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 # 7 # Note: arch/$(SRCARCH)/Kconfig needs to be in 7 # Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can 8 # override the default values in this file. 8 # override the default values in this file. 9 # 9 # 10 source "arch/$(SRCARCH)/Kconfig" 10 source "arch/$(SRCARCH)/Kconfig" 11 11 12 config ARCH_CONFIGURES_CPU_MITIGATIONS << 13 bool << 14 << 15 if !ARCH_CONFIGURES_CPU_MITIGATIONS << 16 config CPU_MITIGATIONS << 17 def_bool y << 18 endif << 19 << 20 menu "General architecture-dependent options" 12 menu "General architecture-dependent options" 21 13 22 config ARCH_HAS_SUBPAGE_FAULTS !! 14 config CRASH_CORE 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 << 31 << 32 config SMT_NUM_THREADS_DYNAMIC << 33 bool 15 bool 34 16 35 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU !! 17 config KEXEC_CORE 36 config HOTPLUG_CORE_SYNC !! 18 select CRASH_CORE 37 bool 19 bool 38 20 39 # Basic CPU dead synchronization selected by a !! 21 config KEXEC_ELF 40 config HOTPLUG_CORE_SYNC_DEAD << 41 bool 22 bool 42 select HOTPLUG_CORE_SYNC << 43 23 44 # Full CPU synchronization with alive state se !! 24 config HAVE_IMA_KEXEC 45 config HOTPLUG_CORE_SYNC_FULL << 46 bool 25 bool 47 select HOTPLUG_CORE_SYNC_DEAD if HOTPL << 48 select HOTPLUG_CORE_SYNC << 49 26 50 config HOTPLUG_SPLIT_STARTUP !! 27 config ARCH_HAS_SUBPAGE_FAULTS 51 bool 28 bool 52 select HOTPLUG_CORE_SYNC_FULL !! 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. 53 33 54 config HOTPLUG_PARALLEL !! 34 config HOTPLUG_SMT 55 bool 35 bool 56 select HOTPLUG_SPLIT_STARTUP << 57 36 58 config GENERIC_ENTRY 37 config GENERIC_ENTRY 59 bool !! 38 bool 60 39 61 config KPROBES 40 config KPROBES 62 bool "Kprobes" 41 bool "Kprobes" >> 42 depends on MODULES 63 depends on HAVE_KPROBES 43 depends on HAVE_KPROBES 64 select KALLSYMS 44 select KALLSYMS 65 select EXECMEM !! 45 select TASKS_RCU if PREEMPTION 66 select NEED_TASKS_RCU << 67 help 46 help 68 Kprobes allows you to trap at almost 47 Kprobes allows you to trap at almost any kernel address and 69 execute a callback function. regist 48 execute a callback function. register_kprobe() establishes 70 a probepoint and specifies the callb 49 a probepoint and specifies the callback. Kprobes is useful 71 for kernel debugging, non-intrusive 50 for kernel debugging, non-intrusive instrumentation and testing. 72 If in doubt, say "N". 51 If in doubt, say "N". 73 52 74 config JUMP_LABEL 53 config JUMP_LABEL 75 bool "Optimize very unlikely/likely br 54 bool "Optimize very unlikely/likely branches" 76 depends on HAVE_ARCH_JUMP_LABEL 55 depends on HAVE_ARCH_JUMP_LABEL 77 select OBJTOOL if HAVE_JUMP_LABEL_HACK 56 select OBJTOOL if HAVE_JUMP_LABEL_HACK 78 help 57 help 79 This option enables a transparent br !! 58 This option enables a transparent branch optimization that 80 makes certain almost-always-true or !! 59 makes certain almost-always-true or almost-always-false branch 81 conditions even cheaper to execute w !! 60 conditions even cheaper to execute within the kernel. 82 !! 61 83 Certain performance-sensitive kernel !! 62 Certain performance-sensitive kernel code, such as trace points, 84 scheduler functionality, networking !! 63 scheduler functionality, networking code and KVM have such 85 branches and include support for thi !! 64 branches and include support for this optimization technique. 86 !! 65 87 If it is detected that the compiler !! 66 If it is detected that the compiler has support for "asm goto", 88 the kernel will compile such branche !! 67 the kernel will compile such branches with just a nop 89 instruction. When the condition flag !! 68 instruction. When the condition flag is toggled to true, the 90 nop will be converted to a jump inst !! 69 nop will be converted to a jump instruction to execute the 91 conditional block of instructions. !! 70 conditional block of instructions. 92 !! 71 93 This technique lowers overhead and s !! 72 This technique lowers overhead and stress on the branch prediction 94 of the processor and generally makes !! 73 of the processor and generally makes the kernel faster. The update 95 of the condition is slower, but thos !! 74 of the condition is slower, but those are always very rare. 96 75 97 ( On 32-bit x86, the necessary optio !! 76 ( On 32-bit x86, the necessary options added to the compiler 98 flags may increase the size of the !! 77 flags may increase the size of the kernel slightly. ) 99 78 100 config STATIC_KEYS_SELFTEST 79 config STATIC_KEYS_SELFTEST 101 bool "Static key selftest" 80 bool "Static key selftest" 102 depends on JUMP_LABEL 81 depends on JUMP_LABEL 103 help 82 help 104 Boot time self-test of the branch pa 83 Boot time self-test of the branch patching code. 105 84 106 config STATIC_CALL_SELFTEST 85 config STATIC_CALL_SELFTEST 107 bool "Static call selftest" 86 bool "Static call selftest" 108 depends on HAVE_STATIC_CALL 87 depends on HAVE_STATIC_CALL 109 help 88 help 110 Boot time self-test of the call patc 89 Boot time self-test of the call patching code. 111 90 112 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 PREEMPTION 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/core-api/unaligned-memory-access.rst for 154 more information on the topic of una 133 more 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/core-api/unaligned-memory-access.rst 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 || HAVE_RETHOOK) 197 176 198 config KRETPROBE_ON_RETHOOK 177 config KRETPROBE_ON_RETHOOK 199 def_bool y 178 def_bool y 200 depends on HAVE_RETHOOK 179 depends on HAVE_RETHOOK 201 depends on KRETPROBES 180 depends on KRETPROBES 202 select RETHOOK 181 select RETHOOK 203 182 204 config USER_RETURN_NOTIFIER 183 config USER_RETURN_NOTIFIER 205 bool 184 bool 206 depends on HAVE_USER_RETURN_NOTIFIER 185 depends on HAVE_USER_RETURN_NOTIFIER 207 help 186 help 208 Provide a kernel-internal notificati 187 Provide a kernel-internal notification when a cpu is about to 209 switch to user mode. 188 switch to user mode. 210 189 211 config HAVE_IOREMAP_PROT 190 config HAVE_IOREMAP_PROT 212 bool 191 bool 213 192 214 config HAVE_KPROBES 193 config HAVE_KPROBES 215 bool 194 bool 216 195 217 config HAVE_KRETPROBES 196 config HAVE_KRETPROBES 218 bool 197 bool 219 198 220 config HAVE_OPTPROBES 199 config HAVE_OPTPROBES 221 bool 200 bool 222 201 223 config HAVE_KPROBES_ON_FTRACE 202 config HAVE_KPROBES_ON_FTRACE 224 bool 203 bool 225 204 226 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 205 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 227 bool 206 bool 228 help 207 help 229 Since kretprobes modifies return add 208 Since kretprobes modifies return address on the stack, the 230 stacktrace may see the kretprobe tra 209 stacktrace may see the kretprobe trampoline address instead 231 of correct one. If the architecture 210 of correct one. If the architecture stacktrace code and 232 unwinder can adjust such entries, se 211 unwinder can adjust such entries, select this configuration. 