1# SPDX-License-Identifier: GPL-2.0 2# 3# General architecture dependent options 4# 5 6# 7# Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can 8# override the default values in this file. 9# 10source "arch/$(SRCARCH)/Kconfig" 11 12menu "General architecture-dependent options" 13 14config CRASH_CORE 15 bool 16 17config KEXEC_CORE 18 select CRASH_CORE 19 bool 20 21config KEXEC_ELF 22 bool 23 24config HAVE_IMA_KEXEC 25 bool 26 27config ARCH_HAS_SUBPAGE_FAULTS 28 bool 29 help 30 Select if the architecture can check permissions at sub-page 31 granularity (e.g. arm64 MTE). The probe_user_*() functions 32 must be implemented. 33 34config HOTPLUG_SMT 35 bool 36 37config GENERIC_ENTRY 38 bool 39 40config KPROBES 41 bool "Kprobes" 42 depends on MODULES 43 depends on HAVE_KPROBES 44 select KALLSYMS 45 select TASKS_RCU if PREEMPTION 46 help 47 Kprobes allows you to trap at almost any kernel address and 48 execute a callback function. register_kprobe() establishes 49 a probepoint and specifies the callback. Kprobes is useful 50 for kernel debugging, non-intrusive instrumentation and testing. 51 If in doubt, say "N". 52 53config JUMP_LABEL 54 bool "Optimize very unlikely/likely branches" 55 depends on HAVE_ARCH_JUMP_LABEL 56 select OBJTOOL if HAVE_JUMP_LABEL_HACK 57 help 58 This option enables a transparent branch optimization that 59 makes certain almost-always-true or almost-always-false branch 60 conditions even cheaper to execute within the kernel. 61 62 Certain performance-sensitive kernel code, such as trace points, 63 scheduler functionality, networking code and KVM have such 64 branches and include support for this optimization technique. 65 66 If it is detected that the compiler has support for "asm goto", 67 the kernel will compile such branches with just a nop 68 instruction. When the condition flag is toggled to true, the 69 nop will be converted to a jump instruction to execute the 70 conditional block of instructions. 71 72 This technique lowers overhead and stress on the branch prediction 73 of the processor and generally makes the kernel faster. The update 74 of the condition is slower, but those are always very rare. 75 76 ( On 32-bit x86, the necessary options added to the compiler 77 flags may increase the size of the kernel slightly. ) 78 79config STATIC_KEYS_SELFTEST 80 bool "Static key selftest" 81 depends on JUMP_LABEL 82 help 83 Boot time self-test of the branch patching code. 84 85config STATIC_CALL_SELFTEST 86 bool "Static call selftest" 87 depends on HAVE_STATIC_CALL 88 help 89 Boot time self-test of the call patching code. 90 91config OPTPROBES 92 def_bool y 93 depends on KPROBES && HAVE_OPTPROBES 94 select TASKS_RCU if PREEMPTION 95 96config KPROBES_ON_FTRACE 97 def_bool y 98 depends on KPROBES && HAVE_KPROBES_ON_FTRACE 99 depends on DYNAMIC_FTRACE_WITH_REGS 100 help 101 If function tracer is enabled and the arch supports full 102 passing of pt_regs to function tracing, then kprobes can 103 optimize on top of function tracing. 104 105config UPROBES 106 def_bool n 107 depends on ARCH_SUPPORTS_UPROBES 108 help 109 Uprobes is the user-space counterpart to kprobes: they 110 enable instrumentation applications (such as 'perf probe') 111 to establish unintrusive probes in user-space binaries and 112 libraries, by executing handler functions when the probes 113 are hit by user-space applications. 114 115 ( These probes come in the form of single-byte breakpoints, 116 managed by the kernel and kept transparent to the probed 117 application. ) 118 119config HAVE_64BIT_ALIGNED_ACCESS 120 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS 121 help 122 Some architectures require 64 bit accesses to be 64 bit 123 aligned, which also requires structs containing 64 bit values 124 to be 64 bit aligned too. This includes some 32 bit 125 architectures which can do 64 bit accesses, as well as 64 bit 126 architectures without unaligned access. 127 128 This symbol should be selected by an architecture if 64 bit 129 accesses are required to be 64 bit aligned in this way even 130 though it is not a 64 bit architecture. 131 132 See Documentation/core-api/unaligned-memory-access.rst for 133 more information on the topic of unaligned memory accesses. 134 135config HAVE_EFFICIENT_UNALIGNED_ACCESS 136 bool 137 help 138 Some architectures are unable to perform unaligned accesses 139 without the use of get_unaligned/put_unaligned. Others are 140 unable to perform such accesses efficiently (e.g. trap on 141 unaligned access and require fixing it up in the exception 142 handler.) 143 144 This symbol should be selected by an architecture if it can 145 perform unaligned accesses efficiently to allow different 146 code paths to be selected for these cases. Some network 147 drivers, for example, could opt to not fix up alignment 148 problems with received packets if doing so would not help 149 much. 150 151 See Documentation/core-api/unaligned-memory-access.rst for more 152 information on the topic of unaligned memory accesses. 153 154config ARCH_USE_BUILTIN_BSWAP 155 bool 156 help 157 Modern versions of GCC (since 4.4) have builtin functions 158 for handling byte-swapping. Using these, instead of the old 159 inline assembler that the architecture code provides in the 160 __arch_bswapXX() macros, allows the compiler to see what's 161 happening and offers more opportunity for optimisation. In 162 particular, the compiler will be able to combine the byteswap 163 with a nearby load or store and use load-and-swap or 164 store-and-swap instructions if the architecture has them. It 165 should almost *never* result in code which is worse than the 166 hand-coded assembler in <asm/swab.h>. But just in case it 167 does, the use of the builtins is optional. 