1 # SPDX-License-Identifier: GPL-2.0
3 # General architecture dependent options
7 # Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can
8 # override the default values in this file.
10 source "arch/$(SRCARCH)/Kconfig"
12 menu "General architecture-dependent options"
28 tristate "OProfile system profiling"
30 depends on HAVE_OPROFILE
32 select RING_BUFFER_ALLOW_SWAP
34 OProfile is a profiling system capable of profiling the
35 whole system, include the kernel, kernel modules, libraries,
40 config OPROFILE_EVENT_MULTIPLEX
41 bool "OProfile multiplexing support (EXPERIMENTAL)"
43 depends on OPROFILE && X86
45 The number of hardware counters is limited. The multiplexing
46 feature enables OProfile to gather more events than counters
47 are provided by the hardware. This is realized by switching
48 between events at a user specified time interval.
55 config OPROFILE_NMI_TIMER
57 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
62 depends on HAVE_KPROBES
65 Kprobes allows you to trap at almost any kernel address and
66 execute a callback function. register_kprobe() establishes
67 a probepoint and specifies the callback. Kprobes is useful
68 for kernel debugging, non-intrusive instrumentation and testing.
72 bool "Optimize very unlikely/likely branches"
73 depends on HAVE_ARCH_JUMP_LABEL
74 depends on CC_HAS_ASM_GOTO
76 This option enables a transparent branch optimization that
77 makes certain almost-always-true or almost-always-false branch
78 conditions even cheaper to execute within the kernel.
80 Certain performance-sensitive kernel code, such as trace points,
81 scheduler functionality, networking code and KVM have such
82 branches and include support for this optimization technique.
84 If it is detected that the compiler has support for "asm goto",
85 the kernel will compile such branches with just a nop
86 instruction. When the condition flag is toggled to true, the
87 nop will be converted to a jump instruction to execute the
88 conditional block of instructions.
90 This technique lowers overhead and stress on the branch prediction
91 of the processor and generally makes the kernel faster. The update
92 of the condition is slower, but those are always very rare.
94 ( On 32-bit x86, the necessary options added to the compiler
95 flags may increase the size of the kernel slightly. )
97 config STATIC_KEYS_SELFTEST
98 bool "Static key selftest"
101 Boot time self-test of the branch patching code.
105 depends on KPROBES && HAVE_OPTPROBES
106 select TASKS_RCU if PREEMPT
108 config KPROBES_ON_FTRACE
110 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
111 depends on DYNAMIC_FTRACE_WITH_REGS
113 If function tracer is enabled and the arch supports full
114 passing of pt_regs to function tracing, then kprobes can
115 optimize on top of function tracing.
119 depends on ARCH_SUPPORTS_UPROBES
121 Uprobes is the user-space counterpart to kprobes: they
122 enable instrumentation applications (such as 'perf probe')
123 to establish unintrusive probes in user-space binaries and
124 libraries, by executing handler functions when the probes
125 are hit by user-space applications.
127 ( These probes come in the form of single-byte breakpoints,
128 managed by the kernel and kept transparent to the probed
131 config HAVE_64BIT_ALIGNED_ACCESS
132 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
134 Some architectures require 64 bit accesses to be 64 bit
135 aligned, which also requires structs containing 64 bit values
136 to be 64 bit aligned too. This includes some 32 bit
137 architectures which can do 64 bit accesses, as well as 64 bit
138 architectures without unaligned access.
140 This symbol should be selected by an architecture if 64 bit
141 accesses are required to be 64 bit aligned in this way even
142 though it is not a 64 bit architecture.
144 See Documentation/unaligned-memory-access.txt for more
145 information on the topic of unaligned memory accesses.
147 config HAVE_EFFICIENT_UNALIGNED_ACCESS
150 Some architectures are unable to perform unaligned accesses
151 without the use of get_unaligned/put_unaligned. Others are
152 unable to perform such accesses efficiently (e.g. trap on
153 unaligned access and require fixing it up in the exception
156 This symbol should be selected by an architecture if it can
157 perform unaligned accesses efficiently to allow different
158 code paths to be selected for these cases. Some network
159 drivers, for example, could opt to not fix up alignment
160 problems with received packets if doing so would not help
163 See Documentation/unaligned-memory-access.txt for more
164 information on the topic of unaligned memory accesses.
