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Kconfig
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Kconfig
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# SPDX-License-Identifier: GPL-2.0
source "arch/powerpc/platforms/Kconfig.cputype"
config 32BIT
bool
default y if PPC32
config 64BIT
bool
default y if PPC64
config MMU
bool
default y
config ARCH_MMAP_RND_BITS_MAX
# On Book3S 64, the default virtual address space for 64-bit processes
# is 2^47 (128TB). As a maximum, allow randomisation to consume up to
# 32T of address space (2^45), which should ensure a reasonable gap
# between bottom-up and top-down allocations for applications that
# consume "normal" amounts of address space. Book3S 64 only supports 64K
# and 4K page sizes.
default 29 if PPC_BOOK3S_64 && PPC_64K_PAGES # 29 = 45 (32T) - 16 (64K)
default 33 if PPC_BOOK3S_64 # 33 = 45 (32T) - 12 (4K)
#
# On all other 64-bit platforms (currently only Book3E), the virtual
# address space is 2^46 (64TB). Allow randomisation to consume up to 16T
# of address space (2^44). Only 4K page sizes are supported.
default 32 if 64BIT # 32 = 44 (16T) - 12 (4K)
#
# For 32-bit, use the compat values, as they're the same.
default ARCH_MMAP_RND_COMPAT_BITS_MAX
config ARCH_MMAP_RND_BITS_MIN
# Allow randomisation to consume up to 1GB of address space (2^30).
default 14 if 64BIT && PPC_64K_PAGES # 14 = 30 (1GB) - 16 (64K)
default 18 if 64BIT # 18 = 30 (1GB) - 12 (4K)
#
# For 32-bit, use the compat values, as they're the same.
default ARCH_MMAP_RND_COMPAT_BITS_MIN
config ARCH_MMAP_RND_COMPAT_BITS_MAX
# Total virtual address space for 32-bit processes is 2^31 (2GB).
# Allow randomisation to consume up to 512MB of address space (2^29).
default 11 if PPC_256K_PAGES # 11 = 29 (512MB) - 18 (256K)
default 13 if PPC_64K_PAGES # 13 = 29 (512MB) - 16 (64K)
default 15 if PPC_16K_PAGES # 15 = 29 (512MB) - 14 (16K)
default 17 # 17 = 29 (512MB) - 12 (4K)
config ARCH_MMAP_RND_COMPAT_BITS_MIN
# Total virtual address space for 32-bit processes is 2^31 (2GB).
# Allow randomisation to consume up to 8MB of address space (2^23).
default 5 if PPC_256K_PAGES # 5 = 23 (8MB) - 18 (256K)
default 7 if PPC_64K_PAGES # 7 = 23 (8MB) - 16 (64K)
default 9 if PPC_16K_PAGES # 9 = 23 (8MB) - 14 (16K)
default 11 # 11 = 23 (8MB) - 12 (4K)
config HAVE_SETUP_PER_CPU_AREA
def_bool PPC64
config NEED_PER_CPU_EMBED_FIRST_CHUNK
def_bool PPC64
config NR_IRQS
int "Number of virtual interrupt numbers"
range 32 32768
default "512"
help
This defines the number of virtual interrupt numbers the kernel
can manage. Virtual interrupt numbers are what you see in
/proc/interrupts. If you configure your system to have too few,
drivers will fail to load or worse - handle with care.
config NMI_IPI
bool
depends on SMP && (DEBUGGER || KEXEC_CORE || HARDLOCKUP_DETECTOR)
default y
config PPC_WATCHDOG
bool
depends on HARDLOCKUP_DETECTOR
depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
default y
help
This is a placeholder when the powerpc hardlockup detector
watchdog is selected (arch/powerpc/kernel/watchdog.c). It is
seleted via the generic lockup detector menu which is why we
have no standalone config option for it here.