168 169 Any architecture with load-and-swap or store-and-swap 170 instructions should set this. And it shouldn't hurt to set it 171 on architectures that don't have such instructions. 172 173config KRETPROBES 174 def_bool y 175 depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK) 176 177config KRETPROBE_ON_RETHOOK 178 def_bool y 179 depends on HAVE_RETHOOK 180 depends on KRETPROBES 181 select RETHOOK 182 183config USER_RETURN_NOTIFIER 184 bool 185 depends on HAVE_USER_RETURN_NOTIFIER 186 help 187 Provide a kernel-internal notification when a cpu is about to 188 switch to user mode. 189 190config HAVE_IOREMAP_PROT 191 bool 192 193config HAVE_KPROBES 194 bool 195 196config HAVE_KRETPROBES 197 bool 198 199config HAVE_OPTPROBES 200 bool 201 202config HAVE_KPROBES_ON_FTRACE 203 bool 204 205config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 206 bool 207 help 208 Since kretprobes modifies return address on the stack, the 209 stacktrace may see the kretprobe trampoline address instead 210 of correct one. If the architecture stacktrace code and 211 unwinder can adjust such entries, select this configuration. 212 213config HAVE_FUNCTION_ERROR_INJECTION 214 bool 215 216config HAVE_NMI 217 bool 218 219config HAVE_FUNCTION_DESCRIPTORS 220 bool 221 222config TRACE_IRQFLAGS_SUPPORT 223 bool 224 225config TRACE_IRQFLAGS_NMI_SUPPORT 226 bool 227 228# 229# An arch should select this if it provides all these things: 230# 231# task_pt_regs() in asm/processor.h or asm/ptrace.h 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 235# linux/regset.h user_regset interfaces 236# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 237# TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit} 238# TIF_NOTIFY_RESUME calls resume_user_mode_work() 239# 240config HAVE_ARCH_TRACEHOOK 241 bool 242 243config HAVE_DMA_CONTIGUOUS 244 bool 245 246config GENERIC_SMP_IDLE_THREAD 247 bool 248 249config GENERIC_IDLE_POLL_SETUP 250 bool 251 252config ARCH_HAS_FORTIFY_SOURCE 253 bool 254 help 255 An architecture should select this when it can successfully 256 build and run with CONFIG_FORTIFY_SOURCE. 257 258# 259# Select if the arch provides a historic keepinit alias for the retain_initrd 260# command line option 261# 262config ARCH_HAS_KEEPINITRD 263 bool 264 265# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h 266config ARCH_HAS_SET_MEMORY 267 bool 268 269# Select if arch has all set_direct_map_invalid/default() functions 270config ARCH_HAS_SET_DIRECT_MAP 271 bool 272 273# 274# Select if the architecture provides the arch_dma_set_uncached symbol to 275# either provide an uncached segment alias for a DMA allocation, or 276# to remap the page tables in place. 277# 278config ARCH_HAS_DMA_SET_UNCACHED 279 bool 280 281# 282# Select if the architectures provides the arch_dma_clear_uncached symbol 283# to undo an in-place page table remap for uncached access. 284# 285config ARCH_HAS_DMA_CLEAR_UNCACHED 286 bool 287 288# Select if arch init_task must go in the __init_task_data section 289config ARCH_TASK_STRUCT_ON_STACK 290 bool 291 292# Select if arch has its private alloc_task_struct() function 293config ARCH_TASK_STRUCT_ALLOCATOR 294 bool 295 296config HAVE_ARCH_THREAD_STRUCT_WHITELIST 297 bool 298 depends on !ARCH_TASK_STRUCT_ALLOCATOR 299 help 300 An architecture should select this to provide hardened usercopy 301 knowledge about what region of the thread_struct should be 302 whitelisted for copying to userspace. Normally this is only the 303 FPU registers. Specifically, arch_thread_struct_whitelist() 304 should be implemented. Without this, the entire thread_struct 305 field in task_struct will be left whitelisted. 306 307# Select if arch has its private alloc_thread_stack() function 308config ARCH_THREAD_STACK_ALLOCATOR 309 bool 310 311# Select if arch wants to size task_struct dynamically via arch_task_struct_size: 312config ARCH_WANTS_DYNAMIC_TASK_STRUCT 313 bool 314 315config ARCH_WANTS_NO_INSTR 316 bool 317 help 318 An architecture should select this if the noinstr macro is being used on 319 functions to denote that the toolchain should avoid instrumenting such 320 functions and is required for correctness. 321 322config ARCH_32BIT_OFF_T 323 bool 324 depends on !64BIT 325 help 326 All new 32-bit architectures should have 64-bit off_t type on 327 userspace side which corresponds to the loff_t kernel type. This 328 is the requirement for modern ABIs. Some existing architectures 329 still support 32-bit off_t. This option is enabled for all such 330 architectures explicitly. 331 332# Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat 333config ARCH_32BIT_USTAT_F_TINODE 334 bool 335 336config HAVE_ASM_MODVERSIONS 337 bool 338 help 339 This symbol should be selected by an architecture if it provides 340 <asm/asm-prototypes.h> to support the module versioning for symbols 341 exported from assembly code. 342 343config HAVE_REGS_AND_STACK_ACCESS_API 344 bool 345 help 346 This symbol should be selected by an architecture if it supports 347 the API needed to access registers and stack entries from pt_regs, 348 declared in asm/ptrace.h 349 For example the kprobes-based event tracer needs this API. 350 351config HAVE_RSEQ 352 bool 353 depends on HAVE_REGS_AND_STACK_ACCESS_API 354 help 355 This symbol should be selected by an architecture if it 356 supports an implementation of restartable sequences. 357 358config HAVE_RUST 359 bool 360 help 361 This symbol should be selected by an architecture if it 362 supports Rust. 363 364config HAVE_FUNCTION_ARG_ACCESS_API 365 bool 366 help 367 This symbol should be selected by an architecture if it supports 368 the API needed to access function arguments from pt_regs, 369 declared in asm/ptrace.h 370 371config HAVE_HW_BREAKPOINT 372 bool 373 depends on PERF_EVENTS 374 375config HAVE_MIXED_BREAKPOINTS_REGS 376 bool 377 depends on HAVE_HW_BREAKPOINT 378 help 379 Depending on the arch implementation of hardware breakpoints, 380 some of them have separate registers for data and instruction 381 breakpoints addresses, others have mixed registers to store 382 them but define the access type in a control register. 