968 lines
28 KiB
Plaintext
968 lines
28 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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#
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# General architecture dependent options
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#
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#
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# Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can
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# override the default values in this file.
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#
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source "arch/$(SRCARCH)/Kconfig"
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menu "General architecture-dependent options"
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config CRASH_CORE
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bool
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config KEXEC_CORE
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select CRASH_CORE
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bool
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config KEXEC_ELF
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bool
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config HAVE_IMA_KEXEC
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bool
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config HOTPLUG_SMT
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bool
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config OPROFILE
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tristate "OProfile system profiling"
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depends on PROFILING
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depends on HAVE_OPROFILE
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select RING_BUFFER
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select RING_BUFFER_ALLOW_SWAP
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help
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OProfile is a profiling system capable of profiling the
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whole system, include the kernel, kernel modules, libraries,
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and applications.
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If unsure, say N.
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config OPROFILE_EVENT_MULTIPLEX
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bool "OProfile multiplexing support (EXPERIMENTAL)"
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default n
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depends on OPROFILE && X86
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help
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The number of hardware counters is limited. The multiplexing
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feature enables OProfile to gather more events than counters
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are provided by the hardware. This is realized by switching
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between events at a user specified time interval.
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If unsure, say N.
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config HAVE_OPROFILE
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bool
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config OPROFILE_NMI_TIMER
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def_bool y
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depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
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config KPROBES
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bool "Kprobes"
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depends on MODULES
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depends on HAVE_KPROBES
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select KALLSYMS
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help
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Kprobes allows you to trap at almost any kernel address and
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execute a callback function. register_kprobe() establishes
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a probepoint and specifies the callback. Kprobes is useful
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for kernel debugging, non-intrusive instrumentation and testing.
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If in doubt, say "N".
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config JUMP_LABEL
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bool "Optimize very unlikely/likely branches"
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depends on HAVE_ARCH_JUMP_LABEL
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depends on CC_HAS_ASM_GOTO
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help
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This option enables a transparent branch optimization that
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makes certain almost-always-true or almost-always-false branch
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conditions even cheaper to execute within the kernel.
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Certain performance-sensitive kernel code, such as trace points,
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scheduler functionality, networking code and KVM have such
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branches and include support for this optimization technique.
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If it is detected that the compiler has support for "asm goto",
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the kernel will compile such branches with just a nop
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instruction. When the condition flag is toggled to true, the
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nop will be converted to a jump instruction to execute the
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conditional block of instructions.
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This technique lowers overhead and stress on the branch prediction
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of the processor and generally makes the kernel faster. The update
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of the condition is slower, but those are always very rare.
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( On 32-bit x86, the necessary options added to the compiler
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flags may increase the size of the kernel slightly. )
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config STATIC_KEYS_SELFTEST
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bool "Static key selftest"
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depends on JUMP_LABEL
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help
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Boot time self-test of the branch patching code.
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config OPTPROBES
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def_bool y
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depends on KPROBES && HAVE_OPTPROBES
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select TASKS_RCU if PREEMPTION
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config KPROBES_ON_FTRACE
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def_bool y
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depends on KPROBES && HAVE_KPROBES_ON_FTRACE
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depends on DYNAMIC_FTRACE_WITH_REGS
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help
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If function tracer is enabled and the arch supports full
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passing of pt_regs to function tracing, then kprobes can
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optimize on top of function tracing.
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config UPROBES
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def_bool n
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depends on ARCH_SUPPORTS_UPROBES
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help
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Uprobes is the user-space counterpart to kprobes: they
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enable instrumentation applications (such as 'perf probe')
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to establish unintrusive probes in user-space binaries and
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libraries, by executing handler functions when the probes
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are hit by user-space applications.
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( These probes come in the form of single-byte breakpoints,
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managed by the kernel and kept transparent to the probed
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application. )
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config HAVE_EFFICIENT_UNALIGNED_ACCESS
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bool
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help
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Some architectures are unable to perform unaligned accesses
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without the use of get_unaligned/put_unaligned. Others are
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unable to perform such accesses efficiently (e.g. trap on
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unaligned access and require fixing it up in the exception
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handler.)
