch between + LITTLE and big cores. Say Y here to enable a workaround for + proper I-Cache support on such systems. If unsure, say N. + +config CPU_DCACHE_DISABLE + bool "Disable D-Cache (C-bit)" + depends on (CPU_CP15 && !SMP) || CPU_V7M + help + Say Y here to disable the processor data cache. Unless + you have a reason not to or are unsure, say N. + +config CPU_DCACHE_SIZE + hex + depends on CPU_ARM740T || CPU_ARM946E + default 0x00001000 if CPU_ARM740T + default 0x00002000 # default size for ARM946E-S + help + Some cores are synthesizable to have various sized cache. For + ARM946E-S case, it can vary from 0KB to 1MB. + To support such cache operations, it is efficient to know the size + before compile time. + If your SoC is configured to have a different size, define the value + here with proper conditions. + +config CPU_DCACHE_WRITETHROUGH + bool "Force write through D-cache" + depends on (CPU_ARM740T || CPU_ARM920T || CPU_ARM922T || CPU_ARM925T || CPU_ARM926T || CPU_ARM940T || CPU_ARM946E || CPU_ARM1020 || CPU_FA526) && !CPU_DCACHE_DISABLE + default y if CPU_ARM925T + help + Say Y here to use the data cache in writethrough mode. Unless you + specifically require this or are unsure, say N. + +config CPU_CACHE_ROUND_ROBIN + bool "Round robin I and D cache replacement algorithm" + depends on (CPU_ARM926T || CPU_ARM946E || CPU_ARM1020) && (!CPU_ICACHE_DISABLE || !CPU_DCACHE_DISABLE) + help + Say Y here to use the predictable round-robin cache replacement + policy. Unless you specifically require this or are unsure, say N. + +config CPU_BPREDICT_DISABLE + bool "Disable branch prediction" + depends on CPU_ARM1020 || CPU_V6 || CPU_V6K || CPU_MOHAWK || CPU_XSC3 || CPU_V7 || CPU_FA526 || CPU_V7M + help + Say Y here to disable branch prediction. If unsure, say N. + +config CPU_SPECTRE + bool + select GENERIC_CPU_VULNERABILITIES + +config HARDEN_BRANCH_PREDICTOR + bool "Harden the branch predictor against aliasing attacks" if EXPERT + depends on CPU_SPECTRE + default y + help + Speculation attacks against some high-performance processors rely + on being able to manipulate the branch predictor for a victim + context by executing aliasing branches in the attacker context. + Such attacks can be partially mitigated against by clearing + internal branch predictor state and limiting the prediction + logic in some situations. + + This config option will take CPU-specific actions to harden + the branch predictor against aliasing attacks and may rely on + specific instruction sequences or control bits being set by + the system firmware. + + If unsure, say Y. + +config HARDEN_BRANCH_HISTORY + bool "Harden Spectre style attacks against branch history" if EXPERT + depends on CPU_SPECTRE + default y + help + Speculation attacks against some high-performance processors can + make use of branch history to influence future speculation. When + taking an exception, a sequence of branches overwrites the branch + history, or branch history is invalidated. + +config TLS_REG_EMUL + bool + select NEED_KUSER_HELPERS + help + An SMP system using a pre-ARMv6 processor (there are apparently + a few prototypes like that in existence) and therefore access to + that required register must be emulated. + +config NEED_KUSER_HELPERS + bool + +config KUSER_HELPERS + bool "Enable kuser helpers in vector page" if !NEED_KUSER_HELPERS + depends on MMU + default y + help + Warning: disabling this option may break user programs. + + Provide kuser helpers in the vector page. The kernel provides + helper code to userspace in read only form at a fixed location + in the high vector page to allow userspace to be independent of + the CPU type fitted to the system. This permits binaries to be + run on ARMv4 through to ARMv7 without modification. + + See Documentation/arm/kernel_user_helpers.rst for details. + + However, the fixed address nature of these helpers can be used + by ROP (return orientated programming) authors when creating + exploits. + + If all of the binaries and libraries which run on your platform + are built specifically for your platform, and make no use of + these helpers, then you can turn this option off to hinder + such exploits. However, in that case, if a binary or library + relying on those helpers is run, it will receive a SIGILL signal, + which will