Lines Matching +full:no +full:- +full:unaligned +full:- +full:direct +full:- +full:access
1 # SPDX-License-Identifier: GPL-2.0
22 # IOMMUs not handled by dma-iommu. Drivers must never select this symbol.
29 menu "General architecture-dependent options"
34 Select if the architecture can check permissions at sub-page
80 for kernel debugging, non-intrusive instrumentation and testing.
89 makes certain almost-always-true or almost-always-false branch
92 Certain performance-sensitive kernel code, such as trace points,
106 ( On 32-bit x86, the necessary options added to the compiler
113 Boot time self-test of the branch patching code.
119 Boot time self-test of the call patching code.
140 Uprobes is the user-space counterpart to kprobes: they
142 to establish unintrusive probes in user-space binaries and
144 are hit by user-space applications.
146 ( These probes come in the form of single-byte breakpoints,
157 architectures without unaligned access.
163 See Documentation/core-api/unaligned-memory-access.rst for
164 more information on the topic of unaligned memory accesses.
169 Some architectures are unable to perform unaligned accesses
172 unaligned access and require fixing it up in the exception
176 perform unaligned accesses efficiently to allow different
182 See Documentation/core-api/unaligned-memory-access.rst for more
183 information on the topic of unaligned memory accesses.
189 for handling byte-swapping. Using these, instead of the old
194 with a nearby load or store and use load-and-swap or
195 store-and-swap instructions if the architecture has them. It
197 hand-coded assembler in <asm/swab.h>. But just in case it
200 Any architecture with load-and-swap or store-and-swap
218 Provide a kernel-internal notification when a cpu is about to
263 # arch_has_single_step() if there is hardware single-step support
264 # arch_has_block_step() if there is hardware block-step support
265 # asm/syscall.h supplying asm-generic/syscall.h interface
314 # to undo an in-place page table remap for uncached access.
322 # The architecture has a per-task state that includes the mm's PASID
352 All new 32-bit architectures should have 64-bit off_t type on
355 still support 32-bit off_t. This option is enabled for all such
366 <asm/asm-prototypes.h> to support the module versioning for symbols
373 the API needed to access registers and stack entries from pt_regs,
375 For example the kprobes-based event tracer needs this API.
394 the API needed to access function arguments from pt_regs,
408 them but define the access type in a control register.
426 The arch chooses to use the generic perf-NMI-based hardlockup
442 bit-mapping of each registers and a unique architecture id.
448 access to the user stack pointer which is not unified across
491 # multi-threaded application), by reducing contention on the mm refcount.
493 # This can be disabled if the architecture ensures no CPUs are using an mm as a
500 # the lazy tlb reference of a kthread's ->active_mm (non-arch code has been
506 # This option allows MMU_LAZY_TLB_REFCOUNT=n. It ensures no CPUs are using an
514 # - At the time of the final mmdrop of the mm, ensure mm_cpumask(mm) contains
516 # - It must meet the requirements for MMU_LAZY_TLB_REFCOUNT=n (see above).
527 arch-specific ELF note section to core files. It must provide two
567 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
568 - __NR_seccomp_read_32
569 - __NR_seccomp_write_32
570 - __NR_seccomp_exit_32
571 - __NR_seccomp_sigreturn_32
578 - all the requirements for HAVE_ARCH_SECCOMP
579 - syscall_get_arch()
580 - syscall_get_arguments()
581 - syscall_rollback()
582 - syscall_set_return_value()
583 - SIGSYS siginfo_t support
584 - secure_computing is called from a ptrace_event()-safe context
585 - secure_computing return value is checked and a return value of -1
587 - seccomp syscall wired up
588 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
615 task-defined system call filtering polices.
617 See Documentation/userspace-api/seccomp_filter.rst for details.
644 - it has implemented a stack canary (e.g. __stack_chk_guard)
649 depends on $(cc-option,-fstack-protector)
652 This option turns on the "stack-protector" GCC feature. This
660 Functions will have the stack-protector canary logic added if they
661 have an 8-byte or larger character array on the stack.
664 gcc with the feature backported ("-fstack-protector").
673 depends on $(cc-option,-fstack-protector-strong)
676 Functions will have the stack-protector canary logic added in any
679 - local variable's address used as part of the right hand side of an
681 - local variable is an array (or union containing an array),
683 - uses register local variables
686 gcc with the feature backported ("-fstack-protector-strong").
