1 # SPDX-License-Identifier: GPL-2.0 1 # SPDX-License-Identifier: GPL-2.0 2 # 2 # 3 # General architecture dependent options 3 # General architecture dependent options 4 # 4 # 5 5 6 # !! 6 config CRASH_CORE 7 # Note: arch/$(SRCARCH)/Kconfig needs to be in << 8 # override the default values in this file. << 9 # << 10 source "arch/$(SRCARCH)/Kconfig" << 11 << 12 config ARCH_CONFIGURES_CPU_MITIGATIONS << 13 bool 7 bool 14 8 15 if !ARCH_CONFIGURES_CPU_MITIGATIONS !! 9 config KEXEC_CORE 16 config CPU_MITIGATIONS !! 10 select CRASH_CORE 17 def_bool y << 18 endif << 19 << 20 menu "General architecture-dependent options" << 21 << 22 config ARCH_HAS_SUBPAGE_FAULTS << 23 bool << 24 help << 25 Select if the architecture can check << 26 granularity (e.g. arm64 MTE). The pr << 27 must be implemented. << 28 << 29 config HOTPLUG_SMT << 30 bool 11 bool 31 12 32 config SMT_NUM_THREADS_DYNAMIC !! 13 config HAVE_IMA_KEXEC 33 bool 14 bool 34 15 35 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU !! 16 config OPROFILE 36 config HOTPLUG_CORE_SYNC !! 17 tristate "OProfile system profiling" 37 bool !! 18 depends on PROFILING >> 19 depends on HAVE_OPROFILE >> 20 select RING_BUFFER >> 21 select RING_BUFFER_ALLOW_SWAP >> 22 help >> 23 OProfile is a profiling system capable of profiling the >> 24 whole system, include the kernel, kernel modules, libraries, >> 25 and applications. 38 26 39 # Basic CPU dead synchronization selected by a !! 27 If unsure, say N. 40 config HOTPLUG_CORE_SYNC_DEAD << 41 bool << 42 select HOTPLUG_CORE_SYNC << 43 28 44 # Full CPU synchronization with alive state se !! 29 config OPROFILE_EVENT_MULTIPLEX 45 config HOTPLUG_CORE_SYNC_FULL !! 30 bool "OProfile multiplexing support (EXPERIMENTAL)" 46 bool !! 31 default n 47 select HOTPLUG_CORE_SYNC_DEAD if HOTPL !! 32 depends on OPROFILE && X86 48 select HOTPLUG_CORE_SYNC !! 33 help >> 34 The number of hardware counters is limited. The multiplexing >> 35 feature enables OProfile to gather more events than counters >> 36 are provided by the hardware. This is realized by switching >> 37 between events at a user specified time interval. 49 38 50 config HOTPLUG_SPLIT_STARTUP !! 39 If unsure, say N. 51 bool << 52 select HOTPLUG_CORE_SYNC_FULL << 53 40 54 config HOTPLUG_PARALLEL !! 41 config HAVE_OPROFILE 55 bool 42 bool 56 select HOTPLUG_SPLIT_STARTUP << 57 43 58 config GENERIC_ENTRY !! 44 config OPROFILE_NMI_TIMER 59 bool !! 45 def_bool y >> 46 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 60 47 61 config KPROBES 48 config KPROBES 62 bool "Kprobes" 49 bool "Kprobes" >> 50 depends on MODULES 63 depends on HAVE_KPROBES 51 depends on HAVE_KPROBES 64 select KALLSYMS 52 select KALLSYMS 65 select EXECMEM << 66 select NEED_TASKS_RCU << 67 help 53 help 68 Kprobes allows you to trap at almost 54 Kprobes allows you to trap at almost any kernel address and 69 execute a callback function. regist 55 execute a callback function. register_kprobe() establishes 70 a probepoint and specifies the callb 56 a probepoint and specifies the callback. Kprobes is useful 71 for kernel debugging, non-intrusive 57 for kernel debugging, non-intrusive instrumentation and testing. 72 If in doubt, say "N". 58 If in doubt, say "N". 73 59 74 config JUMP_LABEL 60 config JUMP_LABEL 75 bool "Optimize very unlikely/likely br !! 61 bool "Optimize very unlikely/likely branches" 76 depends on HAVE_ARCH_JUMP_LABEL !! 62 depends on HAVE_ARCH_JUMP_LABEL 77 select OBJTOOL if HAVE_JUMP_LABEL_HACK !! 63 help 78 help !! 64 This option enables a transparent branch optimization that 79 This option enables a transparent br !! 65 makes certain almost-always-true or almost-always-false branch 80 makes certain almost-always-true or !! 66 conditions even cheaper to execute within the kernel. 81 conditions even cheaper to execute w !! 67 82 !! 68 Certain performance-sensitive kernel code, such as trace points, 83 Certain performance-sensitive kernel !! 69 scheduler functionality, networking code and KVM have such 84 scheduler functionality, networking !! 70 branches and include support for this optimization technique. 85 branches and include support for thi !! 71 86 !! 72 If it is detected that the compiler has support for "asm goto", 87 If it is detected that the compiler !! 73 the kernel will compile such branches with just a nop 88 the kernel will compile such branche !! 74 instruction. When the condition flag is toggled to true, the 89 instruction. When the condition flag !! 75 nop will be converted to a jump instruction to execute the 90 nop will be converted to a jump inst !! 76 conditional block of instructions. 91 conditional block of instructions. !! 77 92 !! 78 This technique lowers overhead and stress on the branch prediction 93 This technique lowers overhead and s !! 79 of the processor and generally makes the kernel faster. The update 94 of the processor and generally makes !! 80 of the condition is slower, but those are always very rare. 95 of the condition is slower, but thos << 96 81 97 ( On 32-bit x86, the necessary optio !! 82 ( On 32-bit x86, the necessary options added to the compiler 98 flags may increase the size of the !! 83 flags may increase the size of the kernel slightly. ) 99 84 100 config STATIC_KEYS_SELFTEST 85 config STATIC_KEYS_SELFTEST 101 bool "Static key selftest" 86 bool "Static key selftest" 102 depends on JUMP_LABEL 87 depends on JUMP_LABEL 103 help 88 help 104 Boot time self-test of the branch pa 89 Boot time self-test of the branch patching code. 105 90 106 config STATIC_CALL_SELFTEST << 107 bool "Static call selftest" << 108 depends on HAVE_STATIC_CALL << 109 help << 110 Boot time self-test of the call patc << 111 << 112 config OPTPROBES 91 config OPTPROBES 113 def_bool y 92 def_bool y 114 depends on KPROBES && HAVE_OPTPROBES 93 depends on KPROBES && HAVE_OPTPROBES 115 select NEED_TASKS_RCU !! 94 select TASKS_RCU if PREEMPT 116 95 117 config KPROBES_ON_FTRACE 96 config KPROBES_ON_FTRACE 118 def_bool y 97 def_bool y 119 depends on KPROBES && HAVE_KPROBES_ON_ 98 depends on KPROBES && HAVE_KPROBES_ON_FTRACE 120 depends on DYNAMIC_FTRACE_WITH_REGS 99 depends on DYNAMIC_FTRACE_WITH_REGS 121 help 100 help 122 If function tracer is enabled and th !! 101 If function tracer is enabled and the arch supports full 123 passing of pt_regs to function traci !! 102 passing of pt_regs to function tracing, then kprobes can 124 optimize on top of function tracing. !! 103 optimize on top of function tracing. 125 104 126 config UPROBES 105 config UPROBES 127 def_bool n 106 def_bool n 128 depends on ARCH_SUPPORTS_UPROBES 107 depends on ARCH_SUPPORTS_UPROBES 129 help 108 help 130 Uprobes is the user-space counterpar 109 Uprobes is the user-space counterpart to kprobes: they 131 enable instrumentation applications 110 enable instrumentation applications (such as 'perf probe') 132 to establish unintrusive probes in u 111 to establish unintrusive probes in user-space binaries and 133 libraries, by executing handler func 112 libraries, by executing handler functions when the probes 134 are hit by user-space applications. 113 are hit by user-space applications. 135 114 136 ( These probes come in the form of s 115 ( These probes come in the form of single-byte breakpoints, 137 managed by the kernel and kept tra 116 managed by the kernel and kept transparent to the probed 138 application. ) 117 application. ) 139 118 140 config HAVE_64BIT_ALIGNED_ACCESS 119 config HAVE_64BIT_ALIGNED_ACCESS 141 def_bool 64BIT && !HAVE_EFFICIENT_UNAL 120 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS 142 help 121 help 143 Some architectures require 64 bit ac 122 Some architectures require 64 bit accesses to be 64 bit 144 aligned, which also requires structs 123 aligned, which also requires structs containing 64 bit values 145 to be 64 bit aligned too. This inclu 124 to be 64 bit aligned too. This includes some 32 bit 146 architectures which can do 64 bit ac 125 architectures which can do 64 bit accesses, as well as 64 bit 147 architectures without unaligned acce 126 architectures without unaligned access. 148 127 149 This symbol should be selected by an 128 This symbol should be selected by an architecture if 64 bit 150 accesses are required to be 64 bit a 129 accesses are required to be 64 bit aligned in this way even 151 though it is not a 64 bit architectu 130 though it is not a 64 bit architecture. 152 131 153 See Documentation/core-api/unaligned !! 132 See Documentation/unaligned-memory-access.txt for more 154 more information on the topic of una !! 133 information on the topic of unaligned memory accesses. 155 134 156 config HAVE_EFFICIENT_UNALIGNED_ACCESS 135 config HAVE_EFFICIENT_UNALIGNED_ACCESS 157 bool 136 bool 158 help 137 help 159 Some architectures are unable to per 138 Some architectures are unable to perform unaligned accesses 160 without the use of get_unaligned/put 139 without the use of get_unaligned/put_unaligned. Others are 161 unable to perform such accesses effi 140 unable to perform such accesses efficiently (e.g. trap on 162 unaligned access and require fixing 141 unaligned access and require fixing it up in the exception 163 handler.) 142 handler.) 164 143 165 This symbol should be selected by an 144 This symbol should be selected by an architecture if it can 166 perform unaligned accesses efficient 145 perform unaligned accesses efficiently to allow different 167 code paths to be selected for these 146 code paths to be selected for these cases. Some network 168 drivers, for example, could opt to n 147 drivers, for example, could opt to not fix up alignment 169 problems with received packets if do 148 problems with received packets if doing so would not help 170 much. 149 much. 171 150 172 See Documentation/core-api/unaligned !! 