config STACKTRACE_SUPPORT
bool
default y
config TRACE_IRQFLAGS_SUPPORT
bool
default y
config LOCKDEP_SUPPORT
bool
default y
config GENERIC_LOCKBREAK
bool
default y
depends on SMP && PREEMPTION
config GENERIC_HWEIGHT
bool
default y
config PPC
bool
default y
#
# Please keep this list sorted alphabetically.
#
select ARCH_32BIT_OFF_T if PPC32
select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_KCOV
select ARCH_HAS_HUGEPD if HUGETLB_PAGE
select ARCH_HAS_MEMREMAP_COMPAT_ALIGN
select ARCH_HAS_MMIOWB if PPC64
select ARCH_HAS_PHYS_TO_DMA
select ARCH_HAS_PMEM_API
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_DEVMAP if PPC_BOOK3S_64
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_MEMBARRIER_CALLBACKS
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64
select ARCH_HAS_STRICT_KERNEL_RWX if (PPC32 && !HIBERNATION)
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UACCESS_FLUSHCACHE
select ARCH_HAS_UACCESS_MCSAFE if PPC64
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select ARCH_KEEP_MEMBLOCK
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if PPC64
select ARCH_USE_QUEUED_RWLOCKS if PPC_QUEUED_SPINLOCKS
select ARCH_USE_QUEUED_SPINLOCKS if PPC_QUEUED_SPINLOCKS
select ARCH_WANT_IPC_PARSE_VERSION
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_TABLE_SORT
select CLONE_BACKWARDS
select DCACHE_WORD_ACCESS if PPC64 && CPU_LITTLE_ENDIAN
select DYNAMIC_FTRACE if FUNCTION_TRACER
select EDAC_ATOMIC_SCRUB
select EDAC_SUPPORT
select GENERIC_ATOMIC64 if PPC32
select GENERIC_CLOCKEVENTS
select GENERIC_CLOCKEVENTS_BROADCAST if SMP
select GENERIC_CMOS_UPDATE
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES if PPC_BARRIER_NOSPEC
select GENERIC_EARLY_IOREMAP
select GENERIC_IRQ_SHOW
select GENERIC_IRQ_SHOW_LEVEL
select GENERIC_PCI_IOMAP if PCI
select GENERIC_SMP_IDLE_THREAD
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select GENERIC_TIME_VSYSCALL
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_HUGE_VMAP if PPC_BOOK3S_64 && PPC_RADIX_MMU
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14
select HAVE_ARCH_KASAN_VMALLOC if PPC32 && PPC_PAGE_SHIFT <= 14
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
select HAVE_ARCH_NVRAM_OPS
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_ASM_MODVERSIONS
select HAVE_C_RECORDMCOUNT
select HAVE_CBPF_JIT if !PPC64
select HAVE_STACKPROTECTOR if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
select HAVE_STACKPROTECTOR if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
select HAVE_CONTEXT_TRACKING if PPC64
select HAVE_TIF_NOHZ if PPC64
select HAVE_COPY_THREAD_TLS
select HAVE_DEBUG_KMEMLEAK
select HAVE_DEBUG_STACKOVERFLOW
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_REGS if MPROFILE_KERNEL
select HAVE_EBPF_JIT if PPC64
select HAVE_EFFICIENT_UNALIGNED_ACCESS if !(CPU_LITTLE_ENDIAN && POWER7_CPU)
select HAVE_FAST_GUP
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER
select HAVE_GCC_PLUGINS if GCC_VERSION >= 50200 # plugin support on gcc <= 5.1 is buggy on PPC
select HAVE_HW_BREAKPOINT if PERF_EVENTS && (PPC_BOOK3S || PPC_8xx)
select HAVE_IDE
select HAVE_IOREMAP_PROT
select HAVE_IRQ_EXIT_ON_IRQ_STACK
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZMA if DEFAULT_UIMAGE
select HAVE_KERNEL_LZO if DEFAULT_UIMAGE
select HAVE_KERNEL_XZ if PPC_BOOK3S || 44x
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S)
select HAVE_HARDLOCKUP_DETECTOR_ARCH if (PPC64 && PPC_BOOK3S)
select HAVE_OPROFILE
select HAVE_OPTPROBES if PPC64
select HAVE_PERF_EVENTS
select HAVE_PERF_EVENTS_NMI if PPC64
select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select MMU_GATHER_RCU_TABLE_FREE
select MMU_GATHER_PAGE_SIZE
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RELIABLE_STACKTRACE if PPC_BOOK3S_64 && CPU_LITTLE_ENDIAN