233 212 234 config HAVE_FUNCTION_ERROR_INJECTION 213 config HAVE_FUNCTION_ERROR_INJECTION 235 bool 214 bool 236 215 237 config HAVE_NMI 216 config HAVE_NMI 238 bool 217 bool 239 218 240 config HAVE_FUNCTION_DESCRIPTORS 219 config HAVE_FUNCTION_DESCRIPTORS 241 bool 220 bool 242 221 243 config TRACE_IRQFLAGS_SUPPORT 222 config TRACE_IRQFLAGS_SUPPORT 244 bool 223 bool 245 224 246 config TRACE_IRQFLAGS_NMI_SUPPORT 225 config TRACE_IRQFLAGS_NMI_SUPPORT 247 bool 226 bool 248 227 249 # 228 # 250 # An arch should select this if it provides al 229 # An arch should select this if it provides all these things: 251 # 230 # 252 # task_pt_regs() in asm/process 231 # task_pt_regs() in asm/processor.h or asm/ptrace.h 253 # arch_has_single_step() if there is ha 232 # arch_has_single_step() if there is hardware single-step support 254 # arch_has_block_step() if there is ha 233 # arch_has_block_step() if there is hardware block-step support 255 # asm/syscall.h supplying asm- 234 # asm/syscall.h supplying asm-generic/syscall.h interface 256 # linux/regset.h user_regset in 235 # linux/regset.h user_regset interfaces 257 # CORE_DUMP_USE_REGSET #define'd in l 236 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h 258 # TIF_SYSCALL_TRACE calls ptrace_r 237 # TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit} 259 # TIF_NOTIFY_RESUME calls resume_u 238 # TIF_NOTIFY_RESUME calls resume_user_mode_work() 260 # 239 # 261 config HAVE_ARCH_TRACEHOOK 240 config HAVE_ARCH_TRACEHOOK 262 bool 241 bool 263 242 264 config HAVE_DMA_CONTIGUOUS 243 config HAVE_DMA_CONTIGUOUS 265 bool 244 bool 266 245 267 config GENERIC_SMP_IDLE_THREAD 246 config GENERIC_SMP_IDLE_THREAD 268 bool 247 bool 269 248 270 config GENERIC_IDLE_POLL_SETUP 249 config GENERIC_IDLE_POLL_SETUP 271 bool 250 bool 272 251 273 config ARCH_HAS_FORTIFY_SOURCE 252 config ARCH_HAS_FORTIFY_SOURCE 274 bool 253 bool 275 help 254 help 276 An architecture should select this w 255 An architecture should select this when it can successfully 277 build and run with CONFIG_FORTIFY_SO 256 build and run with CONFIG_FORTIFY_SOURCE. 278 257 279 # 258 # 280 # Select if the arch provides a historic keepi 259 # Select if the arch provides a historic keepinit alias for the retain_initrd 281 # command line option 260 # command line option 282 # 261 # 283 config ARCH_HAS_KEEPINITRD 262 config ARCH_HAS_KEEPINITRD 284 bool 263 bool 285 264 286 # Select if arch has all set_memory_ro/rw/x/nx 265 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h 287 config ARCH_HAS_SET_MEMORY 266 config ARCH_HAS_SET_MEMORY 288 bool 267 bool 289 268 290 # Select if arch has all set_direct_map_invali 269 # Select if arch has all set_direct_map_invalid/default() functions 291 config ARCH_HAS_SET_DIRECT_MAP 270 config ARCH_HAS_SET_DIRECT_MAP 292 bool 271 bool 293 272 294 # 273 # 295 # Select if the architecture provides the arch 274 # Select if the architecture provides the arch_dma_set_uncached symbol to 296 # either provide an uncached segment alias for 275 # either provide an uncached segment alias for a DMA allocation, or 297 # to remap the page tables in place. 276 # to remap the page tables in place. 298 # 277 # 299 config ARCH_HAS_DMA_SET_UNCACHED 278 config ARCH_HAS_DMA_SET_UNCACHED 300 bool 279 bool 301 280 302 # 281 # 303 # Select if the architectures provides the arc 282 # Select if the architectures provides the arch_dma_clear_uncached symbol 304 # to undo an in-place page table remap for unc 283 # to undo an in-place page table remap for uncached access. 305 # 284 # 306 config ARCH_HAS_DMA_CLEAR_UNCACHED 285 config ARCH_HAS_DMA_CLEAR_UNCACHED 307 bool 286 bool 308 287 309 config ARCH_HAS_CPU_FINALIZE_INIT !! 288 # Select if arch init_task must go in the __init_task_data section >> 289 config ARCH_TASK_STRUCT_ON_STACK 310 bool 290 bool 311 291 312 # The architecture has a per-task state that i !! 292 # Select if arch has its private alloc_task_struct() function 313 config ARCH_HAS_CPU_PASID !! 293 config ARCH_TASK_STRUCT_ALLOCATOR 314 bool 294 bool 315 select IOMMU_MM_DATA << 316 295 317 config HAVE_ARCH_THREAD_STRUCT_WHITELIST 296 config HAVE_ARCH_THREAD_STRUCT_WHITELIST 318 bool 297 bool >> 298 depends on !ARCH_TASK_STRUCT_ALLOCATOR 319 help 299 help 320 An architecture should select this t 300 An architecture should select this to provide hardened usercopy 321 knowledge about what region of the t 301 knowledge about what region of the thread_struct should be 322 whitelisted for copying to userspace 302 whitelisted for copying to userspace. Normally this is only the 323 FPU registers. Specifically, arch_th 303 FPU registers. Specifically, arch_thread_struct_whitelist() 324 should be implemented. Without this, 304 should be implemented. Without this, the entire thread_struct 325 field in task_struct will be left wh 305 field in task_struct will be left whitelisted. 326 306 >> 307 # Select if arch has its private alloc_thread_stack() function >> 308 config ARCH_THREAD_STACK_ALLOCATOR >> 309 bool >> 310 327 # Select if arch wants to size task_struct dyn 311 # Select if arch wants to size task_struct dynamically via arch_task_struct_size: 328 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 312 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 329 bool 313 bool 330 314 331 config ARCH_WANTS_NO_INSTR 315 config ARCH_WANTS_NO_INSTR 332 bool 316 bool 333 help 317 help 334 An architecture should select this i 318 An architecture should select this if the noinstr macro is being used on 335 functions to denote that the toolcha 319 functions to denote that the toolchain should avoid instrumenting such 336 functions and is required for correc 320 functions and is required for correctness. 337 321 338 config ARCH_32BIT_OFF_T 322 config ARCH_32BIT_OFF_T 339 bool 323 bool 340 depends on !64BIT 324 depends on !64BIT 341 help 325 help 342 All new 32-bit architectures should 326 All new 32-bit architectures should have 64-bit off_t type on 343 userspace side which corresponds to 327 userspace side which corresponds to the loff_t kernel type. This 344 is the requirement for modern ABIs. 328 is the requirement for modern ABIs. Some existing architectures 345 still support 32-bit off_t. This opt 329 still support 32-bit off_t. This option is enabled for all such 346 architectures explicitly. 