Current File : //proc/self/root/usr/src/linux-headers-5.15.0-43-generic/arch/arm64/Kconfig
# SPDX-License-Identifier: GPL-2.0-only
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 && PCI)
select ACPI_SPCR_TABLE if ACPI
select ACPI_PPTT if ACPI
select ARCH_HAS_DEBUG_WX
select ARCH_BINFMT_ELF_STATE
select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
select ARCH_ENABLE_MEMORY_HOTPLUG
select ARCH_ENABLE_MEMORY_HOTREMOVE
select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
select ARCH_HAS_CACHE_LINE_SIZE
select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DMA_PREP_COHERENT
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_KCOV
select ARCH_HAS_KEEPINITRD
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_DEVMAP
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_SETUP_DMA_OPS
select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_SET_MEMORY
select ARCH_STACKWALK
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_STRICT_MODULE_RWX
select ARCH_HAS_SYNC_DMA_FOR_DEVICE
select ARCH_HAS_SYNC_DMA_FOR_CPU
select ARCH_HAS_SYSCALL_WRAPPER
select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_ZONE_DMA_SET if EXPERT
select ARCH_HAVE_ELF_PROT
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select ARCH_INLINE_READ_LOCK if !PREEMPTION
select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
select ARCH_KEEP_MEMBLOCK
select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_USE_GNU_PROPERTY
select ARCH_USE_MEMTEST
select ARCH_USE_QUEUED_RWLOCKS
select ARCH_USE_QUEUED_SPINLOCKS
select ARCH_USE_SYM_ANNOTATIONS
select ARCH_SUPPORTS_DEBUG_PAGEALLOC
select ARCH_SUPPORTS_HUGETLBFS
select ARCH_SUPPORTS_MEMORY_FAILURE
select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
select ARCH_SUPPORTS_LTO_CLANG_THIN
select ARCH_SUPPORTS_CFI_CLANG
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
select ARCH_SUPPORTS_NUMA_BALANCING
select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
select ARCH_WANT_DEFAULT_BPF_JIT
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
select ARCH_WANT_LD_ORPHAN_WARN
select ARCH_WANTS_NO_INSTR
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_TABLE_SORT
select CLONE_BACKWARDS
select COMMON_CLK
select CPU_PM if (SUSPEND || CPU_IDLE)
select CRC32
select DCACHE_WORD_ACCESS
select DMA_DIRECT_REMAP
select EDAC_SUPPORT
select FRAME_POINTER
select GENERIC_ALLOCATOR
select GENERIC_ARCH_TOPOLOGY
select GENERIC_CLOCKEVENTS_BROADCAST
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES
select GENERIC_EARLY_IOREMAP
select GENERIC_FIND_FIRST_BIT
select GENERIC_IDLE_POLL_SETUP
select GENERIC_IRQ_IPI
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
select GENERIC_IRQ_SHOW_LEVEL
select GENERIC_LIB_DEVMEM_IS_ALLOWED
select GENERIC_PCI_IOMAP
select GENERIC_PTDUMP
select GENERIC_SCHED_CLOCK
select GENERIC_SMP_IDLE_THREAD
select GENERIC_TIME_VSYSCALL
select GENERIC_GETTIMEOFDAY
select GENERIC_VDSO_TIME_NS
select HANDLE_DOMAIN_IRQ
select HARDIRQS_SW_RESEND
select HAVE_MOVE_PMD
select HAVE_MOVE_PUD
select HAVE_PCI
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_COMPILER_H
select HAVE_ARCH_HUGE_VMAP
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
select HAVE_ARCH_KFENCE
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
select HAVE_ARCH_PREL32_RELOCATIONS
select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_STACKLEAK
select HAVE_ARCH_THREAD_STRUCT_WHITELIST
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
select HAVE_ARCH_VMAP_STACK
select HAVE_ARM_SMCCC
select HAVE_ASM_MODVERSIONS
select HAVE_EBPF_JIT
select HAVE_C_RECORDMCOUNT
select HAVE_CMPXCHG_DOUBLE
select HAVE_CMPXCHG_LOCAL
select HAVE_CONTEXT_TRACKING
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_CONTIGUOUS
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_REGS \
if $(cc-option,-fpatchable-function-entry=2)
select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
if DYNAMIC_FTRACE_WITH_REGS
select HAVE_EFFICIENT_UNALIGNED_ACCESS
select HAVE_FAST_GUP
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_GCC_PLUGINS
select HAVE_HW_BREAKPOINT if PERF_EVENTS
select HAVE_IRQ_TIME_ACCOUNTING
select HAVE_NMI
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_FUNCTION_ARG_ACCESS_API
select HAVE_FUTEX_CMPXCHG if FUTEX