383 Select this option if your arch implements breakpoints under the 384 latter fashion. 385 386config HAVE_USER_RETURN_NOTIFIER 387 bool 388 389config HAVE_PERF_EVENTS_NMI 390 bool 391 help 392 System hardware can generate an NMI using the perf event 393 subsystem. Also has support for calculating CPU cycle events 394 to determine how many clock cycles in a given period. 395 396config HAVE_HARDLOCKUP_DETECTOR_PERF 397 bool 398 depends on HAVE_PERF_EVENTS_NMI 399 help 400 The arch chooses to use the generic perf-NMI-based hardlockup 401 detector. Must define HAVE_PERF_EVENTS_NMI. 402 403config HAVE_NMI_WATCHDOG 404 depends on HAVE_NMI 405 bool 406 help 407 The arch provides a low level NMI watchdog. It provides 408 asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). 409 410config HAVE_HARDLOCKUP_DETECTOR_ARCH 411 bool 412 select HAVE_NMI_WATCHDOG 413 help 414 The arch chooses to provide its own hardlockup detector, which is 415 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config 416 interfaces and parameters provided by hardlockup detector subsystem. 417 418config HAVE_PERF_REGS 419 bool 420 help 421 Support selective register dumps for perf events. This includes 422 bit-mapping of each registers and a unique architecture id. 423 424config HAVE_PERF_USER_STACK_DUMP 425 bool 426 help 427 Support user stack dumps for perf event samples. This needs 428 access to the user stack pointer which is not unified across 429 architectures. 430 431config HAVE_ARCH_JUMP_LABEL 432 bool 433 434config HAVE_ARCH_JUMP_LABEL_RELATIVE 435 bool 436 437config MMU_GATHER_TABLE_FREE 438 bool 439 440config MMU_GATHER_RCU_TABLE_FREE 441 bool 442 select MMU_GATHER_TABLE_FREE 443 444config MMU_GATHER_PAGE_SIZE 445 bool 446 447config MMU_GATHER_NO_RANGE 448 bool 449 select MMU_GATHER_MERGE_VMAS 450 451config MMU_GATHER_NO_FLUSH_CACHE 452 bool 453 454config MMU_GATHER_MERGE_VMAS 455 bool 456 457config MMU_GATHER_NO_GATHER 458 bool 459 depends on MMU_GATHER_TABLE_FREE 460 461config ARCH_WANT_IRQS_OFF_ACTIVATE_MM 462 bool 463 help 464 Temporary select until all architectures can be converted to have 465 irqs disabled over activate_mm. Architectures that do IPI based TLB 466 shootdowns should enable this. 467 468config ARCH_HAVE_NMI_SAFE_CMPXCHG 469 bool 470 471config HAVE_ALIGNED_STRUCT_PAGE 472 bool 473 help 474 This makes sure that struct pages are double word aligned and that 475 e.g. the SLUB allocator can perform double word atomic operations 476 on a struct page for better performance. However selecting this 477 might increase the size of a struct page by a word. 478 479config HAVE_CMPXCHG_LOCAL 480 bool 481 482config HAVE_CMPXCHG_DOUBLE 483 bool 484 485config ARCH_WEAK_RELEASE_ACQUIRE 486 bool 487 488config ARCH_WANT_IPC_PARSE_VERSION 489 bool 490 491config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 492 bool 493 494config ARCH_WANT_OLD_COMPAT_IPC 495 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 496 bool 497 498config HAVE_ARCH_SECCOMP 499 bool 500 help 501 An arch should select this symbol to support seccomp mode 1 (the fixed 502 syscall policy), and must provide an overrides for __NR_seccomp_sigreturn, 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_32 508 509config HAVE_ARCH_SECCOMP_FILTER 510 bool 511 select HAVE_ARCH_SECCOMP 512 help 513 An arch should select this symbol if it provides all of these things: 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 -1 522 results in the system call being skipped immediately. 523 - seccomp syscall wired up 524 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE, 525 SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If 526 COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too. 527 528config SECCOMP 529 prompt "Enable seccomp to safely execute untrusted bytecode" 530 def_bool y 531 depends on HAVE_ARCH_SECCOMP 532 help 533 This kernel feature is useful for number crunching applications 534 that may need to handle untrusted bytecode during their 535 execution. By using pipes or other transports made available 536 to the process as file descriptors supporting the read/write 537 syscalls, it's possible to isolate those applications in their 538 own address space using seccomp. Once seccomp is enabled via 539 prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be 540 disabled and the task is only allowed to execute a few safe 541 syscalls defined by each seccomp mode. 542 543 If unsure, say Y. 544 545config SECCOMP_FILTER 546 def_bool y 547 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 548 help 549 Enable tasks to build secure computing environments defined 550 in terms of Berkeley Packet Filter programs which implement 551 task-defined system call filtering polices. 552 553 See Documentation/userspace-api/seccomp_filter.rst for details. 554 555config SECCOMP_CACHE_DEBUG 556 bool "Show seccomp filter cache status in /proc/pid/seccomp_cache" 557 depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR 558 depends on PROC_FS 559 help 560 This enables the /proc/pid/seccomp_cache interface to monitor 561 seccomp cache data. The file format is subject to change. Reading 562 the file requires CAP_SYS_ADMIN. 563 564 This option is for debugging only. Enabling presents the risk that 565 an adversary may be able to infer the seccomp filter logic. 566 567 If unsure, say N. 568 569config HAVE_ARCH_STACKLEAK 570 bool 571 help 572 An architecture should select this if it has the code which 573 fills the used part of the kernel stack with the STACKLEAK_POISON 574 value before returning from system calls. 