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_VIRT_CPU_ACCOUNTING
select HAVE_IRQ_TIME_ACCOUNTING
select HAVE_RSEQ
select IOMMU_HELPER if PPC64
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
select MODULES_USE_ELF_RELA
select NEED_DMA_MAP_STATE if PPC64 || NOT_COHERENT_CACHE
select NEED_SG_DMA_LENGTH
select OF
select OF_DMA_DEFAULT_COHERENT if !NOT_COHERENT_CACHE
select OF_EARLY_FLATTREE
select OLD_SIGACTION if PPC32
select OLD_SIGSUSPEND
select PCI_DOMAINS if PCI
select PCI_SYSCALL if PCI
select PPC_DAWR if PPC64
select RTC_LIB
select SPARSE_IRQ
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
select VIRT_TO_BUS if !PPC64
#
# Please keep this list sorted alphabetically.
#
config PPC_BARRIER_NOSPEC
bool
default y
depends on PPC_BOOK3S_64 || PPC_FSL_BOOK3E
config EARLY_PRINTK
bool
default y
config PANIC_TIMEOUT
int
default 180
config COMPAT
bool "Enable support for 32bit binaries"
depends on PPC64
default y if !CPU_LITTLE_ENDIAN
select COMPAT_BINFMT_ELF
select ARCH_WANT_OLD_COMPAT_IPC
select COMPAT_OLD_SIGACTION
config SYSVIPC_COMPAT
bool
depends on COMPAT && SYSVIPC
default y
config SCHED_OMIT_FRAME_POINTER
bool
default y
config ARCH_MAY_HAVE_PC_FDC
bool
default PCI
config PPC_UDBG_16550
bool
config GENERIC_TBSYNC
bool
default y if PPC32 && SMP
config AUDIT_ARCH
bool
default y
config GENERIC_BUG
bool
default y
depends on BUG
config SYS_SUPPORTS_APM_EMULATION
default y if PMAC_APM_EMU
bool
config EPAPR_BOOT
bool
help
Used to allow a board to specify it wants an ePAPR compliant wrapper.
config DEFAULT_UIMAGE
bool
help
Used to allow a board to specify it wants a uImage built by default
config ARCH_HIBERNATION_POSSIBLE
bool
default y
config ARCH_SUSPEND_POSSIBLE
def_bool y
depends on ADB_PMU || PPC_EFIKA || PPC_LITE5200 || PPC_83xx || \
(PPC_85xx && !PPC_E500MC) || PPC_86xx || PPC_PSERIES \
|| 44x || 40x
config ARCH_SUSPEND_NONZERO_CPU
def_bool y
depends on PPC_POWERNV || PPC_PSERIES
config PPC_DCR_NATIVE
bool
config PPC_DCR_MMIO
bool
config PPC_DCR
bool
depends on PPC_DCR_NATIVE || PPC_DCR_MMIO
default y
config PPC_OF_PLATFORM_PCI
bool
depends on PCI
depends on PPC64 # not supported on 32 bits yet
config ARCH_SUPPORTS_DEBUG_PAGEALLOC
depends on PPC32 || PPC_BOOK3S_64
def_bool y
config ARCH_SUPPORTS_UPROBES
def_bool y
config PPC_ADV_DEBUG_REGS
bool
depends on 40x || BOOKE
default y
config PPC_ADV_DEBUG_IACS
int
depends on PPC_ADV_DEBUG_REGS
default 4 if 44x
default 2
config PPC_ADV_DEBUG_DACS
int
depends on PPC_ADV_DEBUG_REGS
default 2
config PPC_ADV_DEBUG_DVCS
int
depends on PPC_ADV_DEBUG_REGS
default 2 if 44x
default 0
config PPC_ADV_DEBUG_DAC_RANGE
bool
depends on PPC_ADV_DEBUG_REGS && 44x
default y
config PPC_DAWR
bool
config ZONE_DMA
bool
default y if PPC_BOOK3E_64
config PGTABLE_LEVELS
int
default 2 if !PPC64
default 4
source "arch/powerpc/sysdev/Kconfig"
source "arch/powerpc/platforms/Kconfig"
menu "Kernel options"
config HIGHMEM
bool "High memory support"
depends on PPC32
source "kernel/Kconfig.hz"
config HUGETLB_PAGE_SIZE_VARIABLE
bool
depends on HUGETLB_PAGE && PPC_BOOK3S_64
default y
config MATH_EMULATION
bool "Math emulation"
depends on 4xx || PPC_8xx || PPC_MPC832x || BOOKE
help
Some PowerPC chips designed for embedded applications do not have
a floating-point unit and therefore do not implement the
floating-point instructions in the PowerPC instruction set. If you
say Y here, the kernel will include code to emulate a floating-point
unit, which will allow programs that use floating-point
instructions to run.
