1447 lines
43 KiB
Plaintext
1447 lines
43 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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config ARCH_CONFIGURES_CPU_MITIGATIONS
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bool
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if !ARCH_CONFIGURES_CPU_MITIGATIONS
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config CPU_MITIGATIONS
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def_bool y
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endif
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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 ARCH_HAS_SUBPAGE_FAULTS
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bool
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help
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Select if the architecture can check permissions at sub-page
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granularity (e.g. arm64 MTE). The probe_user_*() functions
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must be implemented.
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config HOTPLUG_SMT
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bool
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config SMT_NUM_THREADS_DYNAMIC
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bool
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config GENERIC_ENTRY
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bool
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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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select TASKS_RCU if PREEMPTION
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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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select OBJTOOL if HAVE_JUMP_LABEL_HACK
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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 STATIC_CALL_SELFTEST
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bool "Static call selftest"
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depends on HAVE_STATIC_CALL
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help
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Boot time self-test of the call 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_64BIT_ALIGNED_ACCESS
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def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
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help
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Some architectures require 64 bit accesses to be 64 bit
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aligned, which also requires structs containing 64 bit values
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to be 64 bit aligned too. This includes some 32 bit
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architectures which can do 64 bit accesses, as well as 64 bit
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architectures without unaligned access.
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This symbol should be selected by an architecture if 64 bit
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accesses are required to be 64 bit aligned in this way even
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though it is not a 64 bit architecture.
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See Documentation/core-api/unaligned-memory-access.rst for
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more information on the topic of unaligned memory accesses.
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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/core-api/unaligned-memory-access.rst 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 || HAVE_RETHOOK)
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config KRETPROBE_ON_RETHOOK
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def_bool y
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depends on HAVE_RETHOOK
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depends on KRETPROBES
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select RETHOOK
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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 ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
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bool
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help
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Since kretprobes modifies return address on the stack, the
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stacktrace may see the kretprobe trampoline address instead
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of correct one. If the architecture stacktrace code and
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unwinder can adjust such entries, select this configuration.
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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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config HAVE_FUNCTION_DESCRIPTORS
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bool
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config TRACE_IRQFLAGS_SUPPORT
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bool
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config TRACE_IRQFLAGS_NMI_SUPPORT
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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 ptrace_report_syscall_{entry,exit}
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# TIF_NOTIFY_RESUME calls resume_user_mode_work()
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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 the architecture provides the arch_dma_set_uncached symbol to
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# either provide an uncached segment alias for a DMA allocation, or
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# to remap the page tables in place.
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#
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config ARCH_HAS_DMA_SET_UNCACHED
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bool
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#
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# Select if the architectures provides the arch_dma_clear_uncached symbol
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# to undo an in-place page table remap for uncached access.
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#
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config ARCH_HAS_DMA_CLEAR_UNCACHED
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bool
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config ARCH_HAS_CPU_FINALIZE_INIT
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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_WANTS_NO_INSTR
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bool
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help
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An architecture should select this if the noinstr macro is being used on
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functions to denote that the toolchain should avoid instrumenting such
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functions and is required for correctness.
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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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# Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat
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config ARCH_32BIT_USTAT_F_TINODE
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bool
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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 architecture 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 architecture 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_RUST
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bool
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help
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This symbol should be selected by an architecture if it
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supports Rust.
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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 architecture 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_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 MMU_GATHER_TABLE_FREE
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bool
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config MMU_GATHER_RCU_TABLE_FREE
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bool
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select MMU_GATHER_TABLE_FREE
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config 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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select MMU_GATHER_MERGE_VMAS
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config MMU_GATHER_NO_FLUSH_CACHE
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bool
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config MMU_GATHER_MERGE_VMAS
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bool
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config MMU_GATHER_NO_GATHER
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bool
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depends on MMU_GATHER_TABLE_FREE
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config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
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bool
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help
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Temporary select until all architectures can be converted to have
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irqs disabled over activate_mm. Architectures that do IPI based TLB
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shootdowns should enable this.
