Lines Matching +full:processor +full:- +full:intensive
1 # SPDX-License-Identifier: GPL-2.0
12 menu "General architecture-dependent options"
17 Select if the architecture can check permissions at sub-page
63 for kernel debugging, non-intrusive instrumentation and testing.
72 makes certain almost-always-true or almost-always-false branch
75 Certain performance-sensitive kernel code, such as trace points,
86 of the processor and generally makes the kernel faster. The update
89 ( On 32-bit x86, the necessary options added to the compiler
96 Boot time self-test of the branch patching code.
102 Boot time self-test of the call patching code.
122 Uprobes is the user-space counterpart to kprobes: they
124 to establish unintrusive probes in user-space binaries and
126 are hit by user-space applications.
128 ( These probes come in the form of single-byte breakpoints,
145 See Documentation/core-api/unaligned-memory-access.rst for
164 See Documentation/core-api/unaligned-memory-access.rst for more
171 for handling byte-swapping. Using these, instead of the old
176 with a nearby load or store and use load-and-swap or
177 store-and-swap instructions if the architecture has them. It
179 hand-coded assembler in <asm/swab.h>. But just in case it
182 Any architecture with load-and-swap or store-and-swap
200 Provide a kernel-internal notification when a cpu is about to
244 # task_pt_regs() in asm/processor.h or asm/ptrace.h
245 # arch_has_single_step() if there is hardware single-step support
246 # arch_has_block_step() if there is hardware block-step support
247 # asm/syscall.h supplying asm-generic/syscall.h interface
296 # to undo an in-place page table remap for uncached access.
342 All new 32-bit architectures should have 64-bit off_t type on
345 still support 32-bit off_t. This option is enabled for all such
356 <asm/asm-prototypes.h> to support the module versioning for symbols
365 For example the kprobes-based event tracer needs this API.
416 The arch chooses to use the generic perf-NMI-based hardlockup
432 bit-mapping of each registers and a unique architecture id.
481 # multi-threaded application), by reducing contention on the mm refcount.
490 # the lazy tlb reference of a kthread's ->active_mm (non-arch code has been
504 # - At the time of the final mmdrop of the mm, ensure mm_cpumask(mm) contains
506 # - It must meet the requirements for MMU_LAZY_TLB_REFCOUNT=n (see above).
548 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
549 - __NR_seccomp_read_32
550 - __NR_seccomp_write_32
551 - __NR_seccomp_exit_32
552 - __NR_seccomp_sigreturn_32
559 - all the requirements for HAVE_ARCH_SECCOMP
560 - syscall_get_arch()
561 - syscall_get_arguments()
562 - syscall_rollback()
563 - syscall_set_return_value()
564 - SIGSYS siginfo_t support
565 - secure_computing is called from a ptrace_event()-safe context
566 - secure_computing return value is checked and a return value of -1
568 - seccomp syscall wired up
569 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
596 task-defined system call filtering polices.
598 See Documentation/userspace-api/seccomp_filter.rst for details.
625 - it has implemented a stack canary (e.g. __stack_chk_guard)
630 depends on $(cc-option,-fstack-protector)
633 This option turns on the "stack-protector" GCC feature. This
641 Functions will have the stack-protector canary logic added if they
642 have an 8-byte or larger character array on the stack.
645 gcc with the feature backported ("-fstack-protector").
654 depends on $(cc-option,-fstack-protector-strong)
657 Functions will have the stack-protector canary logic added in any
660 - local variable's address used as part of the right hand side of an
662 - local variable is an array (or union containing an array),
664 - uses register local variables
667 gcc with the feature backported ("-fstack-protector-strong").
691 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
692 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
722 - compiling with Clang,
723 - compiling inline assembly with Clang's integrated assembler,
724 - and linking with LLD.
735 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
736 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
754 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
800 Control-Flow Integrity (CFI) checking.
808 depends on $(cc-option,-fsanitize=kcfi)
810 This option enables Clang’s forward-edge Control Flow Integrity
844 Syscalls need to be wrapped inside user_exit()-user_enter(), either
860 - Critical entry code isn't preemptible (or better yet:
862 - No use of RCU read side critical sections, unless ct_nmi_enter()
864 - No use of instrumentation, unless instrumentation_begin() got
889 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
892 cputime_t. For example, reading/writing 64-bit cputime_t on
893 some 32-bit arches may require multiple accesses, so proper
924 # Archs that select this would be capable of PMD-sized vmaps (i.e.,
950 just need a simple module loader without arch specific data - those
1006 - arch_mmap_rnd()
1007 - arch_randomize_brk()
1015 - ARCH_MMAP_RND_BITS_MIN
1016 - ARCH_MMAP_RND_BITS_MAX
1054 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1055 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1085 This allows 64bit applications to invoke 32-bit mmap() syscall
1086 and vice-versa 32-bit applications to call 64-bit mmap().
1102 # address by giving priority to top-down scheme only if the process
1106 # - STACK_RND_MASK
1131 Architecture supports objtool compile-time frame pointer rule
1146 file which provides platform-specific implementations of some
1183 Architecture has old sigsuspend(2) syscall, of one-argument variety
1188 Even weirder antique ABI - three-argument sigsuspend(2)
1194 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1202 bool "Provide system calls for 32-bit time_t"
1206 This is relevant on all 32-bit architectures, and 64-bit architectures
1224 - vmalloc space must be large enough to hold many kernel stacks.
1225 This may rule out many 32-bit architectures.
1227 - Stacks in vmalloc space need to work reliably. For example, if
1234 - If the stack overflows into a guard page, something reasonable
1240 bool "Use a virtually-mapped stack"
1244 Enable this if you want the use virtually-mapped kernel stacks
1246 caught immediately rather than causing difficult-to-diagnose
1259 syscall exit. Careful removal of -fstack-protector-strong and
1260 -fstack-protector should also be applied to the entry code and
1274 cross-syscall address exposures.
1300 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1304 If this is set, kernel text and rodata memory will be made read-only,
1305 and non-text memory will be made non-executable. This provides
1320 If this is set, module text and rodata memory will be made read-only,
1321 and non-text memory will be made non-executable. This provides
1324 # select if the architecture provides an asm/dma-direct.h header
1333 linux/compiler-*.h in order to override macro definitions that those
1339 May be selected by an architecture if it supports place-relative
1340 32-bit relocations, both in the toolchain and in the module loader,
1353 Enable light-weight counting of various locking related events
1369 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1427 static key. This should have slightly lower overhead than non-inline
1439 included, size-asserted, or discarded in the linker scripts. This is
1456 If a 32-bit architecture requires 64-bit arguments to be split into
1457 pairs of 32-bit arguments, select this option.
1479 accessed bit in non-leaf PMD entries when using them as part of linear
1485 source "scripts/gcc-plugins/Kconfig"