151 See Documentation/unaligned-memory-access.txt for more 173 information on the topic of unaligne 152 information on the topic of unaligned memory accesses. 174 153 175 config ARCH_USE_BUILTIN_BSWAP 154 config ARCH_USE_BUILTIN_BSWAP 176 bool !! 155 bool 177 help !! 156 help 178 Modern versions of GCC (since 4.4) h !! 157 Modern versions of GCC (since 4.4) have builtin functions 179 for handling byte-swapping. Using th !! 158 for handling byte-swapping. Using these, instead of the old 180 inline assembler that the architectu !! 159 inline assembler that the architecture code provides in the 181 __arch_bswapXX() macros, allows the !! 160 __arch_bswapXX() macros, allows the compiler to see what's 182 happening and offers more opportunit !! 161 happening and offers more opportunity for optimisation. In 183 particular, the compiler will be abl !! 162 particular, the compiler will be able to combine the byteswap 184 with a nearby load or store and use !! 163 with a nearby load or store and use load-and-swap or 185 store-and-swap instructions if the a !! 164 store-and-swap instructions if the architecture has them. It 186 should almost *never* result in code !! 165 should almost *never* result in code which is worse than the 187 hand-coded assembler in <asm/swab.h> !! 166 hand-coded assembler in <asm/swab.h>. But just in case it 188 does, the use of the builtins is opt !! 167 does, the use of the builtins is optional. 189 !! 168 190 Any architecture with load-and-swap !! 169 Any architecture with load-and-swap or store-and-swap 191 instructions should set this. And it !! 170 instructions should set this. And it shouldn't hurt to set it 192 on architectures that don't have suc !! 171 on architectures that don't have such instructions. 193 172 194 config KRETPROBES 173 config KRETPROBES 195 def_bool y 174 def_bool y 196 depends on KPROBES && (HAVE_KRETPROBES !! 175 depends on KPROBES && HAVE_KRETPROBES 197 << 198 config KRETPROBE_ON_RETHOOK << 199 def_bool y << 200 depends on HAVE_RETHOOK << 201 depends on KRETPROBES << 202 select RETHOOK << 203 176 204 config USER_RETURN_NOTIFIER 177 config USER_RETURN_NOTIFIER 205 bool 178 bool 206 depends on HAVE_USER_RETURN_NOTIFIER 179 depends on HAVE_USER_RETURN_NOTIFIER 207 help 180 help 208 Provide a kernel-internal notificati 181 Provide a kernel-internal notification when a cpu is about to 209 switch to user mode. 182 switch to user mode. 210 183 211 config HAVE_IOREMAP_PROT 184 config HAVE_IOREMAP_PROT 212 bool 185 bool 213 186 214 config HAVE_KPROBES 187 config HAVE_KPROBES 215 bool 188 bool 216 189 217 config HAVE_KRETPROBES 190 config HAVE_KRETPROBES 218 bool 191 bool 219 192 220 config HAVE_OPTPROBES 193 config HAVE_OPTPROBES 221 bool 194 bool 222 195 223 config HAVE_KPROBES_ON_FTRACE 196 config HAVE_KPROBES_ON_FTRACE 224 bool 197 bool 225 198 226 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE << 227 bool << 228 help << 229 Since kretprobes modifies return add << 230 stacktrace may see the kretprobe tra << 231 of correct one. If the architecture << 232 unwinder can adjust such entries, se << 233 << 234 config HAVE_FUNCTION_ERROR_INJECTION << 235 bool << 236 << 237 config HAVE_NMI 199 config HAVE_NMI 238 bool 200 bool 239 201 240 config HAVE_FUNCTION_DESCRIPTORS << 241 bool << 242 << 243 config TRACE_IRQFLAGS_SUPPORT << 244 bool << 245 << 246 config TRACE_IRQFLAGS_NMI_SUPPORT << 247 bool << 248 << 249 # 202 # 250 # An arch should select this if it provides al 203 # An arch should select this if it provides all these things: 251 # 204 # 252 # task_pt_regs() in asm/process 205 # task_pt_regs() in asm/processor.h or asm/ptrace.h 253 # arch_has_single_step() if there is ha 206 # arch_has_single_step() if there is hardware single-step support 254 # arch_has_block_step() if there is ha 207 # arch_has_block_step() if there is hardware block-step support 255 # asm/syscall.h supplying asm- 208 # asm/syscall.h supplying asm-generic/syscall.h interface 256 # linux/regset.h user_regset in 209 # linux/regset.h user_regset interfaces 257 # CORE_DUMP_USE_REGSET #define'd in l 210 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h 258 # TIF_SYSCALL_TRACE calls ptrace_r !! 211 # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 259 # TIF_NOTIFY_RESUME calls resume_u !! 212 # TIF_NOTIFY_RESUME calls tracehook_notify_resume() >> 213 # signal delivery calls tracehook_signal_handler() 260 # 214 # 261 config HAVE_ARCH_TRACEHOOK 215 config HAVE_ARCH_TRACEHOOK 262 bool 216 bool 263 217 264 config HAVE_DMA_CONTIGUOUS 218 config HAVE_DMA_CONTIGUOUS 265 bool 219 bool 266 220 267 config GENERIC_SMP_IDLE_THREAD 221 config GENERIC_SMP_IDLE_THREAD 268 bool !! 222 bool 269 223 270 config GENERIC_IDLE_POLL_SETUP 224 config GENERIC_IDLE_POLL_SETUP 271 bool !! 225 bool 272 226 273 config ARCH_HAS_FORTIFY_SOURCE 227 config ARCH_HAS_FORTIFY_SOURCE 274 bool 228 bool 275 help 229 help 276 An architecture should select this w 230 An architecture should select this when it can successfully 277 build and run with CONFIG_FORTIFY_SO 231 build and run with CONFIG_FORTIFY_SOURCE. 278 232 279 # << 280 # Select if the arch provides a historic keepi << 281 # command line option << 282 # << 283 config ARCH_HAS_KEEPINITRD << 284 bool << 285 << 286 # Select if arch has all set_memory_ro/rw/x/nx 233 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h 287 config ARCH_HAS_SET_MEMORY 234 config ARCH_HAS_SET_MEMORY 288 bool 235 bool 289 236 290 # Select if arch has all set_direct_map_invali !! 237 # Select if arch init_task initializer is different to init/init_task.c 291 config ARCH_HAS_SET_DIRECT_MAP !! 238 config ARCH_INIT_TASK 292 bool !! 239 bool 293 << 294 # << 295 # Select if the architecture provides the arch << 296 # either provide an uncached segment alias for << 297 # to remap the page tables in place. << 298 # << 299 config ARCH_HAS_DMA_SET_UNCACHED << 300 bool << 301 << 302 # << 303 # Select if the architectures provides the arc << 304 # to undo an in-place page table remap for unc << 305 # << 306 config ARCH_HAS_DMA_CLEAR_UNCACHED << 307 bool << 308 << 309 config ARCH_HAS_CPU_FINALIZE_INIT << 310 bool << 311 240 312 # The architecture has a per-task state that i !! 241 # Select if arch has its private alloc_task_struct() function 313 config ARCH_HAS_CPU_PASID !! 242 config ARCH_TASK_STRUCT_ALLOCATOR 314 bool 243 bool 315 select IOMMU_MM_DATA << 316 244 317 config HAVE_ARCH_THREAD_STRUCT_WHITELIST !! 245 # Select if arch has its private alloc_thread_stack() function >> 246 config ARCH_THREAD_STACK_ALLOCATOR 318 bool 247 bool 319 help << 320 An architecture should select this t << 321 knowledge about what region of the t << 322 whitelisted for copying to userspace << 323 FPU registers. Specifically, arch_th << 324 should be implemented. Without this, << 325 field in task_struct will be left wh << 326 248 327 # Select if arch wants to size task_struct dyn 249 # Select if arch wants to size task_struct dynamically via arch_task_struct_size: 328 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 250 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 329 bool 251 bool 330 252 331 config ARCH_WANTS_NO_INSTR << 332 bool << 333 help << 334 An architecture should select this i << 335 functions to denote that the toolcha << 336 functions and is required for correc << 337 << 338 config ARCH_32BIT_OFF_T << 339 bool << 340 depends on !64BIT << 341 help << 342 All new 32-bit architectures should << 343 userspace side which corresponds to << 344 is the requirement for modern ABIs. << 345 still support 32-bit off_t. This opt << 346 architectures explicitly. << 347 << 348 # Selected by 64 bit architectures which have << 349 config ARCH_32BIT_USTAT_F_TINODE << 350 bool << 351 << 352 config HAVE_ASM_MODVERSIONS << 353 bool << 354 help << 355 This symbol should be selected by an << 356 <asm/asm-prototypes.h> to support th << 357 exported from assembly code. << 358 << 359 config HAVE_REGS_AND_STACK_ACCESS_API 253 config HAVE_REGS_AND_STACK_ACCESS_API 360 bool 254 bool 361 help 255 help 362 This symbol should be selected by an !! 256 This symbol should be selected by an architecure if it supports 363 the API needed to access registers a 257 the API needed to access registers and stack entries from pt_regs, 364 declared in asm/ptrace.h 258 declared in asm/ptrace.h 365 For example the kprobes-based event 259 For example the kprobes-based event tracer needs this API. 366 260 367 config HAVE_RSEQ !! 261 config HAVE_CLK 368 bool 262 bool 369 depends on HAVE_REGS_AND_STACK_ACCESS_ << 370 help 263 help 371 This symbol should be selected by an !! 264 The <linux/clk.h> calls support software clock gating and 372 supports an implementation of restar !! 265 thus are a key power management tool on many systems. 373 266 374 config HAVE_RUST !! 267 config HAVE_DMA_API_DEBUG 375 bool 268 bool 376 help << 377 This symbol should be selected by an << 378 supports Rust. << 379 << 380 config HAVE_FUNCTION_ARG_ACCESS_API << 381 bool << 382 help << 383 This symbol should be selected by an << 384 the API needed to access function ar << 385 declared in asm/ptrace.h << 386 269 387 config HAVE_HW_BREAKPOINT 270 config HAVE_HW_BREAKPOINT 388 bool 271 bool 389 depends on PERF_EVENTS 272 depends on PERF_EVENTS 390 273 391 config HAVE_MIXED_BREAKPOINTS_REGS 274 config HAVE_MIXED_BREAKPOINTS_REGS 392 bool 275 bool 393 depends on HAVE_HW_BREAKPOINT 276 depends on HAVE_HW_BREAKPOINT 394 help 277 help 395 Depending on the arch implementation 278 Depending on the arch implementation of hardware breakpoints, 396 some of them have separate registers 279 some of them have separate registers for data and instruction 397 breakpoints addresses, others have m 280 breakpoints addresses, others have mixed registers to store 398 them but define the access type in a 281 them but define the access type in a control register. 