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This symbol should be selected by an architecture if it can
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perform unaligned accesses efficiently to allow different
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code paths to be selected for these cases. Some network
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drivers, for example, could opt to not fix up alignment
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problems with received packets if doing so would not help
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much.
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See Documentation/unaligned-memory-access.txt for more
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information on the topic of unaligned memory accesses.
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config ARCH_USE_BUILTIN_BSWAP
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bool
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help
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Modern versions of GCC (since 4.4) have builtin functions
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for handling byte-swapping. Using these, instead of the old
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inline assembler that the architecture code provides in the
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__arch_bswapXX() macros, allows the compiler to see what's
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happening and offers more opportunity for optimisation. In
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particular, the compiler will be able to combine the byteswap
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with a nearby load or store and use load-and-swap or
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store-and-swap instructions if the architecture has them. It
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should almost *never* result in code which is worse than the
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hand-coded assembler in <asm/swab.h>. But just in case it
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does, the use of the builtins is optional.
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Any architecture with load-and-swap or store-and-swap
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instructions should set this. And it shouldn't hurt to set it
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on architectures that don't have such instructions.
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config KRETPROBES
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def_bool y
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depends on KPROBES && HAVE_KRETPROBES
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config USER_RETURN_NOTIFIER
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bool
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depends on HAVE_USER_RETURN_NOTIFIER
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help
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Provide a kernel-internal notification when a cpu is about to
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switch to user mode.
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config HAVE_IOREMAP_PROT
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bool
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config HAVE_KPROBES
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bool
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config HAVE_KRETPROBES
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bool
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config HAVE_OPTPROBES
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bool
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config HAVE_KPROBES_ON_FTRACE
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bool
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config HAVE_FUNCTION_ERROR_INJECTION
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bool
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config HAVE_NMI
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bool
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#
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# An arch should select this if it provides all these things:
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#
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# task_pt_regs() in asm/processor.h or asm/ptrace.h
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# arch_has_single_step() if there is hardware single-step support
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# arch_has_block_step() if there is hardware block-step support
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# asm/syscall.h supplying asm-generic/syscall.h interface
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# linux/regset.h user_regset interfaces
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# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
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# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
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# TIF_NOTIFY_RESUME calls tracehook_notify_resume()
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# signal delivery calls tracehook_signal_handler()
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#
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config HAVE_ARCH_TRACEHOOK
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bool
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config HAVE_DMA_CONTIGUOUS
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bool
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config GENERIC_SMP_IDLE_THREAD
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bool
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config GENERIC_IDLE_POLL_SETUP
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bool
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config ARCH_HAS_FORTIFY_SOURCE
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bool
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help
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An architecture should select this when it can successfully
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build and run with CONFIG_FORTIFY_SOURCE.
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#
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# Select if the arch provides a historic keepinit alias for the retain_initrd
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# command line option
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#
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config ARCH_HAS_KEEPINITRD
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bool
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# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
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config ARCH_HAS_SET_MEMORY
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bool
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# Select if arch has all set_direct_map_invalid/default() functions
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config ARCH_HAS_SET_DIRECT_MAP
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bool
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#
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# Select if arch has an uncached kernel segment and provides the
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# uncached_kernel_address / cached_kernel_address symbols to use it
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#
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config ARCH_HAS_UNCACHED_SEGMENT
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select ARCH_HAS_DMA_PREP_COHERENT
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bool
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# Select if arch init_task must go in the __init_task_data section
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config ARCH_TASK_STRUCT_ON_STACK
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bool
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# Select if arch has its private alloc_task_struct() function
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config ARCH_TASK_STRUCT_ALLOCATOR
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bool
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config HAVE_ARCH_THREAD_STRUCT_WHITELIST
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bool
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depends on !ARCH_TASK_STRUCT_ALLOCATOR
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help
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An architecture should select this to provide hardened usercopy
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knowledge about what region of the thread_struct should be
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whitelisted for copying to userspace. Normally this is only the
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FPU registers. Specifically, arch_thread_struct_whitelist()
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should be implemented. Without this, the entire thread_struct
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field in task_struct will be left whitelisted.
