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_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 LTO 655 bool 656 help 657 Selected if the kernel will be built using the compiler's LTO feature. 658 659config LTO_CLANG 660 bool 661 select LTO 662 help 663 Selected if the kernel will be built using Clang's LTO feature. 664 665config ARCH_SUPPORTS_LTO_CLANG 666 bool 667 help 668 An architecture should select this option if it supports: 669 - compiling with Clang, 670 - compiling inline assembly with Clang's integrated assembler, 671 - and linking with LLD. 672 673config ARCH_SUPPORTS_LTO_CLANG_THIN 674 bool 675 help 676 An architecture should select this option if it can support Clang's 677 ThinLTO mode. 678 679config HAS_LTO_CLANG 680 def_bool y 681 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM 682 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm) 683 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm) 684 depends on ARCH_SUPPORTS_LTO_CLANG 685 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT 686 depends on !KASAN || KASAN_HW_TAGS 687 depends on !GCOV_KERNEL 688 help 689 The compiler and Kconfig options support building with Clang's 690 LTO. 691 692choice 693 prompt "Link Time Optimization (LTO)" 694 default LTO_NONE 695 help 696 This option enables Link Time Optimization (LTO), which allows the 697 compiler to optimize binaries globally. 698 699 If unsure, select LTO_NONE. Note that LTO is very resource-intensive 700 so it's disabled by default. 701 702config LTO_NONE 703 bool "None" 704 help 705 Build the kernel normally, without Link Time Optimization (LTO). 706 707config LTO_CLANG_FULL 708 bool "Clang Full LTO (EXPERIMENTAL)" 709 depends on HAS_LTO_CLANG 710 depends on !COMPILE_TEST 711 select LTO_CLANG 712 help 713 This option enables Clang's full Link Time Optimization (LTO), which 714 allows the compiler to optimize the kernel globally. If you enable 715 this option, the compiler generates LLVM bitcode instead of ELF 716 object files, and the actual compilation from bitcode happens at 717 the LTO link step, which may take several minutes depending on the 718 kernel configuration. More information can be found from LLVM's 719 documentation: 720 721 https://llvm.org/docs/LinkTimeOptimization.html 722 723 During link time, this option can use a large amount of RAM, and 724 may take much longer than the ThinLTO option. 725 726config LTO_CLANG_THIN 727 bool "Clang ThinLTO (EXPERIMENTAL)" 728 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN 729 select LTO_CLANG 730 help 731 This option enables Clang's ThinLTO, which allows for parallel 732 optimization and faster incremental compiles compared to the 733 CONFIG_LTO_CLANG_FULL option. More information can be found 734 from Clang's documentation: 735 736 https://clang.llvm.org/docs/ThinLTO.html 737 738 If unsure, say Y. 739endchoice 740 741config ARCH_SUPPORTS_CFI_CLANG 742 bool 743 help 744 An architecture should select this option if it can support Clang's 745 Control-Flow Integrity (CFI) checking. 746 747config CFI_CLANG 748 bool "Use Clang's Control Flow Integrity (CFI)" 749 depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG 750 depends on CLANG_VERSION >= 140000 751 select KALLSYMS 752 help 753 This option enables Clang’s forward-edge Control Flow Integrity 754 (CFI) checking, where the compiler injects a runtime check to each 755 indirect function call to ensure the target is a valid function with 756 the correct static type. This restricts possible call targets and 757 makes it more difficult for an attacker to exploit bugs that allow 758 the modification of stored function pointers. More information can be 759 found from Clang's documentation: 760 761 https://clang.llvm.org/docs/ControlFlowIntegrity.html 762 763config CFI_CLANG_SHADOW 764 bool "Use CFI shadow to speed up cross-module checks" 765 default y 766 depends on CFI_CLANG && MODULES 767 help 768 If you select this option, the kernel builds a fast look-up table of 769 CFI check functions in loaded modules to reduce performance overhead. 770 771 If unsure, say Y. 772 773config CFI_PERMISSIVE 774 bool "Use CFI in permissive mode" 775 depends on CFI_CLANG 776 help 777 When selected, Control Flow Integrity (CFI) violations result in a 778 warning instead of a kernel panic. This option should only be used 779 for finding indirect call type mismatches during development. 