config ARM64 def_bool y select ACPI_CCA_REQUIRED if ACPI select ACPI_GENERIC_GSI if ACPI select ACPI_GTDT if ACPI select ACPI_IORT if ACPI select ACPI_REDUCED_HARDWARE_ONLY if ACPI select ACPI_MCFG if ACPI select ACPI_SPCR_TABLE if ACPI select ARCH_CLOCKSOURCE_DATA select ARCH_HAS_DEBUG_VIRTUAL select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA select ARCH_HAS_KCOV select ARCH_HAS_SET_MEMORY select ARCH_HAS_SG_CHAIN select ARCH_HAS_STRICT_KERNEL_RWX select ARCH_HAS_STRICT_MODULE_RWX select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAVE_NMI_SAFE_CMPXCHG if ACPI_APEI_SEA select ARCH_USE_CMPXCHG_LOCKREF select ARCH_SUPPORTS_MEMORY_FAILURE select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_NUMA_BALANCING select ARCH_WANT_COMPAT_IPC_PARSE_VERSION select ARCH_WANT_FRAME_POINTERS select ARCH_HAS_UBSAN_SANITIZE_ALL select ARM_AMBA select ARM_ARCH_TIMER select ARM_GIC select AUDIT_ARCH_COMPAT_GENERIC select ARM_GIC_V2M if PCI select ARM_GIC_V3 select ARM_GIC_V3_ITS if PCI select ARM_PSCI_FW select BUILDTIME_EXTABLE_SORT select CLONE_BACKWARDS select COMMON_CLK select CPU_PM if (SUSPEND || CPU_IDLE) select DCACHE_WORD_ACCESS select EDAC_SUPPORT select FRAME_POINTER select GENERIC_ALLOCATOR select GENERIC_ARCH_TOPOLOGY select GENERIC_CLOCKEVENTS select GENERIC_CLOCKEVENTS_BROADCAST select GENERIC_CPU_AUTOPROBE select GENERIC_EARLY_IOREMAP select GENERIC_IDLE_POLL_SETUP select GENERIC_IRQ_PROBE select GENERIC_IRQ_SHOW select GENERIC_IRQ_SHOW_LEVEL select GENERIC_PCI_IOMAP select GENERIC_SCHED_CLOCK select GENERIC_SMP_IDLE_THREAD select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER select GENERIC_TIME_VSYSCALL select HANDLE_DOMAIN_IRQ select HARDIRQS_SW_RESEND select HAVE_ACPI_APEI if (ACPI && EFI) select HAVE_ALIGNED_STRUCT_PAGE if SLUB select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_BITREVERSE select HAVE_ARCH_HUGE_VMAP select HAVE_ARCH_JUMP_LABEL select HAVE_ARCH_KASAN if SPARSEMEM_VMEMMAP && !(ARM64_16K_PAGES && ARM64_VA_BITS_48) select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_VMAP_STACK select HAVE_ARM_SMCCC select HAVE_EBPF_JIT select HAVE_C_RECORDMCOUNT select HAVE_CC_STACKPROTECTOR select HAVE_CMPXCHG_DOUBLE select HAVE_CMPXCHG_LOCAL select HAVE_CONTEXT_TRACKING select HAVE_DEBUG_BUGVERBOSE select HAVE_DEBUG_KMEMLEAK select HAVE_DMA_API_DEBUG select HAVE_DMA_CONTIGUOUS select HAVE_DYNAMIC_FTRACE select HAVE_EFFICIENT_UNALIGNED_ACCESS select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_GRAPH_TRACER select HAVE_GCC_PLUGINS select HAVE_GENERIC_DMA_COHERENT select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_IRQ_TIME_ACCOUNTING select HAVE_MEMBLOCK select HAVE_MEMBLOCK_NODE_MAP if NUMA select HAVE_NMI if ACPI_APEI_SEA select HAVE_PATA_PLATFORM select HAVE_PERF_EVENTS select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RCU_TABLE_FREE select HAVE_SYSCALL_TRACEPOINTS select HAVE_KPROBES select HAVE_KRETPROBES select IOMMU_DMA if IOMMU_SUPPORT select IRQ_DOMAIN select IRQ_FORCED_THREADING select MODULES_USE_ELF_RELA select NO_BOOTMEM select OF select OF_EARLY_FLATTREE select OF_RESERVED_MEM select PCI_ECAM if ACPI select POWER_RESET select POWER_SUPPLY select SPARSE_IRQ select SYSCTL_EXCEPTION_TRACE select THREAD_INFO_IN_TASK help ARM 64-bit (AArch64) Linux support. config 64BIT def_bool y config ARCH_PHYS_ADDR_T_64BIT def_bool y config MMU def_bool y config ARM64_PAGE_SHIFT int default 16 if ARM64_64K_PAGES default 14 if ARM64_16K_PAGES default 12 config ARM64_CONT_SHIFT int default 5 if ARM64_64K_PAGES default 7 if ARM64_16K_PAGES default 4 config ARCH_MMAP_RND_BITS_MIN default 14 if ARM64_64K_PAGES default 16 if ARM64_16K_PAGES default 18 # max bits determined by the following formula: # VA_BITS - PAGE_SHIFT - 3 config ARCH_MMAP_RND_BITS_MAX default 19 if ARM64_VA_BITS=36 default 24 if ARM64_VA_BITS=39 default 27 if ARM64_VA_BITS=42 default 30 if ARM64_VA_BITS=47 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES default 33 if ARM64_VA_BITS=48 default 14 if ARM64_64K_PAGES default 16 if ARM64_16K_PAGES default 18 config ARCH_MMAP_RND_COMPAT_BITS_MIN default 7 if ARM64_64K_PAGES default 9 if ARM64_16K_PAGES default 11 config ARCH_MMAP_RND_COMPAT_BITS_MAX default 16 config NO_IOPORT_MAP def_bool y if !PCI config STACKTRACE_SUPPORT def_bool y config ILLEGAL_POINTER_VALUE hex default 0xdead000000000000 config LOCKDEP_SUPPORT def_bool y config TRACE_IRQFLAGS_SUPPORT def_bool y config RWSEM_XCHGADD_ALGORITHM def_bool y config GENERIC_BUG def_bool y depends on BUG config GENERIC_BUG_RELATIVE_POINTERS def_bool y depends on GENERIC_BUG config GENERIC_HWEIGHT def_bool y config GENERIC_CSUM def_bool y config GENERIC_CALIBRATE_DELAY def_bool y config ZONE_DMA def_bool y config HAVE_GENERIC_GUP def_bool y config ARCH_DMA_ADDR_T_64BIT def_bool y config NEED_DMA_MAP_STATE def_bool y config NEED_SG_DMA_LENGTH def_bool y config SMP def_bool y config SWIOTLB def_bool y config IOMMU_HELPER def_bool SWIOTLB config KERNEL_MODE_NEON def_bool y config FIX_EARLYCON_MEM def_bool y config PGTABLE_LEVELS int default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42 default 3 if ARM64_64K_PAGES && ARM64_VA_BITS_48 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48 config ARCH_SUPPORTS_UPROBES def_bool y config ARCH_PROC_KCORE_TEXT def_bool y source "init/Kconfig" source "kernel/Kconfig.freezer" source "arch/arm64/Kconfig.platforms" menu "Bus support" config PCI bool "PCI support" help This feature enables support for PCI bus system. If you say Y here, the kernel will include drivers and infrastructure code to support PCI bus devices. config PCI_DOMAINS def_bool PCI config PCI_DOMAINS_GENERIC def_bool PCI config PCI_SYSCALL def_bool PCI source "drivers/pci/Kconfig" endmenu menu "Kernel Features" menu "ARM errata workarounds via the alternatives framework" config ARM64_ERRATUM_826319 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted" default y help This option adds an alternative code sequence to work around ARM erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or AXI master interface and an L2 cache. If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors and is unable to accept a certain write via this interface, it will not progress on read data presented on the read data channel and the system can deadlock. The workaround promotes data cache clean instructions to data cache clean-and-invalidate. Please note that this does not necessarily enable the workaround, as it depends on the alternative framework, which will only patch the kernel if an affected CPU is detected. If unsure, say Y. config ARM64_ERRATUM_827319 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect" default y help This option adds an alternative code sequence to work around ARM erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI master interface and an L2 cache. Under certain conditions this erratum can cause a clean line eviction to occur at the same time as another transaction to the same address on the AMBA 5 CHI interface, which can cause data corruption if the interconnect reorders the two transactions. The workaround promotes data cache clean instructions to data cache clean-and-invalidate. Please note that this does not necessarily enable the workaround, as it depends on the alternative framework, which will only patch the kernel if an affected CPU is detected. If unsure, say Y. config ARM64_ERRATUM_824069 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop" default y help This option adds an alternative code sequence to work around ARM erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected to a coherent interconnect. If a Cortex-A53 processor is executing a store or prefetch for write instruction at the same time as a processor in another cluster is executing a cache maintenance operation to the same address, then this erratum might cause a clean cache line to be incorrectly marked