terminate the program. + + Say N here only if you are absolutely certain that you do not + need these helpers; otherwise, the safe option is to say Y. + +config VDSO + bool "Enable VDSO for acceleration of some system calls" + depends on AEABI && MMU && CPU_V7 + default y if ARM_ARCH_TIMER + select HAVE_GENERIC_VDSO + select GENERIC_TIME_VSYSCALL + select GENERIC_VDSO_32 + select GENERIC_GETTIMEOFDAY + help + Place in the process address space an ELF shared object + providing fast implementations of gettimeofday and + clock_gettime. Systems that implement the ARM architected + timer will receive maximum benefit. + + You must have glibc 2.22 or later for programs to seamlessly + take advantage of this. + +config DMA_CACHE_RWFO + bool "Enable read/write for ownership DMA cache maintenance" + depends on CPU_V6K && SMP + default y + help + The Snoop Control Unit on ARM11MPCore does not detect the + cache maintenance operations and the dma_{map,unmap}_area() + functions may leave stale cache entries on other CPUs. By + enabling this option, Read or Write For Ownership in the ARMv6 + DMA cache maintenance functions is performed. These LDR/STR + instructions change the cache line state to shared or modified + so that the cache operation has the desired effect. + + Note that the workaround is only valid on processors that do + not perform speculative loads into the D-cache. For such + processors, if cache maintenance operations are not broadcast + in hardware, other workarounds are needed (e.g. cache + maintenance broadcasting in software via FIQ). + +config OUTER_CACHE + bool + +config OUTER_CACHE_SYNC + bool + select ARM_HEAVY_MB + help + The outer cache has a outer_cache_fns.sync function pointer + that can be used to drain the write buffer of the outer cache. + +config CACHE_B15_RAC + bool "Enable the Broadcom Brahma-B15 read-ahead cache controller" + depends on ARCH_BRCMSTB + default y + help + This option enables the Broadcom Brahma-B15 read-ahead cache + controller. If disabled, the read-ahead cache remains off. + +config CACHE_FEROCEON_L2 + bool "Enable the Feroceon L2 cache controller" + depends on ARCH_MV78XX0 || ARCH_MVEBU + default y + select OUTER_CACHE + help + This option enables the Feroceon L2 cache controller. + +config CACHE_FEROCEON_L2_WRITETHROUGH + bool "Force Feroceon L2 cache write through" + depends on CACHE_FEROCEON_L2 + help + Say Y here to use the Feroceon L2 cache in writethrough mode. + Unless you specifically require this, say N for writeback mode. + +config MIGHT_HAVE_CACHE_L2X0 + bool + help + This option should be selected by machines which have a L2x0 + or PL310 cache controller, but where its use is optional. + + The only effect of this option is to make CACHE_L2X0 and + related options available to the user for configuration. + + Boards or SoCs which always require the cache controller + support to be present should select CACHE_L2X0 directly + instead of this option, thus preventing the user from + inadvertently configuring a broken kernel. + +config CACHE_L2X0 + bool "Enable the L2x0 outer cache controller" if MIGHT_HAVE_CACHE_L2X0 + default MIGHT_HAVE_CACHE_L2X0 + select OUTER_CACHE + select OUTER_CACHE_SYNC + help + This option enables the L2x0 PrimeCell. + +config CACHE_L2X0_PMU + bool "L2x0 performance monitor support" if CACHE_L2X0 + depends on PERF_EVENTS + help + This option enables support for the performance monitoring features + of the L220 and PL310 outer cache controllers. + +if CACHE_L2X0 + +config PL310_ERRATA_588369 + bool "PL310 errata: Clean & Invalidate maintenance operations do not invalidate clean lines" + help + The PL310 L2 cache controller implements three types of Clean & + Invalidate maintenance operations: by Physical Address + (offset 0x7F0), by Index/Way (0x7F8) and by Way (0x7FC). + They are architecturally defined to behave as the execution of a + clean operation followed immediately by an invalidate operation, + both performing to the same memory location. This functionality + is not correctly implemented in PL310 prior to r2p0 (fixed in r2p0) + as clean lines are not invalidated as a result of these operations. + +config PL310_ERRATA_727915 + bool "PL310 errata: Background Clean & Invalidate by Way operation can cause data corruption" + help + PL310 implements the