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# SPDX-License-Identifier: GPL-2.0 # # General architecture dependent options # # # Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can # override the default values in this file. # source "arch/$(SRCARCH)/Kconfig" menu "General architecture-dependent options" config CRASH_CORE bool config KEXEC_CORE select CRASH_CORE bool config KEXEC_ELF bool config HAVE_IMA_KEXEC bool config HOTPLUG_SMT bool config OPROFILE tristate "OProfile system profiling" depends on PROFILING depends on HAVE_OPROFILE select RING_BUFFER select RING_BUFFER_ALLOW_SWAP help OProfile is a profiling system capable of profiling the whole system, include the kernel, kernel modules, libraries, and applications. If unsure, say N. config OPROFILE_EVENT_MULTIPLEX bool "OProfile multiplexing support (EXPERIMENTAL)" default n depends on OPROFILE && X86 help The number of hardware counters is limited. The multiplexing feature enables OProfile to gather more events than counters are provided by the hardware. This is realized by switching between events at a user specified time interval. If unsure, say N. config HAVE_OPROFILE bool config OPROFILE_NMI_TIMER def_bool y depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 config KPROBES bool "Kprobes" depends on MODULES depends on HAVE_KPROBES select KALLSYMS help Kprobes allows you to trap at almost any kernel address and execute a callback function. register_kprobe() establishes a probepoint and specifies the callback. Kprobes is useful for kernel debugging, non-intrusive instrumentation and testing. If in doubt, say "N". config JUMP_LABEL bool "Optimize very unlikely/likely branches" depends on HAVE_ARCH_JUMP_LABEL depends on CC_HAS_ASM_GOTO help This option enables a transparent branch optimization that makes certain almost-always-true or almost-always-false branch conditions even cheaper to execute within the kernel. Certain performance-sensitive kernel code, such as trace points, scheduler functionality, networking code and KVM have such branches and include support for this optimization technique. If it is detected that the compiler has support for "asm goto", the kernel will compile such branches with just a nop instruction. When the condition flag is toggled to true, the nop will be converted to a jump instruction to execute the conditional block of instructions. This technique lowers overhead and stress on the branch prediction of the processor and generally makes the kernel faster. The update of the condition is slower, but those are always very rare. ( On 32-bit x86, the necessary options added to the compiler flags may increase the size of the kernel slightly. ) config STATIC_KEYS_SELFTEST bool "Static key selftest" depends on JUMP_LABEL help Boot time self-test of the branch patching code. config OPTPROBES def_bool y depends on KPROBES && HAVE_OPTPROBES select TASKS_RCU if PREEMPTION config KPROBES_ON_FTRACE def_bool y depends on KPROBES && HAVE_KPROBES_ON_FTRACE depends on DYNAMIC_FTRACE_WITH_REGS help If function tracer is enabled and the arch supports full passing of pt_regs to function tracing, then kprobes can optimize on top of function tracing. config UPROBES def_bool n depends on ARCH_SUPPORTS_UPROBES help Uprobes is the user-space counterpart to kprobes: they enable instrumentation applications (such as 'perf probe') to establish unintrusive probes in user-space binaries and libraries, by executing handler functions when the probes are hit by user-space applications. ( These probes come in the form of single-byte breakpoints, managed by the kernel and kept transparent to the probed application. ) config HAVE_64BIT_ALIGNED_ACCESS def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS help Some architectures require 64 bit accesses to be 64 bit aligned, which also requires structs containing 64 bit values to be 64 bit aligned too. This includes some 32 bit architectures which can do 64 bit accesses, as well as 64 bit architectures without unaligned access. This symbol should be selected by an architecture if 64 bit accesses are required to be 64 bit aligned in this way even though it is not a 64 bit architecture. See Documentation/unaligned-memory-access.txt for more information on the topic of unaligned memory accesses. config HAVE_EFFICIENT_UNALIGNED_ACCESS bool help Some architectures are unable to perform unaligned accesses without the use of get_unaligned/put_unaligned. Others are unable to perform such accesses efficiently (e.g. trap on unaligned access and require fixing it up in the exception