780 781 If unsure, say N. 782 783config HAVE_ARCH_WITHIN_STACK_FRAMES 784 bool 785 help 786 An architecture should select this if it can walk the kernel stack 787 frames to determine if an object is part of either the arguments 788 or local variables (i.e. that it excludes saved return addresses, 789 and similar) by implementing an inline arch_within_stack_frames(), 790 which is used by CONFIG_HARDENED_USERCOPY. 791 792config HAVE_CONTEXT_TRACKING_USER 793 bool 794 help 795 Provide kernel/user boundaries probes necessary for subsystems 796 that need it, such as userspace RCU extended quiescent state. 797 Syscalls need to be wrapped inside user_exit()-user_enter(), either 798 optimized behind static key or through the slow path using TIF_NOHZ 799 flag. Exceptions handlers must be wrapped as well. Irqs are already 800 protected inside ct_irq_enter/ct_irq_exit() but preemption or signal 801 handling on irq exit still need to be protected. 802 803config HAVE_CONTEXT_TRACKING_USER_OFFSTACK 804 bool 805 help 806 Architecture neither relies on exception_enter()/exception_exit() 807 nor on schedule_user(). Also preempt_schedule_notrace() and 808 preempt_schedule_irq() can't be called in a preemptible section 809 while context tracking is CONTEXT_USER. This feature reflects a sane 810 entry implementation where the following requirements are met on 811 critical entry code, ie: before user_exit() or after user_enter(): 812 813 - Critical entry code isn't preemptible (or better yet: 814 not interruptible). 815 - No use of RCU read side critical sections, unless ct_nmi_enter() 816 got called. 817 - No use of instrumentation, unless instrumentation_begin() got 818 called. 819 820config HAVE_TIF_NOHZ 821 bool 822 help 823 Arch relies on TIF_NOHZ and syscall slow path to implement context 824 tracking calls to user_enter()/user_exit(). 825 826config HAVE_VIRT_CPU_ACCOUNTING 827 bool 828 829config HAVE_VIRT_CPU_ACCOUNTING_IDLE 830 bool 831 help 832 Architecture has its own way to account idle CPU time and therefore 833 doesn't implement vtime_account_idle(). 834 835config ARCH_HAS_SCALED_CPUTIME 836 bool 837 838config HAVE_VIRT_CPU_ACCOUNTING_GEN 839 bool 840 default y if 64BIT 841 help 842 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 843 Before enabling this option, arch code must be audited 844 to ensure there are no races in concurrent read/write of 845 cputime_t. For example, reading/writing 64-bit cputime_t on 846 some 32-bit arches may require multiple accesses, so proper 847 locking is needed to protect against concurrent accesses. 848 849config HAVE_IRQ_TIME_ACCOUNTING 850 bool 851 help 852 Archs need to ensure they use a high enough resolution clock to 853 support irq time accounting and then call enable_sched_clock_irqtime(). 854 855config HAVE_MOVE_PUD 856 bool 857 help 858 Architectures that select this are able to move page tables at the 859 PUD level. If there are only 3 page table levels, the move effectively 860 happens at the PGD level. 861 862config HAVE_MOVE_PMD 863 bool 864 help 865 Archs that select this are able to move page tables at the PMD level. 866 867config HAVE_ARCH_TRANSPARENT_HUGEPAGE 868 bool 869 870config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 871 bool 872 873config HAVE_ARCH_HUGE_VMAP 874 bool 875 876# 877# Archs that select this would be capable of PMD-sized vmaps (i.e., 878# arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag 879# must be used to enable allocations to use hugepages. 880# 881config HAVE_ARCH_HUGE_VMALLOC 882 depends on HAVE_ARCH_HUGE_VMAP 883 bool 884 885config ARCH_WANT_HUGE_PMD_SHARE 886 bool 887 888config HAVE_ARCH_SOFT_DIRTY 889 bool 890 891config HAVE_MOD_ARCH_SPECIFIC 892 bool 893 help 894 The arch uses struct mod_arch_specific to store data. Many arches 895 just need a simple module loader without arch specific data - those 896 should not enable this. 897 898config MODULES_USE_ELF_RELA 899 bool 900 help 901 Modules only use ELF RELA relocations. Modules with ELF REL 902 relocations will give an error. 903 904config MODULES_USE_ELF_REL 905 bool 906 help 907 Modules only use ELF REL relocations. Modules with ELF RELA 908 relocations will give an error. 