as dirty. The workaround promotes data cache clean instructions to data cache clean-and-invalidate. Please note that this option does not necessarily enable the workaround, as it depends on the alternative framework, which will only patch the kernel if an affected CPU is detected. If unsure, say Y. config ARM64_ERRATUM_819472 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption" default y help This option adds an alternative code sequence to work around ARM erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache present when it is connected to a coherent interconnect. If the processor is executing a load and store exclusive sequence at the same time as a processor in another cluster is executing a cache maintenance operation to the same address, then this erratum might cause data corruption. The workaround promotes data cache clean instructions to data cache clean-and-invalidate. Please note that this does not necessarily enable the workaround, as it depends on the alternative framework, which will only patch the kernel if an affected CPU is detected. If unsure, say Y. config ARM64_ERRATUM_832075 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads" default y help This option adds an alternative code sequence to work around ARM erratum 832075 on Cortex-A57 parts up to r1p2. Affected Cortex-A57 parts might deadlock when exclusive load/store instructions to Write-Back memory are mixed with Device loads. The workaround is to promote device loads to use Load-Acquire semantics. Please note that this does not necessarily enable the workaround, as it depends on the alternative framework, which will only patch the kernel if an affected CPU is detected. If unsure, say Y. config ARM64_ERRATUM_834220 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault" depends on KVM default y help This option adds an alternative code sequence to work around ARM erratum 834220 on Cortex-A57 parts up to r1p2. Affected Cortex-A57 parts might report a Stage 2 translation fault as the result of a Stage 1 fault for load crossing a page boundary when there is a permission or device memory alignment fault at Stage 1 and a translation fault at Stage 2. The workaround is to verify that the Stage 1 translation doesn't generate a fault before handling the Stage 2 fault. Please note that this does not necessarily enable the workaround, as it depends on the alternative framework, which will only patch the kernel if an affected CPU is detected. If unsure, say Y. config ARM64_ERRATUM_845719 bool "Cortex-A53: 845719: a load might read incorrect data" depends on COMPAT default y help This option adds an alternative code sequence to work around ARM erratum 845719 on Cortex-A53 parts up to r0p4. When running a compat (AArch32) userspace on an affected Cortex-A53 part, a load at EL0 from a virtual address that matches the bottom 32 bits of the virtual address used by a recent load at (AArch64) EL1 might return incorrect data. The workaround is to write the contextidr_el1 register on exception return to a 32-bit task. Please note that this does not necessarily enable the workaround, as it depends on the alternative framework, which will only patch the kernel if an affected CPU is detected. If unsure, say Y. config ARM64_ERRATUM_843419 bool "Cortex-A53: 843419: A load or store might access an incorrect address" default y select ARM64_MODULE_CMODEL_LARGE if MODULES help This option links the kernel with '--fix-cortex-a53-843419' and builds modules using the large memory model in order to avoid the use of the ADRP instruction, which can cause a subsequent memory access to use an incorrect address on Cortex-A53 parts up to r0p4. If unsure, say Y. config CAVIUM_ERRATUM_22375 bool "Cavium erratum 22375, 24313" default y help Enable workaround for erratum 22375, 24313. This implements two gicv3-its errata workarounds for ThunderX. Both with small impact affecting only ITS table allocation. erratum 22375: only