# 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 DMA_OPS if PPC64 select DMA_OPS_BYPASS if PPC64 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_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_PROT_SAO_LPAR bool "Support PROT_SAO mappings in LPARs" depends on PPC_BOOK3S_64 help This option adds support for PROT_SAO mappings from userspace inside LPARs on supported CPUs. This may cause issues when performing guest migration from a CPU that supports SAO to one that does not. 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//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" depends on PPC_CHRP select PPC_I8259 help Find out whether you have ISA slots on your motherboard. ISA is the name of a bus system, i.e. the way the CPU talks to the other stuff inside your box. If you have an Apple machine, say N here; if you have an IBM RS/6000 or pSeries machine, say Y. If you have an embedded board, consult your board documentation. config GENERIC_ISA_DMA bool depends on ISA_DMA_API default y config PPC_INDIRECT_PCI bool depends on PCI default y if 40x || 44x config SBUS bool config FSL_SOC bool config FSL_PCI bool select ARCH_HAS_DMA_SET_MASK select PPC_INDIRECT_PCI select PCI_QUIRKS config FSL_PMC bool default y depends on SUSPEND && (PPC_85xx || PPC_86xx) help Freescale MPC85xx/MPC86xx power management controller support (suspend/resume). For MPC83xx see platforms/83xx/suspend.c config PPC4xx_CPM bool default y depends on SUSPEND && (44x || 40x) help PPC4xx Clock Power Management (CPM) support (suspend/resume). It also enables support for two different idle states (idle-wait and idle-doze). config 4xx_SOC bool config FSL_LBC bool "Freescale Local Bus support" help Enables reporting of errors from the Freescale local bus controller. Also contains some common code used by drivers for specific local bus peripherals. config FSL_GTM bool depends on PPC_83xx || QUICC_ENGINE || CPM2 help Freescale General-purpose Timers support config PCI_8260 bool depends on PCI && 8260 select PPC_INDIRECT_PCI default y config FSL_RIO bool "Freescale Embedded SRIO Controller support" depends on RAPIDIO = y && HAVE_RAPIDIO default "n" help Include support for RapidIO controller on Freescale embedded processors (MPC8548, MPC8641, etc). endmenu config NONSTATIC_KERNEL bool menu "Advanced setup" depends on PPC32 config ADVANCED_OPTIONS bool "Prompt for advanced kernel configuration options" help This option will enable prompting for a variety of advanced kernel configuration options. These options can cause the kernel to not work if they are set incorrectly, but can be used to optimize certain aspects of kernel memory management. Unless you know what you are doing, say N here. comment "Default settings for advanced configuration options are used" depends on !ADVANCED_OPTIONS config LOWMEM_SIZE_BOOL bool "Set maximum low memory" depends on ADVANCED_OPTIONS help This option allows you to set the maximum amount of memory which will be used as "low memory", that is, memory which the kernel can access directly, without having to set up a kernel virtual mapping. This can be useful in optimizing the layout of kernel virtual memory. Say N here unless you know what you are doing. config LOWMEM_SIZE hex "Maximum low memory size (in bytes)" if LOWMEM_SIZE_BOOL default "0x30000000" config LOWMEM_CAM_NUM_BOOL bool "Set number of CAMs to use to map low memory" depends on ADVANCED_OPTIONS && FSL_BOOKE help This option allows you to set the maximum number of CAM slots that will be used to map low memory. There are a limited number of slots available and even more limited number that will fit in the L1 MMU. However, using more entries will allow mapping more low memory. This can be useful in optimizing the layout of kernel virtual memory. Say N here unless you know what you are doing. config LOWMEM_CAM_NUM depends on FSL_BOOKE int "Number of CAMs to use to map low memory" if LOWMEM_CAM_NUM_BOOL default 3 config DYNAMIC_MEMSTART bool "Enable page aligned dynamic load address for kernel" depends on ADVANCED_OPTIONS && FLATMEM && (FSL_BOOKE || 44x) select NONSTATIC_KERNEL help This option enables the kernel to be loaded at any page aligned physical address. The kernel creates a mapping from KERNELBASE to the address where the kernel is loaded. The page size here implies the TLB page size of the mapping for kernel on the particular platform. Please refer to the init code for finding the TLB page size. DYNAMIC_MEMSTART is an easy way of implementing pseudo-RELOCATABLE kernel image, where the only restriction is the page aligned kernel load address. When this option is enabled, the compile time physical address CONFIG_PHYSICAL_START is ignored. This option is overridden by CONFIG_RELOCATABLE config PAGE_OFFSET_BOOL bool "Set custom page offset address" depends on ADVANCED_OPTIONS help This option allows you to set the kernel virtual address at which the kernel will map low memory. This can be useful in optimizing the virtual memory layout of the system. Say N here unless you know what you are doing. config PAGE_OFFSET hex "Virtual address of memory base" if PAGE_OFFSET_BOOL default "0xc0000000" config KERNEL_START_BOOL bool "Set custom kernel base address" depends on ADVANCED_OPTIONS help This option allows you to set the kernel virtual address at which the kernel will be loaded. Normally this should match PAGE_OFFSET however there are times (like kdump) that one might not want them to be the same. Say N here unless you know what you are doing. config KERNEL_START hex "Virtual address of kernel base" if KERNEL_START_BOOL default PAGE_OFFSET if PAGE_OFFSET_BOOL default "0xc2000000" if CRASH_DUMP && !NONSTATIC_KERNEL default "0xc0000000" config PHYSICAL_START_BOOL bool "Set physical address where the kernel is loaded" depends on ADVANCED_OPTIONS && FLATMEM && FSL_BOOKE help This gives the physical address where the kernel is loaded. Say N here unless you know what you are doing. config PHYSICAL_START hex "Physical address where the kernel is loaded" if PHYSICAL_START_BOOL default "0x02000000" if PPC_BOOK3S && CRASH_DUMP && !NONSTATIC_KERNEL default "0x00000000" config PHYSICAL_ALIGN hex default "0x04000000" if FSL_BOOKE help This value puts the alignment restrictions on physical address where kernel is loaded and run from. Kernel is compiled for an address which meets above alignment restriction. config TASK_SIZE_BOOL bool "Set custom user task size" depends on ADVANCED_OPTIONS help This option allows you to set the amount of virtual address space allocated to user tasks. This can be useful in optimizing the virtual memory layout of the system. Say N here unless you know what you are doing. config TASK_SIZE hex "Size of user task space" if TASK_SIZE_BOOL default "0x80000000" if PPC_8xx default "0xb0000000" if PPC_BOOK3S_32 && STRICT_KERNEL_RWX default "0xc0000000" endmenu if PPC64 # This value must have zeroes in the bottom 60 bits otherwise lots will break config PAGE_OFFSET hex default "0xc000000000000000" config KERNEL_START hex default "0xc000000000000000" config PHYSICAL_START hex default "0x00000000" endif config ARCH_RANDOM def_bool n config PPC_LIB_RHEAP bool source "arch/powerpc/kvm/Kconfig" source "kernel/livepatch/Kconfig"