166 config ARCH_USE_BUILTIN_BSWAP
169 Modern versions of GCC (since 4.4) have builtin functions
170 for handling byte-swapping. Using these, instead of the old
171 inline assembler that the architecture code provides in the
172 __arch_bswapXX() macros, allows the compiler to see what's
173 happening and offers more opportunity for optimisation. In
174 particular, the compiler will be able to combine the byteswap
175 with a nearby load or store and use load-and-swap or
176 store-and-swap instructions if the architecture has them. It
177 should almost *never* result in code which is worse than the
178 hand-coded assembler in <asm/swab.h>. But just in case it
179 does, the use of the builtins is optional.
181 Any architecture with load-and-swap or store-and-swap
182 instructions should set this. And it shouldn't hurt to set it
183 on architectures that don't have such instructions.
187 depends on KPROBES && HAVE_KRETPROBES
189 config USER_RETURN_NOTIFIER
191 depends on HAVE_USER_RETURN_NOTIFIER
193 Provide a kernel-internal notification when a cpu is about to
196 config HAVE_IOREMAP_PROT
202 config HAVE_KRETPROBES
205 config HAVE_OPTPROBES
208 config HAVE_KPROBES_ON_FTRACE
211 config HAVE_FUNCTION_ERROR_INJECTION
218 # An arch should select this if it provides all these things:
220 # task_pt_regs() in asm/processor.h or asm/ptrace.h
221 # arch_has_single_step() if there is hardware single-step support
222 # arch_has_block_step() if there is hardware block-step support
223 # asm/syscall.h supplying asm-generic/syscall.h interface
224 # linux/regset.h user_regset interfaces
225 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h
226 # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
227 # TIF_NOTIFY_RESUME calls tracehook_notify_resume()
228 # signal delivery calls tracehook_signal_handler()
230 config HAVE_ARCH_TRACEHOOK
233 config HAVE_DMA_CONTIGUOUS
236 config GENERIC_SMP_IDLE_THREAD
239 config GENERIC_IDLE_POLL_SETUP
242 config ARCH_HAS_FORTIFY_SOURCE
245 An architecture should select this when it can successfully
246 build and run with CONFIG_FORTIFY_SOURCE.
248 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
249 config ARCH_HAS_SET_MEMORY
252 # Select if arch init_task must go in the __init_task_data section
253 config ARCH_TASK_STRUCT_ON_STACK
256 # Select if arch has its private alloc_task_struct() function
257 config ARCH_TASK_STRUCT_ALLOCATOR
260 config HAVE_ARCH_THREAD_STRUCT_WHITELIST
262 depends on !ARCH_TASK_STRUCT_ALLOCATOR
264 An architecture should select this to provide hardened usercopy
265 knowledge about what region of the thread_struct should be
266 whitelisted for copying to userspace. Normally this is only the
267 FPU registers. Specifically, arch_thread_struct_whitelist()
268 should be implemented. Without this, the entire thread_struct
269 field in task_struct will be left whitelisted.
271 # Select if arch has its private alloc_thread_stack() function
272 config ARCH_THREAD_STACK_ALLOCATOR
275 # Select if arch wants to size task_struct dynamically via arch_task_struct_size:
276 config ARCH_WANTS_DYNAMIC_TASK_STRUCT
279 config ARCH_32BIT_OFF_T
283 All new 32-bit architectures should have 64-bit off_t type on
284 userspace side which corresponds to the loff_t kernel type. This
285 is the requirement for modern ABIs. Some existing architectures
286 still support 32-bit off_t. This option is enabled for all such
287 architectures explicitly.
289 config HAVE_REGS_AND_STACK_ACCESS_API
292 This symbol should be selected by an architecure if it supports
293 the API needed to access registers and stack entries from pt_regs,
294 declared in asm/ptrace.h
295 For example the kprobes-based event tracer needs this API.
299 depends on HAVE_REGS_AND_STACK_ACCESS_API
301 This symbol should be selected by an architecture if it
302 supports an implementation of restartable sequences.
304 config HAVE_FUNCTION_ARG_ACCESS_API
307 This symbol should be selected by an architecure if it supports
308 the API needed to access function arguments from pt_regs,
309 declared in asm/ptrace.h
314 The <linux/clk.h> calls support software clock gating and
315 thus are a key power management tool on many systems.