710 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
711 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
741 - compiling with Clang,
742 - compiling inline assembly with Clang's integrated assembler,
743 - and linking with LLD.
754 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
755 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
773 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
828 If no profile is specified, AutoFDO options are
848 If no profile is specified, Propeller options are still passed
858 Control-Flow Integrity (CFI) checking.
866 depends on $(cc-option,-fsanitize=kcfi)
868 This option enables Clang's forward-edge Control Flow Integrity
896 depends on $(cc-option,-fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers)
897 # With GCOV/KASAN we need this fix: https://github.com/llvm/llvm-project/pull/104826
904 # With GCOV/KASAN we need this fix: https://github.com/rust-lang/rust/pull/129373
932 Syscalls need to be wrapped inside user_exit()-user_enter(), either
948 - Critical entry code isn't preemptible (or better yet:
950 - No use of RCU read side critical sections, unless ct_nmi_enter()
952 - No use of instrumentation, unless instrumentation_begin() got
977 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
979 to ensure there are no races in concurrent read/write of
980 cputime_t. For example, reading/writing 64-bit cputime_t on
981 some 32-bit arches may require multiple accesses, so proper
1012 # Archs that select this would be capable of PMD-sized vmaps (i.e.,
1024 # if there are no userspace memory management features that use it
1038 just need a simple module loader without arch specific data - those
1072 with read-only execute permissions. Architecture must implement
1110 - arch_mmap_rnd()
1111 - arch_randomize_brk()
1119 - ARCH_MMAP_RND_BITS_MIN
1120 - ARCH_MMAP_RND_BITS_MAX
1158 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1159 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1189 This allows 64bit applications to invoke 32-bit mmap() syscall
1190 and vice-versa 32-bit applications to call 64-bit mmap().
1240 per-page operations in the kernel at the expense of a larger
1260 This is not suitable for general-purpose workloads but the
1263 large in-memory data rather than small files.
1271 that have been compiled with '-zmax-page-size' set to 256KiB
1295 # address by giving priority to top-down scheme only if the process
1299 # - STACK_RND_MASK
1324 Architecture supports objtool compile-time frame pointer rule
1339 file which provides platform-specific implementations of some
1376 Architecture has old sigsuspend(2) syscall, of one-argument variety
1381 Even weirder antique ABI - three-argument sigsuspend(2)
1387 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1395 bool "Provide system calls for 32-bit time_t"
1399 This is relevant on all 32-bit architectures, and 64-bit architectures
1417 - vmalloc space must be large enough to hold many kernel stacks.
1418 This may rule out many 32-bit architectures.
1420 - Stacks in vmalloc space need to work reliably. For example, if
1427 - If the stack overflows into a guard page, something reasonable
1433 bool "Use a virtually-mapped stack"
1437 Enable this if you want the use virtually-mapped kernel stacks
1439 caught immediately rather than causing difficult-to-diagnose
1452 syscall exit. Careful removal of -fstack-protector-strong and
1453 -fstack-protector should also be applied to the entry code and
1467 cross-syscall address exposures.
1493 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1497 If this is set, kernel text and rodata memory will be made read-only,
1498 and non-text memory will be made non-executable. This provides
1513 If this is set, module text and rodata memory will be made read-only,
1514 and non-text memory will be made non-executable. This provides
1517 # select if the architecture provides an asm/dma-direct.h header
1526 linux/compiler-*.h in order to override macro definitions that those
1540 May be selected by an architecture if it supports place-relative
1541 32-bit relocations, both in the toolchain and in the module loader,
1554 Enable light-weight counting of various locking related events
1570 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1628 static key. This should have slightly lower overhead than non-inline
1640 included, size-asserted, or discarded in the linker scripts. This is
1657 If a 32-bit architecture requires 64-bit arguments to be split into
1658 pairs of 32-bit arguments, select this option.
1688 accessed bit in non-leaf PMD entries when using them as part of linear
1695 Architectures that select this option can run floating-point code in
1696 the kernel, as described in Documentation/core-api/floating-point.rst.
1700 source "scripts/gcc-plugins/Kconfig"
1727 # Detect availability of the GCC option -fmin-function-alignment which
1729 # -falign-functions which the compiler ignores for cold functions.
1730 def_bool $(cc-option, -fmin-function-alignment=8)
1733 # Set if the guaranteed alignment with -fmin-function-alignment is
1735 # strict alignment always, even with -falign-functions.