399 Select this option if your arch impl 282 Select this option if your arch implements breakpoints under the 400 latter fashion. 283 latter fashion. 401 284 402 config HAVE_USER_RETURN_NOTIFIER 285 config HAVE_USER_RETURN_NOTIFIER 403 bool 286 bool 404 287 405 config HAVE_PERF_EVENTS_NMI 288 config HAVE_PERF_EVENTS_NMI 406 bool 289 bool 407 help 290 help 408 System hardware can generate an NMI 291 System hardware can generate an NMI using the perf event 409 subsystem. Also has support for cal 292 subsystem. Also has support for calculating CPU cycle events 410 to determine how many clock cycles i 293 to determine how many clock cycles in a given period. 411 294 412 config HAVE_HARDLOCKUP_DETECTOR_PERF 295 config HAVE_HARDLOCKUP_DETECTOR_PERF 413 bool 296 bool 414 depends on HAVE_PERF_EVENTS_NMI 297 depends on HAVE_PERF_EVENTS_NMI 415 help 298 help 416 The arch chooses to use the generic 299 The arch chooses to use the generic perf-NMI-based hardlockup 417 detector. Must define HAVE_PERF_EVEN 300 detector. Must define HAVE_PERF_EVENTS_NMI. 418 301 419 config HAVE_HARDLOCKUP_DETECTOR_ARCH !! 302 config HAVE_NMI_WATCHDOG >> 303 depends on HAVE_NMI 420 bool 304 bool 421 help 305 help 422 The arch provides its own hardlockup !! 306 The arch provides a low level NMI watchdog. It provides 423 of the generic ones. !! 307 asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). 424 308 425 It uses the same command line parame !! 309 config HAVE_HARDLOCKUP_DETECTOR_ARCH 426 as the generic hardlockup detectors. !! 310 bool >> 311 select HAVE_NMI_WATCHDOG >> 312 help >> 313 The arch chooses to provide its own hardlockup detector, which is >> 314 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config >> 315 interfaces and parameters provided by hardlockup detector subsystem. 427 316 428 config HAVE_PERF_REGS 317 config HAVE_PERF_REGS 429 bool 318 bool 430 help 319 help 431 Support selective register dumps for 320 Support selective register dumps for perf events. This includes 432 bit-mapping of each registers and a 321 bit-mapping of each registers and a unique architecture id. 433 322 434 config HAVE_PERF_USER_STACK_DUMP 323 config HAVE_PERF_USER_STACK_DUMP 435 bool 324 bool 436 help 325 help 437 Support user stack dumps for perf ev 326 Support user stack dumps for perf event samples. This needs 438 access to the user stack pointer whi 327 access to the user stack pointer which is not unified across 439 architectures. 328 architectures. 440 329 441 config HAVE_ARCH_JUMP_LABEL 330 config HAVE_ARCH_JUMP_LABEL 442 bool 331 bool 443 332 444 config HAVE_ARCH_JUMP_LABEL_RELATIVE !! 333 config HAVE_RCU_TABLE_FREE 445 bool << 446 << 447 config MMU_GATHER_TABLE_FREE << 448 bool << 449 << 450 config MMU_GATHER_RCU_TABLE_FREE << 451 bool << 452 select MMU_GATHER_TABLE_FREE << 453 << 454 config MMU_GATHER_PAGE_SIZE << 455 bool << 456 << 457 config MMU_GATHER_NO_RANGE << 458 bool << 459 select MMU_GATHER_MERGE_VMAS << 460 << 461 config MMU_GATHER_NO_FLUSH_CACHE << 462 bool << 463 << 464 config MMU_GATHER_MERGE_VMAS << 465 bool << 466 << 467 config MMU_GATHER_NO_GATHER << 468 bool << 469 depends on MMU_GATHER_TABLE_FREE << 470 << 471 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM << 472 bool << 473 help << 474 Temporary select until all architect << 475 irqs disabled over activate_mm. Arch << 476 shootdowns should enable this. << 477 << 478 # Use normal mm refcounting for MMU_LAZY_TLB k << 479 # MMU_LAZY_TLB_REFCOUNT=n can improve the scal << 480 # to/from kernel threads when the same mm is r << 481 # multi-threaded application), by reducing con << 482 # << 483 # This can be disabled if the architecture ens << 484 # "lazy tlb" beyond its final refcount (i.e., << 485 # or its kernel page tables). This could be ar << 486 # final exit(2) TLB flush, for example. << 487 # << 488 # To implement this, an arch *must*: << 489 # Ensure the _lazy_tlb variants of mmgrab/mmdr << 490 # the lazy tlb reference of a kthread's ->acti << 491 # converted already). << 492 config MMU_LAZY_TLB_REFCOUNT << 493 def_bool y << 494 depends on !MMU_LAZY_TLB_SHOOTDOWN << 495 << 496 # This option allows MMU_LAZY_TLB_REFCOUNT=n. << 497 # mm as a lazy tlb beyond its last reference c << 498 # users before the mm is deallocated. __mmdrop << 499 # be using the mm as a lazy tlb, so that they << 500 # init_mm for their active mm. mm_cpumask(mm) << 501 # may be using mm as a lazy tlb mm. << 502 # << 503 # To implement this, an arch *must*: << 504 # - At the time of the final mmdrop of the mm, << 505 # at least all possible CPUs in which the mm << 506 # - It must meet the requirements for MMU_LAZY << 507 config MMU_LAZY_TLB_SHOOTDOWN << 508 bool 334 bool 509 335 510 config ARCH_HAVE_NMI_SAFE_CMPXCHG 336 config ARCH_HAVE_NMI_SAFE_CMPXCHG 511 bool 337 bool 512 338 513 config ARCH_HAVE_EXTRA_ELF_NOTES << 514 bool << 515 help << 516 An architecture should select this i << 517 arch-specific ELF note section to co << 518 functions: elf_coredump_extra_notes_ << 519 elf_coredump_extra_notes_write() whi << 520 dumper. << 521 << 522 config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS << 523 bool << 524 << 525 config HAVE_ALIGNED_STRUCT_PAGE 339 config HAVE_ALIGNED_STRUCT_PAGE 526 bool 340 bool 527 help 341 help 528 This makes sure that struct pages ar 342 This makes sure that struct pages are double word aligned and that 529 e.g. the SLUB allocator can perform 343 e.g. the SLUB allocator can perform double word atomic operations 530 on a struct page for better performa 344 on a struct page for better performance. However selecting this 531 might increase the size of a struct 345 might increase the size of a struct page by a word. 532 346 533 config HAVE_CMPXCHG_LOCAL 347 config HAVE_CMPXCHG_LOCAL 534 bool 348 bool 535 349 536 config HAVE_CMPXCHG_DOUBLE 350 config HAVE_CMPXCHG_DOUBLE 537 bool 351 bool 538 352 539 config ARCH_WEAK_RELEASE_ACQUIRE 353 config ARCH_WEAK_RELEASE_ACQUIRE 540 bool 354 bool 541 355 542 config ARCH_WANT_IPC_PARSE_VERSION 356 config ARCH_WANT_IPC_PARSE_VERSION 543 bool 357 bool 544 358 545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 359 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 546 bool 360 bool 547 361 548 config ARCH_WANT_OLD_COMPAT_IPC 362 config ARCH_WANT_OLD_COMPAT_IPC 549 select ARCH_WANT_COMPAT_IPC_PARSE_VERS 363 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 550 bool 364 bool 551 365 552 config HAVE_ARCH_SECCOMP << 553 bool << 554 help << 555 An arch should select this symbol to << 556 syscall policy), and must provide an << 557 and compat syscalls if the asm-gener << 558 - __NR_seccomp_read_32 << 559 - __NR_seccomp_write_32 << 560 - __NR_seccomp_exit_32 << 561 - __NR_seccomp_sigreturn_32 << 562 << 563 config HAVE_ARCH_SECCOMP_FILTER 366 config HAVE_ARCH_SECCOMP_FILTER 564 bool 367 bool 565 select HAVE_ARCH_SECCOMP << 566 help 368 help 567 An arch should select this symbol if 369 An arch should select this symbol if it provides all of these things: 568 - all the requirements for HAVE_ARCH << 569 - syscall_get_arch() 370 - syscall_get_arch() 570 - syscall_get_arguments() 371 - syscall_get_arguments() 571 - syscall_rollback() 372 - syscall_rollback() 572 - syscall_set_return_value() 373 - syscall_set_return_value() 573 - SIGSYS siginfo_t support 374 - SIGSYS siginfo_t support 574 - secure_computing is called from a 375 - secure_computing is called from a ptrace_event()-safe context 575 - secure_computing return value is c 376 - secure_computing return value is checked and a return value of -1 576 results in the system call being s 377 results in the system call being skipped immediately. 577 - seccomp syscall wired up 378 - seccomp syscall wired up 578 - if !HAVE_SPARSE_SYSCALL_NR, have S << 579 SECCOMP_ARCH_NATIVE_NR, SECCOMP_AR << 580 COMPAT is supported, have the SECC << 581 << 582 config SECCOMP << 583 prompt "Enable seccomp to safely execu << 584 def_bool y << 585 depends on HAVE_ARCH_SECCOMP << 586 help << 587 This kernel feature is useful for nu << 588 that may need to handle untrusted by << 589 execution. By using pipes or other t << 590 to the process as file descriptors s << 591 syscalls, it's possible to isolate t << 592 own address space using seccomp. Onc << 593 prctl(PR_SET_SECCOMP) or the seccomp << 594 disabled and the task is only allowe << 595 syscalls defined by each seccomp mod << 596 << 597 If unsure, say Y. << 598 379 599 config SECCOMP_FILTER 380 config SECCOMP_FILTER 600 def_bool y 381 def_bool y 601 depends on HAVE_ARCH_SECCOMP_FILTER && 382 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 602 help 383 help 603 Enable tasks to build secure computi 384 Enable tasks to build secure computing environments defined 604 in terms of Berkeley Packet Filter p 385 in terms of Berkeley Packet Filter programs which implement 605 task-defined system call filtering p 386 task-defined system call filtering polices. 606 387 607 See Documentation/userspace-api/secc !! 388 See Documentation/prctl/seccomp_filter.txt for details. 608 389 609 config SECCOMP_CACHE_DEBUG !! 390 config HAVE_GCC_PLUGINS 610 bool "Show seccomp filter cache status !! 391 bool 611 depends on SECCOMP_FILTER && !HAVE_SPA !! 392 help 612 depends on PROC_FS !! 393 An arch should select this symbol if it supports building with 613 help !! 394 GCC plugins. 614 This enables the /proc/pid/seccomp_c << 615 seccomp cache data. The file format << 616 the file requires CAP_SYS_ADMIN. << 617 395 618 This option is for debugging only. E !! 396 menuconfig GCC_PLUGINS 619 an adversary may be able to infer th !! 