select MMU_GATHER_RCU_TABLE_FREE
select HAVE_RSEQ
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_KPROBES
select HAVE_KRETPROBES
select HAVE_GENERIC_VDSO
select IOMMU_DMA if IOMMU_SUPPORT
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
select KASAN_VMALLOC if KASAN_GENERIC
select MODULES_USE_ELF_RELA
select NEED_DMA_MAP_STATE
select NEED_SG_DMA_LENGTH
select OF
select OF_EARLY_FLATTREE
select PCI_DOMAINS_GENERIC if PCI
select PCI_ECAM if (ACPI && PCI)
select PCI_SYSCALL if PCI
select POWER_RESET
select POWER_SUPPLY
select SPARSE_IRQ
select SWIOTLB
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
select TRACE_IRQFLAGS_SUPPORT
help
ARM 64-bit (AArch64) Linux support.
config 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_PTE_SHIFT
int
default 5 if ARM64_64K_PAGES
default 7 if ARM64_16K_PAGES
default 4
config ARM64_CONT_PMD_SHIFT
int
default 5 if ARM64_64K_PAGES
default 5 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 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 ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
def_bool y
config SMP
def_bool y
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 || ARM64_VA_BITS_52)
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
config BROKEN_GAS_INST
def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
config KASAN_SHADOW_OFFSET
hex
depends on KASAN_GENERIC || KASAN_SW_TAGS
default 0xdfff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
default 0xdfffc00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
default 0xefff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
default 0xefffc00000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
default 0xffffffffffffffff
source "arch/arm64/Kconfig.platforms"
menu "Kernel Features"
menu "ARM errata workarounds via the alternatives framework"
config ARM64_WORKAROUND_CLEAN_CACHE
bool
config ARM64_ERRATUM_826319
bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
default y
select ARM64_WORKAROUND_CLEAN_CACHE
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
select ARM64_WORKAROUND_CLEAN_CACHE
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
select ARM64_WORKAROUND_CLEAN_CACHE
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
select ARM64_WORKAROUND_CLEAN_CACHE
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_PLTS if MODULES
help
This option links the kernel with '--fix-cortex-a53-843419' and
enables PLT support to replace certain ADRP instructions, which can
cause subsequent memory accesses to use an incorrect address on
Cortex-A53 parts up to r0p4.
If unsure, say Y.
config ARM64_LD_HAS_FIX_ERRATUM_843419
def_bool $(ld-option,--fix-cortex-a53-843419)
config ARM64_ERRATUM_1024718
bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
default y
help
This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
Affected Cortex-A55 cores (all revisions) could cause incorrect
update of the hardware dirty bit when the DBM/AP bits are updated
without a break-before-make. The workaround is to disable the usage
of hardware DBM locally on the affected cores. CPUs not affected by
this erratum will continue to use the feature.
If unsure, say Y.
config ARM64_ERRATUM_1418040
bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
default y
depends on COMPAT
help
This option adds a workaround for ARM Cortex-A76/Neoverse-N1
errata 1188873 and 1418040.
Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
cause register corruption when accessing the timer registers
from AArch32 userspace.
If unsure, say Y.
config ARM64_WORKAROUND_SPECULATIVE_AT
bool
config ARM64_ERRATUM_1165522
bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
default y
select ARM64_WORKAROUND_SPECULATIVE_AT
help
This option adds a workaround for ARM Cortex-A76 erratum 1165522.
Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
corrupted TLBs by speculating an AT instruction during a guest
context switch.
If unsure, say Y.
config ARM64_ERRATUM_1319367
bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
default y
select ARM64_WORKAROUND_SPECULATIVE_AT
help
This option adds work arounds for ARM Cortex-A57 erratum 1319537
and A72 erratum 1319367
Cortex-A57 and A72 cores could end-up with corrupted TLBs by
speculating an AT instruction during a guest context switch.