909 910config ARCH_WANTS_MODULES_DATA_IN_VMALLOC 911 bool 912 help 913 For architectures like powerpc/32 which have constraints on module 914 allocation and need to allocate module data outside of module area. 915 916config HAVE_IRQ_EXIT_ON_IRQ_STACK 917 bool 918 help 919 Architecture doesn't only execute the irq handler on the irq stack 920 but also irq_exit(). This way we can process softirqs on this irq 921 stack instead of switching to a new one when we call __do_softirq() 922 in the end of an hardirq. 923 This spares a stack switch and improves cache usage on softirq 924 processing. 925 926config HAVE_SOFTIRQ_ON_OWN_STACK 927 bool 928 help 929 Architecture provides a function to run __do_softirq() on a 930 separate stack. 931 932config SOFTIRQ_ON_OWN_STACK 933 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT 934 935config ALTERNATE_USER_ADDRESS_SPACE 936 bool 937 help 938 Architectures set this when the CPU uses separate address 939 spaces for kernel and user space pointers. In this case, the 940 access_ok() check on a __user pointer is skipped. 941 942config PGTABLE_LEVELS 943 int 944 default 2 945 946config ARCH_HAS_ELF_RANDOMIZE 947 bool 948 help 949 An architecture supports choosing randomized locations for 950 stack, mmap, brk, and ET_DYN. Defined functions: 951 - arch_mmap_rnd() 952 - arch_randomize_brk() 953 954config HAVE_ARCH_MMAP_RND_BITS 955 bool 956 help 957 An arch should select this symbol if it supports setting a variable 958 number of bits for use in establishing the base address for mmap 959 allocations, has MMU enabled and provides values for both: 960 - ARCH_MMAP_RND_BITS_MIN 961 - ARCH_MMAP_RND_BITS_MAX 962 963config HAVE_EXIT_THREAD 964 bool 965 help 966 An architecture implements exit_thread. 967 968config ARCH_MMAP_RND_BITS_MIN 969 int 970 971config ARCH_MMAP_RND_BITS_MAX 972 int 973 974config ARCH_MMAP_RND_BITS_DEFAULT 975 int 976 977config ARCH_MMAP_RND_BITS 978 int "Number of bits to use for ASLR of mmap base address" if EXPERT 979 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 980 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 981 default ARCH_MMAP_RND_BITS_MIN 982 depends on HAVE_ARCH_MMAP_RND_BITS 983 help 984 This value can be used to select the number of bits to use to 985 determine the random offset to the base address of vma regions 986 resulting from mmap allocations. This value will be bounded 987 by the architecture's minimum and maximum supported values. 988 989 This value can be changed after boot using the 990 /proc/sys/vm/mmap_rnd_bits tunable 991 992config HAVE_ARCH_MMAP_RND_COMPAT_BITS 993 bool 994 help 995 An arch should select this symbol if it supports running applications 996 in compatibility mode, supports setting a variable number of bits for 997 use in establishing the base address for mmap allocations, has MMU 998 enabled and provides values for both: 999 - ARCH_MMAP_RND_COMPAT_BITS_MIN 1000 - ARCH_MMAP_RND_COMPAT_BITS_MAX 1001 1002config ARCH_MMAP_RND_COMPAT_BITS_MIN 1003 int 1004 1005config ARCH_MMAP_RND_COMPAT_BITS_MAX 1006 int 1007 1008config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1009 int 1010 1011config ARCH_MMAP_RND_COMPAT_BITS 1012 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT 1013 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 1014 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1015 default ARCH_MMAP_RND_COMPAT_BITS_MIN 1016 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 1017 help 1018 This value can be used to select the number of bits to use to 1019 determine the random offset to the base address of vma regions 1020 resulting from mmap allocations for compatible applications This 1021 value will be bounded by the architecture's minimum and maximum 1022 supported values. 1023 1024 This value can be changed after boot using the 1025 /proc/sys/vm/mmap_rnd_compat_bits tunable 1026 1027config HAVE_ARCH_COMPAT_MMAP_BASES 1028 bool 1029 help 1030 This allows 64bit applications to invoke 32-bit mmap() syscall 1031 and vice-versa 32-bit applications to call 64-bit mmap(). 1032 Required for applications doing different bitness syscalls. 