handler.) This symbol should be selected by an architecture if it can perform unaligned accesses efficiently to allow different code paths to be selected for these cases. Some network drivers, for example, could opt to not fix up alignment problems with received packets if doing so would not help much. See Documentation/unaligned-memory-access.txt for more information on the topic of unaligned memory accesses. config ARCH_USE_BUILTIN_BSWAP bool help Modern versions of GCC (since 4.4) have builtin functions for handling byte-swapping. Using these, instead of the old inline assembler that the architecture code provides in the __arch_bswapXX() macros, allows the compiler to see what's happening and offers more opportunity for optimisation. In particular, the compiler will be able to combine the byteswap with a nearby load or store and use load-and-swap or store-and-swap instructions if the architecture has them. It should almost *never* result in code which is worse than the hand-coded assembler in <asm/swab.h>. But just in case it does, the use of the builtins is optional. Any architecture with load-and-swap or store-and-swap instructions should set this. And it shouldn't hurt to set it on architectures that don't have such instructions. config KRETPROBES def_bool y depends on KPROBES && HAVE_KRETPROBES config USER_RETURN_NOTIFIER bool depends on HAVE_USER_RETURN_NOTIFIER help Provide a kernel-internal notification when a cpu is about to switch to user mode. config HAVE_IOREMAP_PROT bool config HAVE_KPROBES bool config HAVE_KRETPROBES bool config HAVE_OPTPROBES bool config HAVE_KPROBES_ON_FTRACE bool config HAVE_FUNCTION_ERROR_INJECTION bool config HAVE_NMI bool # # An arch should select this if it provides all these things: # # task_pt_regs() in asm/processor.h or asm/ptrace.h # arch_has_single_step() if there is hardware single-step support # arch_has_block_step() if there is hardware block-step support # asm/syscall.h supplying asm-generic/syscall.h interface # linux/regset.h user_regset interfaces # CORE_DUMP_USE_REGSET #define'd in linux/elf.h # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} # TIF_NOTIFY_RESUME calls tracehook_notify_resume() # signal delivery calls tracehook_signal_handler() # config HAVE_ARCH_TRACEHOOK bool config HAVE_DMA_CONTIGUOUS bool config GENERIC_SMP_IDLE_THREAD bool config GENERIC_IDLE_POLL_SETUP bool config ARCH_HAS_FORTIFY_SOURCE bool help An architecture should select this when it can successfully build and run with CONFIG_FORTIFY_SOURCE. # # Select if the arch provides a historic keepinit alias for the retain_initrd # command line option # config ARCH_HAS_KEEPINITRD bool # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h config ARCH_HAS_SET_MEMORY bool # Select if arch has all set_direct_map_invalid/default() functions config ARCH_HAS_SET_DIRECT_MAP bool # # Select if arch has an uncached kernel segment and provides the # uncached_kernel_address / cached_kernel_address symbols to use it # config ARCH_HAS_UNCACHED_SEGMENT select ARCH_HAS_DMA_PREP_COHERENT bool config ARCH_HAS_CPU_FINALIZE_INIT bool # Select if arch init_task must go in the __init_task_data section config ARCH_TASK_STRUCT_ON_STACK bool # Select if arch has its private alloc_task_struct() function config ARCH_TASK_STRUCT_ALLOCATOR bool config HAVE_ARCH_THREAD_STRUCT_WHITELIST bool depends on !ARCH_TASK_STRUCT_ALLOCATOR help An architecture should select this to provide hardened usercopy knowledge about what region of the thread_struct should be whitelisted for copying to userspace. Normally this is only the FPU registers. Specifically, arch_thread_struct_whitelist() should be implemented. Without this, the entire thread_struct field in task_struct will be left whitelisted. # Select if arch has its private alloc_thread_stack() function config ARCH_THREAD_STACK_ALLOCATOR bool # Select if arch wants to size task_struct dynamically via arch_task_struct_size: config ARCH_WANTS_DYNAMIC_TASK_STRUCT bool config ARCH_32BIT_OFF_T bool depends on !64BIT help All new 32-bit architectures should have 64-bit off_t type on userspace side which corresponds to the loff_t kernel type. This is the requirement for modern ABIs. Some existing architectures still support 32-bit off_t. This option is enabled for all such architectures explicitly. config HAVE_ASM_MODVERSIONS bool help This symbol should be selected by an architecure if it provides <asm/asm-prototypes.h> to support the module versioning for symbols exported from assembly code. config HAVE_REGS_AND_STACK_ACCESS_API bool help This symbol should be selected