alloc 8MB table size erratum 24313: ignore memory access type The fixes are in ITS initialization and basically ignore memory access type and table size provided by the TYPER and BASER registers. If unsure, say Y. config CAVIUM_ERRATUM_23144 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system" depends on NUMA default y help ITS SYNC command hang for cross node io and collections/cpu mapping. If unsure, say Y. config CAVIUM_ERRATUM_23154 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed" default y help The gicv3 of ThunderX requires a modified version for reading the IAR status to ensure data synchronization (access to icc_iar1_el1 is not sync'ed before and after). If unsure, say Y. config CAVIUM_ERRATUM_27456 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption" default y help On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI instructions may cause the icache to become corrupted if it contains data for a non-current ASID. The fix is to invalidate the icache when changing the mm context. If unsure, say Y. config CAVIUM_ERRATUM_30115 bool "Cavium erratum 30115: Guest may disable interrupts in host" default y help On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through 1.2, and T83 Pass 1.0, KVM guest execution may disable interrupts in host. Trapping both GICv3 group-0 and group-1 accesses sidesteps the issue. If unsure, say Y. config QCOM_FALKOR_ERRATUM_1003 bool "Falkor E1003: Incorrect translation due to ASID change" default y select ARM64_PAN if ARM64_SW_TTBR0_PAN help On Falkor v1, an incorrect ASID may be cached in the TLB when ASID and BADDR are changed together in TTBRx_EL1. The workaround for this issue is to use a reserved ASID in cpu_do_switch_mm() before switching to the new ASID. Saying Y here selects ARM64_PAN if ARM64_SW_TTBR0_PAN is selected. This is done because implementing and maintaining the E1003 workaround in the software PAN emulation code would be an unnecessary complication. The affected Falkor v1 CPU implements ARMv8.1 hardware PAN support and using hardware PAN support versus software PAN emulation is mutually exclusive at runtime. If unsure, say Y. config QCOM_FALKOR_ERRATUM_1009 bool "Falkor E1009: Prematurely complete a DSB after a TLBI" default y help On Falkor v1, the CPU may prematurely complete a DSB following a TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation one more time to fix the issue. If unsure, say Y. config QCOM_QDF2400_ERRATUM_0065 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size" default y help On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have been indicated as 16Bytes (0xf), not 8Bytes (0x7). If unsure, say Y. endmenu choice prompt "Page size" default ARM64_4K_PAGES help Page size (translation granule) configuration. config ARM64_4K_PAGES bool "4KB" help This feature enables 4KB pages support. config ARM64_16K_PAGES bool "16KB" help The system will use 16KB pages support. AArch32 emulation requires applications compiled with 16K (or a multiple of 16K) aligned segments. config ARM64_64K_PAGES bool "64KB" help This feature enables 64KB pages support (4KB by default) allowing only two levels of page tables and faster TLB look-up. AArch32 emulation requires applications compiled with 64K aligned segments. endchoice choice prompt "Virtual address space size" default ARM64_VA_BITS_39 if ARM64_4K_PAGES default ARM64_VA_BITS_47 if ARM64_16K_PAGES default ARM64_VA_BITS_42 if ARM64_64K_PAGES help Allows choosing one of multiple possible virtual address space sizes. The level of translation table is determined by a combination of page size and virtual address space size. config ARM64_VA_BITS_36 bool "36-bit" if EXPERT depends on ARM64_16K_PAGES config ARM64_VA_BITS_39 bool "39-bit" depends on ARM64_4K_PAGES config ARM64_VA_BITS_42 bool "42-bit" depends on ARM64_64K_PAGES config ARM64_VA_BITS_47 bool "47-bit" depends on ARM64_16K_PAGES config ARM64_VA_BITS_48 bool "48-bit" endchoice