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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
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bool
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help
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||
An arch should select this symbol to support seccomp mode 1 (the fixed
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syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
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and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
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||
- __NR_seccomp_read_32
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- __NR_seccomp_write_32
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- __NR_seccomp_exit_32
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- __NR_seccomp_sigreturn_32
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||
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config HAVE_ARCH_SECCOMP_FILTER
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bool
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select HAVE_ARCH_SECCOMP
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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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||
- all the requirements for HAVE_ARCH_SECCOMP
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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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- if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
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||
SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
|
||
COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
|
||
|
||
config SECCOMP
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||
prompt "Enable seccomp to safely execute untrusted bytecode"
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||
def_bool y
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||
depends on HAVE_ARCH_SECCOMP
|
||
help
|
||
This kernel feature is useful for number crunching applications
|
||
that may need to handle untrusted bytecode during their
|
||
execution. By using pipes or other transports made available
|
||
to the process as file descriptors supporting the read/write
|
||
syscalls, it's possible to isolate those applications in their
|
||
own address space using seccomp. Once seccomp is enabled via
|
||
prctl(PR_SET_SECCOMP) or the seccomp() syscall, 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.
|
||
|
||
config SECCOMP_FILTER
|
||
def_bool y
|
||
depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
|
||
help
|
||
Enable tasks to build secure computing environments defined
|
||
in terms of Berkeley Packet Filter programs which implement
|
||
task-defined system call filtering polices.
|
||
|
||
See Documentation/userspace-api/seccomp_filter.rst for details.
|
||
|
||
config SECCOMP_CACHE_DEBUG
|
||
bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
|
||
depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
|
||
depends on PROC_FS
|
||
help
|
||
This enables the /proc/pid/seccomp_cache interface to monitor
|
||
seccomp cache data. The file format is subject to change. Reading
|
||
the file requires CAP_SYS_ADMIN.
|
||
|
||
This option is for debugging only. Enabling presents the risk that
|
||
an adversary may be able to infer the seccomp filter logic.
|
||
|
||
If unsure, say N.
|
||
|
||
config HAVE_ARCH_STACKLEAK
|
||
bool
|
||
help
|
||
An architecture should select this if it has the code which
|
||
fills the used part of the kernel stack with the STACKLEAK_POISON
|
||
value before returning from system calls.
|
||
|
||
config HAVE_STACKPROTECTOR
|
||
bool
|
||
help
|
||
An arch should select this symbol if:
|
||
- it has implemented a stack canary (e.g. __stack_chk_guard)
|
||
|
||
config STACKPROTECTOR
|
||
bool "Stack Protector buffer overflow detection"
|
||
depends on HAVE_STACKPROTECTOR
|
||
depends on $(cc-option,-fstack-protector)
|
||
default y
|
||
help
|
||
This option turns on the "stack-protector" GCC feature. This
|
||
feature puts, at the beginning of functions, a canary value on
|
||
the stack just before the return address, and validates
|
||
the value just before actually returning. Stack based buffer
|
||
overflows (that need to overwrite this return address) now also
|
||
overwrite the canary, which gets detected and the attack is then
|
||
neutralized via a kernel panic.
|
||
|
||
Functions will have the stack-protector canary logic added if they
|
||
have an 8-byte or larger character array on the stack.
|
||
|
||
This feature requires gcc version 4.2 or above, or a distribution
|
||
gcc with the feature backported ("-fstack-protector").
|
||
|
||
On an x86 "defconfig" build, this feature adds canary checks to
|
||
about 3% of all kernel functions, which increases kernel code size
|
||
by about 0.3%.
|
||
|
||
config STACKPROTECTOR_STRONG
|
||
bool "Strong Stack Protector"
|
||
depends on STACKPROTECTOR
|
||
depends on $(cc-option,-fstack-protector-strong)
|
||
default y
|
||
help
|
||
Functions will have the stack-protector canary logic added in any
|
||
of the following conditions:
|
||
|
||
- local variable's address used as part of the right hand side of an
|
||
assignment or function argument
|
||
- local variable is an array (or union containing an array),
|
||
regardless of array type or length
|
||
- uses register local variables
|
||
|
||
This feature requires gcc version 4.9 or above, or a distribution
|
||
gcc with the feature backported ("-fstack-protector-strong").
|
||
|
||
On an x86 "defconfig" build, this feature adds canary checks to
|
||
about 20% of all kernel functions, which increases the kernel code
|
||
size by about 2%.
|
||
|
||
config ARCH_SUPPORTS_SHADOW_CALL_STACK
|
||
bool
|
||
help
|
||
An architecture should select this if it supports the compiler's
|
||
Shadow Call Stack and implements runtime support for shadow stack
|
||
switching.