If unsure, say Y.
config ARM64_ERRATUM_1530923
bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
default y
select ARM64_WORKAROUND_SPECULATIVE_AT
help
This option adds a workaround for ARM Cortex-A55 erratum 1530923.
Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
corrupted TLBs by speculating an AT instruction during a guest
context switch.
If unsure, say Y.
config ARM64_WORKAROUND_REPEAT_TLBI
bool
config ARM64_ERRATUM_1286807
bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
default y
select ARM64_WORKAROUND_REPEAT_TLBI
help
This option adds a workaround for ARM Cortex-A76 erratum 1286807.
On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
address for a cacheable mapping of a location is being
accessed by a core while another core is remapping the virtual
address to a new physical page using the recommended
break-before-make sequence, then under very rare circumstances
TLBI+DSB completes before a read using the translation being
invalidated has been observed by other observers. The
workaround repeats the TLBI+DSB operation.
config ARM64_ERRATUM_1463225
bool "Cortex-A76: Software Step might prevent interrupt recognition"
default y
help
This option adds a workaround for Arm Cortex-A76 erratum 1463225.
On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
of a system call instruction (SVC) can prevent recognition of
subsequent interrupts when software stepping is disabled in the
exception handler of the system call and either kernel debugging
is enabled or VHE is in use.
Work around the erratum by triggering a dummy step exception
when handling a system call from a task that is being stepped
in a VHE configuration of the kernel.
If unsure, say Y.
config ARM64_ERRATUM_1542419
bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
default y
help
This option adds a workaround for ARM Neoverse-N1 erratum
1542419.
Affected Neoverse-N1 cores could execute a stale instruction when
modified by another CPU. The workaround depends on a firmware
counterpart.
Workaround the issue by hiding the DIC feature from EL0. This
forces user-space to perform cache maintenance.
If unsure, say Y.
config ARM64_ERRATUM_1508412
bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
default y
help
This option adds a workaround for Arm Cortex-A77 erratum 1508412.
Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
of a store-exclusive or read of PAR_EL1 and a load with device or
non-cacheable memory attributes. The workaround depends on a firmware
counterpart.
KVM guests must also have the workaround implemented or they can
deadlock the system.
Work around the issue by inserting DMB SY barriers around PAR_EL1
register reads and warning KVM users. The DMB barrier is sufficient
to prevent a speculative PAR_EL1 read.
If unsure, say Y.
config CAVIUM_ERRATUM_22375
bool "Cavium erratum 22375, 24313"
default y
help
Enable workaround for errata 22375 and 24313.
This implements two gicv3-its errata workarounds for ThunderX. Both
with a 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 CAVIUM_TX2_ERRATUM_219
bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
default y
help
On Cavium ThunderX2, a load, store or prefetch instruction between a
TTBR update and the corresponding context synchronizing operation can
cause a spurious Data Abort to be delivered to any hardware thread in
the CPU core.
Work around the issue by avoiding the problematic code sequence and
trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
trap handler performs the corresponding register access, skips the
instruction and ensures context synchronization by virtue of the
exception return.
If unsure, say Y.
config FUJITSU_ERRATUM_010001
bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
default y
help
This option adds a workaround for Fujitsu-A64FX erratum E#010001.
On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
accesses may cause undefined fault (Data abort, DFSC=0b111111).
This fault occurs under a specific hardware condition when a
load/store instruction performs an address translation using:
case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
The workaround is to ensure these bits are clear in TCR_ELx.
The workaround only affects the Fujitsu-A64FX.
If unsure, say Y.
config HISILICON_ERRATUM_161600802
bool "Hip07 161600802: Erroneous redistributor VLPI base"
default y
help
The HiSilicon Hip07 SoC uses the wrong redistributor base
when issued ITS commands such as VMOVP and VMAPP, and requires
a 128kB offset to be applied to the target address in this commands.