1033 1034config PAGE_SIZE_LESS_THAN_64KB 1035 def_bool y 1036 depends on !ARM64_64K_PAGES 1037 depends on !IA64_PAGE_SIZE_64KB 1038 depends on !PAGE_SIZE_64KB 1039 depends on !PARISC_PAGE_SIZE_64KB 1040 depends on PAGE_SIZE_LESS_THAN_256KB 1041 1042config PAGE_SIZE_LESS_THAN_256KB 1043 def_bool y 1044 depends on !PAGE_SIZE_256KB 1045 1046# This allows to use a set of generic functions to determine mmap base 1047# address by giving priority to top-down scheme only if the process 1048# is not in legacy mode (compat task, unlimited stack size or 1049# sysctl_legacy_va_layout). 1050# Architecture that selects this option can provide its own version of: 1051# - STACK_RND_MASK 1052config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 1053 bool 1054 depends on MMU 1055 select ARCH_HAS_ELF_RANDOMIZE 1056 1057config HAVE_OBJTOOL 1058 bool 1059 1060config HAVE_JUMP_LABEL_HACK 1061 bool 1062 1063config HAVE_NOINSTR_HACK 1064 bool 1065 1066config HAVE_NOINSTR_VALIDATION 1067 bool 1068 1069config HAVE_UACCESS_VALIDATION 1070 bool 1071 select OBJTOOL 1072 1073config HAVE_STACK_VALIDATION 1074 bool 1075 help 1076 Architecture supports objtool compile-time frame pointer rule 1077 validation. 1078 1079config HAVE_RELIABLE_STACKTRACE 1080 bool 1081 help 1082 Architecture has either save_stack_trace_tsk_reliable() or 1083 arch_stack_walk_reliable() function which only returns a stack trace 1084 if it can guarantee the trace is reliable. 1085 1086config HAVE_ARCH_HASH 1087 bool 1088 default n 1089 help 1090 If this is set, the architecture provides an <asm/hash.h> 1091 file which provides platform-specific implementations of some 1092 functions in <linux/hash.h> or fs/namei.c. 1093 1094config HAVE_ARCH_NVRAM_OPS 1095 bool 1096 1097config ISA_BUS_API 1098 def_bool ISA 1099 1100# 1101# ABI hall of shame 1102# 1103config CLONE_BACKWARDS 1104 bool 1105 help 1106 Architecture has tls passed as the 4th argument of clone(2), 1107 not the 5th one. 1108 1109config CLONE_BACKWARDS2 1110 bool 1111 help 1112 Architecture has the first two arguments of clone(2) swapped. 1113 1114config CLONE_BACKWARDS3 1115 bool 1116 help 1117 Architecture has tls passed as the 3rd argument of clone(2), 1118 not the 5th one. 1119 1120config ODD_RT_SIGACTION 1121 bool 1122 help 1123 Architecture has unusual rt_sigaction(2) arguments 1124 1125config OLD_SIGSUSPEND 1126 bool 1127 help 1128 Architecture has old sigsuspend(2) syscall, of one-argument variety 1129 1130config OLD_SIGSUSPEND3 1131 bool 1132 help 1133 Even weirder antique ABI - three-argument sigsuspend(2) 1134 1135config OLD_SIGACTION 1136 bool 1137 help 1138 Architecture has old sigaction(2) syscall. Nope, not the same 1139 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 1140 but fairly different variant of sigaction(2), thanks to OSF/1 1141 compatibility... 1142 1143config COMPAT_OLD_SIGACTION 1144 bool 1145 1146config COMPAT_32BIT_TIME 1147 bool "Provide system calls for 32-bit time_t" 1148 default !64BIT || COMPAT 1149 help 1150 This enables 32 bit time_t support in addition to 64 bit time_t support. 1151 This is relevant on all 32-bit architectures, and 64-bit architectures 1152 as part of compat syscall handling. 1153 1154config ARCH_NO_PREEMPT 1155 bool 1156 1157config ARCH_EPHEMERAL_INODES 1158 def_bool n 1159 help 1160 An arch should select this symbol if it doesn't keep track of inode 1161 instances on its own, but instead relies on something else (e.g. the 1162 host kernel for an UML kernel). 1163 1164config ARCH_SUPPORTS_RT 1165 bool 1166 1167config CPU_NO_EFFICIENT_FFS 1168 def_bool n 1169 1170config HAVE_ARCH_VMAP_STACK 1171 def_bool n 1172 help 1173 An arch should select this symbol if it can support kernel stacks 1174 in vmalloc space. This means: 1175 1176 - vmalloc space must be large enough to hold many kernel stacks. 1177 This may rule out many 32-bit architectures. 1178 1179 - Stacks in vmalloc space need to work reliably. For example, if 1180 vmap page tables are created on demand, either this mechanism 1181 needs to work while the stack points to a virtual address with 1182 unpopulated page tables or arch code (switch_to() and switch_mm(), 1183 most likely) needs to ensure that the stack's page table entries 1184 are populated before running on a possibly unpopulated stack. 