317 config HAVE_HW_BREAKPOINT
319 depends on PERF_EVENTS
321 config HAVE_MIXED_BREAKPOINTS_REGS
323 depends on HAVE_HW_BREAKPOINT
325 Depending on the arch implementation of hardware breakpoints,
326 some of them have separate registers for data and instruction
327 breakpoints addresses, others have mixed registers to store
328 them but define the access type in a control register.
329 Select this option if your arch implements breakpoints under the
332 config HAVE_USER_RETURN_NOTIFIER
335 config HAVE_PERF_EVENTS_NMI
338 System hardware can generate an NMI using the perf event
339 subsystem. Also has support for calculating CPU cycle events
340 to determine how many clock cycles in a given period.
342 config HAVE_HARDLOCKUP_DETECTOR_PERF
344 depends on HAVE_PERF_EVENTS_NMI
346 The arch chooses to use the generic perf-NMI-based hardlockup
347 detector. Must define HAVE_PERF_EVENTS_NMI.
349 config HAVE_NMI_WATCHDOG
353 The arch provides a low level NMI watchdog. It provides
354 asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
356 config HAVE_HARDLOCKUP_DETECTOR_ARCH
358 select HAVE_NMI_WATCHDOG
360 The arch chooses to provide its own hardlockup detector, which is
361 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
362 interfaces and parameters provided by hardlockup detector subsystem.
364 config HAVE_PERF_REGS
367 Support selective register dumps for perf events. This includes
368 bit-mapping of each registers and a unique architecture id.
370 config HAVE_PERF_USER_STACK_DUMP
373 Support user stack dumps for perf event samples. This needs
374 access to the user stack pointer which is not unified across
377 config HAVE_ARCH_JUMP_LABEL
380 config HAVE_ARCH_JUMP_LABEL_RELATIVE
383 config HAVE_RCU_TABLE_FREE
386 config HAVE_RCU_TABLE_NO_INVALIDATE
389 config HAVE_MMU_GATHER_PAGE_SIZE
392 config HAVE_MMU_GATHER_NO_GATHER
395 config ARCH_HAVE_NMI_SAFE_CMPXCHG
398 config HAVE_ALIGNED_STRUCT_PAGE
401 This makes sure that struct pages are double word aligned and that
402 e.g. the SLUB allocator can perform double word atomic operations
403 on a struct page for better performance. However selecting this
404 might increase the size of a struct page by a word.
406 config HAVE_CMPXCHG_LOCAL
409 config HAVE_CMPXCHG_DOUBLE
412 config ARCH_WEAK_RELEASE_ACQUIRE
415 config ARCH_WANT_IPC_PARSE_VERSION
418 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
421 config ARCH_WANT_OLD_COMPAT_IPC
422 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
425 config HAVE_ARCH_SECCOMP_FILTER
428 An arch should select this symbol if it provides all of these things:
430 - syscall_get_arguments()
432 - syscall_set_return_value()
433 - SIGSYS siginfo_t support
434 - secure_computing is called from a ptrace_event()-safe context
435 - secure_computing return value is checked and a return value of -1
436 results in the system call being skipped immediately.
437 - seccomp syscall wired up
439 config SECCOMP_FILTER
441 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
443 Enable tasks to build secure computing environments defined
444 in terms of Berkeley Packet Filter programs which implement
445 task-defined system call filtering polices.
447 See Documentation/userspace-api/seccomp_filter.rst for details.
449 config HAVE_ARCH_STACKLEAK
452 An architecture should select this if it has the code which
453 fills the used part of the kernel stack with the STACKLEAK_POISON
454 value before returning from system calls.
456 config HAVE_STACKPROTECTOR
459 An arch should select this symbol if:
460 - it has implemented a stack canary (e.g. __stack_chk_guard)
462 config CC_HAS_STACKPROTECTOR_NONE
463 def_bool $(cc-option,-fno-stack-protector)
465 config STACKPROTECTOR
466 bool "Stack Protector buffer overflow detection"
467 depends on HAVE_STACKPROTECTOR
468 depends on $(cc-option,-fstack-protector)
471 This option turns on the "stack-protector" GCC feature. This
472 feature puts, at the beginning of functions, a canary value on
473 the stack just before the return address, and validates
474 the value just before actually returning. Stack based buffer
475 overflows (that need to overwrite this return address) now also
476 overwrite the canary, which gets detected and the attack is then
477 neutralized via a kernel panic.