config ARM64_VA_BITS int default 36 if ARM64_VA_BITS_36 default 39 if ARM64_VA_BITS_39 default 42 if ARM64_VA_BITS_42 default 47 if ARM64_VA_BITS_47 default 48 if ARM64_VA_BITS_48 config CPU_BIG_ENDIAN bool "Build big-endian kernel" help Say Y if you plan on running a kernel in big-endian mode. config SCHED_MC bool "Multi-core scheduler support" help Multi-core scheduler support improves the CPU scheduler's decision making when dealing with multi-core CPU chips at a cost of slightly increased overhead in some places. If unsure say N here. config SCHED_SMT bool "SMT scheduler support" help Improves the CPU scheduler's decision making when dealing with MultiThreading at a cost of slightly increased overhead in some places. If unsure say N here. config NR_CPUS int "Maximum number of CPUs (2-4096)" range 2 4096 # These have to remain sorted largest to smallest default "64" config HOTPLUG_CPU bool "Support for hot-pluggable CPUs" select GENERIC_IRQ_MIGRATION help Say Y here to experiment with turning CPUs off and on. CPUs can be controlled through /sys/devices/system/cpu. # Common NUMA Features config NUMA bool "Numa Memory Allocation and Scheduler Support" select ACPI_NUMA if ACPI select OF_NUMA help Enable NUMA (Non Uniform Memory Access) support. The kernel will try to allocate memory used by a CPU on the local memory of the CPU and add some more NUMA awareness to the kernel. config NODES_SHIFT int "Maximum NUMA Nodes (as a power of 2)" range 1 10 default "2" depends on NEED_MULTIPLE_NODES help Specify the maximum number of NUMA Nodes available on the target system. Increases memory reserved to accommodate various tables. config USE_PERCPU_NUMA_NODE_ID def_bool y depends on NUMA config HAVE_SETUP_PER_CPU_AREA def_bool y depends on NUMA config NEED_PER_CPU_EMBED_FIRST_CHUNK def_bool y depends on NUMA config HOLES_IN_ZONE def_bool y depends on NUMA source kernel/Kconfig.preempt source kernel/Kconfig.hz config ARCH_SUPPORTS_DEBUG_PAGEALLOC def_bool y config ARCH_HAS_HOLES_MEMORYMODEL def_bool y if SPARSEMEM config ARCH_SPARSEMEM_ENABLE def_bool y select SPARSEMEM_VMEMMAP_ENABLE config ARCH_SPARSEMEM_DEFAULT def_bool ARCH_SPARSEMEM_ENABLE config ARCH_SELECT_MEMORY_MODEL def_bool ARCH_SPARSEMEM_ENABLE config HAVE_ARCH_PFN_VALID def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM config HW_PERF_EVENTS def_bool y depends on ARM_PMU config SYS_SUPPORTS_HUGETLBFS def_bool y config ARCH_WANT_HUGE_PMD_SHARE def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) config ARCH_HAS_CACHE_LINE_SIZE def_bool y source "mm/Kconfig" config SECCOMP bool "Enable seccomp to safely compute untrusted bytecode" ---help--- This kernel feature is useful for number crunching applications that may need to compute untrusted bytecode during their execution. By using pipes or other transports made available to the process as file descriptors supporting the read/write syscalls, it's possible to isolate those applications in their own address space using seccomp. Once seccomp is enabled via prctl(PR_SET_SECCOMP), it cannot be disabled and the task is only allowed to execute a few safe syscalls defined by each seccomp mode. config PARAVIRT bool "Enable paravirtualization code" help This changes the kernel so it can modify itself when it is run under a hypervisor, potentially improving performance significantly over full virtualization. config PARAVIRT_TIME_ACCOUNTING bool "Paravirtual steal time accounting" select PARAVIRT default n help Select this option to enable fine granularity task steal time accounting. Time spent executing other tasks in parallel with the current vCPU is discounted from the vCPU power. To account for that, there can be a small performance impact. If in doubt, say N here. config KEXEC depends on PM_SLEEP_SMP select KEXEC_CORE bool "kexec system call" ---help--- kexec is a system call that implements the ability to shutdown your current kernel, and to start another kernel. It is like a