1185 1186 - If the stack overflows into a guard page, something reasonable 1187 should happen. The definition of "reasonable" is flexible, but 1188 instantly rebooting without logging anything would be unfriendly. 1189 1190config VMAP_STACK 1191 default y 1192 bool "Use a virtually-mapped stack" 1193 depends on HAVE_ARCH_VMAP_STACK 1194 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC 1195 help 1196 Enable this if you want the use virtually-mapped kernel stacks 1197 with guard pages. This causes kernel stack overflows to be 1198 caught immediately rather than causing difficult-to-diagnose 1199 corruption. 1200 1201 To use this with software KASAN modes, the architecture must support 1202 backing virtual mappings with real shadow memory, and KASAN_VMALLOC 1203 must be enabled. 1204 1205config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1206 def_bool n 1207 help 1208 An arch should select this symbol if it can support kernel stack 1209 offset randomization with calls to add_random_kstack_offset() 1210 during syscall entry and choose_random_kstack_offset() during 1211 syscall exit. Careful removal of -fstack-protector-strong and 1212 -fstack-protector should also be applied to the entry code and 1213 closely examined, as the artificial stack bump looks like an array 1214 to the compiler, so it will attempt to add canary checks regardless 1215 of the static branch state. 1216 1217config RANDOMIZE_KSTACK_OFFSET 1218 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT 1219 default y 1220 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1221 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000 1222 help 1223 The kernel stack offset can be randomized (after pt_regs) by 1224 roughly 5 bits of entropy, frustrating memory corruption 1225 attacks that depend on stack address determinism or 1226 cross-syscall address exposures. 1227 1228 The feature is controlled via the "randomize_kstack_offset=on/off" 1229 kernel boot param, and if turned off has zero overhead due to its use 1230 of static branches (see JUMP_LABEL). 1231 1232 If unsure, say Y. 1233 1234config RANDOMIZE_KSTACK_OFFSET_DEFAULT 1235 bool "Default state of kernel stack offset randomization" 1236 depends on RANDOMIZE_KSTACK_OFFSET 1237 help 1238 Kernel stack offset randomization is controlled by kernel boot param 1239 "randomize_kstack_offset=on/off", and this config chooses the default 1240 boot state. 1241 1242config ARCH_OPTIONAL_KERNEL_RWX 1243 def_bool n 1244 1245config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1246 def_bool n 1247 1248config ARCH_HAS_STRICT_KERNEL_RWX 1249 def_bool n 1250 1251config STRICT_KERNEL_RWX 1252 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 1253 depends on ARCH_HAS_STRICT_KERNEL_RWX 1254 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1255 help 1256 If this is set, kernel text and rodata memory will be made read-only, 1257 and non-text memory will be made non-executable. This provides 1258 protection against certain security exploits (e.g. executing the heap 1259 or modifying text) 1260 1261 These features are considered standard security practice these days. 1262 You should say Y here in almost all cases. 1263 1264config ARCH_HAS_STRICT_MODULE_RWX 1265 def_bool n 1266 1267config STRICT_MODULE_RWX 1268 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX 1269 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 1270 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1271 help 1272 If this is set, module text and rodata memory will be made read-only, 1273 and non-text memory will be made non-executable. This provides 1274 protection against certain security exploits (e.g. writing to text) 1275 1276# select if the architecture provides an asm/dma-direct.h header 1277config ARCH_HAS_PHYS_TO_DMA 1278 bool 1279 1280config HAVE_ARCH_COMPILER_H 1281 bool 1282 help 1283 An architecture can select this if it provides an 1284 asm/compiler.h header that should be included after 1285 linux/compiler-*.h in order to override macro definitions that those 1286 headers generally provide. 1287 1288config HAVE_ARCH_PREL32_RELOCATIONS 1289 bool 1290 help 1291 May be selected by an architecture if it supports place-relative 1292 32-bit relocations, both in the toolchain and in the module loader, 1293 in which case relative references can be used in special sections 1294 for PCI fixup, initcalls etc which are only half the size on 64 bit 1295 architectures, and don't require runtime relocation on relocatable 1296 kernels. 