This is also useful to emulate missing (optional) instructions
such as fsqrt on cores that do have an FPU but do not implement
them (such as Freescale BookE).
choice
prompt "Math emulation options"
default MATH_EMULATION_FULL
depends on MATH_EMULATION
config MATH_EMULATION_FULL
bool "Emulate all the floating point instructions"
help
Select this option will enable the kernel to support to emulate
all the floating point instructions. If your SoC doesn't have
a FPU, you should select this.
config MATH_EMULATION_HW_UNIMPLEMENTED
bool "Just emulate the FPU unimplemented instructions"
help
Select this if you know there does have a hardware FPU on your
SoC, but some floating point instructions are not implemented by that.
endchoice
config PPC_TRANSACTIONAL_MEM
bool "Transactional Memory support for POWERPC"
depends on PPC_BOOK3S_64
depends on SMP
select ALTIVEC
select VSX
help
Support user-mode Transactional Memory on POWERPC.
config PPC_UV
bool "Ultravisor support"
depends on KVM_BOOK3S_HV_POSSIBLE
depends on DEVICE_PRIVATE
default n
help
This option paravirtualizes the kernel to run in POWER platforms that
supports the Protected Execution Facility (PEF). On such platforms,
the ultravisor firmware runs at a privilege level above the
hypervisor.
If unsure, say "N".
config LD_HEAD_STUB_CATCH
bool "Reserve 256 bytes to cope with linker stubs in HEAD text" if EXPERT
depends on PPC64
help
Very large kernels can cause linker branch stubs to be generated by
code in head_64.S, which moves the head text sections out of their
specified location. This option can work around the problem.
If unsure, say "N".
config MPROFILE_KERNEL
depends on PPC64 && CPU_LITTLE_ENDIAN && FUNCTION_TRACER
def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-mprofile-kernel.sh $(CC) -I$(srctree)/include -D__KERNEL__)
config HOTPLUG_CPU
bool "Support for enabling/disabling CPUs"
depends on SMP && (PPC_PSERIES || \
PPC_PMAC || PPC_POWERNV || FSL_SOC_BOOKE)
help
Say Y here to be able to disable and re-enable individual
CPUs at runtime on SMP machines.
Say N if you are unsure.
config PPC_QUEUED_SPINLOCKS
bool "Queued spinlocks"
depends on SMP
help
Say Y here to use queued spinlocks which give better scalability and
fairness on large SMP and NUMA systems without harming single threaded
performance.
This option is currently experimental, the code is more complex and
less tested so it defaults to "N" for the moment.
If unsure, say "N".
config ARCH_CPU_PROBE_RELEASE
def_bool y
depends on HOTPLUG_CPU
config ARCH_ENABLE_MEMORY_HOTPLUG
def_bool y
config ARCH_ENABLE_MEMORY_HOTREMOVE
def_bool y
config PPC64_SUPPORTS_MEMORY_FAILURE
bool "Add support for memory hwpoison"
depends on PPC_BOOK3S_64
default "y" if PPC_POWERNV
select ARCH_SUPPORTS_MEMORY_FAILURE
config KEXEC
bool "kexec system call"
depends on (PPC_BOOK3S || FSL_BOOKE || (44x && !SMP)) || PPC_BOOK3E
select KEXEC_CORE
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.
The name comes from the similarity to the exec system call.
It is an ongoing process to be certain the hardware in a machine
is properly shutdown, so do not be surprised if this code does not
initially work for you. As of this writing the exact hardware
interface is strongly in flux, so no good recommendation can be
made.
config KEXEC_FILE
bool "kexec file based system call"
select KEXEC_CORE
select HAVE_IMA_KEXEC
select BUILD_BIN2C
select KEXEC_ELF
depends on PPC64
depends on CRYPTO=y
depends on CRYPTO_SHA256=y
help
This is a new version of the kexec system call. This call is
file based and takes in file descriptors as system call arguments
for kernel and initramfs as opposed to a list of segments as is the
case for the older kexec call.
config ARCH_HAS_KEXEC_PURGATORY
def_bool KEXEC_FILE
config RELOCATABLE
bool "Build a relocatable kernel"
depends on PPC64 || (FLATMEM && (44x || FSL_BOOKE))
select NONSTATIC_KERNEL
select MODULE_REL_CRCS if MODVERSIONS
help
This builds a kernel image that is capable of running at the
location the kernel is loaded at. For ppc32, there is no any
alignment restrictions, and this feature is a superset of
DYNAMIC_MEMSTART and hence overrides it. For ppc64, we should use
16k-aligned base address. The kernel is linked as a
position-independent executable (PIE) and contains dynamic relocations
which are processed early in the bootup process.