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# Select if arch has its private alloc_thread_stack() function
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config ARCH_THREAD_STACK_ALLOCATOR
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bool
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# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
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config ARCH_WANTS_DYNAMIC_TASK_STRUCT
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bool
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config ARCH_32BIT_OFF_T
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bool
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depends on !64BIT
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help
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All new 32-bit architectures should have 64-bit off_t type on
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userspace side which corresponds to the loff_t kernel type. This
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is the requirement for modern ABIs. Some existing architectures
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still support 32-bit off_t. This option is enabled for all such
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architectures explicitly.
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config HAVE_ASM_MODVERSIONS
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bool
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help
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This symbol should be selected by an architecure if it provides
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<asm/asm-prototypes.h> to support the module versioning for symbols
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exported from assembly code.
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config HAVE_REGS_AND_STACK_ACCESS_API
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bool
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help
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This symbol should be selected by an architecure if it supports
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the API needed to access registers and stack entries from pt_regs,
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declared in asm/ptrace.h
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For example the kprobes-based event tracer needs this API.
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config HAVE_RSEQ
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bool
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depends on HAVE_REGS_AND_STACK_ACCESS_API
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help
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This symbol should be selected by an architecture if it
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supports an implementation of restartable sequences.
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config HAVE_FUNCTION_ARG_ACCESS_API
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bool
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help
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This symbol should be selected by an architecure if it supports
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the API needed to access function arguments from pt_regs,
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declared in asm/ptrace.h
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config HAVE_CLK
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bool
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help
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The <linux/clk.h> calls support software clock gating and
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thus are a key power management tool on many systems.
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config HAVE_HW_BREAKPOINT
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bool
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depends on PERF_EVENTS
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config HAVE_MIXED_BREAKPOINTS_REGS
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bool
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depends on HAVE_HW_BREAKPOINT
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help
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Depending on the arch implementation of hardware breakpoints,
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some of them have separate registers for data and instruction
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breakpoints addresses, others have mixed registers to store
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them but define the access type in a control register.
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Select this option if your arch implements breakpoints under the
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latter fashion.
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config HAVE_USER_RETURN_NOTIFIER
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bool
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config HAVE_PERF_EVENTS_NMI
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bool
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help
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System hardware can generate an NMI using the perf event
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subsystem. Also has support for calculating CPU cycle events
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to determine how many clock cycles in a given period.
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config HAVE_HARDLOCKUP_DETECTOR_PERF
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bool
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depends on HAVE_PERF_EVENTS_NMI
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help
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The arch chooses to use the generic perf-NMI-based hardlockup
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detector. Must define HAVE_PERF_EVENTS_NMI.
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config HAVE_NMI_WATCHDOG
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depends on HAVE_NMI
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bool
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help
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The arch provides a low level NMI watchdog. It provides
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asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
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config HAVE_HARDLOCKUP_DETECTOR_ARCH
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bool
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select HAVE_NMI_WATCHDOG
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help
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The arch chooses to provide its own hardlockup detector, which is
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a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
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interfaces and parameters provided by hardlockup detector subsystem.
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config HAVE_PERF_REGS
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bool
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help
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Support selective register dumps for perf events. This includes
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bit-mapping of each registers and a unique architecture id.
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config HAVE_PERF_USER_STACK_DUMP
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bool
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help
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Support user stack dumps for perf event samples. This needs
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access to the user stack pointer which is not unified across
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architectures.
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config HAVE_ARCH_JUMP_LABEL
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bool
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config HAVE_ARCH_JUMP_LABEL_RELATIVE
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bool
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config HAVE_RCU_TABLE_FREE
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bool
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config HAVE_MMU_GATHER_PAGE_SIZE
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bool
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config MMU_GATHER_NO_RANGE
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bool
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config HAVE_MMU_GATHER_NO_GATHER
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bool
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config ARCH_HAVE_NMI_SAFE_CMPXCHG
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bool
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config HAVE_ALIGNED_STRUCT_PAGE
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bool
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help
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This makes sure that struct pages are double word aligned and that
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e.g. the SLUB allocator can perform double word atomic operations
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on a struct page for better performance. However selecting this
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might increase the size of a struct page by a word.