|
||
|
||
config SHADOW_CALL_STACK
|
||
bool "Shadow Call Stack"
|
||
depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
|
||
depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
|
||
depends on MMU
|
||
help
|
||
This option enables the compiler's Shadow Call Stack, which
|
||
uses a shadow stack to protect function return addresses from
|
||
being overwritten by an attacker. More information can be found
|
||
in the compiler's documentation:
|
||
|
||
- Clang: https://clang.llvm.org/docs/ShadowCallStack.html
|
||
- GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
|
||
|
||
Note that security guarantees in the kernel differ from the
|
||
ones documented for user space. The kernel must store addresses
|
||
of shadow stacks in memory, which means an attacker capable of
|
||
reading and writing arbitrary memory may be able to locate them
|
||
and hijack control flow by modifying the stacks.
|
||
|
||
config LTO
|
||
bool
|
||
help
|
||
Selected if the kernel will be built using the compiler's LTO feature.
|
||
|
||
config LTO_CLANG
|
||
bool
|
||
select LTO
|
||
help
|
||
Selected if the kernel will be built using Clang's LTO feature.
|
||
|
||
config ARCH_SUPPORTS_LTO_CLANG
|
||
bool
|
||
help
|
||
An architecture should select this option if it supports:
|
||
- compiling with Clang,
|
||
- compiling inline assembly with Clang's integrated assembler,
|
||
- and linking with LLD.
|
||
|
||
config ARCH_SUPPORTS_LTO_CLANG_THIN
|
||
bool
|
||
help
|
||
An architecture should select this option if it can support Clang's
|
||
ThinLTO mode.
|
||
|
||
config HAS_LTO_CLANG
|
||
def_bool y
|
||
depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM
|
||
depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
|
||
depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
|
||
depends on ARCH_SUPPORTS_LTO_CLANG
|
||
depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
|
||
depends on !KASAN || KASAN_HW_TAGS
|
||
depends on !GCOV_KERNEL
|
||
help
|
||
The compiler and Kconfig options support building with Clang's
|
||
LTO.
|
||
|
||
choice
|
||
prompt "Link Time Optimization (LTO)"
|
||
default LTO_NONE
|
||
help
|
||
This option enables Link Time Optimization (LTO), which allows the
|
||
compiler to optimize binaries globally.
|
||
|
||
If unsure, select LTO_NONE. Note that LTO is very resource-intensive
|
||
so it's disabled by default.
|
||
|
||
config LTO_NONE
|
||
bool "None"
|
||
help
|
||
Build the kernel normally, without Link Time Optimization (LTO).
|
||
|
||
config LTO_CLANG_FULL
|
||
bool "Clang Full LTO (EXPERIMENTAL)"
|
||
depends on HAS_LTO_CLANG
|
||
depends on !COMPILE_TEST
|
||
select LTO_CLANG
|
||
help
|
||
This option enables Clang's full Link Time Optimization (LTO), which
|
||
allows the compiler to optimize the kernel globally. If you enable
|
||
this option, the compiler generates LLVM bitcode instead of ELF
|
||
object files, and the actual compilation from bitcode happens at
|
||
the LTO link step, which may take several minutes depending on the
|
||
kernel configuration. More information can be found from LLVM's
|
||
documentation:
|
||
|
||
https://llvm.org/docs/LinkTimeOptimization.html
|
||
|
||
During link time, this option can use a large amount of RAM, and
|
||
may take much longer than the ThinLTO option.
|
||
|
||
config LTO_CLANG_THIN
|
||
bool "Clang ThinLTO (EXPERIMENTAL)"
|
||
depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
|
||
select LTO_CLANG
|
||
help
|
||
This option enables Clang's ThinLTO, which allows for parallel
|
||
optimization and faster incremental compiles compared to the
|
||
CONFIG_LTO_CLANG_FULL option. More information can be found
|
||
from Clang's documentation:
|
||
|
||
https://clang.llvm.org/docs/ThinLTO.html
|
||
|
||
If unsure, say Y.
|
||
endchoice
|
||
|
||
config ARCH_SUPPORTS_CFI_CLANG
|
||
bool
|
||
help
|
||
An architecture should select this option if it can support Clang's
|
||
Control-Flow Integrity (CFI) checking.