One use is for the kexec on panic case where the recovery kernel
must live at a different physical address than the primary
kernel.
Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
it has been loaded at and the compile time physical addresses
CONFIG_PHYSICAL_START is ignored. However CONFIG_PHYSICAL_START
setting can still be useful to bootwrappers that need to know the
load address of the kernel (eg. u-boot/mkimage).
config RANDOMIZE_BASE
bool "Randomize the address of the kernel image"
depends on (FSL_BOOKE && FLATMEM && PPC32)
depends on 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.
If unsure, say Y.
config RELOCATABLE_TEST
bool "Test relocatable kernel"
depends on (PPC64 && RELOCATABLE)
help
This runs the relocatable kernel at the address it was initially
loaded at, which tends to be non-zero and therefore test the
relocation code.
config CRASH_DUMP
bool "Build a dump capture kernel"
depends on PPC64 || PPC_BOOK3S_32 || FSL_BOOKE || (44x && !SMP)
select RELOCATABLE if PPC64 || 44x || FSL_BOOKE
help
Build a kernel suitable for use as a dump capture kernel.
The same kernel binary can be used as production kernel and dump
capture kernel.
config FA_DUMP
bool "Firmware-assisted dump"
depends on PPC64 && (PPC_RTAS || PPC_POWERNV)
select CRASH_CORE
select CRASH_DUMP
help
A robust mechanism to get reliable kernel crash dump with
assistance from firmware. This approach does not use kexec,
instead firmware assists in booting the capture kernel
while preserving memory contents. Firmware-assisted dump
is meant to be a kdump replacement offering robustness and
speed not possible without system firmware assistance.
If unsure, say "y". Only special kernels like petitboot may
need to say "N" here.
config PRESERVE_FA_DUMP
bool "Preserve Firmware-assisted dump"
depends on PPC64 && PPC_POWERNV && !FA_DUMP
help
On a kernel with FA_DUMP disabled, this option helps to preserve
crash data from a previously crash'ed kernel. Useful when the next
memory preserving kernel boot would process this crash data.
Petitboot kernel is the typical usecase for this option.
config OPAL_CORE
bool "Export OPAL memory as /sys/firmware/opal/core"
depends on PPC64 && PPC_POWERNV
help
This option uses the MPIPL support in firmware to provide an
ELF core of OPAL memory after a crash. The ELF core is exported
as /sys/firmware/opal/core file which is helpful in debugging
OPAL crashes using GDB.
config IRQ_ALL_CPUS
bool "Distribute interrupts on all CPUs by default"
depends on SMP
help
This option gives the kernel permission to distribute IRQs across
multiple CPUs. Saying N here will route all IRQs to the first
CPU. Generally saying Y is safe, although some problems have been
reported with SMP Power Macintoshes with this option enabled.
config NUMA
bool "NUMA support"
depends on PPC64
default y if SMP && PPC_PSERIES
config NODES_SHIFT
int
default "8" if PPC64
default "4"
depends on NEED_MULTIPLE_NODES
config USE_PERCPU_NUMA_NODE_ID
def_bool y
depends on NUMA
config HAVE_MEMORYLESS_NODES
def_bool y
depends on NUMA
config ARCH_SELECT_MEMORY_MODEL
def_bool y
depends on PPC64
config ARCH_FLATMEM_ENABLE
def_bool y
depends on (PPC64 && !NUMA) || PPC32
config ARCH_SPARSEMEM_ENABLE
def_bool y
depends on PPC64
select SPARSEMEM_VMEMMAP_ENABLE
config ARCH_SPARSEMEM_DEFAULT
def_bool y
depends on PPC_BOOK3S_64
config SYS_SUPPORTS_HUGETLBFS
bool
config ILLEGAL_POINTER_VALUE
hex
# This is roughly half way between the top of user space and the bottom
# of kernel space, which seems about as good as we can get.
default 0x5deadbeef0000000 if PPC64
default 0
config ARCH_MEMORY_PROBE
def_bool y
depends on MEMORY_HOTPLUG
config STDBINUTILS
bool "Using standard binutils settings"
depends on 44x
default y
help
Turning this option off allows you to select 256KB PAGE_SIZE on 44x.