397 bool "GCC plugins" >> 398 depends on HAVE_GCC_PLUGINS >> 399 depends on !COMPILE_TEST >> 400 help >> 401 GCC plugins are loadable modules that provide extra features to the >> 402 compiler. They are useful for runtime instrumentation and static analysis. 620 403 621 If unsure, say N. !! 404 See Documentation/gcc-plugins.txt for details. 622 405 623 config HAVE_ARCH_STACKLEAK !! 406 config GCC_PLUGIN_CYC_COMPLEXITY 624 bool !! 407 bool "Compute the cyclomatic complexity of a function" if EXPERT >> 408 depends on GCC_PLUGINS >> 409 depends on !COMPILE_TEST 625 help 410 help 626 An architecture should select this i !! 411 The complexity M of a function's control flow graph is defined as: 627 fills the used part of the kernel st !! 412 M = E - N + 2P 628 value before returning from system c !! 413 where >> 414 >> 415 E = the number of edges >> 416 N = the number of nodes >> 417 P = the number of connected components (exit nodes). >> 418 >> 419 Enabling this plugin reports the complexity to stderr during the >> 420 build. It mainly serves as a simple example of how to create a >> 421 gcc plugin for the kernel. >> 422 >> 423 config GCC_PLUGIN_SANCOV >> 424 bool >> 425 depends on GCC_PLUGINS >> 426 help >> 427 This plugin inserts a __sanitizer_cov_trace_pc() call at the start of >> 428 basic blocks. It supports all gcc versions with plugin support (from >> 429 gcc-4.5 on). It is based on the commit "Add fuzzing coverage support" >> 430 by Dmitry Vyukov <dvyukov@google.com>. >> 431 >> 432 config GCC_PLUGIN_LATENT_ENTROPY >> 433 bool "Generate some entropy during boot and runtime" >> 434 depends on GCC_PLUGINS >> 435 help >> 436 By saying Y here the kernel will instrument some kernel code to >> 437 extract some entropy from both original and artificially created >> 438 program state. This will help especially embedded systems where >> 439 there is little 'natural' source of entropy normally. The cost >> 440 is some slowdown of the boot process (about 0.5%) and fork and >> 441 irq processing. >> 442 >> 443 Note that entropy extracted this way is not cryptographically >> 444 secure! >> 445 >> 446 This plugin was ported from grsecurity/PaX. More information at: >> 447 * https://grsecurity.net/ >> 448 * https://pax.grsecurity.net/ >> 449 >> 450 config GCC_PLUGIN_STRUCTLEAK >> 451 bool "Force initialization of variables containing userspace addresses" >> 452 depends on GCC_PLUGINS >> 453 help >> 454 This plugin zero-initializes any structures containing a >> 455 __user attribute. This can prevent some classes of information >> 456 exposures. >> 457 >> 458 This plugin was ported from grsecurity/PaX. More information at: >> 459 * https://grsecurity.net/ >> 460 * https://pax.grsecurity.net/ >> 461 >> 462 config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL >> 463 bool "Force initialize all struct type variables passed by reference" >> 464 depends on GCC_PLUGIN_STRUCTLEAK >> 465 help >> 466 Zero initialize any struct type local variable that may be passed by >> 467 reference without having been initialized. >> 468 >> 469 config GCC_PLUGIN_STRUCTLEAK_VERBOSE >> 470 bool "Report forcefully initialized variables" >> 471 depends on GCC_PLUGIN_STRUCTLEAK >> 472 depends on !COMPILE_TEST >> 473 help >> 474 This option will cause a warning to be printed each time the >> 475 structleak plugin finds a variable it thinks needs to be >> 476 initialized. Since not all existing initializers are detected >> 477 by the plugin, this can produce false positive warnings. >> 478 >> 479 config GCC_PLUGIN_RANDSTRUCT >> 480 bool "Randomize layout of sensitive kernel structures" >> 481 depends on GCC_PLUGINS >> 482 select MODVERSIONS if MODULES >> 483 help >> 484 If you say Y here, the layouts of structures that are entirely >> 485 function pointers (and have not been manually annotated with >> 486 __no_randomize_layout), or structures that have been explicitly >> 487 marked with __randomize_layout, will be randomized at compile-time. >> 488 This can introduce the requirement of an additional information >> 489 exposure vulnerability for exploits targeting these structure >> 490 types. >> 491 >> 492 Enabling this feature will introduce some performance impact, >> 493 slightly increase memory usage, and prevent the use of forensic >> 494 tools like Volatility against the system (unless the kernel >> 495 source tree isn't cleaned after kernel installation). >> 496 >> 497 The seed used for compilation is located at >> 498 scripts/gcc-plgins/randomize_layout_seed.h. It remains after >> 499 a make clean to allow for external modules to be compiled with >> 500 the existing seed and will be removed by a make mrproper or >> 501 make distclean. >> 502 >> 503 Note that the implementation requires gcc 4.7 or newer. >> 504 >> 505 This plugin was ported from grsecurity/PaX. More information at: >> 506 * https://grsecurity.net/ >> 507 * https://pax.grsecurity.net/ >> 508 >> 509 config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE >> 510 bool "Use cacheline-aware structure randomization" >> 511 depends on GCC_PLUGIN_RANDSTRUCT >> 512 depends on !COMPILE_TEST >> 513 help >> 514 If you say Y here, the RANDSTRUCT randomization will make a >> 515 best effort at restricting randomization to cacheline-sized >> 516 groups of elements. It will further not randomize bitfields >> 517 in structures. This reduces the performance hit of RANDSTRUCT >> 518 at the cost of weakened randomization. 629 519 630 config HAVE_STACKPROTECTOR !! 520 config HAVE_CC_STACKPROTECTOR 631 bool 521 bool 632 help 522 help 633 An arch should select this symbol if 523 An arch should select this symbol if: >> 524 - its compiler supports the -fstack-protector option 634 - it has implemented a stack canary 525 - it has implemented a stack canary (e.g. __stack_chk_guard) 635 526 636 config STACKPROTECTOR !! 527 config CC_STACKPROTECTOR 637 bool "Stack Protector buffer overflow !! 528 def_bool n 638 depends on HAVE_STACKPROTECTOR !! 529 help 639 depends on $(cc-option,-fstack-protect !! 530 Set when a stack-protector mode is enabled, so that the build 640 default y !! 531 can enable kernel-side support for the GCC feature. >> 532 >> 533 choice >> 534 prompt "Stack Protector buffer overflow detection" >> 535 depends on HAVE_CC_STACKPROTECTOR >> 536 default CC_STACKPROTECTOR_NONE 641 help 537 help 642 This option turns on the "stack-prot 538 This option turns on the "stack-protector" GCC feature. This 643 feature puts, at the beginning of fu 539 feature puts, at the beginning of functions, a canary value on 644 the stack just before the return add 540 the stack just before the return address, and validates 645 the value just before actually retur 541 the value just before actually returning. Stack based buffer 646 overflows (that need to overwrite th 542 overflows (that need to overwrite this return address) now also 647 overwrite the canary, which gets det 543 overwrite the canary, which gets detected and the attack is then 648 neutralized via a kernel panic. 544 neutralized via a kernel panic. 649 545 >> 546 config CC_STACKPROTECTOR_NONE >> 547 bool "None" >> 548 help >> 549 Disable "stack-protector" GCC feature. >> 550 >> 551 config CC_STACKPROTECTOR_REGULAR >> 552 bool "Regular" >> 553 select CC_STACKPROTECTOR >> 554 help 650 Functions will have the stack-protec 555 Functions will have the stack-protector canary logic added if they 651 have an 8-byte or larger character a 556 have an 8-byte or larger character array on the stack. 652 557 653 This feature requires gcc version 4. 558 This feature requires gcc version 4.2 or above, or a distribution 654 gcc with the feature backported ("-f 559 gcc with the feature backported ("-fstack-protector"). 655 560 656 On an x86 "defconfig" build, this fe 561 On an x86 "defconfig" build, this feature adds canary checks to 657 about 3% of all kernel functions, wh 562 about 3% of all kernel functions, which increases kernel code size 658 by about 0.3%. 563 by about 0.3%. 659 564 660 config STACKPROTECTOR_STRONG !! 565 config CC_STACKPROTECTOR_STRONG 661 bool "Strong Stack Protector" !! 566 bool "Strong" 662 depends on STACKPROTECTOR !! 567 select CC_STACKPROTECTOR 663 depends on $(cc-option,-fstack-protect << 664 default y << 665 help 568 help 666 Functions will have the stack-protec 569 Functions will have the stack-protector canary logic added in any 667 of the following conditions: 570 of the following conditions: 668 571 669 - local variable's address used as p 572 - local variable's address used as part of the right hand side of an 670 assignment or function argument 573 assignment or function argument 671 - local variable is an array (or uni 574 - local variable is an array (or union containing an array), 672 regardless of array type or length 575 regardless of array type or length 673 - uses register local variables 576 - uses register local variables 674 577 675 This feature requires gcc version 4. 578 This feature requires gcc version 4.9 or above, or a distribution 676 gcc with the feature backported ("-f 579 gcc with the feature backported ("-fstack-protector-strong"). 677 580 678 On an x86 "defconfig" build, this fe 581 On an x86 "defconfig" build, this feature adds canary checks to 679 about 20% of all kernel functions, w 582 about 20% of all kernel functions, which increases the kernel code 680 size by about 2%. 583 size by about 2%. 