by an architecure if it supports the API needed to access registers and stack entries from pt_regs, declared in asm/ptrace.h For example the kprobes-based event tracer needs this API. config HAVE_RSEQ bool depends on HAVE_REGS_AND_STACK_ACCESS_API help This symbol should be selected by an architecture if it supports an implementation of restartable sequences. config HAVE_FUNCTION_ARG_ACCESS_API bool help This symbol should be selected by an architecure if it supports the API needed to access function arguments from pt_regs, declared in asm/ptrace.h config HAVE_CLK bool help The <linux/clk.h> calls support software clock gating and thus are a key power management tool on many systems. config HAVE_HW_BREAKPOINT bool depends on PERF_EVENTS config HAVE_MIXED_BREAKPOINTS_REGS bool depends on HAVE_HW_BREAKPOINT help Depending on the arch implementation of hardware breakpoints, some of them have separate registers for data and instruction breakpoints addresses, others have mixed registers to store them but define the access type in a control register. Select this option if your arch implements breakpoints under the latter fashion. config HAVE_USER_RETURN_NOTIFIER bool config HAVE_PERF_EVENTS_NMI bool help System hardware can generate an NMI using the perf event subsystem. Also has support for calculating CPU cycle events to determine how many clock cycles in a given period. config HAVE_HARDLOCKUP_DETECTOR_PERF bool depends on HAVE_PERF_EVENTS_NMI help The arch chooses to use the generic perf-NMI-based hardlockup detector. Must define HAVE_PERF_EVENTS_NMI. config HAVE_NMI_WATCHDOG depends on HAVE_NMI bool help The arch provides a low level NMI watchdog. It provides asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). config HAVE_HARDLOCKUP_DETECTOR_ARCH bool select HAVE_NMI_WATCHDOG help The arch chooses to provide its own hardlockup detector, which is a superset of the HAVE_NMI_WATCHDOG. It also conforms to config interfaces and parameters provided by hardlockup detector subsystem. config HAVE_PERF_REGS bool help Support selective register dumps for perf events. This includes bit-mapping of each registers and a unique architecture id. config HAVE_PERF_USER_STACK_DUMP bool help Support user stack dumps for perf event samples. This needs access to the user stack pointer which is not unified across architectures. config HAVE_ARCH_JUMP_LABEL bool config HAVE_ARCH_JUMP_LABEL_RELATIVE bool config HAVE_RCU_TABLE_FREE bool config HAVE_MMU_GATHER_PAGE_SIZE bool config MMU_GATHER_NO_RANGE bool config HAVE_MMU_GATHER_NO_GATHER bool config ARCH_WANT_IRQS_OFF_ACTIVATE_MM bool help Temporary select until all architectures can be converted to have irqs disabled over activate_mm. Architectures that do IPI based TLB shootdowns should enable this. config ARCH_HAVE_NMI_SAFE_CMPXCHG bool config HAVE_ALIGNED_STRUCT_PAGE bool help This makes sure that struct pages are double word aligned and that e.g. the SLUB allocator can perform double word atomic operations on a struct page for better performance. However selecting this might increase the size of a struct page by a word. config HAVE_CMPXCHG_LOCAL bool config HAVE_CMPXCHG_DOUBLE bool config ARCH_WEAK_RELEASE_ACQUIRE bool config ARCH_WANT_IPC_PARSE_VERSION bool config ARCH_WANT_COMPAT_IPC_PARSE_VERSION bool config ARCH_WANT_OLD_COMPAT_IPC select ARCH_WANT_COMPAT_IPC_PARSE_VERSION bool config HAVE_ARCH_SECCOMP_FILTER bool help An arch should select this symbol if it provides all of these things: - syscall_get_arch() - syscall_get_arguments() - syscall_rollback() - syscall_set_return_value() - SIGSYS siginfo_t support - secure_computing is called from a ptrace_event()-safe context - secure_computing return value is checked and a return value of -1 results in the system call being skipped immediately. - seccomp syscall wired up 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 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 CC_HAS_STACKPROTECTOR_NONE def_bool $(cc-option,-fno-stack-protector) 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 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 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() through the slow path using TIF_NOHZ flag. Exceptions handlers must be wrapped as well. Irqs are already protected inside rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on irq exit still need to be protected. config HAVE_VIRT_CPU_ACCOUNTING bool 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_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 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