330 architectures explicitly. 347 331 348 # Selected by 64 bit architectures which have 332 # Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat 349 config ARCH_32BIT_USTAT_F_TINODE 333 config ARCH_32BIT_USTAT_F_TINODE 350 bool 334 bool 351 335 352 config HAVE_ASM_MODVERSIONS 336 config HAVE_ASM_MODVERSIONS 353 bool 337 bool 354 help 338 help 355 This symbol should be selected by an 339 This symbol should be selected by an architecture if it provides 356 <asm/asm-prototypes.h> to support th 340 <asm/asm-prototypes.h> to support the module versioning for symbols 357 exported from assembly code. 341 exported from assembly code. 358 342 359 config HAVE_REGS_AND_STACK_ACCESS_API 343 config HAVE_REGS_AND_STACK_ACCESS_API 360 bool 344 bool 361 help 345 help 362 This symbol should be selected by an 346 This symbol should be selected by an architecture if it supports 363 the API needed to access registers a 347 the API needed to access registers and stack entries from pt_regs, 364 declared in asm/ptrace.h 348 declared in asm/ptrace.h 365 For example the kprobes-based event 349 For example the kprobes-based event tracer needs this API. 366 350 367 config HAVE_RSEQ 351 config HAVE_RSEQ 368 bool 352 bool 369 depends on HAVE_REGS_AND_STACK_ACCESS_ 353 depends on HAVE_REGS_AND_STACK_ACCESS_API 370 help 354 help 371 This symbol should be selected by an 355 This symbol should be selected by an architecture if it 372 supports an implementation of restar 356 supports an implementation of restartable sequences. 373 357 374 config HAVE_RUST << 375 bool << 376 help << 377 This symbol should be selected by an << 378 supports Rust. << 379 << 380 config HAVE_FUNCTION_ARG_ACCESS_API 358 config HAVE_FUNCTION_ARG_ACCESS_API 381 bool 359 bool 382 help 360 help 383 This symbol should be selected by an 361 This symbol should be selected by an architecture if it supports 384 the API needed to access function ar 362 the API needed to access function arguments from pt_regs, 385 declared in asm/ptrace.h 363 declared in asm/ptrace.h 386 364 387 config HAVE_HW_BREAKPOINT 365 config HAVE_HW_BREAKPOINT 388 bool 366 bool 389 depends on PERF_EVENTS 367 depends on PERF_EVENTS 390 368 391 config HAVE_MIXED_BREAKPOINTS_REGS 369 config HAVE_MIXED_BREAKPOINTS_REGS 392 bool 370 bool 393 depends on HAVE_HW_BREAKPOINT 371 depends on HAVE_HW_BREAKPOINT 394 help 372 help 395 Depending on the arch implementation 373 Depending on the arch implementation of hardware breakpoints, 396 some of them have separate registers 374 some of them have separate registers for data and instruction 397 breakpoints addresses, others have m 375 breakpoints addresses, others have mixed registers to store 398 them but define the access type in a 376 them but define the access type in a control register. 399 Select this option if your arch impl 377 Select this option if your arch implements breakpoints under the 400 latter fashion. 378 latter fashion. 401 379 402 config HAVE_USER_RETURN_NOTIFIER 380 config HAVE_USER_RETURN_NOTIFIER 403 bool 381 bool 404 382 405 config HAVE_PERF_EVENTS_NMI 383 config HAVE_PERF_EVENTS_NMI 406 bool 384 bool 407 help 385 help 408 System hardware can generate an NMI 386 System hardware can generate an NMI using the perf event 409 subsystem. Also has support for cal 387 subsystem. Also has support for calculating CPU cycle events 410 to determine how many clock cycles i 388 to determine how many clock cycles in a given period. 411 389 412 config HAVE_HARDLOCKUP_DETECTOR_PERF 390 config HAVE_HARDLOCKUP_DETECTOR_PERF 413 bool 391 bool 414 depends on HAVE_PERF_EVENTS_NMI 392 depends on HAVE_PERF_EVENTS_NMI 415 help 393 help 416 The arch chooses to use the generic 394 The arch chooses to use the generic perf-NMI-based hardlockup 417 detector. Must define HAVE_PERF_EVEN 395 detector. Must define HAVE_PERF_EVENTS_NMI. 418 396 419 config HAVE_HARDLOCKUP_DETECTOR_ARCH !! 397 config HAVE_NMI_WATCHDOG >> 398 depends on HAVE_NMI 420 bool 399 bool 421 help 400 help 422 The arch provides its own hardlockup !! 401 The arch provides a low level NMI watchdog. It provides 423 of the generic ones. !! 402 asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). 424 403 425 It uses the same command line parame !! 404 config HAVE_HARDLOCKUP_DETECTOR_ARCH 426 as the generic hardlockup detectors. !! 405 bool >> 406 select HAVE_NMI_WATCHDOG >> 407 help >> 408 The arch chooses to provide its own hardlockup detector, which is >> 409 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config >> 410 interfaces and parameters provided by hardlockup detector subsystem. 427 411 428 config HAVE_PERF_REGS 412 config HAVE_PERF_REGS 429 bool 413 bool 430 help 414 help 431 Support selective register dumps for 415 Support selective register dumps for perf events. This includes 432 bit-mapping of each registers and a 416 bit-mapping of each registers and a unique architecture id. 433 417 434 config HAVE_PERF_USER_STACK_DUMP 418 config HAVE_PERF_USER_STACK_DUMP 435 bool 419 bool 436 help 420 help 437 Support user stack dumps for perf ev 421 Support user stack dumps for perf event samples. This needs 438 access to the user stack pointer whi 422 access to the user stack pointer which is not unified across 439 architectures. 423 architectures. 440 424 441 config HAVE_ARCH_JUMP_LABEL 425 config HAVE_ARCH_JUMP_LABEL 442 bool 426 bool 443 427 444 config HAVE_ARCH_JUMP_LABEL_RELATIVE 428 config HAVE_ARCH_JUMP_LABEL_RELATIVE 445 bool 429 bool 446 430 447 config MMU_GATHER_TABLE_FREE 431 config MMU_GATHER_TABLE_FREE 448 bool 432 bool 449 433 450 config MMU_GATHER_RCU_TABLE_FREE 434 config MMU_GATHER_RCU_TABLE_FREE 451 bool 435 bool 452 select MMU_GATHER_TABLE_FREE 436 select MMU_GATHER_TABLE_FREE 453 437 454 config MMU_GATHER_PAGE_SIZE 438 config MMU_GATHER_PAGE_SIZE 455 bool 439 bool 456 440 457 config MMU_GATHER_NO_RANGE 441 config MMU_GATHER_NO_RANGE 458 bool 442 bool 459 select MMU_GATHER_MERGE_VMAS 443 select MMU_GATHER_MERGE_VMAS 460 444 461 config MMU_GATHER_NO_FLUSH_CACHE 445 config MMU_GATHER_NO_FLUSH_CACHE 462 bool 446 bool 463 447 464 config MMU_GATHER_MERGE_VMAS 448 config MMU_GATHER_MERGE_VMAS 465 bool 449 bool 466 450 467 config MMU_GATHER_NO_GATHER 451 config MMU_GATHER_NO_GATHER 468 bool 452 bool 469 depends on MMU_GATHER_TABLE_FREE 453 depends on MMU_GATHER_TABLE_FREE 470 454 471 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM 455 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM 472 bool 456 bool 473 help 457 help 474 Temporary select until all architect 458 Temporary select until all architectures can be converted to have 