575 576config HAVE_STACKPROTECTOR 577 bool 578 help 579 An arch should select this symbol if: 580 - it has implemented a stack canary (e.g. __stack_chk_guard) 581 582config STACKPROTECTOR 583 bool "Stack Protector buffer overflow detection" 584 depends on HAVE_STACKPROTECTOR 585 depends on $(cc-option,-fstack-protector) 586 default y 587 help 588 This option turns on the "stack-protector" GCC feature. This 589 feature puts, at the beginning of functions, a canary value on 590 the stack just before the return address, and validates 591 the value just before actually returning. Stack based buffer 592 overflows (that need to overwrite this return address) now also 593 overwrite the canary, which gets detected and the attack is then 594 neutralized via a kernel panic. 595 596 Functions will have the stack-protector canary logic added if they 597 have an 8-byte or larger character array on the stack. 598 599 This feature requires gcc version 4.2 or above, or a distribution 600 gcc with the feature backported ("-fstack-protector"). 601 602 On an x86 "defconfig" build, this feature adds canary checks to 603 about 3% of all kernel functions, which increases kernel code size 604 by about 0.3%. 605 606config STACKPROTECTOR_STRONG 607 bool "Strong Stack Protector" 608 depends on STACKPROTECTOR 609 depends on $(cc-option,-fstack-protector-strong) 610 default y 611 help 612 Functions will have the stack-protector canary logic added in any 613 of the following conditions: 614 615 - local variable's address used as part of the right hand side of an 616 assignment or function argument 617 - local variable is an array (or union containing an array), 618 regardless of array type or length 619 - uses register local variables 620 621 This feature requires gcc version 4.9 or above, or a distribution 622 gcc with the feature backported ("-fstack-protector-strong"). 623 624 On an x86 "defconfig" build, this feature adds canary checks to 625 about 20% of all kernel functions, which increases the kernel code 626 size by about 2%. 627 628config ARCH_SUPPORTS_SHADOW_CALL_STACK 629 bool 630 help 631 An architecture should select this if it supports the compiler's 632 Shadow Call Stack and implements runtime support for shadow stack 633 switching. 634 635config SHADOW_CALL_STACK 636 bool "Shadow Call Stack" 637 depends on ARCH_SUPPORTS_SHADOW_CALL_STACK 638 depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER 639 help 640 This option enables the compiler's Shadow Call Stack, which 641 uses a shadow stack to protect function return addresses from 642 being overwritten by an attacker. More information can be found 643 in the compiler's documentation: 644 645 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html 646 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options 647 648 Note that security guarantees in the kernel differ from the 649 ones documented for user space. The kernel must store addresses 650 of shadow stacks in memory, which means an attacker capable of 651 reading and writing arbitrary memory may be able to locate them 652 and hijack control flow by modifying the stacks. 653 654config DYNAMIC_SCS 655 bool 656 help 657 Set by the arch code if it relies on code patching to insert the 658 shadow call stack push and pop instructions rather than on the 659 compiler. 660 661config LTO 662 bool 663 help 664 Selected if the kernel will be built using the compiler's LTO feature. 665 666config LTO_CLANG 667 bool 668 select LTO 669 help 670 Selected if the kernel will be built using Clang's LTO feature. 671 672config ARCH_SUPPORTS_LTO_CLANG 673 bool 674 help 675 An architecture should select this option if it supports: 676 - compiling with Clang, 677 - compiling inline assembly with Clang's integrated assembler, 678 - and linking with LLD. 679 680config ARCH_SUPPORTS_LTO_CLANG_THIN 681 bool 682 help 683 An architecture should select this option if it can support Clang's 684 ThinLTO mode. 685 686config HAS_LTO_CLANG 687 def_bool y 688 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM 689 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm) 690 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm) 691 depends on ARCH_SUPPORTS_LTO_CLANG 692 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT 693 depends on !KASAN || KASAN_HW_TAGS 694 depends on !GCOV_KERNEL 695 help 696 The compiler and Kconfig options support building with Clang's 697 LTO. 698 699choice 700 prompt "Link Time Optimization (LTO)" 701 default LTO_NONE 702 help 703 This option enables Link Time Optimization (LTO), which allows the 704 compiler to optimize binaries globally. 705 706 If unsure, select LTO_NONE. Note that LTO is very resource-intensive 707 so it's disabled by default. 708 709config LTO_NONE 710 bool "None" 711 help 712 Build the kernel normally, without Link Time Optimization (LTO). 713 714config LTO_CLANG_FULL 715 bool "Clang Full LTO (EXPERIMENTAL)" 716 depends on HAS_LTO_CLANG 717 depends on !COMPILE_TEST 718 select LTO_CLANG 719 help 720 This option enables Clang's full Link Time Optimization (LTO), which 721 allows the compiler to optimize the kernel globally. If you enable 722 this option, the compiler generates LLVM bitcode instead of ELF 723 object files, and the actual compilation from bitcode happens at 724 the LTO link step, which may take several minutes depending on the 725 kernel configuration. More information can be found from LLVM's 726 documentation: 727 728 https://llvm.org/docs/LinkTimeOptimization.html 729 730 During link time, this option can use a large amount of RAM, and 731 may take much longer than the ThinLTO option. 