Note, that kernel will be able to run only those applications,
which had been compiled using binutils later than 2.17.50.0.3 with
'-zmax-page-size' set to 256K (the default is 64K). Or, if using
the older binutils, you can patch them with a trivial patch, which
changes the ELF_MAXPAGESIZE definition from 0x10000 to 0x40000.
choice
prompt "Page size"
default PPC_4K_PAGES
help
Select the kernel logical page size. Increasing the page size
will reduce software overhead at each page boundary, allow
hardware prefetch mechanisms to be more effective, and allow
larger dma transfers increasing IO efficiency and reducing
overhead. However the utilization of memory will increase.
For example, each cached file will using a multiple of the
page size to hold its contents and the difference between the
end of file and the end of page is wasted.
Some dedicated systems, such as software raid serving with
accelerated calculations, have shown significant increases.
If you configure a 64 bit kernel for 64k pages but the
processor does not support them, then the kernel will simulate
them with 4k pages, loading them on demand, but with the
reduced software overhead and larger internal fragmentation.
For the 32 bit kernel, a large page option will not be offered
unless it is supported by the configured processor.
If unsure, choose 4K_PAGES.
config PPC_4K_PAGES
bool "4k page size"
select HAVE_ARCH_SOFT_DIRTY if PPC_BOOK3S_64
config PPC_16K_PAGES
bool "16k page size"
depends on 44x || PPC_8xx
config PPC_64K_PAGES
bool "64k page size"
depends on 44x || PPC_BOOK3S_64
select HAVE_ARCH_SOFT_DIRTY if PPC_BOOK3S_64
config PPC_256K_PAGES
bool "256k page size"
depends on 44x && !STDBINUTILS
help
Make the page size 256k.
As the ELF standard only requires alignment to support page
sizes up to 64k, you will need to compile all of your user
space applications with a non-standard binutils settings
(see the STDBINUTILS description for details).
Say N unless you know what you are doing.
endchoice
config PPC_PAGE_SHIFT
int
default 18 if PPC_256K_PAGES
default 16 if PPC_64K_PAGES
default 14 if PPC_16K_PAGES
default 12
config THREAD_SHIFT
int "Thread shift" if EXPERT
range 13 15
default "15" if PPC_256K_PAGES
default "14" if PPC64
default "14" if KASAN
default "13"
help
Used to define the stack size. The default is almost always what you
want. Only change this if you know what you are doing.
config DATA_SHIFT_BOOL
bool "Set custom data alignment"
depends on ADVANCED_OPTIONS
depends on STRICT_KERNEL_RWX || DEBUG_PAGEALLOC
depends on PPC_BOOK3S_32 || (PPC_8xx && !PIN_TLB_DATA && \
(!PIN_TLB_TEXT || !STRICT_KERNEL_RWX))
help
This option allows you to set the kernel data alignment. When
RAM is mapped by blocks, the alignment needs to fit the size and
number of possible blocks. The default should be OK for most configs.
Say N here unless you know what you are doing.
config DATA_SHIFT
int "Data shift" if DATA_SHIFT_BOOL
default 24 if STRICT_KERNEL_RWX && PPC64
range 17 28 if (STRICT_KERNEL_RWX || DEBUG_PAGEALLOC) && PPC_BOOK3S_32
range 19 23 if (STRICT_KERNEL_RWX || DEBUG_PAGEALLOC) && PPC_8xx
default 22 if STRICT_KERNEL_RWX && PPC_BOOK3S_32
default 18 if DEBUG_PAGEALLOC && PPC_BOOK3S_32
default 23 if STRICT_KERNEL_RWX && PPC_8xx
default 23 if DEBUG_PAGEALLOC && PPC_8xx && PIN_TLB_DATA
default 19 if DEBUG_PAGEALLOC && PPC_8xx
default PPC_PAGE_SHIFT
help
On Book3S 32 (603+), DBATs are used to map kernel text and rodata RO.
Smaller is the alignment, greater is the number of necessary DBATs.