475 irqs disabled over activate_mm. Arch 459 irqs disabled over activate_mm. Architectures that do IPI based TLB 476 shootdowns should enable this. 460 shootdowns should enable this. 477 461 478 # 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 << 509 << 510 config ARCH_HAVE_NMI_SAFE_CMPXCHG 462 config ARCH_HAVE_NMI_SAFE_CMPXCHG 511 bool 463 bool 512 464 513 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 465 config HAVE_ALIGNED_STRUCT_PAGE 526 bool 466 bool 527 help 467 help 528 This makes sure that struct pages ar 468 This makes sure that struct pages are double word aligned and that 529 e.g. the SLUB allocator can perform 469 e.g. the SLUB allocator can perform double word atomic operations 530 on a struct page for better performa 470 on a struct page for better performance. However selecting this 531 might increase the size of a struct 471 might increase the size of a struct page by a word. 532 472 533 config HAVE_CMPXCHG_LOCAL 473 config HAVE_CMPXCHG_LOCAL 534 bool 474 bool 535 475 536 config HAVE_CMPXCHG_DOUBLE 476 config HAVE_CMPXCHG_DOUBLE 537 bool 477 bool 538 478 539 config ARCH_WEAK_RELEASE_ACQUIRE 479 config ARCH_WEAK_RELEASE_ACQUIRE 540 bool 480 bool 541 481 542 config ARCH_WANT_IPC_PARSE_VERSION 482 config ARCH_WANT_IPC_PARSE_VERSION 543 bool 483 bool 544 484 545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 485 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 546 bool 486 bool 547 487 548 config ARCH_WANT_OLD_COMPAT_IPC 488 config ARCH_WANT_OLD_COMPAT_IPC 549 select ARCH_WANT_COMPAT_IPC_PARSE_VERS 489 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 550 bool 490 bool 551 491 552 config HAVE_ARCH_SECCOMP 492 config HAVE_ARCH_SECCOMP 553 bool 493 bool 554 help 494 help 555 An arch should select this symbol to 495 An arch should select this symbol to support seccomp mode 1 (the fixed 556 syscall policy), and must provide an 496 syscall policy), and must provide an overrides for __NR_seccomp_sigreturn, 557 and compat syscalls if the asm-gener 497 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment: 558 - __NR_seccomp_read_32 498 - __NR_seccomp_read_32 559 - __NR_seccomp_write_32 499 - __NR_seccomp_write_32 560 - __NR_seccomp_exit_32 500 - __NR_seccomp_exit_32 561 - __NR_seccomp_sigreturn_32 501 - __NR_seccomp_sigreturn_32 562 502 563 config HAVE_ARCH_SECCOMP_FILTER 503 config HAVE_ARCH_SECCOMP_FILTER 564 bool 504 bool 565 select HAVE_ARCH_SECCOMP 505 select HAVE_ARCH_SECCOMP 566 help 506 help 567 An arch should select this symbol if 507 An arch should select this symbol if it provides all of these things: 568 - all the requirements for HAVE_ARCH 508 - all the requirements for HAVE_ARCH_SECCOMP 569 - syscall_get_arch() 509 - syscall_get_arch() 570 - syscall_get_arguments() 510 - syscall_get_arguments() 571 - syscall_rollback() 511 - syscall_rollback() 572 - syscall_set_return_value() 512 - syscall_set_return_value() 573 - SIGSYS siginfo_t support 513 - SIGSYS siginfo_t support 574 - secure_computing is called from a 514 - secure_computing is called from a ptrace_event()-safe context 575 - secure_computing return value is c 515 - secure_computing return value is checked and a return value of -1 576 results in the system call being s 516 results in the system call being skipped immediately. 577 - seccomp syscall wired up 517 - seccomp syscall wired up 578 - if !HAVE_SPARSE_SYSCALL_NR, have S 518 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE, 579 SECCOMP_ARCH_NATIVE_NR, SECCOMP_AR 519 SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If 580 COMPAT is supported, have the SECC 520 COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too. 581 521 582 config SECCOMP 522 config SECCOMP 583 prompt "Enable seccomp to safely execu 523 prompt "Enable seccomp to safely execute untrusted bytecode" 584 def_bool y 524 def_bool y 585 depends on HAVE_ARCH_SECCOMP 525 depends on HAVE_ARCH_SECCOMP 586 help 526 help 587 This kernel feature is useful for nu 527 This kernel feature is useful for number crunching applications 588 that may need to handle untrusted by 528 that may need to handle untrusted bytecode during their 589 execution. By using pipes or other t 529 execution. By using pipes or other transports made available 590 to the process as file descriptors s 530 to the process as file descriptors supporting the read/write 591 syscalls, it's possible to isolate t 531 syscalls, it's possible to isolate those applications in their 592 own address space using seccomp. Onc 532 own address space using seccomp. Once seccomp is enabled via 593 prctl(PR_SET_SECCOMP) or the seccomp 533 prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be 594 disabled and the task is only allowe 534 disabled and the task is only allowed to execute a few safe 595 syscalls defined by each seccomp mod 535 syscalls defined by each seccomp mode. 596 536 597 If unsure, say Y. 537 If unsure, say Y. 598 538 599 config SECCOMP_FILTER 539 config SECCOMP_FILTER 600 def_bool y 540 def_bool y 601 depends on HAVE_ARCH_SECCOMP_FILTER && 541 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 602 help 542 help 603 Enable tasks to build secure computi 543 Enable tasks to build secure computing environments defined 604 in terms of Berkeley Packet Filter p 544 in terms of Berkeley Packet Filter programs which implement 605 task-defined system call filtering p 545 task-defined system call filtering polices. 606 546 607 See Documentation/userspace-api/secc 547 See Documentation/userspace-api/seccomp_filter.rst for details. 608 548 609 config SECCOMP_CACHE_DEBUG 549 config SECCOMP_CACHE_DEBUG 610 bool "Show seccomp filter cache status 550 bool "Show seccomp filter cache status in /proc/pid/seccomp_cache" 611 depends on SECCOMP_FILTER && !HAVE_SPA 551 depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR 612 depends on PROC_FS 552 depends on PROC_FS 613 help 553 help 614 This enables the /proc/pid/seccomp_c 554 This enables the /proc/pid/seccomp_cache interface to monitor 615 seccomp cache data. The file format 555 seccomp cache data. The file format is subject to change. Reading 616 the file requires CAP_SYS_ADMIN. 556 the file requires CAP_SYS_ADMIN. 617 557 618 This option is for debugging only. E 558 This option is for debugging only. Enabling presents the risk that 619 an adversary may be able to infer th 559 an adversary may be able to infer the seccomp filter logic. 620 560 621 If unsure, say N. 561 If unsure, say N. 622 562 623 config HAVE_ARCH_STACKLEAK 563 config HAVE_ARCH_STACKLEAK 624 bool 564 bool 625 help 565 help 626 An architecture should select this i 566 An architecture should select this if it has the code which 627 fills the used part of the kernel st 567 fills the used part of the kernel stack with the STACKLEAK_POISON 628 value before returning from system c 568 value before returning from system calls. 