479 Functions will have the stack-protector canary logic added if they
480 have an 8-byte or larger character array on the stack.
482 This feature requires gcc version 4.2 or above, or a distribution
483 gcc with the feature backported ("-fstack-protector").
485 On an x86 "defconfig" build, this feature adds canary checks to
486 about 3% of all kernel functions, which increases kernel code size
489 config STACKPROTECTOR_STRONG
490 bool "Strong Stack Protector"
491 depends on STACKPROTECTOR
492 depends on $(cc-option,-fstack-protector-strong)
495 Functions will have the stack-protector canary logic added in any
496 of the following conditions:
498 - local variable's address used as part of the right hand side of an
499 assignment or function argument
500 - local variable is an array (or union containing an array),
501 regardless of array type or length
502 - uses register local variables
504 This feature requires gcc version 4.9 or above, or a distribution
505 gcc with the feature backported ("-fstack-protector-strong").
507 On an x86 "defconfig" build, this feature adds canary checks to
508 about 20% of all kernel functions, which increases the kernel code
511 config HAVE_ARCH_WITHIN_STACK_FRAMES
514 An architecture should select this if it can walk the kernel stack
515 frames to determine if an object is part of either the arguments
516 or local variables (i.e. that it excludes saved return addresses,
517 and similar) by implementing an inline arch_within_stack_frames(),
518 which is used by CONFIG_HARDENED_USERCOPY.
520 config HAVE_CONTEXT_TRACKING
523 Provide kernel/user boundaries probes necessary for subsystems
524 that need it, such as userspace RCU extended quiescent state.
525 Syscalls need to be wrapped inside user_exit()-user_enter() through
526 the slow path using TIF_NOHZ flag. Exceptions handlers must be
527 wrapped as well. Irqs are already protected inside
528 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
529 irq exit still need to be protected.
531 config HAVE_VIRT_CPU_ACCOUNTING
534 config ARCH_HAS_SCALED_CPUTIME
537 config HAVE_VIRT_CPU_ACCOUNTING_GEN
541 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
542 Before enabling this option, arch code must be audited
543 to ensure there are no races in concurrent read/write of
544 cputime_t. For example, reading/writing 64-bit cputime_t on
545 some 32-bit arches may require multiple accesses, so proper
546 locking is needed to protect against concurrent accesses.
549 config HAVE_IRQ_TIME_ACCOUNTING
552 Archs need to ensure they use a high enough resolution clock to
553 support irq time accounting and then call enable_sched_clock_irqtime().
558 Archs that select this are able to move page tables at the PMD level.
560 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
563 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
566 config HAVE_ARCH_HUGE_VMAP
569 config HAVE_ARCH_SOFT_DIRTY
572 config HAVE_MOD_ARCH_SPECIFIC
575 The arch uses struct mod_arch_specific to store data. Many arches
576 just need a simple module loader without arch specific data - those
577 should not enable this.
579 config MODULES_USE_ELF_RELA
582 Modules only use ELF RELA relocations. Modules with ELF REL
583 relocations will give an error.
585 config MODULES_USE_ELF_REL
588 Modules only use ELF REL relocations. Modules with ELF RELA
589 relocations will give an error.
591 config HAVE_IRQ_EXIT_ON_IRQ_STACK
594 Architecture doesn't only execute the irq handler on the irq stack
595 but also irq_exit(). This way we can process softirqs on this irq
596 stack instead of switching to a new one when we call __do_softirq()
597 in the end of an hardirq.