681 584 682 config ARCH_SUPPORTS_SHADOW_CALL_STACK << 683 bool << 684 help << 685 An architecture should select this i << 686 Shadow Call Stack and implements run << 687 switching. << 688 << 689 config SHADOW_CALL_STACK << 690 bool "Shadow Call Stack" << 691 depends on ARCH_SUPPORTS_SHADOW_CALL_S << 692 depends on DYNAMIC_FTRACE_WITH_ARGS || << 693 depends on MMU << 694 help << 695 This option enables the compiler's S << 696 uses a shadow stack to protect funct << 697 being overwritten by an attacker. Mo << 698 in the compiler's documentation: << 699 << 700 - Clang: https://clang.llvm.org/docs << 701 - GCC: https://gcc.gnu.org/onlinedoc << 702 << 703 Note that security guarantees in the << 704 ones documented for user space. The << 705 of shadow stacks in memory, which me << 706 reading and writing arbitrary memory << 707 and hijack control flow by modifying << 708 << 709 config DYNAMIC_SCS << 710 bool << 711 help << 712 Set by the arch code if it relies on << 713 shadow call stack push and pop instr << 714 compiler. << 715 << 716 config LTO << 717 bool << 718 help << 719 Selected if the kernel will be built << 720 << 721 config LTO_CLANG << 722 bool << 723 select LTO << 724 help << 725 Selected if the kernel will be built << 726 << 727 config ARCH_SUPPORTS_LTO_CLANG << 728 bool << 729 help << 730 An architecture should select this o << 731 - compiling with Clang, << 732 - compiling inline assembly with Cla << 733 - and linking with LLD. << 734 << 735 config ARCH_SUPPORTS_LTO_CLANG_THIN << 736 bool << 737 help << 738 An architecture should select this o << 739 ThinLTO mode. << 740 << 741 config HAS_LTO_CLANG << 742 def_bool y << 743 depends on CC_IS_CLANG && LD_IS_LLD && << 744 depends on $(success,$(NM) --help | he << 745 depends on $(success,$(AR) --help | he << 746 depends on ARCH_SUPPORTS_LTO_CLANG << 747 depends on !FTRACE_MCOUNT_USE_RECORDMC << 748 # https://github.com/ClangBuiltLinux/l << 749 depends on (!KASAN || KASAN_HW_TAGS || << 750 depends on (!KCOV || CLANG_VERSION >= << 751 depends on !GCOV_KERNEL << 752 help << 753 The compiler and Kconfig options sup << 754 LTO. << 755 << 756 choice << 757 prompt "Link Time Optimization (LTO)" << 758 default LTO_NONE << 759 help << 760 This option enables Link Time Optimi << 761 compiler to optimize binaries global << 762 << 763 If unsure, select LTO_NONE. Note tha << 764 so it's disabled by default. << 765 << 766 config LTO_NONE << 767 bool "None" << 768 help << 769 Build the kernel normally, without L << 770 << 771 config LTO_CLANG_FULL << 772 bool "Clang Full LTO (EXPERIMENTAL)" << 773 depends on HAS_LTO_CLANG << 774 depends on !COMPILE_TEST << 775 select LTO_CLANG << 776 help << 777 This option enables Clang's full Lin << 778 allows the compiler to optimize the << 779 this option, the compiler generates << 780 object files, and the actual compila << 781 the LTO link step, which may take se << 782 kernel configuration. More informati << 783 documentation: << 784 << 785 https://llvm.org/docs/LinkTimeOpti << 786 << 787 During link time, this option can us << 788 may take much longer than the ThinLT << 789 << 790 config LTO_CLANG_THIN << 791 bool "Clang ThinLTO (EXPERIMENTAL)" << 792 depends on HAS_LTO_CLANG && ARCH_SUPPO << 793 select LTO_CLANG << 794 help << 795 This option enables Clang's ThinLTO, << 796 optimization and faster incremental << 797 CONFIG_LTO_CLANG_FULL option. More i << 798 from Clang's documentation: << 799 << 800 https://clang.llvm.org/docs/ThinLT << 801 << 802 If unsure, say Y. << 803 endchoice 585 endchoice 804 586 805 config ARCH_SUPPORTS_CFI_CLANG !! 587 config THIN_ARCHIVES 806 bool !! 588 def_bool y 807 help 589 help 808 An architecture should select this o !! 590 Select this if the architecture wants to use thin archives 809 Control-Flow Integrity (CFI) checkin !! 591 instead of ld -r to create the built-in.o files. 810 592 811 config ARCH_USES_CFI_TRAPS !! 593 config LD_DEAD_CODE_DATA_ELIMINATION 812 bool 594 bool 813 << 814 config CFI_CLANG << 815 bool "Use Clang's Control Flow Integri << 816 depends on ARCH_SUPPORTS_CFI_CLANG << 817 depends on $(cc-option,-fsanitize=kcfi << 818 help << 819 This option enables Clang's forward- << 820 (CFI) checking, where the compiler i << 821 indirect function call to ensure the << 822 the correct static type. This restri << 823 makes it more difficult for an attac << 824 the modification of stored function << 825 found from Clang's documentation: << 826 << 827 https://clang.llvm.org/docs/Contro << 828 << 829 config CFI_PERMISSIVE << 830 bool "Use CFI in permissive mode" << 831 depends on CFI_CLANG << 832 help 595 help 833 When selected, Control Flow Integrit !! 596 Select this if the architecture wants to do dead code and 834 warning instead of a kernel panic. T !! 597 data elimination with the linker by compiling with 835 for finding indirect call type misma !! 598 -ffunction-sections -fdata-sections and linking with >> 599 --gc-sections. 836 600 837 If unsure, say N. !! 601 This requires that the arch annotates or otherwise protects >> 602 its external entry points from being discarded. Linker scripts >> 603 must also merge .text.*, .data.*, and .bss.* correctly into >> 604 output sections. Care must be taken not to pull in unrelated >> 605 sections (e.g., '.text.init'). Typically '.' in section names >> 606 is used to distinguish them from label names / C identifiers. 838 607 839 config HAVE_ARCH_WITHIN_STACK_FRAMES 608 config HAVE_ARCH_WITHIN_STACK_FRAMES 840 bool 609 bool 841 help 610 help 842 An architecture should select this i 611 An architecture should select this if it can walk the kernel stack 843 frames to determine if an object is 612 frames to determine if an object is part of either the arguments 844 or local variables (i.e. that it exc 613 or local variables (i.e. that it excludes saved return addresses, 845 and similar) by implementing an inli 614 and similar) by implementing an inline arch_within_stack_frames(), 846 which is used by CONFIG_HARDENED_USE 615 which is used by CONFIG_HARDENED_USERCOPY. 847 616 848 config HAVE_CONTEXT_TRACKING_USER !! 617 config HAVE_CONTEXT_TRACKING 849 bool 618 bool 850 help 619 help 851 Provide kernel/user boundaries probe 620 Provide kernel/user boundaries probes necessary for subsystems 852 that need it, such as userspace RCU 621 that need it, such as userspace RCU extended quiescent state. 853 Syscalls need to be wrapped inside u !! 622 Syscalls need to be wrapped inside user_exit()-user_enter() through 854 optimized behind static key or throu !! 623 the slow path using TIF_NOHZ flag. Exceptions handlers must be 855 flag. Exceptions handlers must be wr !! 624 wrapped as well. Irqs are already protected inside 856 protected inside ct_irq_enter/ct_irq !! 625 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on 857 handling on irq exit still need to b !! 626 irq exit still need to be protected. 858 << 859 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK << 860 bool << 861 help << 862 Architecture neither relies on excep << 863 nor on schedule_user(). Also preempt << 864 preempt_schedule_irq() can't be call << 865 while context tracking is CONTEXT_US << 866 entry implementation where the follo << 867 critical entry code, ie: before user << 868 << 869 - Critical entry code isn't preempti << 870 not interruptible). << 871 - No use of RCU read side critical s << 872 got called. << 873 - No use of instrumentation, unless << 874 called. << 875 << 876 config HAVE_TIF_NOHZ << 877 bool << 878 help << 879 Arch relies on TIF_NOHZ and syscall << 880 tracking calls to user_enter()/user_ << 881 627 882 config HAVE_VIRT_CPU_ACCOUNTING 628 config HAVE_VIRT_CPU_ACCOUNTING 883 bool 629 bool 884 630 885 config HAVE_VIRT_CPU_ACCOUNTING_IDLE << 886 bool << 887 help << 888 Architecture has its own way to acco << 889 doesn't implement vtime_account_idle << 890 << 891 config ARCH_HAS_SCALED_CPUTIME 631 config ARCH_HAS_SCALED_CPUTIME 892 bool 632 bool 893 633 894 config HAVE_VIRT_CPU_ACCOUNTING_GEN 634 config HAVE_VIRT_CPU_ACCOUNTING_GEN 895 bool 635 bool 896 default y if 64BIT 636 default y if 64BIT 897 help 637 help 898 With VIRT_CPU_ACCOUNTING_GEN, cputim 638 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 899 Before enabling this option, arch co 639 Before enabling this option, arch code must be audited 900 to ensure there are no races in conc 640 to ensure there are no races in concurrent read/write of 901 cputime_t. For example, reading/writ 641 cputime_t. For example, reading/writing 64-bit cputime_t on 902 some 32-bit arches may require multi 642 some 32-bit arches may require multiple accesses, so proper 903 locking is needed to protect against 643 locking is needed to protect against concurrent accesses. 904 644 >> 645 905 config HAVE_IRQ_TIME_ACCOUNTING 646 config HAVE_IRQ_TIME_ACCOUNTING 906 bool 647 bool 907 help 648 help 908 Archs need to ensure they use a high 649 Archs need to ensure they use a high enough resolution clock to 909 support irq time accounting and then 650 support irq time accounting and then call enable_sched_clock_irqtime(). 