|
||
|
||
config ARCH_USES_CFI_TRAPS
|
||
bool
|
||
|
||
config CFI_CLANG
|
||
bool "Use Clang's Control Flow Integrity (CFI)"
|
||
depends on ARCH_SUPPORTS_CFI_CLANG
|
||
depends on $(cc-option,-fsanitize=kcfi)
|
||
help
|
||
This option enables Clang’s forward-edge Control Flow Integrity
|
||
(CFI) checking, where the compiler injects a runtime check to each
|
||
indirect function call to ensure the target is a valid function with
|
||
the correct static type. This restricts possible call targets and
|
||
makes it more difficult for an attacker to exploit bugs that allow
|
||
the modification of stored function pointers. More information can be
|
||
found from Clang's documentation:
|
||
|
||
https://clang.llvm.org/docs/ControlFlowIntegrity.html
|
||
|
||
config CFI_PERMISSIVE
|
||
bool "Use CFI in permissive mode"
|
||
depends on CFI_CLANG
|
||
help
|
||
When selected, Control Flow Integrity (CFI) violations result in a
|
||
warning instead of a kernel panic. This option should only be used
|
||
for finding indirect call type mismatches during development.
|
||
|
||
If unsure, say N.
|
||
|
||
config HAVE_ARCH_WITHIN_STACK_FRAMES
|
||
bool
|
||
help
|
||
An architecture should select this if it can walk the kernel stack
|
||
frames to determine if an object is part of either the arguments
|
||
or local variables (i.e. that it excludes saved return addresses,
|
||
and similar) by implementing an inline arch_within_stack_frames(),
|
||
which is used by CONFIG_HARDENED_USERCOPY.
|
||
|
||
config HAVE_CONTEXT_TRACKING_USER
|
||
bool
|
||
help
|
||
Provide kernel/user boundaries probes necessary for subsystems
|
||
that need it, such as userspace RCU extended quiescent state.
|
||
Syscalls need to be wrapped inside user_exit()-user_enter(), either
|
||
optimized behind static key or through the slow path using TIF_NOHZ
|
||
flag. Exceptions handlers must be wrapped as well. Irqs are already
|
||
protected inside ct_irq_enter/ct_irq_exit() but preemption or signal
|
||
handling on irq exit still need to be protected.
|
||
|
||
config HAVE_CONTEXT_TRACKING_USER_OFFSTACK
|
||
bool
|
||
help
|
||
Architecture neither relies on exception_enter()/exception_exit()
|
||
nor on schedule_user(). Also preempt_schedule_notrace() and
|
||
preempt_schedule_irq() can't be called in a preemptible section
|
||
while context tracking is CONTEXT_USER. This feature reflects a sane
|
||
entry implementation where the following requirements are met on
|
||
critical entry code, ie: before user_exit() or after user_enter():
|
||
|
||
- Critical entry code isn't preemptible (or better yet:
|
||
not interruptible).
|
||
- No use of RCU read side critical sections, unless ct_nmi_enter()
|
||
got called.
|
||
- No use of instrumentation, unless instrumentation_begin() got
|
||
called.
|
||
|
||
config HAVE_TIF_NOHZ
|
||
bool
|
||
help
|
||
Arch relies on TIF_NOHZ and syscall slow path to implement context
|
||
tracking calls to user_enter()/user_exit().
|
||
|
||
config HAVE_VIRT_CPU_ACCOUNTING
|
||
bool
|
||
|
||
config HAVE_VIRT_CPU_ACCOUNTING_IDLE
|
||
bool
|
||
help
|
||
Architecture has its own way to account idle CPU time and therefore
|
||
doesn't implement vtime_account_idle().
|
||
|
||
config ARCH_HAS_SCALED_CPUTIME
|
||
bool
|
||
|
||
config HAVE_VIRT_CPU_ACCOUNTING_GEN
|
||
bool
|
||
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_PUD
|
||
bool
|
||
help
|
||
Architectures that select this are able to move page tables at the
|
||
PUD level. If there are only 3 page table levels, the move effectively
|
||
happens at the PGD level.
|
||
|
||
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
|
||
|
||
#
|
||
# Archs that select this would be capable of PMD-sized vmaps (i.e.,
|
||
# arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag
|
||
# must be used to enable allocations to use hugepages.
|
||
#
|
||
config HAVE_ARCH_HUGE_VMALLOC
|
||
depends on 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 ARCH_WANTS_MODULES_DATA_IN_VMALLOC
|
||
bool
|
||
help
|
||
For architectures like powerpc/32 which have constraints on module
|
||
allocation and need to allocate module data outside of module area.