629 569 630 config HAVE_STACKPROTECTOR 570 config HAVE_STACKPROTECTOR 631 bool 571 bool 632 help 572 help 633 An arch should select this symbol if 573 An arch should select this symbol if: 634 - it has implemented a stack canary 574 - it has implemented a stack canary (e.g. __stack_chk_guard) 635 575 636 config STACKPROTECTOR 576 config STACKPROTECTOR 637 bool "Stack Protector buffer overflow 577 bool "Stack Protector buffer overflow detection" 638 depends on HAVE_STACKPROTECTOR 578 depends on HAVE_STACKPROTECTOR 639 depends on $(cc-option,-fstack-protect 579 depends on $(cc-option,-fstack-protector) 640 default y 580 default y 641 help 581 help 642 This option turns on the "stack-prot 582 This option turns on the "stack-protector" GCC feature. This 643 feature puts, at the beginning of fu 583 feature puts, at the beginning of functions, a canary value on 644 the stack just before the return add 584 the stack just before the return address, and validates 645 the value just before actually retur 585 the value just before actually returning. Stack based buffer 646 overflows (that need to overwrite th 586 overflows (that need to overwrite this return address) now also 647 overwrite the canary, which gets det 587 overwrite the canary, which gets detected and the attack is then 648 neutralized via a kernel panic. 588 neutralized via a kernel panic. 649 589 650 Functions will have the stack-protec 590 Functions will have the stack-protector canary logic added if they 651 have an 8-byte or larger character a 591 have an 8-byte or larger character array on the stack. 652 592 653 This feature requires gcc version 4. 593 This feature requires gcc version 4.2 or above, or a distribution 654 gcc with the feature backported ("-f 594 gcc with the feature backported ("-fstack-protector"). 655 595 656 On an x86 "defconfig" build, this fe 596 On an x86 "defconfig" build, this feature adds canary checks to 657 about 3% of all kernel functions, wh 597 about 3% of all kernel functions, which increases kernel code size 658 by about 0.3%. 598 by about 0.3%. 659 599 660 config STACKPROTECTOR_STRONG 600 config STACKPROTECTOR_STRONG 661 bool "Strong Stack Protector" 601 bool "Strong Stack Protector" 662 depends on STACKPROTECTOR 602 depends on STACKPROTECTOR 663 depends on $(cc-option,-fstack-protect 603 depends on $(cc-option,-fstack-protector-strong) 664 default y 604 default y 665 help 605 help 666 Functions will have the stack-protec 606 Functions will have the stack-protector canary logic added in any 667 of the following conditions: 607 of the following conditions: 668 608 669 - local variable's address used as p 609 - local variable's address used as part of the right hand side of an 670 assignment or function argument 610 assignment or function argument 671 - local variable is an array (or uni 611 - local variable is an array (or union containing an array), 672 regardless of array type or length 612 regardless of array type or length 673 - uses register local variables 613 - uses register local variables 674 614 675 This feature requires gcc version 4. 615 This feature requires gcc version 4.9 or above, or a distribution 676 gcc with the feature backported ("-f 616 gcc with the feature backported ("-fstack-protector-strong"). 677 617 678 On an x86 "defconfig" build, this fe 618 On an x86 "defconfig" build, this feature adds canary checks to 679 about 20% of all kernel functions, w 619 about 20% of all kernel functions, which increases the kernel code 680 size by about 2%. 620 size by about 2%. 681 621 682 config ARCH_SUPPORTS_SHADOW_CALL_STACK 622 config ARCH_SUPPORTS_SHADOW_CALL_STACK 683 bool 623 bool 684 help 624 help 685 An architecture should select this i 625 An architecture should select this if it supports the compiler's 686 Shadow Call Stack and implements run 626 Shadow Call Stack and implements runtime support for shadow stack 687 switching. 627 switching. 688 628 689 config SHADOW_CALL_STACK 629 config SHADOW_CALL_STACK 690 bool "Shadow Call Stack" 630 bool "Shadow Call Stack" 691 depends on ARCH_SUPPORTS_SHADOW_CALL_S 631 depends on ARCH_SUPPORTS_SHADOW_CALL_STACK 692 depends on DYNAMIC_FTRACE_WITH_ARGS || 632 depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER 693 depends on MMU << 694 help 633 help 695 This option enables the compiler's S 634 This option enables the compiler's Shadow Call Stack, which 696 uses a shadow stack to protect funct 635 uses a shadow stack to protect function return addresses from 697 being overwritten by an attacker. Mo 636 being overwritten by an attacker. More information can be found 698 in the compiler's documentation: 637 in the compiler's documentation: 699 638 700 - Clang: https://clang.llvm.org/docs 639 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html 701 - GCC: https://gcc.gnu.org/onlinedoc 640 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options 702 641 703 Note that security guarantees in the 642 Note that security guarantees in the kernel differ from the 704 ones documented for user space. The 643 ones documented for user space. The kernel must store addresses 705 of shadow stacks in memory, which me 644 of shadow stacks in memory, which means an attacker capable of 706 reading and writing arbitrary memory 645 reading and writing arbitrary memory may be able to locate them 707 and hijack control flow by modifying 646 and hijack control flow by modifying the stacks. 708 647 709 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 648 config LTO 717 bool 649 bool 718 help 650 help 719 Selected if the kernel will be built 651 Selected if the kernel will be built using the compiler's LTO feature. 720 652 721 config LTO_CLANG 653 config LTO_CLANG 722 bool 654 bool 723 select LTO 655 select LTO 724 help 656 help 725 Selected if the kernel will be built 657 Selected if the kernel will be built using Clang's LTO feature. 