910 651 911 config HAVE_MOVE_PUD << 912 bool << 913 help << 914 Architectures that select this are a << 915 PUD level. If there are only 3 page << 916 happens at the PGD level. << 917 << 918 config HAVE_MOVE_PMD << 919 bool << 920 help << 921 Archs that select this are able to m << 922 << 923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 652 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 924 bool 653 bool 925 654 926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 655 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 927 bool 656 bool 928 657 929 config HAVE_ARCH_HUGE_VMAP 658 config HAVE_ARCH_HUGE_VMAP 930 bool 659 bool 931 660 932 # << 933 # Archs that select this would be capable of << 934 # arch_vmap_pmd_supported() returns true). Th << 935 # must be used to enable allocations to use h << 936 # << 937 config HAVE_ARCH_HUGE_VMALLOC << 938 depends on HAVE_ARCH_HUGE_VMAP << 939 bool << 940 << 941 config ARCH_WANT_HUGE_PMD_SHARE << 942 bool << 943 << 944 # Archs that want to use pmd_mkwrite on kernel << 945 # if there are no userspace memory management << 946 config ARCH_WANT_KERNEL_PMD_MKWRITE << 947 bool << 948 << 949 config ARCH_WANT_PMD_MKWRITE << 950 def_bool TRANSPARENT_HUGEPAGE || ARCH_ << 951 << 952 config HAVE_ARCH_SOFT_DIRTY 661 config HAVE_ARCH_SOFT_DIRTY 953 bool 662 bool 954 663 955 config HAVE_MOD_ARCH_SPECIFIC 664 config HAVE_MOD_ARCH_SPECIFIC 956 bool 665 bool 957 help 666 help 958 The arch uses struct mod_arch_specif 667 The arch uses struct mod_arch_specific to store data. Many arches 959 just need a simple module loader wit 668 just need a simple module loader without arch specific data - those 960 should not enable this. 669 should not enable this. 961 670 962 config MODULES_USE_ELF_RELA 671 config MODULES_USE_ELF_RELA 963 bool 672 bool 964 help 673 help 965 Modules only use ELF RELA relocation 674 Modules only use ELF RELA relocations. Modules with ELF REL 966 relocations will give an error. 675 relocations will give an error. 967 676 968 config MODULES_USE_ELF_REL 677 config MODULES_USE_ELF_REL 969 bool 678 bool 970 help 679 help 971 Modules only use ELF REL relocations 680 Modules only use ELF REL relocations. Modules with ELF RELA 972 relocations will give an error. 681 relocations will give an error. 973 682 974 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC !! 683 config HAVE_UNDERSCORE_SYMBOL_PREFIX 975 bool 684 bool 976 help 685 help 977 For architectures like powerpc/32 wh !! 686 Some architectures generate an _ in front of C symbols; things like 978 allocation and need to allocate modu !! 687 module loading and assembly files need to know about this. 979 << 980 config ARCH_WANTS_EXECMEM_LATE << 981 bool << 982 help << 983 For architectures that do not alloca << 984 boot, but rather require its initial << 985 enough entropy for module space rand << 986 arm64. << 987 688 988 config HAVE_IRQ_EXIT_ON_IRQ_STACK 689 config HAVE_IRQ_EXIT_ON_IRQ_STACK 989 bool 690 bool 990 help 691 help 991 Architecture doesn't only execute th 692 Architecture doesn't only execute the irq handler on the irq stack 992 but also irq_exit(). This way we can 693 but also irq_exit(). This way we can process softirqs on this irq 993 stack instead of switching to a new 694 stack instead of switching to a new one when we call __do_softirq() 994 in the end of an hardirq. 695 in the end of an hardirq. 995 This spares a stack switch and impro 696 This spares a stack switch and improves cache usage on softirq 996 processing. 697 processing. 997 698 998 config HAVE_SOFTIRQ_ON_OWN_STACK << 999 bool << 1000 help << 1001 Architecture provides a function to << 1002 separate stack. << 1003 << 1004 config SOFTIRQ_ON_OWN_STACK << 1005 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && << 1006 << 1007 config ALTERNATE_USER_ADDRESS_SPACE << 1008 bool << 1009 help << 1010 Architectures set this when the CPU << 1011 spaces for kernel and user space po << 1012 access_ok() check on a __user point << 1013 << 1014 config PGTABLE_LEVELS 699 config PGTABLE_LEVELS 1015 int 700 int 1016 default 2 701 default 2 1017 702 1018 config ARCH_HAS_ELF_RANDOMIZE 703 config ARCH_HAS_ELF_RANDOMIZE 1019 bool 704 bool 1020 help 705 help 1021 An architecture supports choosing r 706 An architecture supports choosing randomized locations for 1022 stack, mmap, brk, and ET_DYN. Defin 707 stack, mmap, brk, and ET_DYN. Defined functions: 1023 - arch_mmap_rnd() 708 - arch_mmap_rnd() 1024 - arch_randomize_brk() 709 - arch_randomize_brk() 1025 710 1026 config HAVE_ARCH_MMAP_RND_BITS 711 config HAVE_ARCH_MMAP_RND_BITS 1027 bool 712 bool 1028 help 713 help 1029 An arch should select this symbol i 714 An arch should select this symbol if it supports setting a variable 1030 number of bits for use in establish 715 number of bits for use in establishing the base address for mmap 1031 allocations, has MMU enabled and pr 716 allocations, has MMU enabled and provides values for both: 1032 - ARCH_MMAP_RND_BITS_MIN 717 - ARCH_MMAP_RND_BITS_MIN 1033 - ARCH_MMAP_RND_BITS_MAX 718 - ARCH_MMAP_RND_BITS_MAX 1034 719 1035 config HAVE_EXIT_THREAD 720 config HAVE_EXIT_THREAD 1036 bool 721 bool 1037 help 722 help 1038 An architecture implements exit_thr 723 An architecture implements exit_thread. 1039 724 1040 config ARCH_MMAP_RND_BITS_MIN 725 config ARCH_MMAP_RND_BITS_MIN 1041 int 726 int 1042 727 1043 config ARCH_MMAP_RND_BITS_MAX 728 config ARCH_MMAP_RND_BITS_MAX 1044 int 729 int 1045 730 1046 config ARCH_MMAP_RND_BITS_DEFAULT 731 config ARCH_MMAP_RND_BITS_DEFAULT 1047 int 732 int 1048 733 1049 config ARCH_MMAP_RND_BITS 734 config ARCH_MMAP_RND_BITS 1050 int "Number of bits to use for ASLR o 735 int "Number of bits to use for ASLR of mmap base address" if EXPERT 1051 range ARCH_MMAP_RND_BITS_MIN ARCH_MMA 736 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 1052 default ARCH_MMAP_RND_BITS_DEFAULT if 737 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 1053 default ARCH_MMAP_RND_BITS_MIN 738 default ARCH_MMAP_RND_BITS_MIN 1054 depends on HAVE_ARCH_MMAP_RND_BITS 739 depends on HAVE_ARCH_MMAP_RND_BITS 1055 help 740 help 1056 This value can be used to select th 741 This value can be used to select the number of bits to use to 1057 determine the random offset to the 742 determine the random offset to the base address of vma regions 1058 resulting from mmap allocations. Th 743 resulting from mmap allocations. This value will be bounded 1059 by the architecture's minimum and m 744 by the architecture's minimum and maximum supported values. 1060 745 1061 This value can be changed after boo 746 This value can be changed after boot using the 1062 /proc/sys/vm/mmap_rnd_bits tunable 747 /proc/sys/vm/mmap_rnd_bits tunable 1063 748 1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 749 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 1065 bool 750 bool 1066 help 751 help 1067 An arch should select this symbol i 752 An arch should select this symbol if it supports running applications 1068 in compatibility mode, supports set 753 in compatibility mode, supports setting a variable number of bits for 1069 use in establishing the base addres 754 use in establishing the base address for mmap allocations, has MMU 1070 enabled and provides values for bot 755 enabled and provides values for both: 1071 - ARCH_MMAP_RND_COMPAT_BITS_MIN 756 - ARCH_MMAP_RND_COMPAT_BITS_MIN 1072 - ARCH_MMAP_RND_COMPAT_BITS_MAX 757 - ARCH_MMAP_RND_COMPAT_BITS_MAX 1073 758 1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN 759 config ARCH_MMAP_RND_COMPAT_BITS_MIN 1075 int 760 int 1076 761 1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX 762 config ARCH_MMAP_RND_COMPAT_BITS_MAX 1078 int 763 int 1079 764 1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 765 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1081 int 766 int 1082 767 1083 config ARCH_MMAP_RND_COMPAT_BITS 768 config ARCH_MMAP_RND_COMPAT_BITS 1084 int "Number of bits to use for ASLR o 769 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT 1085 range ARCH_MMAP_RND_COMPAT_BITS_MIN A 770 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 1086 default ARCH_MMAP_RND_COMPAT_BITS_DEF 771 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1087 default ARCH_MMAP_RND_COMPAT_BITS_MIN 772 default ARCH_MMAP_RND_COMPAT_BITS_MIN 1088 depends on HAVE_ARCH_MMAP_RND_COMPAT_ 773 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 1089 help 774 help 1090 This value can be used to select th 775 This value can be used to select the number of bits to use to 1091 determine the random offset to the 776 determine the random offset to the base address of vma regions 1092 resulting from mmap allocations for 777 resulting from mmap allocations for compatible applications This 1093 value will be bounded by the archit 778 value will be bounded by the architecture's minimum and maximum 1094 supported values. 779 supported values. 1095 780 1096 This value can be changed after boo 781 This value can be changed after boot using the 1097 /proc/sys/vm/mmap_rnd_compat_bits t 782 /proc/sys/vm/mmap_rnd_compat_bits tunable 1098 783 1099 config HAVE_ARCH_COMPAT_MMAP_BASES 784 config HAVE_ARCH_COMPAT_MMAP_BASES 1100 bool 785 bool 1101 help 786 help 1102 This allows 64bit applications to i 787 This allows 64bit applications to invoke 32-bit mmap() syscall 1103 and vice-versa 32-bit applications 788 and vice-versa 32-bit applications to call 64-bit mmap(). 1104 Required for applications doing dif 789 Required for applications doing different bitness syscalls. 1105 790 1106 config HAVE_PAGE_SIZE_4KB !! 791 config HAVE_COPY_THREAD_TLS 1107 bool << 1108 << 1109 config HAVE_PAGE_SIZE_8KB << 1110 bool << 1111 << 1112 config HAVE_PAGE_SIZE_16KB << 1113 bool << 1114 << 1115 config HAVE_PAGE_SIZE_32KB << 1116 bool 792 bool 1117 !! 793 help 1118 config HAVE_PAGE_SIZE_64KB !! 794 Architecture provides copy_thread_tls to accept tls argument via 1119 bool !! 795 normal C parameter passing, rather than extracting the syscall 1120 !! 