|
||
|
||
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 HAVE_SOFTIRQ_ON_OWN_STACK
|
||
bool
|
||
help
|
||
Architecture provides a function to run __do_softirq() on a
|
||
separate stack.
|
||
|
||
config SOFTIRQ_ON_OWN_STACK
|
||
def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT
|
||
|
||
config ALTERNATE_USER_ADDRESS_SPACE
|
||
bool
|
||
help
|
||
Architectures set this when the CPU uses separate address
|
||
spaces for kernel and user space pointers. In this case, the
|
||
access_ok() check on a __user pointer is skipped.
|
||
|
||
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.
|
||
|
||
config PAGE_SIZE_LESS_THAN_64KB
|
||
def_bool y
|
||
depends on !ARM64_64K_PAGES
|
||
depends on !IA64_PAGE_SIZE_64KB
|
||
depends on !PAGE_SIZE_64KB
|
||
depends on !PARISC_PAGE_SIZE_64KB
|
||
depends on PAGE_SIZE_LESS_THAN_256KB
|
||
|
||
config PAGE_SIZE_LESS_THAN_256KB
|
||
def_bool y
|
||
depends on !PAGE_SIZE_256KB
|
||
|
||
# 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_OBJTOOL
|
||
bool
|
||
|
||
config HAVE_JUMP_LABEL_HACK
|
||
bool
|
||
|
||
config HAVE_NOINSTR_HACK
|
||
bool
|
||
|
||
config HAVE_NOINSTR_VALIDATION
|
||
bool
|
||
|
||
config HAVE_UACCESS_VALIDATION
|
||
bool
|
||
select OBJTOOL
|
||
|
||
config HAVE_STACK_VALIDATION
|
||
bool
|
||
help
|
||
Architecture supports objtool compile-time frame pointer rule
|
||
validation.
|
||
|
||
config HAVE_RELIABLE_STACKTRACE
|
||
bool
|
||
help
|
||
Architecture has either save_stack_trace_tsk_reliable() or
|
||
arch_stack_walk_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 COMPAT_32BIT_TIME
|
||
bool "Provide system calls for 32-bit time_t"
|
||
default !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_EPHEMERAL_INODES
|
||
def_bool n
|
||
help
|
||
An arch should select this symbol if it doesn't keep track of inode
|
||
instances on its own, but instead relies on something else (e.g. the
|
||
host kernel for an UML kernel).
|
||
|
||
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
|
||
depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
|
||
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.
|
||
|
||
To use this with software KASAN modes, the architecture must support
|
||
backing virtual mappings with real shadow memory, and KASAN_VMALLOC
|
||
must be enabled.
|
||
|
||
config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
|
||
def_bool n
|
||
help
|
||
An arch should select this symbol if it can support kernel stack
|
||
offset randomization with calls to add_random_kstack_offset()
|
||
during syscall entry and choose_random_kstack_offset() during
|
||
syscall exit. Careful removal of -fstack-protector-strong and
|
||
-fstack-protector should also be applied to the entry code and
|
||
closely examined, as the artificial stack bump looks like an array
|
||
to the compiler, so it will attempt to add canary checks regardless
|
||
of the static branch state.
|
||
|
||
config RANDOMIZE_KSTACK_OFFSET
|
||
bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT
|
||
default y
|
||
depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
|
||
depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
|
||
help
|
||
The kernel stack offset can be randomized (after pt_regs) by
|
||
roughly 5 bits of entropy, frustrating memory corruption
|
||
attacks that depend on stack address determinism or
|
||
cross-syscall address exposures.
|
||
|
||
The feature is controlled via the "randomize_kstack_offset=on/off"
|
||
kernel boot param, and if turned off has zero overhead due to its use
|
||
of static branches (see JUMP_LABEL).
|
||
|
||
If unsure, say Y.
|
||
|
||
config RANDOMIZE_KSTACK_OFFSET_DEFAULT
|
||
bool "Default state of kernel stack offset randomization"
|
||
depends on RANDOMIZE_KSTACK_OFFSET
|
||
help
|
||
Kernel stack offset randomization is controlled by kernel boot param
|
||
"randomize_kstack_offset=on/off", and this config chooses the default
|
||
boot state.