On 8xx, large pages (512kb or 8M) are used to map kernel linear
memory. Aligning to 8M reduces TLB misses as only 8M pages are used
in that case. If PIN_TLB is selected, it must be aligned to 8M as
8M pages will be pinned.
config FORCE_MAX_ZONEORDER
int "Maximum zone order"
range 8 9 if PPC64 && PPC_64K_PAGES
default "9" if PPC64 && PPC_64K_PAGES
range 13 13 if PPC64 && !PPC_64K_PAGES
default "13" if PPC64 && !PPC_64K_PAGES
range 9 64 if PPC32 && PPC_16K_PAGES
default "9" if PPC32 && PPC_16K_PAGES
range 7 64 if PPC32 && PPC_64K_PAGES
default "7" if PPC32 && PPC_64K_PAGES
range 5 64 if PPC32 && PPC_256K_PAGES
default "5" if PPC32 && PPC_256K_PAGES
range 11 64
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.
The page size is not necessarily 4KB. For example, on 64-bit
systems, 64KB pages can be enabled via CONFIG_PPC_64K_PAGES. Keep
this in mind when choosing a value for this option.
config PPC_SUBPAGE_PROT
bool "Support setting protections for 4k subpages (subpage_prot syscall)"
default n
depends on PPC_BOOK3S_64 && PPC_64K_PAGES
help
This option adds support for system call to allow user programs
to set access permissions (read/write, readonly, or no access)
on the 4k subpages of each 64k page.
If unsure, say N here.
config PPC_COPRO_BASE
bool
config SCHED_SMT
bool "SMT (Hyperthreading) scheduler support"
depends on PPC64 && SMP
help
SMT scheduler support improves the CPU scheduler's decision making
when dealing with POWER5 cpus at a cost of slightly increased
overhead in some places. If unsure say N here.
config PPC_DENORMALISATION
bool "PowerPC denormalisation exception handling"
depends on PPC_BOOK3S_64
default "y" if PPC_POWERNV
help
Add support for handling denormalisation of single precision
values. Useful for bare metal only. If unsure say Y here.
config CMDLINE
string "Initial kernel command string"
default ""
help
On some platforms, there is currently no way for the boot loader to
pass arguments to the kernel. For these platforms, you can supply
some command-line options at build time by entering them here. In
most cases you will need to specify the root device here.
choice
prompt "Kernel command line type" if CMDLINE != ""
default CMDLINE_FROM_BOOTLOADER
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_EXTEND
bool "Extend bootloader kernel arguments"
help
The command-line arguments provided by the boot loader will be
appended to the default kernel command string.
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 EXTRA_TARGETS
string "Additional default image types"
help
List additional targets to be built by the bootwrapper here (separated
by spaces). This is useful for targets that depend of device tree
files in the .dts directory.
Targets in this list will be build as part of the default build
target, or when the user does a 'make zImage' or a
'make zImage.initrd'.
If unsure, leave blank
config ARCH_WANTS_FREEZER_CONTROL
def_bool y
depends on ADB_PMU
source "kernel/power/Kconfig"
config SECCOMP
bool "Enable seccomp to safely compute untrusted bytecode"
depends on PROC_FS
default y
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 /proc/<pid>/seccomp, it cannot be disabled
and the task is only allowed to execute a few safe syscalls
defined by each seccomp mode.
If unsure, say Y. Only embedded should say N here.
config PPC_MEM_KEYS
prompt "PowerPC Memory Protection Keys"
def_bool y
depends on PPC_BOOK3S_64
select ARCH_USES_HIGH_VMA_FLAGS
select ARCH_HAS_PKEYS
help
Memory Protection Keys provides a mechanism for enforcing
page-based protections, but without requiring modification of the
page tables when an application changes protection domains.
For details, see Documentation/core-api/protection-keys.rst
If unsure, say y.
config PPC_SECURE_BOOT
prompt "Enable secure boot support"
bool
depends on PPC_POWERNV
depends on IMA_ARCH_POLICY
imply IMA_SECURE_AND_OR_TRUSTED_BOOT
help
Systems with firmware secure boot enabled need to define security
policies to extend secure boot to the OS. This config allows a user
to enable OS secure boot on systems that have firmware support for
it. If in doubt say N.
config PPC_SECVAR_SYSFS
bool "Enable sysfs interface for POWER secure variables"
default y
depends on PPC_SECURE_BOOT
depends on SYSFS
help
POWER secure variables are managed and controlled by firmware.
These variables are exposed to userspace via sysfs to enable
read/write operations on these variables. Say Y if you have
secure boot enabled and want to expose variables to userspace.
endmenu
config ISA_DMA_API
bool
default PCI
menu "Bus options"
config ISA
bool "Support for ISA-bus hardware"