598 This spares a stack switch and improves cache usage on softirq
601 config PGTABLE_LEVELS
605 config ARCH_HAS_ELF_RANDOMIZE
608 An architecture supports choosing randomized locations for
609 stack, mmap, brk, and ET_DYN. Defined functions:
611 - arch_randomize_brk()
613 config HAVE_ARCH_MMAP_RND_BITS
616 An arch should select this symbol if it supports setting a variable
617 number of bits for use in establishing the base address for mmap
618 allocations, has MMU enabled and provides values for both:
619 - ARCH_MMAP_RND_BITS_MIN
620 - ARCH_MMAP_RND_BITS_MAX
622 config HAVE_EXIT_THREAD
625 An architecture implements exit_thread.
627 config ARCH_MMAP_RND_BITS_MIN
630 config ARCH_MMAP_RND_BITS_MAX
633 config ARCH_MMAP_RND_BITS_DEFAULT
636 config ARCH_MMAP_RND_BITS
637 int "Number of bits to use for ASLR of mmap base address" if EXPERT
638 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
639 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
640 default ARCH_MMAP_RND_BITS_MIN
641 depends on HAVE_ARCH_MMAP_RND_BITS
643 This value can be used to select the number of bits to use to
644 determine the random offset to the base address of vma regions
645 resulting from mmap allocations. This value will be bounded
646 by the architecture's minimum and maximum supported values.
648 This value can be changed after boot using the
649 /proc/sys/vm/mmap_rnd_bits tunable
651 config HAVE_ARCH_MMAP_RND_COMPAT_BITS
654 An arch should select this symbol if it supports running applications
655 in compatibility mode, supports setting a variable number of bits for
656 use in establishing the base address for mmap allocations, has MMU
657 enabled and provides values for both:
658 - ARCH_MMAP_RND_COMPAT_BITS_MIN
659 - ARCH_MMAP_RND_COMPAT_BITS_MAX
661 config ARCH_MMAP_RND_COMPAT_BITS_MIN
664 config ARCH_MMAP_RND_COMPAT_BITS_MAX
667 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
670 config ARCH_MMAP_RND_COMPAT_BITS
671 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
672 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
673 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
674 default ARCH_MMAP_RND_COMPAT_BITS_MIN
675 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
677 This value can be used to select the number of bits to use to
678 determine the random offset to the base address of vma regions
679 resulting from mmap allocations for compatible applications This
680 value will be bounded by the architecture's minimum and maximum
683 This value can be changed after boot using the
684 /proc/sys/vm/mmap_rnd_compat_bits tunable
686 config HAVE_ARCH_COMPAT_MMAP_BASES
689 This allows 64bit applications to invoke 32-bit mmap() syscall
690 and vice-versa 32-bit applications to call 64-bit mmap().
691 Required for applications doing different bitness syscalls.
693 config HAVE_COPY_THREAD_TLS
696 Architecture provides copy_thread_tls to accept tls argument via
697 normal C parameter passing, rather than extracting the syscall
698 argument from pt_regs.
700 config HAVE_STACK_VALIDATION
703 Architecture supports the 'objtool check' host tool command, which
704 performs compile-time stack metadata validation.
706 config HAVE_RELIABLE_STACKTRACE
709 Architecture has a save_stack_trace_tsk_reliable() function which
710 only returns a stack trace if it can guarantee the trace is reliable.
712 config HAVE_ARCH_HASH
716 If this is set, the architecture provides an <asm/hash.h>
717 file which provides platform-specific implementations of some
718 functions in <linux/hash.h> or fs/namei.c.
720 config HAVE_ARCH_NVRAM_OPS
729 config CLONE_BACKWARDS
732 Architecture has tls passed as the 4th argument of clone(2),
735 config CLONE_BACKWARDS2
738 Architecture has the first two arguments of clone(2) swapped.
740 config CLONE_BACKWARDS3
743 Architecture has tls passed as the 3rd argument of clone(2),
746 config ODD_RT_SIGACTION
749 Architecture has unusual rt_sigaction(2) arguments
751 config OLD_SIGSUSPEND
754 Architecture has old sigsuspend(2) syscall, of one-argument variety
756 config OLD_SIGSUSPEND3
759 Even weirder antique ABI - three-argument sigsuspend(2)
764 Architecture has old sigaction(2) syscall. Nope, not the same
765 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
766 but fairly different variant of sigaction(2), thanks to OSF/1
769 config COMPAT_OLD_SIGACTION
773 def_bool ARCH_HAS_64BIT_TIME
775 This should be selected by all architectures that need to support
776 new system calls with a 64-bit time_t. This is relevant on all 32-bit
777 architectures, and 64-bit architectures as part of compat syscall
780 config COMPAT_32BIT_TIME
781 def_bool !64BIT || COMPAT
783 This enables 32 bit time_t support in addition to 64 bit time_t support.
784 This is relevant on all 32-bit architectures, and 64-bit architectures
785 as part of compat syscall handling.