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config HAVE_CMPXCHG_LOCAL
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bool
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config HAVE_CMPXCHG_DOUBLE
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bool
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config ARCH_WEAK_RELEASE_ACQUIRE
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bool
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config ARCH_WANT_IPC_PARSE_VERSION
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bool
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config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
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bool
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config ARCH_WANT_OLD_COMPAT_IPC
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select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
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bool
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config HAVE_ARCH_SECCOMP_FILTER
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bool
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help
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An arch should select this symbol if it provides all of these things:
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- syscall_get_arch()
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- syscall_get_arguments()
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- syscall_rollback()
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- syscall_set_return_value()
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- SIGSYS siginfo_t support
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- secure_computing is called from a ptrace_event()-safe context
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- secure_computing return value is checked and a return value of -1
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results in the system call being skipped immediately.
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- seccomp syscall wired up
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config SECCOMP_FILTER
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def_bool y
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depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
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help
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Enable tasks to build secure computing environments defined
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in terms of Berkeley Packet Filter programs which implement
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task-defined system call filtering polices.
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See Documentation/userspace-api/seccomp_filter.rst for details.
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config HAVE_ARCH_STACKLEAK
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bool
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help
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An architecture should select this if it has the code which
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fills the used part of the kernel stack with the STACKLEAK_POISON
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value before returning from system calls.
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config HAVE_STACKPROTECTOR
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bool
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help
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An arch should select this symbol if:
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- it has implemented a stack canary (e.g. __stack_chk_guard)
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config CC_HAS_STACKPROTECTOR_NONE
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def_bool $(cc-option,-fno-stack-protector)
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config STACKPROTECTOR
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bool "Stack Protector buffer overflow detection"
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depends on HAVE_STACKPROTECTOR
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depends on $(cc-option,-fstack-protector)
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default y
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help
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This option turns on the "stack-protector" GCC feature. This
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feature puts, at the beginning of functions, a canary value on
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the stack just before the return address, and validates
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the value just before actually returning. Stack based buffer
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overflows (that need to overwrite this return address) now also
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overwrite the canary, which gets detected and the attack is then
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neutralized via a kernel panic.
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Functions will have the stack-protector canary logic added if they
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have an 8-byte or larger character array on the stack.
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This feature requires gcc version 4.2 or above, or a distribution
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gcc with the feature backported ("-fstack-protector").
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On an x86 "defconfig" build, this feature adds canary checks to
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about 3% of all kernel functions, which increases kernel code size
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by about 0.3%.
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config STACKPROTECTOR_STRONG
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bool "Strong Stack Protector"
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depends on STACKPROTECTOR
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depends on $(cc-option,-fstack-protector-strong)
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default y
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help
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Functions will have the stack-protector canary logic added in any
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of the following conditions:
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- local variable's address used as part of the right hand side of an
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assignment or function argument
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- local variable is an array (or union containing an array),
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regardless of array type or length
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- uses register local variables
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This feature requires gcc version 4.9 or above, or a distribution
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gcc with the feature backported ("-fstack-protector-strong").
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On an x86 "defconfig" build, this feature adds canary checks to
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about 20% of all kernel functions, which increases the kernel code
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size by about 2%.
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config HAVE_ARCH_WITHIN_STACK_FRAMES
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bool
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help
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An architecture should select this if it can walk the kernel stack
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frames to determine if an object is part of either the arguments
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or local variables (i.e. that it excludes saved return addresses,
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and similar) by implementing an inline arch_within_stack_frames(),
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which is used by CONFIG_HARDENED_USERCOPY.
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config HAVE_CONTEXT_TRACKING
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bool
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help
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Provide kernel/user boundaries probes necessary for subsystems
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that need it, such as userspace RCU extended quiescent state.