726 658 727 config ARCH_SUPPORTS_LTO_CLANG 659 config ARCH_SUPPORTS_LTO_CLANG 728 bool 660 bool 729 help 661 help 730 An architecture should select this o 662 An architecture should select this option if it supports: 731 - compiling with Clang, 663 - compiling with Clang, 732 - compiling inline assembly with Cla 664 - compiling inline assembly with Clang's integrated assembler, 733 - and linking with LLD. 665 - and linking with LLD. 734 666 735 config ARCH_SUPPORTS_LTO_CLANG_THIN 667 config ARCH_SUPPORTS_LTO_CLANG_THIN 736 bool 668 bool 737 help 669 help 738 An architecture should select this o 670 An architecture should select this option if it can support Clang's 739 ThinLTO mode. 671 ThinLTO mode. 740 672 741 config HAS_LTO_CLANG 673 config HAS_LTO_CLANG 742 def_bool y 674 def_bool y 743 depends on CC_IS_CLANG && LD_IS_LLD && 675 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM 744 depends on $(success,$(NM) --help | he 676 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm) 745 depends on $(success,$(AR) --help | he 677 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm) 746 depends on ARCH_SUPPORTS_LTO_CLANG 678 depends on ARCH_SUPPORTS_LTO_CLANG 747 depends on !FTRACE_MCOUNT_USE_RECORDMC 679 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT 748 # https://github.com/ClangBuiltLinux/l !! 680 depends on !KASAN || KASAN_HW_TAGS 749 depends on (!KASAN || KASAN_HW_TAGS || << 750 depends on (!KCOV || CLANG_VERSION >= << 751 depends on !GCOV_KERNEL 681 depends on !GCOV_KERNEL 752 help 682 help 753 The compiler and Kconfig options sup 683 The compiler and Kconfig options support building with Clang's 754 LTO. 684 LTO. 755 685 756 choice 686 choice 757 prompt "Link Time Optimization (LTO)" 687 prompt "Link Time Optimization (LTO)" 758 default LTO_NONE 688 default LTO_NONE 759 help 689 help 760 This option enables Link Time Optimi 690 This option enables Link Time Optimization (LTO), which allows the 761 compiler to optimize binaries global 691 compiler to optimize binaries globally. 762 692 763 If unsure, select LTO_NONE. Note tha 693 If unsure, select LTO_NONE. Note that LTO is very resource-intensive 764 so it's disabled by default. 694 so it's disabled by default. 765 695 766 config LTO_NONE 696 config LTO_NONE 767 bool "None" 697 bool "None" 768 help 698 help 769 Build the kernel normally, without L 699 Build the kernel normally, without Link Time Optimization (LTO). 770 700 771 config LTO_CLANG_FULL 701 config LTO_CLANG_FULL 772 bool "Clang Full LTO (EXPERIMENTAL)" 702 bool "Clang Full LTO (EXPERIMENTAL)" 773 depends on HAS_LTO_CLANG 703 depends on HAS_LTO_CLANG 774 depends on !COMPILE_TEST 704 depends on !COMPILE_TEST 775 select LTO_CLANG 705 select LTO_CLANG 776 help 706 help 777 This option enables Clang's full Lin !! 707 This option enables Clang's full Link Time Optimization (LTO), which 778 allows the compiler to optimize the !! 708 allows the compiler to optimize the kernel globally. If you enable 779 this option, the compiler generates !! 709 this option, the compiler generates LLVM bitcode instead of ELF 780 object files, and the actual compila !! 710 object files, and the actual compilation from bitcode happens at 781 the LTO link step, which may take se !! 711 the LTO link step, which may take several minutes depending on the 782 kernel configuration. More informati !! 712 kernel configuration. More information can be found from LLVM's 783 documentation: !! 713 documentation: 784 714 785 https://llvm.org/docs/LinkTimeOpti 715 https://llvm.org/docs/LinkTimeOptimization.html 786 716 787 During link time, this option can us 717 During link time, this option can use a large amount of RAM, and 788 may take much longer than the ThinLT 718 may take much longer than the ThinLTO option. 789 719 790 config LTO_CLANG_THIN 720 config LTO_CLANG_THIN 791 bool "Clang ThinLTO (EXPERIMENTAL)" 721 bool "Clang ThinLTO (EXPERIMENTAL)" 792 depends on HAS_LTO_CLANG && ARCH_SUPPO 722 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN 793 select LTO_CLANG 723 select LTO_CLANG 794 help 724 help 795 This option enables Clang's ThinLTO, 725 This option enables Clang's ThinLTO, which allows for parallel 796 optimization and faster incremental 726 optimization and faster incremental compiles compared to the 797 CONFIG_LTO_CLANG_FULL option. More i 727 CONFIG_LTO_CLANG_FULL option. More information can be found 798 from Clang's documentation: 728 from Clang's documentation: 799 729 800 https://clang.llvm.org/docs/ThinLT 730 https://clang.llvm.org/docs/ThinLTO.html 801 731 802 If unsure, say Y. 732 If unsure, say Y. 803 endchoice 733 endchoice 804 734 805 config ARCH_SUPPORTS_CFI_CLANG 735 config ARCH_SUPPORTS_CFI_CLANG 806 bool 736 bool 807 help 737 help 808 An architecture should select this o 738 An architecture should select this option if it can support Clang's 809 Control-Flow Integrity (CFI) checkin 739 Control-Flow Integrity (CFI) checking. 810 740 811 config ARCH_USES_CFI_TRAPS << 812 bool << 813 << 814 config CFI_CLANG 741 config CFI_CLANG 815 bool "Use Clang's Control Flow Integri 742 bool "Use Clang's Control Flow Integrity (CFI)" 816 depends on ARCH_SUPPORTS_CFI_CLANG !! 743 depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG 817 depends on $(cc-option,-fsanitize=kcfi !! 744 depends on CLANG_VERSION >= 140000 >> 745 select KALLSYMS 818 help 746 help 819 This option enables Clang's forward- !! 747 This option enables Clang’s forward-edge Control Flow Integrity 820 (CFI) checking, where the compiler i 748 (CFI) checking, where the compiler injects a runtime check to each 821 indirect function call to ensure the 749 indirect function call to ensure the target is a valid function with 822 the correct static type. This restri 750 the correct static type. This restricts possible call targets and 823 makes it more difficult for an attac 751 makes it more difficult for an attacker to exploit bugs that allow 824 the modification of stored function 752 the modification of stored function pointers. More information can be 825 found from Clang's documentation: 753 found from Clang's documentation: 826 754 827 https://clang.llvm.org/docs/Contro 755 https://clang.llvm.org/docs/ControlFlowIntegrity.html 828 756 >> 757 config CFI_CLANG_SHADOW >> 758 bool "Use CFI shadow to speed up cross-module checks" >> 759 default y >> 760 depends on CFI_CLANG && MODULES >> 761 help >> 762 If you select this option, the kernel builds a fast look-up table of >> 763 CFI check functions in loaded modules to reduce performance overhead. >> 764 >> 765 If unsure, say Y. >> 766 829 config CFI_PERMISSIVE 767 config CFI_PERMISSIVE 830 bool "Use CFI in permissive mode" 768 bool "Use CFI in permissive mode" 831 depends on CFI_CLANG 769 depends on CFI_CLANG 832 help 770 help 833 When selected, Control Flow Integrit 771 When selected, Control Flow Integrity (CFI) violations result in a 834 warning instead of a kernel panic. T 772 warning instead of a kernel panic. This option should only be used 835 for finding indirect call type misma 773 for finding indirect call type mismatches during development. 