|
||
|
||
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 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
|
||
|
||
config ARCH_HAS_CC_PLATFORM
|
||
bool
|
||
|
||
config HAVE_SPARSE_SYSCALL_NR
|
||
bool
|
||
help
|
||
An architecture should select this if its syscall numbering is sparse
|
||
to save space. For example, MIPS architecture has a syscall array with
|
||
entries at 4000, 5000 and 6000 locations. This option turns on syscall
|
||
related optimizations for a given architecture.
|
||
|
||
config ARCH_HAS_VDSO_DATA
|
||
bool
|
||
|
||
config HAVE_STATIC_CALL
|
||
bool
|
||
|
||
config HAVE_STATIC_CALL_INLINE
|
||
bool
|
||
depends on HAVE_STATIC_CALL
|
||
select OBJTOOL
|
||
|
||
config HAVE_PREEMPT_DYNAMIC
|
||
bool
|
||
|
||
config HAVE_PREEMPT_DYNAMIC_CALL
|
||
bool
|
||
depends on HAVE_STATIC_CALL
|
||
select HAVE_PREEMPT_DYNAMIC
|
||
help
|
||
An architecture should select this if it can handle the preemption
|
||
model being selected at boot time using static calls.
|
||
|
||
Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a
|
||
preemption function will be patched directly.
|
||
|
||
Where an architecture does not select HAVE_STATIC_CALL_INLINE, any
|
||
call to a preemption function will go through a trampoline, and the
|
||
trampoline will be patched.
|
||
|
||
It is strongly advised to support inline static call to avoid any
|
||
overhead.
|
||
|
||
config HAVE_PREEMPT_DYNAMIC_KEY
|
||
bool
|
||
depends on HAVE_ARCH_JUMP_LABEL
|
||
select HAVE_PREEMPT_DYNAMIC
|
||
help
|
||
An architecture should select this if it can handle the preemption
|
||
model being selected at boot time using static keys.
|
||
|
||
Each preemption function will be given an early return based on a
|
||
static key. This should have slightly lower overhead than non-inline
|
||
static calls, as this effectively inlines each trampoline into the
|
||
start of its callee. This may avoid redundant work, and may
|
||
integrate better with CFI schemes.
|
||
|
||
This will have greater overhead than using inline static calls as
|
||
the call to the preemption function cannot be entirely elided.
|
||
|
||
config ARCH_WANT_LD_ORPHAN_WARN
|
||
bool
|
||
help
|
||
An arch should select this symbol once all linker sections are explicitly
|
||
included, size-asserted, or discarded in the linker scripts. This is
|
||
important because we never want expected sections to be placed heuristically
|
||
by the linker, since the locations of such sections can change between linker
|
||
versions.
|
||
|
||
config HAVE_ARCH_PFN_VALID
|
||
bool
|
||
|
||
config ARCH_SUPPORTS_DEBUG_PAGEALLOC
|
||
bool
|
||
|
||
config ARCH_SUPPORTS_PAGE_TABLE_CHECK
|
||
bool
|
||
|
||
config ARCH_SPLIT_ARG64
|
||
bool
|
||
help
|
||
If a 32-bit architecture requires 64-bit arguments to be split into
|
||
pairs of 32-bit arguments, select this option.
|
||
|
||
config ARCH_HAS_ELFCORE_COMPAT
|
||
bool
|
||
|
||
config ARCH_HAS_PARANOID_L1D_FLUSH
|
||
bool
|
||
|
||
config ARCH_HAVE_TRACE_MMIO_ACCESS
|
||
bool
|
||
|
||
config DYNAMIC_SIGFRAME
|
||
bool
|
||
|
||
# Select, if arch has a named attribute group bound to NUMA device nodes.
|
||
config HAVE_ARCH_NODE_DEV_GROUP
|
||
bool
|
||
|
||
config ARCH_HAS_NONLEAF_PMD_YOUNG
|
||
bool
|
||
help
|
||
Architectures that select this option are capable of setting the
|
||
accessed bit in non-leaf PMD entries when using them as part of linear
|
||
address translations. Page table walkers that clear the accessed bit
|
||
may use this capability to reduce their search space.
|
||
|
||
source "kernel/gcov/Kconfig"
|
||
|
||
source "scripts/gcc-plugins/Kconfig"
|
||
|
||
endmenu
|