732 733config LTO_CLANG_THIN 734 bool "Clang ThinLTO (EXPERIMENTAL)" 735 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN 736 select LTO_CLANG 737 help 738 This option enables Clang's ThinLTO, which allows for parallel 739 optimization and faster incremental compiles compared to the 740 CONFIG_LTO_CLANG_FULL option. More information can be found 741 from Clang's documentation: 742 743 https://clang.llvm.org/docs/ThinLTO.html 744 745 If unsure, say Y. 746endchoice 747 748config ARCH_SUPPORTS_CFI_CLANG 749 bool 750 help 751 An architecture should select this option if it can support Clang's 752 Control-Flow Integrity (CFI) checking. 753 754config ARCH_USES_CFI_TRAPS 755 bool 756 757config CFI_CLANG 758 bool "Use Clang's Control Flow Integrity (CFI)" 759 depends on ARCH_SUPPORTS_CFI_CLANG 760 depends on $(cc-option,-fsanitize=kcfi) 761 help 762 This option enables Clang’s forward-edge Control Flow Integrity 763 (CFI) checking, where the compiler injects a runtime check to each 764 indirect function call to ensure the target is a valid function with 765 the correct static type. This restricts possible call targets and 766 makes it more difficult for an attacker to exploit bugs that allow 767 the modification of stored function pointers. More information can be 768 found from Clang's documentation: 769 770 https://clang.llvm.org/docs/ControlFlowIntegrity.html 771 772config CFI_PERMISSIVE 773 bool "Use CFI in permissive mode" 774 depends on CFI_CLANG 775 help 776 When selected, Control Flow Integrity (CFI) violations result in a 777 warning instead of a kernel panic. This option should only be used 778 for finding indirect call type mismatches during development. 779 780 If unsure, say N. 781 782config HAVE_ARCH_WITHIN_STACK_FRAMES 783 bool 784 help 785 An architecture should select this if it can walk the kernel stack 786 frames to determine if an object is part of either the arguments 787 or local variables (i.e. that it excludes saved return addresses, 788 and similar) by implementing an inline arch_within_stack_frames(), 789 which is used by CONFIG_HARDENED_USERCOPY. 790 791config HAVE_CONTEXT_TRACKING_USER 792 bool 793 help 794 Provide kernel/user boundaries probes necessary for subsystems 795 that need it, such as userspace RCU extended quiescent state. 796 Syscalls need to be wrapped inside user_exit()-user_enter(), either 797 optimized behind static key or through the slow path using TIF_NOHZ 798 flag. Exceptions handlers must be wrapped as well. Irqs are already 799 protected inside ct_irq_enter/ct_irq_exit() but preemption or signal 800 handling on irq exit still need to be protected. 801 802config HAVE_CONTEXT_TRACKING_USER_OFFSTACK 803 bool 804 help 805 Architecture neither relies on exception_enter()/exception_exit() 806 nor on schedule_user(). Also preempt_schedule_notrace() and 807 preempt_schedule_irq() can't be called in a preemptible section 808 while context tracking is CONTEXT_USER. This feature reflects a sane 809 entry implementation where the following requirements are met on 810 critical entry code, ie: before user_exit() or after user_enter(): 811 812 - Critical entry code isn't preemptible (or better yet: 813 not interruptible). 814 - No use of RCU read side critical sections, unless ct_nmi_enter() 815 got called. 816 - No use of instrumentation, unless instrumentation_begin() got 817 called. 818 819config HAVE_TIF_NOHZ 820 bool 821 help 822 Arch relies on TIF_NOHZ and syscall slow path to implement context 823 tracking calls to user_enter()/user_exit(). 824 825config HAVE_VIRT_CPU_ACCOUNTING 826 bool 827 828config HAVE_VIRT_CPU_ACCOUNTING_IDLE 829 bool 830 help 831 Architecture has its own way to account idle CPU time and therefore 832 doesn't implement vtime_account_idle(). 833 834config ARCH_HAS_SCALED_CPUTIME 835 bool 836 837config HAVE_VIRT_CPU_ACCOUNTING_GEN 838 bool 839 default y if 64BIT 840 help 841 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 842 Before enabling this option, arch code must be audited 843 to ensure there are no races in concurrent read/write of 844 cputime_t. For example, reading/writing 64-bit cputime_t on 845 some 32-bit arches may require multiple accesses, so proper 846 locking is needed to protect against concurrent accesses. 847 848config HAVE_IRQ_TIME_ACCOUNTING 849 bool 850 help 851 Archs need to ensure they use a high enough resolution clock to 852 support irq time accounting and then call enable_sched_clock_irqtime(). 853 854config HAVE_MOVE_PUD 855 bool 856 help 857 Architectures that select this are able to move page tables at the 858 PUD level. If there are only 3 page table levels, the move effectively 859 happens at the PGD level. 860 861config HAVE_MOVE_PMD 862 bool 863 help 864 Archs that select this are able to move page tables at the PMD level. 865 866config HAVE_ARCH_TRANSPARENT_HUGEPAGE 867 bool 868 869config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 870 bool 871 872config HAVE_ARCH_HUGE_VMAP 873 bool 874 875# 876# Archs that select this would be capable of PMD-sized vmaps (i.e., 877# arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag 878# must be used to enable allocations to use hugepages. 879# 880config HAVE_ARCH_HUGE_VMALLOC 881 depends on HAVE_ARCH_HUGE_VMAP 882 bool 883 884config ARCH_WANT_HUGE_PMD_SHARE 885 bool 886 887config HAVE_ARCH_SOFT_DIRTY 888 bool 889 890config HAVE_MOD_ARCH_SPECIFIC 891 bool 892 help 893 The arch uses struct mod_arch_specific to store data. Many arches 894 just need a simple module loader without arch specific data - those 895 should not enable this. 896 897config MODULES_USE_ELF_RELA 898 bool 899 help 900 Modules only use ELF RELA relocations. Modules with ELF REL 901 relocations will give an error. 902 903config MODULES_USE_ELF_REL 904 bool 905 help 906 Modules only use ELF REL relocations. Modules with ELF RELA 907 relocations will give an error. 