836 774 837 If unsure, say N. 775 If unsure, say N. 838 776 839 config HAVE_ARCH_WITHIN_STACK_FRAMES 777 config HAVE_ARCH_WITHIN_STACK_FRAMES 840 bool 778 bool 841 help 779 help 842 An architecture should select this i 780 An architecture should select this if it can walk the kernel stack 843 frames to determine if an object is 781 frames to determine if an object is part of either the arguments 844 or local variables (i.e. that it exc 782 or local variables (i.e. that it excludes saved return addresses, 845 and similar) by implementing an inli 783 and similar) by implementing an inline arch_within_stack_frames(), 846 which is used by CONFIG_HARDENED_USE 784 which is used by CONFIG_HARDENED_USERCOPY. 847 785 848 config HAVE_CONTEXT_TRACKING_USER 786 config HAVE_CONTEXT_TRACKING_USER 849 bool 787 bool 850 help 788 help 851 Provide kernel/user boundaries probe 789 Provide kernel/user boundaries probes necessary for subsystems 852 that need it, such as userspace RCU 790 that need it, such as userspace RCU extended quiescent state. 853 Syscalls need to be wrapped inside u 791 Syscalls need to be wrapped inside user_exit()-user_enter(), either 854 optimized behind static key or throu 792 optimized behind static key or through the slow path using TIF_NOHZ 855 flag. Exceptions handlers must be wr 793 flag. Exceptions handlers must be wrapped as well. Irqs are already 856 protected inside ct_irq_enter/ct_irq 794 protected inside ct_irq_enter/ct_irq_exit() but preemption or signal 857 handling on irq exit still need to b 795 handling on irq exit still need to be protected. 858 796 859 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK 797 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK 860 bool 798 bool 861 help 799 help 862 Architecture neither relies on excep 800 Architecture neither relies on exception_enter()/exception_exit() 863 nor on schedule_user(). Also preempt 801 nor on schedule_user(). Also preempt_schedule_notrace() and 864 preempt_schedule_irq() can't be call 802 preempt_schedule_irq() can't be called in a preemptible section 865 while context tracking is CONTEXT_US 803 while context tracking is CONTEXT_USER. This feature reflects a sane 866 entry implementation where the follo 804 entry implementation where the following requirements are met on 867 critical entry code, ie: before user 805 critical entry code, ie: before user_exit() or after user_enter(): 868 806 869 - Critical entry code isn't preempti 807 - Critical entry code isn't preemptible (or better yet: 870 not interruptible). 808 not interruptible). 871 - No use of RCU read side critical s 809 - No use of RCU read side critical sections, unless ct_nmi_enter() 872 got called. 810 got called. 873 - No use of instrumentation, unless 811 - No use of instrumentation, unless instrumentation_begin() got 874 called. 812 called. 875 813 876 config HAVE_TIF_NOHZ 814 config HAVE_TIF_NOHZ 877 bool 815 bool 878 help 816 help 879 Arch relies on TIF_NOHZ and syscall 817 Arch relies on TIF_NOHZ and syscall slow path to implement context 880 tracking calls to user_enter()/user_ 818 tracking calls to user_enter()/user_exit(). 881 819 882 config HAVE_VIRT_CPU_ACCOUNTING 820 config HAVE_VIRT_CPU_ACCOUNTING 883 bool 821 bool 884 822 885 config HAVE_VIRT_CPU_ACCOUNTING_IDLE 823 config HAVE_VIRT_CPU_ACCOUNTING_IDLE 886 bool 824 bool 887 help 825 help 888 Architecture has its own way to acco 826 Architecture has its own way to account idle CPU time and therefore 889 doesn't implement vtime_account_idle 827 doesn't implement vtime_account_idle(). 890 828 891 config ARCH_HAS_SCALED_CPUTIME 829 config ARCH_HAS_SCALED_CPUTIME 892 bool 830 bool 893 831 894 config HAVE_VIRT_CPU_ACCOUNTING_GEN 832 config HAVE_VIRT_CPU_ACCOUNTING_GEN 895 bool 833 bool 896 default y if 64BIT 834 default y if 64BIT 897 help 835 help 898 With VIRT_CPU_ACCOUNTING_GEN, cputim 836 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 899 Before enabling this option, arch co 837 Before enabling this option, arch code must be audited 900 to ensure there are no races in conc 838 to ensure there are no races in concurrent read/write of 901 cputime_t. For example, reading/writ 839 cputime_t. For example, reading/writing 64-bit cputime_t on 902 some 32-bit arches may require multi 840 some 32-bit arches may require multiple accesses, so proper 903 locking is needed to protect against 841 locking is needed to protect against concurrent accesses. 904 842 905 config HAVE_IRQ_TIME_ACCOUNTING 843 config HAVE_IRQ_TIME_ACCOUNTING 906 bool 844 bool 907 help 845 help 908 Archs need to ensure they use a high 846 Archs need to ensure they use a high enough resolution clock to 909 support irq time accounting and then 847 support irq time accounting and then call enable_sched_clock_irqtime(). 910 848 911 config HAVE_MOVE_PUD 849 config HAVE_MOVE_PUD 912 bool 850 bool 913 help 851 help 914 Architectures that select this are a 852 Architectures that select this are able to move page tables at the 915 PUD level. If there are only 3 page 853 PUD level. If there are only 3 page table levels, the move effectively 916 happens at the PGD level. 854 happens at the PGD level. 917 855 918 config HAVE_MOVE_PMD 856 config HAVE_MOVE_PMD 919 bool 857 bool 920 help 858 help 921 Archs that select this are able to m 859 Archs that select this are able to move page tables at the PMD level. 922 860 923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 861 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 924 bool 862 bool 925 863 926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 864 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 927 bool 865 bool 928 866 929 config HAVE_ARCH_HUGE_VMAP 867 config HAVE_ARCH_HUGE_VMAP 930 bool 868 bool 931 869 932 # 870 # 933 # Archs that select this would be capable of 871 # Archs that select this would be capable of PMD-sized vmaps (i.e., 934 # arch_vmap_pmd_supported() returns true). Th 872 # arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag 935 # must be used to enable allocations to use h 873 # must be used to enable allocations to use hugepages. 936 # 874 # 937 config HAVE_ARCH_HUGE_VMALLOC 875 config HAVE_ARCH_HUGE_VMALLOC 938 depends on HAVE_ARCH_HUGE_VMAP 876 depends on HAVE_ARCH_HUGE_VMAP 939 bool 877 bool 940 878 941 config ARCH_WANT_HUGE_PMD_SHARE 879 config ARCH_WANT_HUGE_PMD_SHARE 942 bool 880 bool 943 881 944 # 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 882 config HAVE_ARCH_SOFT_DIRTY 953 bool 883 bool 954 884 955 config HAVE_MOD_ARCH_SPECIFIC 885 config HAVE_MOD_ARCH_SPECIFIC 956 bool 886 bool 957 help 887 help 958 The arch uses struct mod_arch_specif 888 The arch uses struct mod_arch_specific to store data. Many arches 959 just need a simple module loader wit 889 just need a simple module loader without arch specific data - those 960 should not enable this. 890 should not enable this. 961 891 962 config MODULES_USE_ELF_RELA 892 config MODULES_USE_ELF_RELA 963 bool 893 bool 964 help 894 help 965 Modules only use ELF RELA relocation 895 Modules only use ELF RELA relocations. Modules with ELF REL 966 relocations will give an error. 