reboot but it is independent of the system firmware. And like a reboot you can start any kernel with it, not just Linux. config CRASH_DUMP bool "Build kdump crash kernel" help Generate crash dump after being started by kexec. This should be normally only set in special crash dump kernels which are loaded in the main kernel with kexec-tools into a specially reserved region and then later executed after a crash by kdump/kexec. For more details see Documentation/kdump/kdump.txt config XEN_DOM0 def_bool y depends on XEN config XEN bool "Xen guest support on ARM64" depends on ARM64 && OF select SWIOTLB_XEN select PARAVIRT help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64. config FORCE_MAX_ZONEORDER int default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) default "11" help The kernel memory allocator divides physically contiguous memory blocks into "zones", where each zone is a power of two number of pages. This option selects the largest power of two that the kernel keeps in the memory allocator. If you need to allocate very large blocks of physically contiguous memory, then you may need to increase this value. This config option is actually maximum order plus one. For example, a value of 11 means that the largest free memory block is 2^10 pages. We make sure that we can allocate upto a HugePage size for each configuration. Hence we have : MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us 4M allocations matching the default size used by generic code. menuconfig ARMV8_DEPRECATED bool "Emulate deprecated/obsolete ARMv8 instructions" depends on COMPAT help Legacy software support may require certain instructions that have been deprecated or obsoleted in the architecture. Enable this config to enable selective emulation of these features. If unsure, say Y if ARMV8_DEPRECATED config SWP_EMULATION bool "Emulate SWP/SWPB instructions" help ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that they are always undefined. Say Y here to enable software emulation of these instructions for userspace using LDXR/STXR. 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, LDXR/STXR 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 CP15_BARRIER_EMULATION bool "Emulate CP15 Barrier instructions" help The CP15 barrier instructions - CP15ISB, CP15DSB, and CP15DMB - are deprecated in ARMv8 (and ARMv7). It is strongly recommended to use the ISB, DSB, and DMB instructions instead. Say Y here to enable software emulation of these instructions for AArch32 userspace code. When this option is enabled, CP15 barrier usage is traced which can help identify software that needs updating. If unsure, say Y config SETEND_EMULATION bool "Emulate SETEND instruction" help The SETEND instruction alters the data-endianness of the AArch32 EL0, and is deprecated in ARMv8. Say Y here to enable software emulation of the instruction for AArch32 userspace code. Note: All the cpus on the system must have mixed endian support at EL0 for this feature to be enabled. If a new CPU - which doesn't support mixed endian - is hotplugged in after this feature has been enabled, there could be unexpected results in the applications. If unsure, say Y endif config ARM64_SW_TTBR0_PAN bool "Emulate Privileged Access Never using TTBR0_EL1 switching" help Enabling this option prevents the kernel from accessing user-space memory directly by pointing TTBR0_EL1 to a reserved zeroed area and reserved ASID. The user access routines restore the valid TTBR0_EL1 temporarily. menu "ARMv8.1 architectural features" config ARM64_HW_AFDBM bool "Support for hardware updates of the Access and Dirty page flags" default y help The ARMv8.1 architecture extensions introduce support for hardware updates of the access and dirty information in page table entries. When enabled in TCR_EL1 (HA and HD bits) on capable processors, accesses to pages with PTE_AF cleared will set this bit instead of raising an access flag fault. Similarly, writes