If unsure, say Y.
config QCOM_FALKOR_ERRATUM_1003
bool "Falkor E1003: Incorrect translation due to ASID change"
default y
help
On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
in TTBR1_EL1, this situation only occurs in the entry trampoline and
then only for entries in the walk cache, since the leaf translation
is unchanged. Work around the erratum by invalidating the walk cache
entries for the trampoline before entering the kernel proper.
config QCOM_FALKOR_ERRATUM_1009
bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
default y
select ARM64_WORKAROUND_REPEAT_TLBI
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.
config QCOM_FALKOR_ERRATUM_E1041
bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
default y
help
Falkor CPU may speculatively fetch instructions from an improper
memory location when MMU translation is changed from SCTLR_ELn[M]=1
to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
If unsure, say Y.
config NVIDIA_CARMEL_CNP_ERRATUM
bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores"
default y
help
If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not
invalidate shared TLB entries installed by a different core, as it would
on standard ARM cores.
If unsure, say Y.
config SOCIONEXT_SYNQUACER_PREITS
bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
default y
help
Socionext Synquacer SoCs implement a separate h/w block to generate
MSI doorbell writes with non-zero values for the device ID.
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"
config ARM64_VA_BITS_52
bool "52-bit"
depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
help
Enable 52-bit virtual addressing for userspace when explicitly
requested via a hint to mmap(). The kernel will also use 52-bit
virtual addresses for its own mappings (provided HW support for
this feature is available, otherwise it reverts to 48-bit).
NOTE: Enabling 52-bit virtual addressing in conjunction with
ARMv8.3 Pointer Authentication will result in the PAC being
reduced from 7 bits to 3 bits, which may have a significant
impact on its susceptibility to brute-force attacks.
If unsure, select 48-bit virtual addressing instead.
endchoice
config ARM64_FORCE_52BIT
bool "Force 52-bit virtual addresses for userspace"
depends on ARM64_VA_BITS_52 && EXPERT
help
For systems with 52-bit userspace VAs enabled, the kernel will attempt
to maintain compatibility with older software by providing 48-bit VAs
unless a hint is supplied to mmap.
This configuration option disables the 48-bit compatibility logic, and
forces all userspace addresses to be 52-bit on HW that supports it. One
should only enable this configuration option for stress testing userspace
memory management code. If unsure say N here.
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
default 52 if ARM64_VA_BITS_52
choice
prompt "Physical address space size"
default ARM64_PA_BITS_48
help
Choose the maximum physical address range that the kernel will
support.
config ARM64_PA_BITS_48
bool "48-bit"
config ARM64_PA_BITS_52
bool "52-bit (ARMv8.2)"
depends on ARM64_64K_PAGES
depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
help
Enable support for a 52-bit physical address space, introduced as
part of the ARMv8.2-LPA extension.
With this enabled, the kernel will also continue to work on CPUs that
do not support ARMv8.2-LPA, but with some added memory overhead (and
minor performance overhead).
endchoice
config ARM64_PA_BITS
int
default 48 if ARM64_PA_BITS_48
default 52 if ARM64_PA_BITS_52
choice
prompt "Endianness"
default CPU_LITTLE_ENDIAN
help
Select the endianness of data accesses performed by the CPU. Userspace
applications will need to be compiled and linked for the endianness
that is selected here.
config CPU_BIG_ENDIAN
bool "Build big-endian kernel"
depends on !LD_IS_LLD || LLD_VERSION >= 130000
help
Say Y if you plan on running a kernel with a big-endian userspace.
config CPU_LITTLE_ENDIAN
bool "Build little-endian kernel"
help
Say Y if you plan on running a kernel with a little-endian userspace.
This is usually the case for distributions targeting arm64.
endchoice
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
default "256"
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 GENERIC_ARCH_NUMA
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 "4"
depends on NUMA
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
source "kernel/Kconfig.hz"
config ARCH_SPARSEMEM_ENABLE
def_bool y
select SPARSEMEM_VMEMMAP_ENABLE
select SPARSEMEM_VMEMMAP
config HW_PERF_EVENTS
def_bool y
depends on ARM_PMU
# Supported by clang >= 7.0
config CC_HAVE_SHADOW_CALL_STACK
def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
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
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 KEXEC_FILE
bool "kexec file based system call"
select KEXEC_CORE
select HAVE_IMA_KEXEC if IMA
help
This is new version of kexec system call. This system call is
file based and takes file descriptors as system call argument
for kernel and initramfs as opposed to list of segments as
accepted by previous system call.
config KEXEC_SIG
bool "Verify kernel signature during kexec_file_load() syscall"
depends on KEXEC_FILE
help
Select this option to verify a signature with loaded kernel
image. If configured, any attempt of loading a image without
valid signature will fail.