Clean & Invalidate by Way L2 cache maintenance + operation (offset 0x7FC). This operation runs in background so that + PL310 can handle normal accesses while it is in progress. Under very + rare circumstances, due to this erratum, write data can be lost when + PL310 treats a cacheable write transaction during a Clean & + Invalidate by Way operation. Revisions prior to r3p1 are affected by + this errata (fixed in r3p1). + +config PL310_ERRATA_753970 + bool "PL310 errata: cache sync operation may be faulty" + help + This option enables the workaround for the 753970 PL310 (r3p0) erratum. + + Under some condition the effect of cache sync operation on + the store buffer still remains when the operation completes. + This means that the store buffer is always asked to drain and + this prevents it from merging any further writes. The workaround + is to replace the normal offset of cache sync operation (0x730) + by another offset targeting an unmapped PL310 register 0x740. + This has the same effect as the cache sync operation: store buffer + drain and waiting for all buffers empty. + +config PL310_ERRATA_769419 + bool "PL310 errata: no automatic Store Buffer drain" + help + On revisions of the PL310 prior to r3p2, the Store Buffer does + not automatically drain. This can cause normal, non-cacheable + writes to be retained when the memory system is idle, leading + to suboptimal I/O performance for drivers using coherent DMA. + This option adds a write barrier to the cpu_idle loop so that, + on systems with an outer cache, the store buffer is drained + explicitly. + +endif + +config CACHE_TAUROS2 + bool "Enable the Tauros2 L2 cache controller" + depends on (CPU_MOHAWK || CPU_PJ4) + default y + select OUTER_CACHE + help + This option enables the Tauros2 L2 cache controller (as + found on PJ1/PJ4). + +config CACHE_UNIPHIER + bool "Enable the UniPhier outer cache controller" + depends on ARCH_UNIPHIER + select ARM_L1_CACHE_SHIFT_7 + select OUTER_CACHE + select OUTER_CACHE_SYNC + help + This option enables the UniPhier outer cache (system cache) + controller. + +config CACHE_XSC3L2 + bool "Enable the L2 cache on XScale3" + depends on CPU_XSC3 + default y + select OUTER_CACHE + help + This option enables the L2 cache on XScale3. + +config ARM_L1_CACHE_SHIFT_6 + bool + default y if CPU_V7 + help + Setting ARM L1 cache line size to 64 Bytes. + +config ARM_L1_CACHE_SHIFT_7 + bool + help + Setting ARM L1 cache line size to 128 Bytes. + +config ARM_L1_CACHE_SHIFT + int + default 7 if ARM_L1_CACHE_SHIFT_7 + default 6 if ARM_L1_CACHE_SHIFT_6 + default 5 + +config ARM_DMA_MEM_BUFFERABLE + bool "Use non-cacheable memory for DMA" if (CPU_V6 || CPU_V6K || CPU_V7M) && !CPU_V7 + default y if CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M + help + Historically, the kernel has used strongly ordered mappings to + provide DMA coherent memory. With the advent of ARMv7, mapping + memory with differing types results in unpredictable behaviour, + so on these CPUs, this option is forced on. + + Multiple mappings with differing attributes is also unpredictable + on ARMv6 CPUs, but since they do not have aggressive speculative + prefetch, no harm appears to occur. + + However, drivers may be missing the necessary barriers for ARMv6, + and therefore turning this on may result in unpredictable driver + behaviour. Therefore, we offer this as an option. + + On some of the beefier ARMv7-M machines (with DMA and write + buffers) you likely want this enabled, while those that + didn't need it until now also won't need it in the future. + + You are recommended say 'Y' here and debug any affected drivers. + +config ARM_HEAVY_MB + bool + +config ARCH_SUPPORTS_BIG_ENDIAN + bool + help + This option specifies the architecture can support big endian + operation. + +config DEBUG_ALIGN_RODATA + bool "Make rodata strictly non-executable" + depends on STRICT_KERNEL_RWX + default y + help + If this is set, rodata will be made explicitly non-executable. This + provides protection on the rare chance that attackers might find and + use ROP gadgets that exist in the rodata section. This adds an + additional section-aligned split of rodata from kernel text so it + can be made explicitly non-executable. This padding may waste memory + space to gain the additional protection. |