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Syscalls need to be wrapped inside user_exit()-user_enter() through
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the slow path using TIF_NOHZ flag. Exceptions handlers must be
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wrapped as well. Irqs are already protected inside
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rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
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irq exit still need to be protected.
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config HAVE_VIRT_CPU_ACCOUNTING
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bool
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config ARCH_HAS_SCALED_CPUTIME
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bool
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config HAVE_VIRT_CPU_ACCOUNTING_GEN
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bool
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default y if 64BIT
|
|
help
|
|
With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
|
|
Before enabling this option, arch code must be audited
|
|
to ensure there are no races in concurrent read/write of
|
|
cputime_t. For example, reading/writing 64-bit cputime_t on
|
|
some 32-bit arches may require multiple accesses, so proper
|
|
locking is needed to protect against concurrent accesses.
|
|
|
|
|
|
config HAVE_IRQ_TIME_ACCOUNTING
|
|
bool
|
|
help
|
|
Archs need to ensure they use a high enough resolution clock to
|
|
support irq time accounting and then call enable_sched_clock_irqtime().
|
|
|
|
config HAVE_MOVE_PMD
|
|
bool
|
|
help
|
|
Archs that select this are able to move page tables at the PMD level.
|
|
|
|
config HAVE_ARCH_TRANSPARENT_HUGEPAGE
|
|
bool
|
|
|
|
config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
|
|
bool
|
|
|
|
config HAVE_ARCH_HUGE_VMAP
|
|
bool
|
|
|
|
config ARCH_WANT_HUGE_PMD_SHARE
|
|
bool
|
|
|
|
config HAVE_ARCH_SOFT_DIRTY
|
|
bool
|
|
|
|
config HAVE_MOD_ARCH_SPECIFIC
|
|
bool
|
|
help
|
|
The arch uses struct mod_arch_specific to store data. Many arches
|
|
just need a simple module loader without arch specific data - those
|
|
should not enable this.
|
|
|
|
config MODULES_USE_ELF_RELA
|
|
bool
|
|
help
|
|
Modules only use ELF RELA relocations. Modules with ELF REL
|
|
relocations will give an error.
|
|
|
|
config MODULES_USE_ELF_REL
|
|
bool
|
|
help
|
|
Modules only use ELF REL relocations. Modules with ELF RELA
|
|
relocations will give an error.
|
|
|
|
config HAVE_IRQ_EXIT_ON_IRQ_STACK
|
|
bool
|
|
help
|
|
Architecture doesn't only execute the irq handler on the irq stack
|
|
but also irq_exit(). This way we can process softirqs on this irq
|
|
stack instead of switching to a new one when we call __do_softirq()
|
|
in the end of an hardirq.
|
|
This spares a stack switch and improves cache usage on softirq
|
|
processing.
|
|
|
|
config PGTABLE_LEVELS
|
|
int
|
|
default 2
|
|
|
|
config ARCH_HAS_ELF_RANDOMIZE
|
|
bool
|
|
help
|
|
An architecture supports choosing randomized locations for
|
|
stack, mmap, brk, and ET_DYN. Defined functions:
|
|
- arch_mmap_rnd()
|
|
- arch_randomize_brk()
|
|
|
|
config HAVE_ARCH_MMAP_RND_BITS
|
|
bool
|
|
help
|
|
An arch should select this symbol if it supports setting a variable
|
|
number of bits for use in establishing the base address for mmap
|
|
allocations, has MMU enabled and provides values for both:
|
|
- ARCH_MMAP_RND_BITS_MIN
|
|
- ARCH_MMAP_RND_BITS_MAX
|
|
|
|
config HAVE_EXIT_THREAD
|
|
bool
|
|
help
|
|
An architecture implements exit_thread.