908 909config ARCH_WANTS_MODULES_DATA_IN_VMALLOC 910 bool 911 help 912 For architectures like powerpc/32 which have constraints on module 913 allocation and need to allocate module data outside of module area. 914 915config HAVE_IRQ_EXIT_ON_IRQ_STACK 916 bool 917 help 918 Architecture doesn't only execute the irq handler on the irq stack 919 but also irq_exit(). This way we can process softirqs on this irq 920 stack instead of switching to a new one when we call __do_softirq() 921 in the end of an hardirq. 922 This spares a stack switch and improves cache usage on softirq 923 processing. 924 925config HAVE_SOFTIRQ_ON_OWN_STACK 926 bool 927 help 928 Architecture provides a function to run __do_softirq() on a 929 separate stack. 930 931config SOFTIRQ_ON_OWN_STACK 932 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT 933 934config ALTERNATE_USER_ADDRESS_SPACE 935 bool 936 help 937 Architectures set this when the CPU uses separate address 938 spaces for kernel and user space pointers. In this case, the 939 access_ok() check on a __user pointer is skipped. 940 941config PGTABLE_LEVELS 942 int 943 default 2 944 945config ARCH_HAS_ELF_RANDOMIZE 946 bool 947 help 948 An architecture supports choosing randomized locations for 949 stack, mmap, brk, and ET_DYN. Defined functions: 950 - arch_mmap_rnd() 951 - arch_randomize_brk() 952 953config HAVE_ARCH_MMAP_RND_BITS 954 bool 955 help 956 An arch should select this symbol if it supports setting a variable 957 number of bits for use in establishing the base address for mmap 958 allocations, has MMU enabled and provides values for both: 959 - ARCH_MMAP_RND_BITS_MIN 960 - ARCH_MMAP_RND_BITS_MAX 961 962config HAVE_EXIT_THREAD 963 bool 964 help 965 An architecture implements exit_thread. 966 967config ARCH_MMAP_RND_BITS_MIN 968 int 969 970config ARCH_MMAP_RND_BITS_MAX 971 int 972 973config ARCH_MMAP_RND_BITS_DEFAULT 974 int 975 976config ARCH_MMAP_RND_BITS 977 int "Number of bits to use for ASLR of mmap base address" if EXPERT 978 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 979 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 980 default ARCH_MMAP_RND_BITS_MIN 981 depends on HAVE_ARCH_MMAP_RND_BITS 982 help 983 This value can be used to select the number of bits to use to 984 determine the random offset to the base address of vma regions 985 resulting from mmap allocations. This value will be bounded 986 by the architecture's minimum and maximum supported values. 987 988 This value can be changed after boot using the 989 /proc/sys/vm/mmap_rnd_bits tunable 990 991config HAVE_ARCH_MMAP_RND_COMPAT_BITS 992 bool 993 help 994 An arch should select this symbol if it supports running applications 995 in compatibility mode, supports setting a variable number of bits for 996 use in establishing the base address for mmap allocations, has MMU 997 enabled and provides values for both: 998 - ARCH_MMAP_RND_COMPAT_BITS_MIN 999 - ARCH_MMAP_RND_COMPAT_BITS_MAX 1000 1001config ARCH_MMAP_RND_COMPAT_BITS_MIN 1002 int 1003 1004config ARCH_MMAP_RND_COMPAT_BITS_MAX 1005 int 1006 1007config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1008 int 1009 1010config ARCH_MMAP_RND_COMPAT_BITS 1011 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT 1012 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 1013 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1014 default ARCH_MMAP_RND_COMPAT_BITS_MIN 1015 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 1016 help 1017 This value can be used to select the number of bits to use to 1018 determine the random offset to the base address of vma regions 1019 resulting from mmap allocations for compatible applications This 1020 value will be bounded by the architecture's minimum and maximum 1021 supported values. 1022 1023 This value can be changed after boot using the 1024 /proc/sys/vm/mmap_rnd_compat_bits tunable 1025 1026config HAVE_ARCH_COMPAT_MMAP_BASES 1027 bool 1028 help 1029 This allows 64bit applications to invoke 32-bit mmap() syscall 1030 and vice-versa 32-bit applications to call 64-bit mmap(). 1031 Required for applications doing different bitness syscalls. 1032 1033config PAGE_SIZE_LESS_THAN_64KB 1034 def_bool y 1035 depends on !ARM64_64K_PAGES 1036 depends on !IA64_PAGE_SIZE_64KB 1037 depends on !PAGE_SIZE_64KB 1038 depends on !PARISC_PAGE_SIZE_64KB 1039 depends on PAGE_SIZE_LESS_THAN_256KB 1040 1041config PAGE_SIZE_LESS_THAN_256KB 1042 def_bool y 1043 depends on !PAGE_SIZE_256KB 1044 1045# This allows to use a set of generic functions to determine mmap base 1046# address by giving priority to top-down scheme only if the process 1047# is not in legacy mode (compat task, unlimited stack size or 1048# sysctl_legacy_va_layout). 1049# Architecture that selects this option can provide its own version of: 1050# - STACK_RND_MASK 1051config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 1052 bool 1053 depends on MMU 1054 select ARCH_HAS_ELF_RANDOMIZE 1055 1056config HAVE_OBJTOOL 1057 bool 1058 1059config HAVE_JUMP_LABEL_HACK 1060 bool 1061 1062config HAVE_NOINSTR_HACK 1063 bool 1064 1065config HAVE_NOINSTR_VALIDATION 1066 bool 1067 1068config HAVE_UACCESS_VALIDATION 1069 bool 1070 select OBJTOOL 1071 1072config HAVE_STACK_VALIDATION 1073 bool 1074 help 1075 Architecture supports objtool compile-time frame pointer rule 1076 validation. 1077 1078config HAVE_RELIABLE_STACKTRACE 1079 bool 1080 help 1081 Architecture has either save_stack_trace_tsk_reliable() or 1082 arch_stack_walk_reliable() function which only returns a stack trace 1083 if it can guarantee the trace is reliable. 