In addition to that option, you need to enable signature
verification for the corresponding kernel image type being
loaded in order for this to work.
config KEXEC_IMAGE_VERIFY_SIG
bool "Enable Image signature verification support"
default y
depends on KEXEC_SIG
depends on EFI && SIGNED_PE_FILE_VERIFICATION
help
Enable Image signature verification support.
comment "Support for PE file signature verification disabled"
depends on KEXEC_SIG
depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
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/admin-guide/kdump/kdump.rst
config TRANS_TABLE
def_bool y
depends on HIBERNATION
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
default "13" if (ARCH_THUNDER && ARM64_4K_PAGES)
default "12" if ARM64_16K_PAGES
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.
config UNMAP_KERNEL_AT_EL0
bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
default y
help
Speculation attacks against some high-performance processors can
be used to bypass MMU permission checks and leak kernel data to
userspace. This can be defended against by unmapping the kernel
when running in userspace, mapping it back in on exception entry
via a trampoline page in the vector table.
If unsure, say Y.
config MITIGATE_SPECTRE_BRANCH_HISTORY
bool "Mitigate Spectre style attacks against branch history" if EXPERT
default y
help
Speculation attacks against some high-performance processors can
make use of branch history to influence future speculation.
When taking an exception from user-space, a sequence of branches
or a firmware call overwrites the branch history.
config RODATA_FULL_DEFAULT_ENABLED
bool "Apply r/o permissions of VM areas also to their linear aliases"
default y
help
Apply read-only attributes of VM areas to the linear alias of
the backing pages as well. This prevents code or read-only data
from being modified (inadvertently or intentionally) via another
mapping of the same memory page. This additional enhancement can
be turned off at runtime by passing rodata=[off|on] (and turned on
with rodata=full if this option is set to 'n')
This requires the linear region to be mapped down to pages,
which may adversely affect performance in some cases.
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.
config ARM64_TAGGED_ADDR_ABI
bool "Enable the tagged user addresses syscall ABI"
default y
help
When this option is enabled, user applications can opt in to a
relaxed ABI via prctl() allowing tagged addresses to be passed
to system calls as pointer arguments. For details, see
Documentation/arm64/tagged-address-abi.rst.
menuconfig COMPAT
bool "Kernel support for 32-bit EL0"
depends on ARM64_4K_PAGES || EXPERT
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.
if COMPAT
config KUSER_HELPERS
bool "Enable kuser helpers page for 32-bit applications"
default y
help
Warning: disabling this option may break 32-bit user programs.
Provide kuser helpers to compat tasks. The kernel provides
helper code to userspace in read only form at a fixed location
to allow userspace to be independent of the CPU type fitted to
the system. This permits binaries to be run on ARMv4 through
to ARMv8 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 not function correctly.
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 COMPAT_VDSO
bool "Enable vDSO for 32-bit applications"
depends on !CPU_BIG_ENDIAN
depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != ""
select GENERIC_COMPAT_VDSO
default y
help
Place in the process address space of 32-bit applications an
ELF shared object providing fast implementations of gettimeofday
and clock_gettime.
You must have a 32-bit build of glibc 2.22 or later for programs
to seamlessly take advantage of this.
config THUMB2_COMPAT_VDSO
bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
depends on COMPAT_VDSO
default y
help
Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
otherwise with '-marm'.
menuconfig ARMV8_DEPRECATED
bool "Emulate deprecated/obsolete ARMv8 instructions"
depends on SYSCTL
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.
This feature can be controlled at runtime with the abi.swp
sysctl which is disabled by default.
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. This feature can be
controlled at runtime with the abi.cp15_barrier sysctl.
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. This feature can be controlled
at runtime with the abi.setend sysctl.