796 argument from pt_regs. 1121 config HAVE_PAGE_SIZE_256KB << 1122 bool << 1123 << 1124 choice << 1125 prompt "MMU page size" << 1126 << 1127 config PAGE_SIZE_4KB << 1128 bool "4KiB pages" << 1129 depends on HAVE_PAGE_SIZE_4KB << 1130 help << 1131 This option select the standard 4Ki << 1132 available option on many architectu << 1133 minimize memory consumption and is << 1134 memory systems. << 1135 Some software that is written for x << 1136 assumptions about the page size and << 1137 << 1138 config PAGE_SIZE_8KB << 1139 bool "8KiB pages" << 1140 depends on HAVE_PAGE_SIZE_8KB << 1141 help << 1142 This option is the only supported p << 1143 processors, and can be slightly fas << 1144 << 1145 config PAGE_SIZE_16KB << 1146 bool "16KiB pages" << 1147 depends on HAVE_PAGE_SIZE_16KB << 1148 help << 1149 This option is usually a good compr << 1150 consumption and performance for typ << 1151 workloads, often saving a level of << 1152 to 4KB pages as well as reducing TL << 1153 per-page operations in the kernel a << 1154 page cache. << 1155 << 1156 config PAGE_SIZE_32KB << 1157 bool "32KiB pages" << 1158 depends on HAVE_PAGE_SIZE_32KB << 1159 help << 1160 Using 32KiB page size will result i << 1161 kernel at the price of higher memor << 1162 16KiB pages. This option is availa << 1163 Note that you will need a suitable << 1164 support this. << 1165 << 1166 config PAGE_SIZE_64KB << 1167 bool "64KiB pages" << 1168 depends on HAVE_PAGE_SIZE_64KB << 1169 help << 1170 Using 64KiB page size will result i << 1171 kernel at the price of much higher << 1172 4KiB or 16KiB pages. << 1173 This is not suitable for general-pu << 1174 better performance may be worth the << 1175 supercomputing or database applicat << 1176 large in-memory data rather than sm << 1177 << 1178 config PAGE_SIZE_256KB << 1179 bool "256KiB pages" << 1180 depends on HAVE_PAGE_SIZE_256KB << 1181 help << 1182 256KiB pages have little practical << 1183 memory usage. The kernel will only << 1184 that have been compiled with '-zmax << 1185 (the default is 64KiB or 4KiB on mo << 1186 << 1187 endchoice << 1188 << 1189 config PAGE_SIZE_LESS_THAN_64KB << 1190 def_bool y << 1191 depends on !PAGE_SIZE_64KB << 1192 depends on PAGE_SIZE_LESS_THAN_256KB << 1193 << 1194 config PAGE_SIZE_LESS_THAN_256KB << 1195 def_bool y << 1196 depends on !PAGE_SIZE_256KB << 1197 << 1198 config PAGE_SHIFT << 1199 int << 1200 default 12 if PAGE_SIZE_4KB << 1201 default 13 if PAGE_SIZE_8KB << 1202 default 14 if PAGE_SIZE_16KB << 1203 default 15 if PAGE_SIZE_32KB << 1204 default 16 if PAGE_SIZE_64KB << 1205 default 18 if PAGE_SIZE_256KB << 1206 << 1207 # This allows to use a set of generic functio << 1208 # address by giving priority to top-down sche << 1209 # is not in legacy mode (compat task, unlimit << 1210 # sysctl_legacy_va_layout). << 1211 # Architecture that selects this option can p << 1212 # - STACK_RND_MASK << 1213 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT << 1214 bool << 1215 depends on MMU << 1216 select ARCH_HAS_ELF_RANDOMIZE << 1217 << 1218 config HAVE_OBJTOOL << 1219 bool << 1220 << 1221 config HAVE_JUMP_LABEL_HACK << 1222 bool << 1223 << 1224 config HAVE_NOINSTR_HACK << 1225 bool << 1226 << 1227 config HAVE_NOINSTR_VALIDATION << 1228 bool << 1229 << 1230 config HAVE_UACCESS_VALIDATION << 1231 bool << 1232 select OBJTOOL << 1233 797 1234 config HAVE_STACK_VALIDATION 798 config HAVE_STACK_VALIDATION 1235 bool 799 bool 1236 help 800 help 1237 Architecture supports objtool compi !! 801 Architecture supports the 'objtool check' host tool command, which 1238 validation. !! 802 performs compile-time stack metadata validation. 1239 803 1240 config HAVE_RELIABLE_STACKTRACE 804 config HAVE_RELIABLE_STACKTRACE 1241 bool 805 bool 1242 help 806 help 1243 Architecture has either save_stack_ !! 807 Architecture has a save_stack_trace_tsk_reliable() function which 1244 arch_stack_walk_reliable() function !! 808 only returns a stack trace if it can guarantee the trace is reliable. 1245 if it can guarantee the trace is re << 1246 809 1247 config HAVE_ARCH_HASH 810 config HAVE_ARCH_HASH 1248 bool 811 bool 1249 default n 812 default n 1250 help 813 help 1251 If this is set, the architecture pr 814 If this is set, the architecture provides an <asm/hash.h> 1252 file which provides platform-specif 815 file which provides platform-specific implementations of some 1253 functions in <linux/hash.h> or fs/n 816 functions in <linux/hash.h> or fs/namei.c. 1254 817 1255 config HAVE_ARCH_NVRAM_OPS << 1256 bool << 1257 << 1258 config ISA_BUS_API 818 config ISA_BUS_API 1259 def_bool ISA 819 def_bool ISA 1260 820 1261 # 821 # 1262 # ABI hall of shame 822 # ABI hall of shame 1263 # 823 # 1264 config CLONE_BACKWARDS 824 config CLONE_BACKWARDS 1265 bool 825 bool 1266 help 826 help 1267 Architecture has tls passed as the 827 Architecture has tls passed as the 4th argument of clone(2), 1268 not the 5th one. 828 not the 5th one. 1269 829 1270 config CLONE_BACKWARDS2 830 config CLONE_BACKWARDS2 1271 bool 831 bool 1272 help 832 help 1273 Architecture has the first two argu 833 Architecture has the first two arguments of clone(2) swapped. 1274 834 1275 config CLONE_BACKWARDS3 835 config CLONE_BACKWARDS3 1276 bool 836 bool 1277 help 837 help 1278 Architecture has tls passed as the 838 Architecture has tls passed as the 3rd argument of clone(2), 1279 not the 5th one. 839 not the 5th one. 1280 840 1281 config ODD_RT_SIGACTION 841 config ODD_RT_SIGACTION 1282 bool 842 bool 1283 help 843 help 1284 Architecture has unusual rt_sigacti 844 Architecture has unusual rt_sigaction(2) arguments 1285 845 1286 config OLD_SIGSUSPEND 846 config OLD_SIGSUSPEND 1287 bool 847 bool 1288 help 848 help 1289 Architecture has old sigsuspend(2) 849 Architecture has old sigsuspend(2) syscall, of one-argument variety 1290 850 1291 config OLD_SIGSUSPEND3 851 config OLD_SIGSUSPEND3 1292 bool 852 bool 1293 help 853 help 1294 Even weirder antique ABI - three-ar 854 Even weirder antique ABI - three-argument sigsuspend(2) 1295 855 1296 config OLD_SIGACTION 856 config OLD_SIGACTION 1297 bool 857 bool 1298 help 858 help 1299 Architecture has old sigaction(2) s 859 Architecture has old sigaction(2) syscall. Nope, not the same 1300 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 860 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 1301 but fairly different variant of sig 861 but fairly different variant of sigaction(2), thanks to OSF/1 1302 compatibility... 862 compatibility... 1303 863 1304 config COMPAT_OLD_SIGACTION 864 config COMPAT_OLD_SIGACTION 1305 bool 865 bool 1306 866 1307 config COMPAT_32BIT_TIME !! 867 config ARCH_NO_COHERENT_DMA_MMAP 1308 bool "Provide system calls for 32-bit << 1309 default !64BIT || COMPAT << 1310 help << 1311 This enables 32 bit time_t support << 1312 This is relevant on all 32-bit arch << 1313 as part of compat syscall handling. << 1314 << 1315 config ARCH_NO_PREEMPT << 1316 bool << 1317 << 1318 config ARCH_SUPPORTS_RT << 1319 bool 868 bool 1320 869 1321 config CPU_NO_EFFICIENT_FFS 870 config CPU_NO_EFFICIENT_FFS 1322 def_bool n 871 def_bool n 1323 872 1324 config HAVE_ARCH_VMAP_STACK 873 config HAVE_ARCH_VMAP_STACK 1325 def_bool n 874 def_bool n 1326 help 875 help 1327 An arch should select this symbol i 876 An arch should select this symbol if it can support kernel stacks 1328 in vmalloc space. This means: 877 in vmalloc space. This means: 1329 878 1330 - vmalloc space must be large enoug 879 - vmalloc space must be large enough to hold many kernel stacks. 1331 This may rule out many 32-bit arc 880 This may rule out many 32-bit architectures. 1332 881 1333 - Stacks in vmalloc space need to w 882 - Stacks in vmalloc space need to work reliably. For example, if 1334 vmap page tables are created on d 883 vmap page tables are created on demand, either this mechanism 1335 needs to work while the stack poi 884 needs to work while the stack points to a virtual address with 1336 unpopulated page tables or arch c 885 unpopulated page tables or arch code (switch_to() and switch_mm(), 1337 most likely) needs to ensure that 886 most likely) needs to ensure that the stack's page table entries 1338 are populated before running on a 887 are populated before running on a possibly unpopulated stack. 1339 888 1340 - If the stack overflows into a gua 889 - If the stack overflows into a guard page, something reasonable 1341 should happen. The definition of 890 should happen. The definition of "reasonable" is flexible, but 1342 instantly rebooting without loggi 891 instantly rebooting without logging anything would be unfriendly. 1343 892 1344 config VMAP_STACK 893 config VMAP_STACK 1345 default y 894 default y 1346 bool "Use a virtually-mapped stack" 895 bool "Use a virtually-mapped stack" 1347 depends on HAVE_ARCH_VMAP_STACK !! 896 depends on HAVE_ARCH_VMAP_STACK && !KASAN 1348 depends on !KASAN || KASAN_HW_TAGS || !! 897 ---help--- 1349 help << 1350 Enable this if you want the use vir 898 Enable this if you want the use virtually-mapped kernel stacks 1351 with guard pages. This causes kern 899 with guard pages. This causes kernel stack overflows to be 1352 caught immediately rather than caus 900 caught immediately rather than causing difficult-to-diagnose 1353 corruption. 901 corruption. 1354 902 1355 To use this with software KASAN mod !! 903 This is presently incompatible with KASAN because KASAN expects 1356 backing virtual mappings with real !! 904 the stack to map directly to the KASAN shadow map using a formula 1357 must be enabled. !! 905 that is incorrect if the stack is in vmalloc space. 