to read-only pages with the DBM bit set will clear the read-only bit (AP[2]) instead of raising a permission fault. Kernels built with this configuration option enabled continue to work on pre-ARMv8.1 hardware and the performance impact is minimal. If unsure, say Y. config ARM64_PAN bool "Enable support for Privileged Access Never (PAN)" default y help Privileged Access Never (PAN; part of the ARMv8.1 Extensions) prevents the kernel or hypervisor from accessing user-space (EL0) memory directly. Choosing this option will cause any unprotected (not using copy_to_user et al) memory access to fail with a permission fault. The feature is detected at runtime, and will remain as a 'nop' instruction if the cpu does not implement the feature. config ARM64_LSE_ATOMICS bool "Atomic instructions" help As part of the Large System Extensions, ARMv8.1 introduces new atomic instructions that are designed specifically to scale in very large systems. Say Y here to make use of these instructions for the in-kernel atomic routines. This incurs a small overhead on CPUs that do not support these instructions and requires the kernel to be built with binutils >= 2.25. config ARM64_VHE bool "Enable support for Virtualization Host Extensions (VHE)" default y help Virtualization Host Extensions (VHE) allow the kernel to run directly at EL2 (instead of EL1) on processors that support it. This leads to better performance for KVM, as they reduce the cost of the world switch. Selecting this option allows the VHE feature to be detected at runtime, and does not affect processors that do not implement this feature. endmenu menu "ARMv8.2 architectural features" config ARM64_UAO bool "Enable support for User Access Override (UAO)" default y help User Access Override (UAO; part of the ARMv8.2 Extensions) causes the 'unprivileged' variant of the load/store instructions to be overriden to be privileged. This option changes get_user() and friends to use the 'unprivileged' variant of the load/store instructions. This ensures that user-space really did have access to the supplied memory. When addr_limit is set to kernel memory the UAO bit will be set, allowing privileged access to kernel memory. Choosing this option will cause copy_to_user() et al to use user-space memory permissions. The feature is detected at runtime, the kernel will use the regular load/store instructions if the cpu does not implement the feature. config ARM64_PMEM bool "Enable support for persistent memory" select ARCH_HAS_PMEM_API select ARCH_HAS_UACCESS_FLUSHCACHE help Say Y to enable support for the persistent memory API based on the ARMv8.2 DCPoP feature. The feature is detected at runtime, and the kernel will use DC CVAC operations if DC CVAP is not supported (following the behaviour of DC CVAP itself if the system does not define a point of persistence). endmenu config ARM64_MODULE_CMODEL_LARGE bool config ARM64_MODULE_PLTS bool select ARM64_MODULE_CMODEL_LARGE select HAVE_MOD_ARCH_SPECIFIC config RELOCATABLE bool help This builds the kernel as a Position Independent Executable (PIE), which retains all relocation metadata required to relocate the kernel binary at runtime to a different virtual address than the address it was linked at. Since AArch64 uses the RELA relocation format, this requires a relocation pass at runtime even if the kernel is loaded at the same address it was linked at. config RANDOMIZE_BASE bool "Randomize the address of the kernel image" select ARM64_MODULE_PLTS if MODULES select RELOCATABLE help Randomizes the virtual address at which the kernel image is loaded, as a security feature that deters exploit attempts relying on knowledge of the location of kernel internals. It is the bootloader's job to provide entropy, by passing a random u64 value in /chosen/kaslr-seed at kernel entry. When booting via the UEFI stub, it will invoke the firmware's EFI_RNG_PROTOCOL implementation (if available) to supply entropy to the