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
endif
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 AS_HAS_LDAPR
def_bool $(as-instr,.arch_extension rcpc)
config AS_HAS_LSE_ATOMICS
def_bool $(as-instr,.arch_extension lse)
config ARM64_LSE_ATOMICS
bool
default ARM64_USE_LSE_ATOMICS
depends on AS_HAS_LSE_ATOMICS
config ARM64_USE_LSE_ATOMICS
bool "Atomic instructions"
depends on JUMP_LABEL
default y
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 in order for the new instructions
to be used.
endmenu
menu "ARMv8.2 architectural features"
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).
config ARM64_RAS_EXTN
bool "Enable support for RAS CPU Extensions"
default y
help
CPUs that support the Reliability, Availability and Serviceability
(RAS) Extensions, part of ARMv8.2 are able to track faults and
errors, classify them and report them to software.
On CPUs with these extensions system software can use additional
barriers to determine if faults are pending and read the
classification from a new set of registers.
Selecting this feature will allow the kernel to use these barriers
and access the new registers if the system supports the extension.
Platform RAS features may additionally depend on firmware support.
config ARM64_CNP
bool "Enable support for Common Not Private (CNP) translations"
default y
depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
help
Common Not Private (CNP) allows translation table entries to
be shared between different PEs in the same inner shareable
domain, so the hardware can use this fact to optimise the
caching of such entries in the TLB.
Selecting this option allows the CNP feature to be detected
at runtime, and does not affect PEs that do not implement
this feature.
endmenu
menu "ARMv8.3 architectural features"
config ARM64_PTR_AUTH
bool "Enable support for pointer authentication"
default y
help
Pointer authentication (part of the ARMv8.3 Extensions) provides
instructions for signing and authenticating pointers against secret
keys, which can be used to mitigate Return Oriented Programming (ROP)
and other attacks.
This option enables these instructions at EL0 (i.e. for userspace).
Choosing this option will cause the kernel to initialise secret keys
for each process at exec() time, with these keys being
context-switched along with the process.
The feature is detected at runtime. If the feature is not present in
hardware it will not be advertised to userspace/KVM guest nor will it
be enabled.
If the feature is present on the boot CPU but not on a late CPU, then
the late CPU will be parked. Also, if the boot CPU does not have
address auth and the late CPU has then the late CPU will still boot
but with the feature disabled. On such a system, this option should
not be selected.
config ARM64_PTR_AUTH_KERNEL
bool "Use pointer authentication for kernel"
default y
depends on ARM64_PTR_AUTH
depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
# Modern compilers insert a .note.gnu.property section note for PAC
# which is only understood by binutils starting with version 2.33.1.
depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
help
If the compiler supports the -mbranch-protection or
-msign-return-address flag (e.g. GCC 7 or later), then this option
will cause the kernel itself to be compiled with return address
protection. In this case, and if the target hardware is known to
support pointer authentication, then CONFIG_STACKPROTECTOR can be
disabled with minimal loss of protection.
This feature works with FUNCTION_GRAPH_TRACER option only if
DYNAMIC_FTRACE_WITH_REGS is enabled.
config CC_HAS_BRANCH_PROT_PAC_RET
# GCC 9 or later, clang 8 or later
def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
config CC_HAS_SIGN_RETURN_ADDRESS
# GCC 7, 8
def_bool $(cc-option,-msign-return-address=all)
config AS_HAS_PAC
def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
config AS_HAS_CFI_NEGATE_RA_STATE
def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
endmenu
menu "ARMv8.4 architectural features"
config ARM64_AMU_EXTN
bool "Enable support for the Activity Monitors Unit CPU extension"
default y
help
The activity monitors extension is an optional extension introduced
by the ARMv8.4 CPU architecture. This enables support for version 1
of the activity monitors architecture, AMUv1.
To enable the use of this extension on CPUs that implement it, say Y.
Note that for architectural reasons, firmware _must_ implement AMU
support when running on CPUs that present the activity monitors
extension. The required support is present in:
* Version 1.5 and later of the ARM Trusted Firmware
For kernels that have this configuration enabled but boot with broken
firmware, you may need to say N here until the firmware is fixed.
Otherwise you may experience firmware panics or lockups when
accessing the counter registers. Even if you are not observing these
symptoms, the values returned by the register reads might not
correctly reflect reality. Most commonly, the value read will be 0,
indicating that the counter is not enabled.
config AS_HAS_ARMV8_4
def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
config ARM64_TLB_RANGE
bool "Enable support for tlbi range feature"
default y
depends on AS_HAS_ARMV8_4
help
ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
range of input addresses.