1297 1298config ARCH_USE_MEMREMAP_PROT 1299 bool 1300 1301config LOCK_EVENT_COUNTS 1302 bool "Locking event counts collection" 1303 depends on DEBUG_FS 1304 help 1305 Enable light-weight counting of various locking related events 1306 in the system with minimal performance impact. This reduces 1307 the chance of application behavior change because of timing 1308 differences. The counts are reported via debugfs. 1309 1310# Select if the architecture has support for applying RELR relocations. 1311config ARCH_HAS_RELR 1312 bool 1313 1314config RELR 1315 bool "Use RELR relocation packing" 1316 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR 1317 default y 1318 help 1319 Store the kernel's dynamic relocations in the RELR relocation packing 1320 format. Requires a compatible linker (LLD supports this feature), as 1321 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy 1322 are compatible). 1323 1324config ARCH_HAS_MEM_ENCRYPT 1325 bool 1326 1327config ARCH_HAS_CC_PLATFORM 1328 bool 1329 1330config HAVE_SPARSE_SYSCALL_NR 1331 bool 1332 help 1333 An architecture should select this if its syscall numbering is sparse 1334 to save space. For example, MIPS architecture has a syscall array with 1335 entries at 4000, 5000 and 6000 locations. This option turns on syscall 1336 related optimizations for a given architecture. 1337 1338config ARCH_HAS_VDSO_DATA 1339 bool 1340 1341config HAVE_STATIC_CALL 1342 bool 1343 1344config HAVE_STATIC_CALL_INLINE 1345 bool 1346 depends on HAVE_STATIC_CALL 1347 select OBJTOOL 1348 1349config HAVE_PREEMPT_DYNAMIC 1350 bool 1351 1352config HAVE_PREEMPT_DYNAMIC_CALL 1353 bool 1354 depends on HAVE_STATIC_CALL 1355 select HAVE_PREEMPT_DYNAMIC 1356 help 1357 An architecture should select this if it can handle the preemption 1358 model being selected at boot time using static calls. 1359 1360 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a 1361 preemption function will be patched directly. 1362 1363 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any 1364 call to a preemption function will go through a trampoline, and the 1365 trampoline will be patched. 1366 1367 It is strongly advised to support inline static call to avoid any 1368 overhead. 1369 1370config HAVE_PREEMPT_DYNAMIC_KEY 1371 bool 1372 depends on HAVE_ARCH_JUMP_LABEL 1373 select HAVE_PREEMPT_DYNAMIC 1374 help 1375 An architecture should select this if it can handle the preemption 1376 model being selected at boot time using static keys. 1377 1378 Each preemption function will be given an early return based on a 1379 static key. This should have slightly lower overhead than non-inline 1380 static calls, as this effectively inlines each trampoline into the 1381 start of its callee. This may avoid redundant work, and may 1382 integrate better with CFI schemes. 1383 1384 This will have greater overhead than using inline static calls as 1385 the call to the preemption function cannot be entirely elided. 1386 1387config ARCH_WANT_LD_ORPHAN_WARN 1388 bool 1389 help 1390 An arch should select this symbol once all linker sections are explicitly 1391 included, size-asserted, or discarded in the linker scripts. This is 1392 important because we never want expected sections to be placed heuristically 1393 by the linker, since the locations of such sections can change between linker 1394 versions. 1395 1396config HAVE_ARCH_PFN_VALID 1397 bool 1398 1399config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1400 bool 1401 1402config ARCH_SUPPORTS_PAGE_TABLE_CHECK 1403 bool 1404 1405config ARCH_SPLIT_ARG64 1406 bool 1407 help 1408 If a 32-bit architecture requires 64-bit arguments to be split into 1409 pairs of 32-bit arguments, select this option. 1410 1411config ARCH_HAS_ELFCORE_COMPAT 1412 bool 1413 1414config ARCH_HAS_PARANOID_L1D_FLUSH 1415 bool 1416 1417config ARCH_HAVE_TRACE_MMIO_ACCESS 1418 bool 1419 1420config DYNAMIC_SIGFRAME 1421 bool 1422 1423# Select, if arch has a named attribute group bound to NUMA device nodes. 1424config HAVE_ARCH_NODE_DEV_GROUP 1425 bool 1426 1427source "kernel/gcov/Kconfig" 1428 1429source "scripts/gcc-plugins/Kconfig" 1430 1431endmenu 1432