1358 << 1359 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET << 1360 def_bool n << 1361 help << 1362 An arch should select this symbol i << 1363 offset randomization with calls to << 1364 during syscall entry and choose_ran << 1365 syscall exit. Careful removal of -f << 1366 -fstack-protector should also be ap << 1367 closely examined, as the artificial << 1368 to the compiler, so it will attempt << 1369 of the static branch state. << 1370 << 1371 config RANDOMIZE_KSTACK_OFFSET << 1372 bool "Support for randomizing kernel << 1373 default y << 1374 depends on HAVE_ARCH_RANDOMIZE_KSTACK << 1375 depends on INIT_STACK_NONE || !CC_IS_ << 1376 help << 1377 The kernel stack offset can be rand << 1378 roughly 5 bits of entropy, frustrat << 1379 attacks that depend on stack addres << 1380 cross-syscall address exposures. << 1381 << 1382 The feature is controlled via the " << 1383 kernel boot param, and if turned of << 1384 of static branches (see JUMP_LABEL) << 1385 << 1386 If unsure, say Y. << 1387 << 1388 config RANDOMIZE_KSTACK_OFFSET_DEFAULT << 1389 bool "Default state of kernel stack o << 1390 depends on RANDOMIZE_KSTACK_OFFSET << 1391 help << 1392 Kernel stack offset randomization i << 1393 "randomize_kstack_offset=on/off", a << 1394 boot state. << 1395 906 1396 config ARCH_OPTIONAL_KERNEL_RWX 907 config ARCH_OPTIONAL_KERNEL_RWX 1397 def_bool n 908 def_bool n 1398 909 1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 910 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1400 def_bool n 911 def_bool n 1401 912 1402 config ARCH_HAS_STRICT_KERNEL_RWX 913 config ARCH_HAS_STRICT_KERNEL_RWX 1403 def_bool n 914 def_bool n 1404 915 1405 config STRICT_KERNEL_RWX 916 config STRICT_KERNEL_RWX 1406 bool "Make kernel text and rodata rea 917 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 1407 depends on ARCH_HAS_STRICT_KERNEL_RWX 918 depends on ARCH_HAS_STRICT_KERNEL_RWX 1408 default !ARCH_OPTIONAL_KERNEL_RWX || 919 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1409 help 920 help 1410 If this is set, kernel text and rod 921 If this is set, kernel text and rodata memory will be made read-only, 1411 and non-text memory will be made no 922 and non-text memory will be made non-executable. This provides 1412 protection against certain security 923 protection against certain security exploits (e.g. executing the heap 1413 or modifying text) 924 or modifying text) 1414 925 1415 These features are considered stand 926 These features are considered standard security practice these days. 1416 You should say Y here in almost all 927 You should say Y here in almost all cases. 1417 928 1418 config ARCH_HAS_STRICT_MODULE_RWX 929 config ARCH_HAS_STRICT_MODULE_RWX 1419 def_bool n 930 def_bool n 1420 931 1421 config STRICT_MODULE_RWX 932 config STRICT_MODULE_RWX 1422 bool "Set loadable kernel module data 933 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX 1423 depends on ARCH_HAS_STRICT_MODULE_RWX 934 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 1424 default !ARCH_OPTIONAL_KERNEL_RWX || 935 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1425 help 936 help 1426 If this is set, module text and rod 937 If this is set, module text and rodata memory will be made read-only, 1427 and non-text memory will be made no 938 and non-text memory will be made non-executable. This provides 1428 protection against certain security 939 protection against certain security exploits (e.g. writing to text) 1429 940 1430 # select if the architecture provides an asm/ !! 941 config ARCH_HAS_REFCOUNT 1431 config ARCH_HAS_PHYS_TO_DMA << 1432 bool << 1433 << 1434 config HAVE_ARCH_COMPILER_H << 1435 bool 942 bool 1436 help 943 help 1437 An architecture can select this if !! 944 An architecture selects this when it has implemented refcount_t 1438 asm/compiler.h header that should b !! 945 using open coded assembly primitives that provide an optimized 1439 linux/compiler-*.h in order to over !! 946 refcount_t implementation, possibly at the expense of some full 1440 headers generally provide. !! 947 refcount state checks of CONFIG_REFCOUNT_FULL=y. 1441 !! 948 1442 config HAVE_ARCH_PREL32_RELOCATIONS !! 949 The refcount overflow check behavior, however, must be retained. 1443 bool !! 950 Catching overflows is the primary security concern for protecting 1444 help !! 951 against bugs in reference counts. 1445 May be selected by an architecture !! 952 1446 32-bit relocations, both in the too !! 953 config REFCOUNT_FULL 1447 in which case relative references c !! 954 bool "Perform full reference count validation at the expense of speed" 1448 for PCI fixup, initcalls etc which !! 955 help 1449 architectures, and don't require ru !! 956 Enabling this switches the refcounting infrastructure from a fast 1450 kernels. !! 957 unchecked atomic_t implementation to a fully state checked 1451 !! 958 implementation, which can be (slightly) slower but provides protections 1452 config ARCH_USE_MEMREMAP_PROT !! 959 against various use-after-free conditions that can be used in 1453 bool !! 960 security flaw exploits. 1454 << 1455 config LOCK_EVENT_COUNTS << 1456 bool "Locking event counts collection << 1457 depends on DEBUG_FS << 1458 help << 1459 Enable light-weight counting of var << 1460 in the system with minimal performa << 1461 the chance of application behavior << 1462 differences. The counts are reporte << 1463 << 1464 # Select if the architecture has support for << 1465 config ARCH_HAS_RELR << 1466 bool << 1467 << 1468 config RELR << 1469 bool "Use RELR relocation packing" << 1470 depends on ARCH_HAS_RELR && TOOLS_SUP << 1471 default y << 1472 help << 1473 Store the kernel's dynamic relocati << 1474 format. Requires a compatible linke << 1475 well as compatible NM and OBJCOPY u << 1476 are compatible). << 1477 << 1478 config ARCH_HAS_MEM_ENCRYPT << 1479 bool << 1480 << 1481 config ARCH_HAS_CC_PLATFORM << 1482 bool << 1483 << 1484 config HAVE_SPARSE_SYSCALL_NR << 1485 bool << 1486 help << 1487 An architecture should select this << 1488 to save space. For example, MIPS ar << 1489 entries at 4000, 5000 and 6000 loca << 1490 related optimizations for a given a << 1491 << 1492 config ARCH_HAS_VDSO_DATA << 1493 bool << 1494 << 1495 config HAVE_STATIC_CALL << 1496 bool << 1497 << 1498 config HAVE_STATIC_CALL_INLINE << 1499 bool << 1500 depends on HAVE_STATIC_CALL << 1501 select OBJTOOL << 1502 << 1503 config HAVE_PREEMPT_DYNAMIC << 1504 bool << 1505 << 1506 config HAVE_PREEMPT_DYNAMIC_CALL << 1507 bool << 1508 depends on HAVE_STATIC_CALL << 1509 select HAVE_PREEMPT_DYNAMIC << 1510 help << 1511 An architecture should select this << 1512 model being selected at boot time u << 1513 << 1514 Where an architecture selects HAVE_ << 1515 preemption function will be patched << 1516 << 1517 Where an architecture does not sele << 1518 call to a preemption function will << 1519 trampoline will be patched. << 1520 << 1521 It is strongly advised to support i << 1522 overhead. << 1523 << 1524 config HAVE_PREEMPT_DYNAMIC_KEY << 1525 bool << 1526 depends on HAVE_ARCH_JUMP_LABEL << 1527 select HAVE_PREEMPT_DYNAMIC << 1528 help << 1529 An architecture should select this << 1530 model being selected at boot time u << 1531 << 1532 Each preemption function will be gi << 1533 static key. This should have slight << 1534 static calls, as this effectively i << 1535 start of its callee. This may avoid << 1536 integrate better with CFI schemes. << 1537 << 1538 This will have greater overhead tha << 1539 the call to the preemption function << 1540 << 1541 config ARCH_WANT_LD_ORPHAN_WARN << 1542 bool << 1543 help << 1544 An arch should select this symbol o << 1545 included, size-asserted, or discard << 1546 important because we never want exp << 1547 by the linker, since the locations << 1548 versions. << 1549 << 1550 config HAVE_ARCH_PFN_VALID << 1551 bool << 1552 << 1553 config ARCH_SUPPORTS_DEBUG_PAGEALLOC << 1554 bool << 1555 << 1556 config ARCH_SUPPORTS_PAGE_TABLE_CHECK << 1557 bool << 1558 << 1559 config ARCH_SPLIT_ARG64 << 1560 bool << 1561 help << 1562 If a 32-bit architecture requires 6 << 1563 pairs of 32-bit arguments, select t << 1564 << 1565 config ARCH_HAS_ELFCORE_COMPAT << 1566 bool << 1567 << 1568 config ARCH_HAS_PARANOID_L1D_FLUSH << 1569 bool << 1570 << 1571 config ARCH_HAVE_TRACE_MMIO_ACCESS << 1572 bool << 1573 << 1574 config DYNAMIC_SIGFRAME << 1575 bool << 1576 << 1577 # Select, if arch has a named attribute group << 1578 config HAVE_ARCH_NODE_DEV_GROUP << 1579 bool << 1580 << 1581 config ARCH_HAS_HW_PTE_YOUNG << 1582 bool << 1583 help << 1584 Architectures that select this opti << 1585 accessed bit in PTE entries when us << 1586 translations. Architectures that re << 1587 this option and override arch_has_h << 1588 << 1589 config ARCH_HAS_NONLEAF_PMD_YOUNG << 1590 bool << 1591 help << 1592 Architectures that select this opti << 1593 accessed bit in non-leaf PMD entrie << 1594 address translations. Page table wa << 1595 may use this capability to reduce t << 1596 << 1597 config ARCH_HAS_KERNEL_FPU_SUPPORT << 1598 bool << 1599 help << 1600 Architectures that select this opti << 1601 the kernel, as described in Documen << 1602 961 1603 source "kernel/gcov/Kconfig" 962 source "kernel/gcov/Kconfig" 1604 << 1605 source "scripts/gcc-plugins/Kconfig" << 1606 << 1607 config FUNCTION_ALIGNMENT_4B << 1608 bool << 1609 << 1610 config FUNCTION_ALIGNMENT_8B << 1611 bool << 1612 << 1613 config FUNCTION_ALIGNMENT_16B << 1614 bool << 1615 << 1616 config FUNCTION_ALIGNMENT_32B << 1617 bool << 1618 << 1619 config FUNCTION_ALIGNMENT_64B << 1620 bool << 1621 << 1622 config FUNCTION_ALIGNMENT << 1623 int << 1624 default 64 if FUNCTION_ALIGNMENT_64B << 1625 default 32 if FUNCTION_ALIGNMENT_32B << 1626 default 16 if FUNCTION_ALIGNMENT_16B << 1627 default 8 if FUNCTION_ALIGNMENT_8B << 1628 default 4 if FUNCTION_ALIGNMENT_4B << 1629 default 0 << 1630 << 1631 config CC_HAS_MIN_FUNCTION_ALIGNMENT << 1632 # Detect availability of the GCC opti << 1633 # guarantees minimal alignment for al << 1634 # -falign-functions which the compile << 1635 def_bool $(cc-option, -fmin-function- << 1636 << 1637 config CC_HAS_SANE_FUNCTION_ALIGNMENT << 1638 # Set if the guaranteed alignment wit << 1639 # available or extra care is required << 1640 # strict alignment always, even with << 1641 def_bool CC_HAS_MIN_FUNCTION_ALIGNMEN << 1642 << 1643 config ARCH_NEED_CMPXCHG_1_EMU << 1644 bool << 1645 << 1646 endmenu <<
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