787 config ARCH_NO_COHERENT_DMA_MMAP
790 config ARCH_NO_PREEMPT
793 config CPU_NO_EFFICIENT_FFS
796 config HAVE_ARCH_VMAP_STACK
799 An arch should select this symbol if it can support kernel stacks
800 in vmalloc space. This means:
802 - vmalloc space must be large enough to hold many kernel stacks.
803 This may rule out many 32-bit architectures.
805 - Stacks in vmalloc space need to work reliably. For example, if
806 vmap page tables are created on demand, either this mechanism
807 needs to work while the stack points to a virtual address with
808 unpopulated page tables or arch code (switch_to() and switch_mm(),
809 most likely) needs to ensure that the stack's page table entries
810 are populated before running on a possibly unpopulated stack.
812 - If the stack overflows into a guard page, something reasonable
813 should happen. The definition of "reasonable" is flexible, but
814 instantly rebooting without logging anything would be unfriendly.
818 bool "Use a virtually-mapped stack"
819 depends on HAVE_ARCH_VMAP_STACK && !KASAN
821 Enable this if you want the use virtually-mapped kernel stacks
822 with guard pages. This causes kernel stack overflows to be
823 caught immediately rather than causing difficult-to-diagnose
826 This is presently incompatible with KASAN because KASAN expects
827 the stack to map directly to the KASAN shadow map using a formula
828 that is incorrect if the stack is in vmalloc space.
830 config ARCH_OPTIONAL_KERNEL_RWX
833 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
836 config ARCH_HAS_STRICT_KERNEL_RWX
839 config STRICT_KERNEL_RWX
840 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
841 depends on ARCH_HAS_STRICT_KERNEL_RWX
842 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
844 If this is set, kernel text and rodata memory will be made read-only,
845 and non-text memory will be made non-executable. This provides
846 protection against certain security exploits (e.g. executing the heap
849 These features are considered standard security practice these days.
850 You should say Y here in almost all cases.
852 config ARCH_HAS_STRICT_MODULE_RWX
855 config STRICT_MODULE_RWX
856 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
857 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
858 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
860 If this is set, module text and rodata memory will be made read-only,
861 and non-text memory will be made non-executable. This provides
862 protection against certain security exploits (e.g. writing to text)
864 # select if the architecture provides an asm/dma-direct.h header
865 config ARCH_HAS_PHYS_TO_DMA
868 config ARCH_HAS_REFCOUNT
871 An architecture selects this when it has implemented refcount_t
872 using open coded assembly primitives that provide an optimized
873 refcount_t implementation, possibly at the expense of some full
874 refcount state checks of CONFIG_REFCOUNT_FULL=y.
876 The refcount overflow check behavior, however, must be retained.
877 Catching overflows is the primary security concern for protecting
878 against bugs in reference counts.
881 bool "Perform full reference count validation at the expense of speed"
883 Enabling this switches the refcounting infrastructure from a fast
884 unchecked atomic_t implementation to a fully state checked
885 implementation, which can be (slightly) slower but provides protections
886 against various use-after-free conditions that can be used in
887 security flaw exploits.
889 config HAVE_ARCH_COMPILER_H
892 An architecture can select this if it provides an
893 asm/compiler.h header that should be included after
894 linux/compiler-*.h in order to override macro definitions that those
895 headers generally provide.
897 config HAVE_ARCH_PREL32_RELOCATIONS
900 May be selected by an architecture if it supports place-relative
901 32-bit relocations, both in the toolchain and in the module loader,
902 in which case relative references can be used in special sections
903 for PCI fixup, initcalls etc which are only half the size on 64 bit
904 architectures, and don't require runtime relocation on relocatable
907 config ARCH_USE_MEMREMAP_PROT
910 config LOCK_EVENT_COUNTS
911 bool "Locking event counts collection"
914 Enable light-weight counting of various locking related events
915 in the system with minimal performance impact. This reduces
916 the chance of application behavior change because of timing
917 differences. The counts are reported via debugfs.
919 source "kernel/gcov/Kconfig"
921 source "scripts/gcc-plugins/Kconfig"