|
|
|
|
config ARCH_MMAP_RND_BITS_MIN
|
|
int
|
|
|
|
config ARCH_MMAP_RND_BITS_MAX
|
|
int
|
|
|
|
config ARCH_MMAP_RND_BITS_DEFAULT
|
|
int
|
|
|
|
config ARCH_MMAP_RND_BITS
|
|
int "Number of bits to use for ASLR of mmap base address" if EXPERT
|
|
range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
|
|
default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
|
|
default ARCH_MMAP_RND_BITS_MIN
|
|
depends on HAVE_ARCH_MMAP_RND_BITS
|
|
help
|
|
This value can be used to select the number of bits to use to
|
|
determine the random offset to the base address of vma regions
|
|
resulting from mmap allocations. This value will be bounded
|
|
by the architecture's minimum and maximum supported values.
|
|
|
|
This value can be changed after boot using the
|
|
/proc/sys/vm/mmap_rnd_bits tunable
|
|
|
|
config HAVE_ARCH_MMAP_RND_COMPAT_BITS
|
|
bool
|
|
help
|
|
An arch should select this symbol if it supports running applications
|
|
in compatibility mode, supports setting a variable number of bits for
|
|
use in establishing the base address for mmap allocations, has MMU
|
|
enabled and provides values for both:
|
|
- ARCH_MMAP_RND_COMPAT_BITS_MIN
|
|
- ARCH_MMAP_RND_COMPAT_BITS_MAX
|
|
|
|
config ARCH_MMAP_RND_COMPAT_BITS_MIN
|
|
int
|
|
|
|
config ARCH_MMAP_RND_COMPAT_BITS_MAX
|
|
int
|
|
|
|
config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
|
|
int
|
|
|
|
config ARCH_MMAP_RND_COMPAT_BITS
|
|
int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
|
|
range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
|
|
default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
|
|
default ARCH_MMAP_RND_COMPAT_BITS_MIN
|
|
depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
|
|
help
|
|
This value can be used to select the number of bits to use to
|
|
determine the random offset to the base address of vma regions
|
|
resulting from mmap allocations for compatible applications This
|
|
value will be bounded by the architecture's minimum and maximum
|
|
supported values.
|
|
|
|
This value can be changed after boot using the
|
|
/proc/sys/vm/mmap_rnd_compat_bits tunable
|
|
|
|
config HAVE_ARCH_COMPAT_MMAP_BASES
|
|
bool
|
|
help
|
|
This allows 64bit applications to invoke 32-bit mmap() syscall
|
|
and vice-versa 32-bit applications to call 64-bit mmap().
|
|
Required for applications doing different bitness syscalls.
|
|
|
|
# This allows to use a set of generic functions to determine mmap base
|
|
# address by giving priority to top-down scheme only if the process
|
|
# is not in legacy mode (compat task, unlimited stack size or
|
|
# sysctl_legacy_va_layout).
|
|
# Architecture that selects this option can provide its own version of:
|
|
# - STACK_RND_MASK
|
|
config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
|
|
bool
|
|
depends on MMU
|
|
select ARCH_HAS_ELF_RANDOMIZE
|
|
|
|
config HAVE_COPY_THREAD_TLS
|
|
bool
|
|
help
|
|
Architecture provides copy_thread_tls to accept tls argument via
|
|
normal C parameter passing, rather than extracting the syscall
|
|
argument from pt_regs.
|
|
|
|
config HAVE_STACK_VALIDATION
|
|
bool
|
|
help
|
|
Architecture supports the 'objtool check' host tool command, which
|
|
performs compile-time stack metadata validation.
|
|
|
|
config HAVE_RELIABLE_STACKTRACE
|
|
bool
|
|
help
|
|
Architecture has a save_stack_trace_tsk_reliable() function which
|
|
only returns a stack trace if it can guarantee the trace is reliable.
|
|
|
|
config HAVE_ARCH_HASH
|
|
bool
|
|
default n
|
|
help
|
|
If this is set, the architecture provides an <asm/hash.h>
|
|
file which provides platform-specific implementations of some
|
|
functions in <linux/hash.h> or fs/namei.c.
