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Diffstat (limited to 'arch/Kconfig')
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diff --git a/arch/Kconfig b/arch/Kconfig new file mode 100644 index 000000000..dd71b34fe --- /dev/null +++ b/arch/Kconfig @@ -0,0 +1,880 @@ +# 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 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 PREEMPT + +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 arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h +config ARCH_HAS_SET_MEMORY + 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 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_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_RCU_TABLE_FREE + bool + +config HAVE_RCU_TABLE_INVALIDATE + 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_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_ARCH_TRANSPARENT_HUGEPAGE + bool + +config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD + bool + +config HAVE_ARCH_HUGE_VMAP + 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. + +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 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 ARCH_HAS_64BIT_TIME + 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 && 64BIT_TIME) || 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_COHERENT_DMA_MMAP + bool + +config ARCH_NO_PREEMPT + bool + +config CPU_NO_EFFICIENT_FFS + def_bool n + +config HAVE_ARCH_VMAP_STACK + def_bool n + help + An arch should select this symbol if it can support kernel stacks + in vmalloc space. This means: + + - vmalloc space must be large enough to hold many kernel stacks. + This may rule out many 32-bit architectures. + + - Stacks in vmalloc space need to work reliably. For example, if + vmap page tables are created on demand, either this mechanism + needs to work while the stack points to a virtual address with + unpopulated page tables or arch code (switch_to() and switch_mm(), + most likely) needs to ensure that the stack's page table entries + are populated before running on a possibly unpopulated stack. + + - If the stack overflows into a guard page, something reasonable + should happen. The definition of "reasonable" is flexible, but + instantly rebooting without logging anything would be unfriendly. + +config VMAP_STACK + default y + bool "Use a virtually-mapped stack" + depends on HAVE_ARCH_VMAP_STACK && !KASAN + ---help--- + Enable this if you want the use virtually-mapped kernel stacks + with guard pages. This causes kernel stack overflows to be + caught immediately rather than causing difficult-to-diagnose + corruption. + + This is presently incompatible with KASAN because KASAN expects + the stack to map directly to the KASAN shadow map using a formula + that is incorrect if the stack is in vmalloc space. + +config ARCH_OPTIONAL_KERNEL_RWX + def_bool n + +config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT + def_bool n + +config ARCH_HAS_STRICT_KERNEL_RWX + def_bool n + +config STRICT_KERNEL_RWX + bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX + depends on ARCH_HAS_STRICT_KERNEL_RWX + default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT + help + If this is set, kernel text and rodata memory will be made read-only, + and non-text memory will be made non-executable. This provides + protection against certain security exploits (e.g. executing the heap + or modifying text) + + These features are considered standard security practice these days. + You should say Y here in almost all cases. + +config ARCH_HAS_STRICT_MODULE_RWX + def_bool n + +config STRICT_MODULE_RWX + bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX + depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES + default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT + help + If this is set, module text and rodata memory will be made read-only, + and non-text memory will be made non-executable. This provides + protection against certain security exploits (e.g. writing to text) + +# select if the architecture provides an asm/dma-direct.h header +config ARCH_HAS_PHYS_TO_DMA + bool + +config ARCH_HAS_REFCOUNT + bool + help + An architecture selects this when it has implemented refcount_t + using open coded assembly primitives that provide an optimized + refcount_t implementation, possibly at the expense of some full + refcount state checks of CONFIG_REFCOUNT_FULL=y. + + The refcount overflow check behavior, however, must be retained. + Catching overflows is the primary security concern for protecting + against bugs in reference counts. + +config REFCOUNT_FULL + bool "Perform full reference count validation at the expense of speed" + help + Enabling this switches the refcounting infrastructure from a fast + unchecked atomic_t implementation to a fully state checked + implementation, which can be (slightly) slower but provides protections + against various use-after-free conditions that can be used in + security flaw exploits. + +config HAVE_ARCH_COMPILER_H + bool + help + An architecture can select this if it provides an + asm/compiler.h header that should be included after + linux/compiler-*.h in order to override macro definitions that those + headers generally provide. + +config HAVE_ARCH_PREL32_RELOCATIONS + bool + help + May be selected by an architecture if it supports place-relative + 32-bit relocations, both in the toolchain and in the module loader, + in which case relative references can be used in special sections + for PCI fixup, initcalls etc which are only half the size on 64 bit + architectures, and don't require runtime relocation on relocatable + kernels. + +config ARCH_USE_MEMREMAP_PROT + bool + +source "kernel/gcov/Kconfig" + +source "scripts/gcc-plugins/Kconfig" + +endmenu |