The feature introduces new assembly instructions, and they were
support when binutils >= 2.30.
endmenu
menu "ARMv8.5 architectural features"
config AS_HAS_ARMV8_5
def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
config ARM64_BTI
bool "Branch Target Identification support"
default y
help
Branch Target Identification (part of the ARMv8.5 Extensions)
provides a mechanism to limit the set of locations to which computed
branch instructions such as BR or BLR can jump.
To make use of BTI on CPUs that support it, say Y.
BTI is intended to provide complementary protection to other control
flow integrity protection mechanisms, such as the Pointer
authentication mechanism provided as part of the ARMv8.3 Extensions.
For this reason, it does not make sense to enable this option without
also enabling support for pointer authentication. Thus, when
enabling this option you should also select ARM64_PTR_AUTH=y.
Userspace binaries must also be specifically compiled to make use of
this mechanism. If you say N here or the hardware does not support
BTI, such binaries can still run, but you get no additional
enforcement of branch destinations.
config ARM64_BTI_KERNEL
bool "Use Branch Target Identification for kernel"
default y
depends on ARM64_BTI
depends on ARM64_PTR_AUTH_KERNEL
depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
depends on !CC_IS_GCC || GCC_VERSION >= 100100
# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
help
Build the kernel with Branch Target Identification annotations
and enable enforcement of this for kernel code. When this option
is enabled and the system supports BTI all kernel code including
modular code must have BTI enabled.
config CC_HAS_BRANCH_PROT_PAC_RET_BTI
# GCC 9 or later, clang 8 or later
def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
config ARM64_E0PD
bool "Enable support for E0PD"
default y
help
E0PD (part of the ARMv8.5 extensions) allows us to ensure
that EL0 accesses made via TTBR1 always fault in constant time,
providing similar benefits to KASLR as those provided by KPTI, but
with lower overhead and without disrupting legitimate access to
kernel memory such as SPE.
This option enables E0PD for TTBR1 where available.
config ARCH_RANDOM
bool "Enable support for random number generation"
default y
help
Random number generation (part of the ARMv8.5 Extensions)
provides a high bandwidth, cryptographically secure
hardware random number generator.
config ARM64_AS_HAS_MTE
# Initial support for MTE went in binutils 2.32.0, checked with
# ".arch armv8.5-a+memtag" below. However, this was incomplete
# as a late addition to the final architecture spec (LDGM/STGM)
# is only supported in the newer 2.32.x and 2.33 binutils
# versions, hence the extra "stgm" instruction check below.
def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
config ARM64_MTE
bool "Memory Tagging Extension support"
default y
depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
depends on AS_HAS_ARMV8_5
depends on AS_HAS_LSE_ATOMICS
# Required for tag checking in the uaccess routines
depends on ARM64_PAN
select ARCH_USES_HIGH_VMA_FLAGS
help
Memory Tagging (part of the ARMv8.5 Extensions) provides
architectural support for run-time, always-on detection of
various classes of memory error to aid with software debugging
to eliminate vulnerabilities arising from memory-unsafe
languages.
This option enables the support for the Memory Tagging
Extension at EL0 (i.e. for userspace).
Selecting this option allows the feature to be detected at
runtime. Any secondary CPU not implementing this feature will
not be allowed a late bring-up.
Userspace binaries that want to use this feature must
explicitly opt in. The mechanism for the userspace is
described in:
Documentation/arm64/memory-tagging-extension.rst.
endmenu
menu "ARMv8.7 architectural features"
config ARM64_EPAN
bool "Enable support for Enhanced Privileged Access Never (EPAN)"
default y
depends on ARM64_PAN
help
Enhanced Privileged Access Never (EPAN) allows Privileged
Access Never to be used with Execute-only mappings.
The feature is detected at runtime, and will remain disabled
if the cpu does not implement the feature.
endmenu
config ARM64_SVE
bool "ARM Scalable Vector Extension support"
default y
help
The Scalable Vector Extension (SVE) is an extension to the AArch64
execution state which complements and extends the SIMD functionality
of the base architecture to support much larger vectors and to enable
additional vectorisation opportunities.