kernel proper. In addition, it will randomise the physical location of the kernel Image as well. If unsure, say N. config RANDOMIZE_MODULE_REGION_FULL bool "Randomize the module region independently from the core kernel" depends on RANDOMIZE_BASE default y help Randomizes the location of the module region without considering the location of the core kernel. This way, it is impossible for modules to leak information about the location of core kernel data structures but it does imply that function calls between modules and the core kernel will need to be resolved via veneers in the module PLT. When this option is not set, the module region will be randomized over a limited range that contains the [_stext, _etext] interval of the core kernel, so branch relocations are always in range. endmenu menu "Boot options" config ARM64_ACPI_PARKING_PROTOCOL bool "Enable support for the ARM64 ACPI parking protocol" depends on ACPI help Enable support for the ARM64 ACPI parking protocol. If disabled the kernel will not allow booting through the ARM64 ACPI parking protocol even if the corresponding data is present in the ACPI MADT table. config CMDLINE string "Default kernel command string" default "" help Provide a set of default command-line options at build time by entering them here. As a minimum, you should specify the the root device (e.g. root=/dev/nfs). config CMDLINE_FORCE bool "Always use the default kernel command string" help Always use the default kernel command string, even if the boot loader passes other arguments to the kernel. This is useful if you cannot or don't want to change the command-line options your boot loader passes to the kernel. config EFI_STUB bool config EFI bool "UEFI runtime support" depends on OF && !CPU_BIG_ENDIAN select LIBFDT select UCS2_STRING select EFI_PARAMS_FROM_FDT select EFI_RUNTIME_WRAPPERS select EFI_STUB select EFI_ARMSTUB default y help This option provides support for runtime services provided by UEFI firmware (such as non-volatile variables, realtime clock, and platform reset). A UEFI stub is also provided to allow the kernel to be booted as an EFI application. This is only useful on systems that have UEFI firmware. config DMI bool "Enable support for SMBIOS (DMI) tables" depends on EFI default y help This enables SMBIOS/DMI feature for systems. This option is only useful on systems that have UEFI firmware. However, even with this option, the resultant kernel should continue to boot on existing non-UEFI platforms. endmenu menu "Userspace binary formats" source "fs/Kconfig.binfmt" config COMPAT bool "Kernel support for 32-bit EL0" depends on ARM64_4K_PAGES || EXPERT select COMPAT_BINFMT_ELF if BINFMT_ELF select HAVE_UID16 select OLD_SIGSUSPEND3 select COMPAT_OLD_SIGACTION help This option enables support for a 32-bit EL0 running under a 64-bit kernel at EL1. AArch32-specific components such as system calls, the user helper functions, VFP support and the ptrace interface are handled appropriately by the kernel. If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware that you will only be able to execute AArch32 binaries that were compiled with page size aligned segments. If you want to execute 32-bit userspace applications, say Y. config SYSVIPC_COMPAT def_bool y depends on COMPAT && SYSVIPC endmenu menu "Power management options" source "kernel/power/Kconfig" config ARCH_HIBERNATION_POSSIBLE def_bool y depends on CPU_PM config ARCH_HIBERNATION_HEADER def_bool y depends on HIBERNATION config ARCH_SUSPEND_POSSIBLE def_bool y endmenu menu "CPU Power Management" source "drivers/cpuidle/Kconfig" source "drivers/cpufreq/Kconfig" endmenu source "net/Kconfig" source "drivers/Kconfig" source "drivers/firmware/Kconfig" source "drivers/acpi/Kconfig" source "fs/Kconfig" source "arch/arm64/kvm/Kconfig" source "arch/arm64/Kconfig.debug" source "security/Kconfig" source "crypto/Kconfig" if CRYPTO source "arch/arm64/crypto/Kconfig" endif source "lib/Kconfig"