|
|
|
|
config HAVE_ARCH_NVRAM_OPS
|
|
bool
|
|
|
|
config ISA_BUS_API
|
|
def_bool ISA
|
|
|
|
#
|
|
# ABI hall of shame
|
|
#
|
|
config CLONE_BACKWARDS
|
|
bool
|
|
help
|
|
Architecture has tls passed as the 4th argument of clone(2),
|
|
not the 5th one.
|
|
|
|
config CLONE_BACKWARDS2
|
|
bool
|
|
help
|
|
Architecture has the first two arguments of clone(2) swapped.
|
|
|
|
config CLONE_BACKWARDS3
|
|
bool
|
|
help
|
|
Architecture has tls passed as the 3rd argument of clone(2),
|
|
not the 5th one.
|
|
|
|
config ODD_RT_SIGACTION
|
|
bool
|
|
help
|
|
Architecture has unusual rt_sigaction(2) arguments
|
|
|
|
config OLD_SIGSUSPEND
|
|
bool
|
|
help
|
|
Architecture has old sigsuspend(2) syscall, of one-argument variety
|
|
|
|
config OLD_SIGSUSPEND3
|
|
bool
|
|
help
|
|
Even weirder antique ABI - three-argument sigsuspend(2)
|
|
|
|
config OLD_SIGACTION
|
|
bool
|
|
help
|
|
Architecture has old sigaction(2) syscall. Nope, not the same
|
|
as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
|
|
but fairly different variant of sigaction(2), thanks to OSF/1
|
|
compatibility...
|
|
|
|
config COMPAT_OLD_SIGACTION
|
|
bool
|
|
|
|
config 64BIT_TIME
|
|
def_bool y
|
|
help
|
|
This should be selected by all architectures that need to support
|
|
new system calls with a 64-bit time_t. This is relevant on all 32-bit
|
|
architectures, and 64-bit architectures as part of compat syscall
|
|
handling.
|
|
|
|
config COMPAT_32BIT_TIME
|
|
def_bool !64BIT || COMPAT
|
|
help
|
|
This enables 32 bit time_t support in addition to 64 bit time_t support.
|
|
This is relevant on all 32-bit architectures, and 64-bit architectures
|
|
as part of compat syscall handling.
|
|
|
|
config ARCH_NO_PREEMPT
|
|
bool
|
|
|
|
config ARCH_SUPPORTS_RT
|
|
bool
|
|
|
|
config CPU_NO_EFFICIENT_FFS
|
|
def_bool n
|
|
|
|
config HAVE_ARCH_VMAP_STACK
|
|
def_bool n
|
|
help
|
|
An arch should select this symbol if it can support kernel stacks
|
|
in vmalloc space. This means:
|
|
|
|
- vmalloc space must be large enough to hold many kernel stacks.
|
|
This may rule out many 32-bit architectures.
|
|
|
|
- Stacks in vmalloc space need to work reliably. For example, if
|
|
vmap page tables are created on demand, either this mechanism
|
|
needs to work while the stack points to a virtual address with
|
|
unpopulated page tables or arch code (switch_to() and switch_mm(),
|
|
most likely) needs to ensure that the stack's page table entries
|
|
are populated before running on a possibly unpopulated stack.
|
|
|
|
- If the stack overflows into a guard page, something reasonable
|
|
should happen. The definition of "reasonable" is flexible, but
|
|
instantly rebooting without logging anything would be unfriendly.
|
|
|
|
config VMAP_STACK
|
|
default y
|
|
bool "Use a virtually-mapped stack"
|
|
depends on HAVE_ARCH_VMAP_STACK && !KASAN
|
|
---help---
|
|
Enable this if you want the use virtually-mapped kernel stacks
|
|
with guard pages. This causes kernel stack overflows to be
|
|
caught immediately rather than causing difficult-to-diagnose
|
|
corruption.
|
|
|
|
This is presently incompatible with KASAN because KASAN expects
|
|
the stack to map directly to the KASAN shadow map using a formula
|
|
that is incorrect if the stack is in vmalloc space.