To enable use of this extension on CPUs that implement it, say Y.
On CPUs that support the SVE2 extensions, this option will enable
those too.
Note that for architectural reasons, firmware _must_ implement SVE
support when running on SVE capable hardware. The required support
is present in:
* version 1.5 and later of the ARM Trusted Firmware
* the AArch64 boot wrapper since commit 5e1261e08abf
("bootwrapper: SVE: Enable SVE for EL2 and below").
For other firmware implementations, consult the firmware documentation
or vendor.
If you need the kernel to boot on SVE-capable hardware with broken
firmware, you may need to say N here until you get your firmware
fixed. Otherwise, you may experience firmware panics or lockups when
booting the kernel. If unsure and you are not observing these
symptoms, you should assume that it is safe to say Y.
config ARM64_MODULE_PLTS
bool "Use PLTs to allow module memory to spill over into vmalloc area"
depends on MODULES
select HAVE_MOD_ARCH_SPECIFIC
help
Allocate PLTs when loading modules so that jumps and calls whose
targets are too far away for their relative offsets to be encoded
in the instructions themselves can be bounced via veneers in the
module's PLT. This allows modules to be allocated in the generic
vmalloc area after the dedicated module memory area has been
exhausted.
When running with address space randomization (KASLR), the module
region itself may be too far away for ordinary relative jumps and
calls, and so in that case, module PLTs are required and cannot be
disabled.
Specific errata workaround(s) might also force module PLTs to be
enabled (ARM64_ERRATUM_843419).
config ARM64_PSEUDO_NMI
bool "Support for NMI-like interrupts"
select ARM_GIC_V3
help
Adds support for mimicking Non-Maskable Interrupts through the use of
GIC interrupt priority. This support requires version 3 or later of
ARM GIC.
This high priority configuration for interrupts needs to be
explicitly enabled by setting the kernel parameter
"irqchip.gicv3_pseudo_nmi" to 1.
If unsure, say N
if ARM64_PSEUDO_NMI
config ARM64_DEBUG_PRIORITY_MASKING
bool "Debug interrupt priority masking"
help
This adds runtime checks to functions enabling/disabling
interrupts when using priority masking. The additional checks verify
the validity of ICC_PMR_EL1 when calling concerned functions.
If unsure, say N
endif
config RELOCATABLE
bool "Build a relocatable kernel image" if EXPERT
select ARCH_HAS_RELR
default y
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 over a 2 GB range"
depends on RANDOMIZE_BASE
default y
help
Randomizes the location of the module region inside a 2 GB window
covering the core kernel. This way, it is less likely 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 almost always in range unless
ARM64_MODULE_PLTS is enabled and the region is exhausted. In this
particular case of region exhaustion, modules might be able to fall
back to a larger 2GB area.
config CC_HAVE_STACKPROTECTOR_SYSREG
def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
config STACKPROTECTOR_PER_TASK
def_bool y
depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
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).
choice
prompt "Kernel command line type" if CMDLINE != ""
default CMDLINE_FROM_BOOTLOADER
help
Choose how the kernel will handle the provided default kernel
command line string.
config CMDLINE_FROM_BOOTLOADER
bool "Use bootloader kernel arguments if available"
help
Uses the command-line options passed by the boot loader. If
the boot loader doesn't provide any, the default kernel command
string provided in CMDLINE will be used.
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.
endchoice
config EFI_STUB
bool
config EFI
bool "UEFI runtime support"
depends on OF && !CPU_BIG_ENDIAN
depends on KERNEL_MODE_NEON
select ARCH_SUPPORTS_ACPI
select LIBFDT
select UCS2_STRING
select EFI_PARAMS_FROM_FDT
select EFI_RUNTIME_WRAPPERS
select EFI_STUB
select EFI_GENERIC_STUB
imply IMA_SECURE_AND_OR_TRUSTED_BOOT
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
config SYSVIPC_COMPAT
def_bool y
depends on COMPAT && SYSVIPC
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 "drivers/acpi/Kconfig"
source "arch/arm64/kvm/Kconfig"
if CRYPTO
source "arch/arm64/crypto/Kconfig"
endif
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