Lines Matching +full:no +full:- +full:unaligned +full:- +full:direct +full:- +full:access
1 # SPDX-License-Identifier: GPL-2.0
12 menu "General architecture-dependent options"
30 Select if the architecture can check permissions at sub-page
50 for kernel debugging, non-intrusive instrumentation and testing.
59 makes certain almost-always-true or almost-always-false branch
62 Certain performance-sensitive kernel code, such as trace points,
76 ( On 32-bit x86, the necessary options added to the compiler
83 Boot time self-test of the branch patching code.
89 Boot time self-test of the call patching code.
109 Uprobes is the user-space counterpart to kprobes: they
111 to establish unintrusive probes in user-space binaries and
113 are hit by user-space applications.
115 ( These probes come in the form of single-byte breakpoints,
126 architectures without unaligned access.
132 See Documentation/core-api/unaligned-memory-access.rst for
133 more information on the topic of unaligned memory accesses.
138 Some architectures are unable to perform unaligned accesses
141 unaligned access and require fixing it up in the exception
145 perform unaligned accesses efficiently to allow different
151 See Documentation/core-api/unaligned-memory-access.rst for more
152 information on the topic of unaligned memory accesses.
158 for handling byte-swapping. Using these, instead of the old
163 with a nearby load or store and use load-and-swap or
164 store-and-swap instructions if the architecture has them. It
166 hand-coded assembler in <asm/swab.h>. But just in case it
169 Any architecture with load-and-swap or store-and-swap
187 Provide a kernel-internal notification when a cpu is about to
232 # arch_has_single_step() if there is hardware single-step support
233 # arch_has_block_step() if there is hardware block-step support
234 # asm/syscall.h supplying asm-generic/syscall.h interface
283 # to undo an in-place page table remap for uncached access.
326 All new 32-bit architectures should have 64-bit off_t type on
329 still support 32-bit off_t. This option is enabled for all such
340 <asm/asm-prototypes.h> to support the module versioning for symbols
347 the API needed to access registers and stack entries from pt_regs,
349 For example the kprobes-based event tracer needs this API.
368 the API needed to access function arguments from pt_regs,
382 them but define the access type in a control register.
400 The arch chooses to use the generic perf-NMI-based hardlockup
422 bit-mapping of each registers and a unique architecture id.
428 access to the user stack pointer which is not unified across
503 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
504 - __NR_seccomp_read_32
505 - __NR_seccomp_write_32
506 - __NR_seccomp_exit_32
507 - __NR_seccomp_sigreturn_32
514 - all the requirements for HAVE_ARCH_SECCOMP
515 - syscall_get_arch()
516 - syscall_get_arguments()
517 - syscall_rollback()
518 - syscall_set_return_value()
519 - SIGSYS siginfo_t support
520 - secure_computing is called from a ptrace_event()-safe context
521 - secure_computing return value is checked and a return value of -1
523 - seccomp syscall wired up
524 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
551 task-defined system call filtering polices.
553 See Documentation/userspace-api/seccomp_filter.rst for details.
580 - it has implemented a stack canary (e.g. __stack_chk_guard)
585 depends on $(cc-option,-fstack-protector)
588 This option turns on the "stack-protector" GCC feature. This
596 Functions will have the stack-protector canary logic added if they
597 have an 8-byte or larger character array on the stack.
600 gcc with the feature backported ("-fstack-protector").
609 depends on $(cc-option,-fstack-protector-strong)
612 Functions will have the stack-protector canary logic added in any
615 - local variable's address used as part of the right hand side of an
617 - local variable is an array (or union containing an array),
619 - uses register local variables
622 gcc with the feature backported ("-fstack-protector-strong").
645 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
646 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
669 - compiling with Clang,
670 - compiling inline assembly with Clang's integrated assembler,
671 - and linking with LLD.
682 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
683 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
699 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
745 Control-Flow Integrity (CFI) checking.
753 depends on $(cc-option,-fsanitize=kcfi)
755 This option enables Clang’s forward-edge Control Flow Integrity
789 Syscalls need to be wrapped inside user_exit()-user_enter(), either
805 - Critical entry code isn't preemptible (or better yet:
807 - No use of RCU read side critical sections, unless ct_nmi_enter()
809 - No use of instrumentation, unless instrumentation_begin() got
834 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
836 to ensure there are no races in concurrent read/write of
837 cputime_t. For example, reading/writing 64-bit cputime_t on
838 some 32-bit arches may require multiple accesses, so proper
869 # Archs that select this would be capable of PMD-sized vmaps (i.e.,
887 just need a simple module loader without arch specific data - those
943 - arch_mmap_rnd()
944 - arch_randomize_brk()
952 - ARCH_MMAP_RND_BITS_MIN
953 - ARCH_MMAP_RND_BITS_MAX
991 - ARCH_MMAP_RND_COMPAT_BITS_MIN
992 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1022 This allows 64bit applications to invoke 32-bit mmap() syscall
1023 and vice-versa 32-bit applications to call 64-bit mmap().
1039 # address by giving priority to top-down scheme only if the process
1043 # - STACK_RND_MASK
1068 Architecture supports objtool compile-time frame pointer rule
1083 file which provides platform-specific implementations of some
1120 Architecture has old sigsuspend(2) syscall, of one-argument variety
1125 Even weirder antique ABI - three-argument sigsuspend(2)
1131 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1139 bool "Provide system calls for 32-bit time_t"
1143 This is relevant on all 32-bit architectures, and 64-bit architectures
1168 - vmalloc space must be large enough to hold many kernel stacks.
1169 This may rule out many 32-bit architectures.
1171 - Stacks in vmalloc space need to work reliably. For example, if
1178 - If the stack overflows into a guard page, something reasonable
1184 bool "Use a virtually-mapped stack"
1188 Enable this if you want the use virtually-mapped kernel stacks
1190 caught immediately rather than causing difficult-to-diagnose
1203 syscall exit. Careful removal of -fstack-protector-strong and
1204 -fstack-protector should also be applied to the entry code and
1218 cross-syscall address exposures.
1244 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1248 If this is set, kernel text and rodata memory will be made read-only,
1249 and non-text memory will be made non-executable. This provides
1264 If this is set, module text and rodata memory will be made read-only,
1265 and non-text memory will be made non-executable. This provides
1268 # select if the architecture provides an asm/dma-direct.h header
1277 linux/compiler-*.h in order to override macro definitions that those
1283 May be selected by an architecture if it supports place-relative
1284 32-bit relocations, both in the toolchain and in the module loader,
1297 Enable light-weight counting of various locking related events
1313 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1371 static key. This should have slightly lower overhead than non-inline
1383 included, size-asserted, or discarded in the linker scripts. This is
1400 If a 32-bit architecture requires 64-bit arguments to be split into
1401 pairs of 32-bit arguments, select this option.
1423 accessed bit in non-leaf PMD entries when using them as part of linear
1429 source "scripts/gcc-plugins/Kconfig"