|
|
|
|
config ARCH_OPTIONAL_KERNEL_RWX
|
|
def_bool n
|
|
|
|
config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
|
|
def_bool n
|
|
|
|
config ARCH_HAS_STRICT_KERNEL_RWX
|
|
def_bool n
|
|
|
|
config STRICT_KERNEL_RWX
|
|
bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
|
|
depends on ARCH_HAS_STRICT_KERNEL_RWX
|
|
default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
|
|
help
|
|
If this is set, kernel text and rodata memory will be made read-only,
|
|
and non-text memory will be made non-executable. This provides
|
|
protection against certain security exploits (e.g. executing the heap
|
|
or modifying text)
|
|
|
|
These features are considered standard security practice these days.
|
|
You should say Y here in almost all cases.
|
|
|
|
config ARCH_HAS_STRICT_MODULE_RWX
|
|
def_bool n
|
|
|
|
config STRICT_MODULE_RWX
|
|
bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
|
|
depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
|
|
default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
|
|
help
|
|
If this is set, module text and rodata memory will be made read-only,
|
|
and non-text memory will be made non-executable. This provides
|
|
protection against certain security exploits (e.g. writing to text)
|
|
|
|
# select if the architecture provides an asm/dma-direct.h header
|
|
config ARCH_HAS_PHYS_TO_DMA
|
|
bool
|
|
|
|
config ARCH_HAS_REFCOUNT
|
|
bool
|
|
help
|
|
An architecture selects this when it has implemented refcount_t
|
|
using open coded assembly primitives that provide an optimized
|
|
refcount_t implementation, possibly at the expense of some full
|
|
refcount state checks of CONFIG_REFCOUNT_FULL=y.
|
|
|
|
The refcount overflow check behavior, however, must be retained.
|
|
Catching overflows is the primary security concern for protecting
|
|
against bugs in reference counts.
|
|
|
|
config REFCOUNT_FULL
|
|
bool "Perform full reference count validation at the expense of speed"
|
|
help
|
|
Enabling this switches the refcounting infrastructure from a fast
|
|
unchecked atomic_t implementation to a fully state checked
|
|
implementation, which can be (slightly) slower but provides protections
|
|
against various use-after-free conditions that can be used in
|
|
security flaw exploits.
|
|
|
|
config HAVE_ARCH_COMPILER_H
|
|
bool
|
|
help
|
|
An architecture can select this if it provides an
|
|
asm/compiler.h header that should be included after
|
|
linux/compiler-*.h in order to override macro definitions that those
|
|
headers generally provide.
|
|
|
|
config HAVE_ARCH_PREL32_RELOCATIONS
|
|
bool
|
|
help
|
|
May be selected by an architecture if it supports place-relative
|
|
32-bit relocations, both in the toolchain and in the module loader,
|
|
in which case relative references can be used in special sections
|
|
for PCI fixup, initcalls etc which are only half the size on 64 bit
|
|
architectures, and don't require runtime relocation on relocatable
|
|
kernels.
|
|
|
|
config ARCH_USE_MEMREMAP_PROT
|
|
bool
|
|
|
|
config LOCK_EVENT_COUNTS
|
|
bool "Locking event counts collection"
|
|
depends on DEBUG_FS
|
|
---help---
|
|
Enable light-weight counting of various locking related events
|
|
in the system with minimal performance impact. This reduces
|
|
the chance of application behavior change because of timing
|
|
differences. The counts are reported via debugfs.
|
|
|
|
# Select if the architecture has support for applying RELR relocations.
|
|
config ARCH_HAS_RELR
|
|
bool
|
|
|
|
config RELR
|
|
bool "Use RELR relocation packing"
|
|
depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
|
|
default y
|
|
help
|
|
Store the kernel's dynamic relocations in the RELR relocation packing
|
|
format. Requires a compatible linker (LLD supports this feature), as
|
|
well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
|
|
are compatible).
|
|
|
|
config ARCH_HAS_MEM_ENCRYPT
|
|
bool
|
|
|
|
source "kernel/gcov/Kconfig"
|
|
|
|
source "scripts/gcc-plugins/Kconfig"
|
|
|
|
endmenu
|