1084 1085config HAVE_ARCH_HASH 1086 bool 1087 default n 1088 help 1089 If this is set, the architecture provides an <asm/hash.h> 1090 file which provides platform-specific implementations of some 1091 functions in <linux/hash.h> or fs/namei.c. 1092 1093config HAVE_ARCH_NVRAM_OPS 1094 bool 1095 1096config ISA_BUS_API 1097 def_bool ISA 1098 1099# 1100# ABI hall of shame 1101# 1102config CLONE_BACKWARDS 1103 bool 1104 help 1105 Architecture has tls passed as the 4th argument of clone(2), 1106 not the 5th one. 1107 1108config CLONE_BACKWARDS2 1109 bool 1110 help 1111 Architecture has the first two arguments of clone(2) swapped. 1112 1113config CLONE_BACKWARDS3 1114 bool 1115 help 1116 Architecture has tls passed as the 3rd argument of clone(2), 1117 not the 5th one. 1118 1119config ODD_RT_SIGACTION 1120 bool 1121 help 1122 Architecture has unusual rt_sigaction(2) arguments 1123 1124config OLD_SIGSUSPEND 1125 bool 1126 help 1127 Architecture has old sigsuspend(2) syscall, of one-argument variety 1128 1129config OLD_SIGSUSPEND3 1130 bool 1131 help 1132 Even weirder antique ABI - three-argument sigsuspend(2) 1133 1134config OLD_SIGACTION 1135 bool 1136 help 1137 Architecture has old sigaction(2) syscall. Nope, not the same 1138 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 1139 but fairly different variant of sigaction(2), thanks to OSF/1 1140 compatibility... 1141 1142config COMPAT_OLD_SIGACTION 1143 bool 1144 1145config COMPAT_32BIT_TIME 1146 bool "Provide system calls for 32-bit time_t" 1147 default !64BIT || COMPAT 1148 help 1149 This enables 32 bit time_t support in addition to 64 bit time_t support. 1150 This is relevant on all 32-bit architectures, and 64-bit architectures 1151 as part of compat syscall handling. 1152 1153config ARCH_NO_PREEMPT 1154 bool 1155 1156config ARCH_EPHEMERAL_INODES 1157 def_bool n 1158 help 1159 An arch should select this symbol if it doesn't keep track of inode 1160 instances on its own, but instead relies on something else (e.g. the 1161 host kernel for an UML kernel). 1162 1163config ARCH_SUPPORTS_RT 1164 bool 1165 1166config CPU_NO_EFFICIENT_FFS 1167 def_bool n 1168 1169config HAVE_ARCH_VMAP_STACK 1170 def_bool n 1171 help 1172 An arch should select this symbol if it can support kernel stacks 1173 in vmalloc space. This means: 1174 1175 - vmalloc space must be large enough to hold many kernel stacks. 1176 This may rule out many 32-bit architectures. 1177 1178 - Stacks in vmalloc space need to work reliably. For example, if 1179 vmap page tables are created on demand, either this mechanism 1180 needs to work while the stack points to a virtual address with 1181 unpopulated page tables or arch code (switch_to() and switch_mm(), 1182 most likely) needs to ensure that the stack's page table entries 1183 are populated before running on a possibly unpopulated stack. 1184 1185 - If the stack overflows into a guard page, something reasonable 1186 should happen. The definition of "reasonable" is flexible, but 1187 instantly rebooting without logging anything would be unfriendly. 1188 1189config VMAP_STACK 1190 default y 1191 bool "Use a virtually-mapped stack" 1192 depends on HAVE_ARCH_VMAP_STACK 1193 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC 1194 help 1195 Enable this if you want the use virtually-mapped kernel stacks 1196 with guard pages. This causes kernel stack overflows to be 1197 caught immediately rather than causing difficult-to-diagnose 1198 corruption. 1199 1200 To use this with software KASAN modes, the architecture must support 1201 backing virtual mappings with real shadow memory, and KASAN_VMALLOC 1202 must be enabled. 1203 1204config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1205 def_bool n 1206 help 1207 An arch should select this symbol if it can support kernel stack 1208 offset randomization with calls to add_random_kstack_offset() 1209 during syscall entry and choose_random_kstack_offset() during 1210 syscall exit. Careful removal of -fstack-protector-strong and 1211 -fstack-protector should also be applied to the entry code and 1212 closely examined, as the artificial stack bump looks like an array 1213 to the compiler, so it will attempt to add canary checks regardless 1214 of the static branch state. 1215 1216config RANDOMIZE_KSTACK_OFFSET 1217 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT 1218 default y 1219 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1220 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000 1221 help 1222 The kernel stack offset can be randomized (after pt_regs) by 1223 roughly 5 bits of entropy, frustrating memory corruption 1224 attacks that depend on stack address determinism or 1225 cross-syscall address exposures. 1226 1227 The feature is controlled via the "randomize_kstack_offset=on/off" 1228 kernel boot param, and if turned off has zero overhead due to its use 1229 of static branches (see JUMP_LABEL). 1230 1231 If unsure, say Y. 1232 1233config RANDOMIZE_KSTACK_OFFSET_DEFAULT 1234 bool "Default state of kernel stack offset randomization" 1235 depends on RANDOMIZE_KSTACK_OFFSET 1236 help 1237 Kernel stack offset randomization is controlled by kernel boot param 1238 "randomize_kstack_offset=on/off", and this config chooses the default 1239 boot state. 1240 1241config ARCH_OPTIONAL_KERNEL_RWX 1242 def_bool n 1243 1244config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1245 def_bool n 1246 1247config ARCH_HAS_STRICT_KERNEL_RWX 1248 def_bool n 1249 1250config STRICT_KERNEL_RWX 1251 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 1252 depends on ARCH_HAS_STRICT_KERNEL_RWX 1253 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1254 help 1255 If this is set, kernel text and rodata memory will be made read-only, 1256 and non-text memory will be made non-executable. This provides 1257 protection against certain security exploits (e.g. executing the heap 1258 or modifying text) 1259 1260 These features are considered standard security practice these days. 1261 You should say Y here in almost all cases. 1262 1263config ARCH_HAS_STRICT_MODULE_RWX 1264 def_bool n 1265 1266config STRICT_MODULE_RWX 1267 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX 1268 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 1269 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1270 help 1271 If this is set, module text and rodata memory will be made read-only, 1272 and non-text memory will be made non-executable. This provides 1273 protection against certain security exploits (e.g. writing to text) 1274 1275# select if the architecture provides an asm/dma-direct.h header 1276config ARCH_HAS_PHYS_TO_DMA 1277 bool 1278 1279config HAVE_ARCH_COMPILER_H 1280 bool 1281 help 1282 An architecture can select this if it provides an 1283 asm/compiler.h header that should be included after 1284 linux/compiler-*.h in order to override macro definitions that those 1285 headers generally provide. 1286 1287config HAVE_ARCH_PREL32_RELOCATIONS 1288 bool 1289 help 1290 May be selected by an architecture if it supports place-relative 1291 32-bit relocations, both in the toolchain and in the module loader, 1292 in which case relative references can be used in special sections 1293 for PCI fixup, initcalls etc which are only half the size on 64 bit 1294 architectures, and don't require runtime relocation on relocatable 1295 kernels. 1296 1297config ARCH_USE_MEMREMAP_PROT 1298 bool 1299 1300config LOCK_EVENT_COUNTS 1301 bool "Locking event counts collection" 1302 depends on DEBUG_FS 1303 help 1304 Enable light-weight counting of various locking related events 1305 in the system with minimal performance impact. This reduces 1306 the chance of application behavior change because of timing 1307 differences. The counts are reported via debugfs. 1308 1309# Select if the architecture has support for applying RELR relocations. 1310config ARCH_HAS_RELR 1311 bool 1312 1313config RELR 1314 bool "Use RELR relocation packing" 1315 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR 1316 default y 1317 help 1318 Store the kernel's dynamic relocations in the RELR relocation packing 1319 format. Requires a compatible linker (LLD supports this feature), as 1320 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy 1321 are compatible). 1322 1323config ARCH_HAS_MEM_ENCRYPT 1324 bool 1325 1326config ARCH_HAS_CC_PLATFORM 1327 bool 1328 1329config HAVE_SPARSE_SYSCALL_NR 1330 bool 1331 help 1332 An architecture should select this if its syscall numbering is sparse 1333 to save space. For example, MIPS architecture has a syscall array with 1334 entries at 4000, 5000 and 6000 locations. This option turns on syscall 1335 related optimizations for a given architecture. 1336 1337config ARCH_HAS_VDSO_DATA 1338 bool 1339 1340config HAVE_STATIC_CALL 1341 bool 1342 1343config HAVE_STATIC_CALL_INLINE 1344 bool 1345 depends on HAVE_STATIC_CALL 1346 select OBJTOOL 1347 1348config HAVE_PREEMPT_DYNAMIC 1349 bool 1350 1351config HAVE_PREEMPT_DYNAMIC_CALL 1352 bool 1353 depends on HAVE_STATIC_CALL 1354 select HAVE_PREEMPT_DYNAMIC 1355 help 1356 An architecture should select this if it can handle the preemption 1357 model being selected at boot time using static calls. 1358 1359 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a 1360 preemption function will be patched directly. 1361 1362 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any 1363 call to a preemption function will go through a trampoline, and the 1364 trampoline will be patched. 1365 1366 It is strongly advised to support inline static call to avoid any 1367 overhead. 1368 1369config HAVE_PREEMPT_DYNAMIC_KEY 1370 bool 1371 depends on HAVE_ARCH_JUMP_LABEL 1372 select HAVE_PREEMPT_DYNAMIC 1373 help 1374 An architecture should select this if it can handle the preemption 1375 model being selected at boot time using static keys. 1376 1377 Each preemption function will be given an early return based on a 1378 static key. This should have slightly lower overhead than non-inline 1379 static calls, as this effectively inlines each trampoline into the 1380 start of its callee. This may avoid redundant work, and may 1381 integrate better with CFI schemes. 1382 1383 This will have greater overhead than using inline static calls as 1384 the call to the preemption function cannot be entirely elided. 1385 1386config ARCH_WANT_LD_ORPHAN_WARN 1387 bool 1388 help 1389 An arch should select this symbol once all linker sections are explicitly 1390 included, size-asserted, or discarded in the linker scripts. This is 1391 important because we never want expected sections to be placed heuristically 1392 by the linker, since the locations of such sections can change between linker 1393 versions. 1394 1395config HAVE_ARCH_PFN_VALID 1396 bool 1397 1398config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1399 bool 1400 1401config ARCH_SUPPORTS_PAGE_TABLE_CHECK 1402 bool 1403 1404config ARCH_SPLIT_ARG64 1405 bool 1406 help 1407 If a 32-bit architecture requires 64-bit arguments to be split into 1408 pairs of 32-bit arguments, select this option. 1409 1410config ARCH_HAS_ELFCORE_COMPAT 1411 bool 1412 1413config ARCH_HAS_PARANOID_L1D_FLUSH 1414 bool 1415 1416config ARCH_HAVE_TRACE_MMIO_ACCESS 1417 bool 1418 1419config DYNAMIC_SIGFRAME 1420 bool 1421 1422# Select, if arch has a named attribute group bound to NUMA device nodes. 1423config HAVE_ARCH_NODE_DEV_GROUP 1424 bool 1425 1426config ARCH_HAS_NONLEAF_PMD_YOUNG 1427 bool 1428 help 1429 Architectures that select this option are capable of setting the 1430 accessed bit in non-leaf PMD entries when using them as part of linear 1431 address translations. Page table walkers that clear the accessed bit 1432 may use this capability to reduce their search space. 1433 1434source "kernel/gcov/Kconfig" 1435 1436source "scripts/gcc-plugins/Kconfig" 1437 1438endmenu 1439