896 relocations will give an error. 967 897 968 config MODULES_USE_ELF_REL 898 config MODULES_USE_ELF_REL 969 bool 899 bool 970 help 900 help 971 Modules only use ELF REL relocations 901 Modules only use ELF REL relocations. Modules with ELF RELA 972 relocations will give an error. 902 relocations will give an error. 973 903 974 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC 904 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC 975 bool 905 bool 976 help 906 help 977 For architectures like powerpc/32 wh 907 For architectures like powerpc/32 which have constraints on module 978 allocation and need to allocate modu 908 allocation and need to allocate module data outside of module area. 979 909 980 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 << 988 config HAVE_IRQ_EXIT_ON_IRQ_STACK 910 config HAVE_IRQ_EXIT_ON_IRQ_STACK 989 bool 911 bool 990 help 912 help 991 Architecture doesn't only execute th 913 Architecture doesn't only execute the irq handler on the irq stack 992 but also irq_exit(). This way we can 914 but also irq_exit(). This way we can process softirqs on this irq 993 stack instead of switching to a new 915 stack instead of switching to a new one when we call __do_softirq() 994 in the end of an hardirq. 916 in the end of an hardirq. 995 This spares a stack switch and impro 917 This spares a stack switch and improves cache usage on softirq 996 processing. 918 processing. 997 919 998 config HAVE_SOFTIRQ_ON_OWN_STACK 920 config HAVE_SOFTIRQ_ON_OWN_STACK 999 bool 921 bool 1000 help 922 help 1001 Architecture provides a function to 923 Architecture provides a function to run __do_softirq() on a 1002 separate stack. 924 separate stack. 1003 925 1004 config SOFTIRQ_ON_OWN_STACK 926 config SOFTIRQ_ON_OWN_STACK 1005 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && 927 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT 1006 928 1007 config ALTERNATE_USER_ADDRESS_SPACE 929 config ALTERNATE_USER_ADDRESS_SPACE 1008 bool 930 bool 1009 help 931 help 1010 Architectures set this when the CPU 932 Architectures set this when the CPU uses separate address 1011 spaces for kernel and user space po 933 spaces for kernel and user space pointers. In this case, the 1012 access_ok() check on a __user point 934 access_ok() check on a __user pointer is skipped. 1013 935 1014 config PGTABLE_LEVELS 936 config PGTABLE_LEVELS 1015 int 937 int 1016 default 2 938 default 2 1017 939 1018 config ARCH_HAS_ELF_RANDOMIZE 940 config ARCH_HAS_ELF_RANDOMIZE 1019 bool 941 bool 1020 help 942 help 1021 An architecture supports choosing r 943 An architecture supports choosing randomized locations for 1022 stack, mmap, brk, and ET_DYN. Defin 944 stack, mmap, brk, and ET_DYN. Defined functions: 1023 - arch_mmap_rnd() 945 - arch_mmap_rnd() 1024 - arch_randomize_brk() 946 - arch_randomize_brk() 1025 947 1026 config HAVE_ARCH_MMAP_RND_BITS 948 config HAVE_ARCH_MMAP_RND_BITS 1027 bool 949 bool 1028 help 950 help 1029 An arch should select this symbol i 951 An arch should select this symbol if it supports setting a variable 1030 number of bits for use in establish 952 number of bits for use in establishing the base address for mmap 1031 allocations, has MMU enabled and pr 953 allocations, has MMU enabled and provides values for both: 1032 - ARCH_MMAP_RND_BITS_MIN 954 - ARCH_MMAP_RND_BITS_MIN 1033 - ARCH_MMAP_RND_BITS_MAX 955 - ARCH_MMAP_RND_BITS_MAX 1034 956 1035 config HAVE_EXIT_THREAD 957 config HAVE_EXIT_THREAD 1036 bool 958 bool 1037 help 959 help 1038 An architecture implements exit_thr 960 An architecture implements exit_thread. 1039 961 1040 config ARCH_MMAP_RND_BITS_MIN 962 config ARCH_MMAP_RND_BITS_MIN 1041 int 963 int 1042 964 1043 config ARCH_MMAP_RND_BITS_MAX 965 config ARCH_MMAP_RND_BITS_MAX 1044 int 966 int 1045 967 1046 config ARCH_MMAP_RND_BITS_DEFAULT 968 config ARCH_MMAP_RND_BITS_DEFAULT 1047 int 969 int 1048 970 1049 config ARCH_MMAP_RND_BITS 971 config ARCH_MMAP_RND_BITS 1050 int "Number of bits to use for ASLR o 972 int "Number of bits to use for ASLR of mmap base address" if EXPERT 1051 range ARCH_MMAP_RND_BITS_MIN ARCH_MMA 973 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 1052 default ARCH_MMAP_RND_BITS_DEFAULT if 974 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 1053 default ARCH_MMAP_RND_BITS_MIN 975 default ARCH_MMAP_RND_BITS_MIN 1054 depends on HAVE_ARCH_MMAP_RND_BITS 976 depends on HAVE_ARCH_MMAP_RND_BITS 1055 help 977 help 1056 This value can be used to select th 978 This value can be used to select the number of bits to use to 1057 determine the random offset to the 979 determine the random offset to the base address of vma regions 1058 resulting from mmap allocations. Th 980 resulting from mmap allocations. This value will be bounded 1059 by the architecture's minimum and m 981 by the architecture's minimum and maximum supported values. 1060 982 1061 This value can be changed after boo 983 This value can be changed after boot using the 1062 /proc/sys/vm/mmap_rnd_bits tunable 984 /proc/sys/vm/mmap_rnd_bits tunable 1063 985 1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 986 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 1065 bool 987 bool 1066 help 988 help 1067 An arch should select this symbol i 989 An arch should select this symbol if it supports running applications 1068 in compatibility mode, supports set 990 in compatibility mode, supports setting a variable number of bits for 1069 use in establishing the base addres 991 use in establishing the base address for mmap allocations, has MMU 1070 enabled and provides values for bot 992 enabled and provides values for both: 1071 - ARCH_MMAP_RND_COMPAT_BITS_MIN 993 - ARCH_MMAP_RND_COMPAT_BITS_MIN 1072 - ARCH_MMAP_RND_COMPAT_BITS_MAX 994 - ARCH_MMAP_RND_COMPAT_BITS_MAX 1073 995 1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN 996 config ARCH_MMAP_RND_COMPAT_BITS_MIN 1075 int 997 int 1076 998 1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX 999 config ARCH_MMAP_RND_COMPAT_BITS_MAX 1078 int 1000 int 1079 1001 1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1002 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1081 int 1003 int 1082 1004 1083 config ARCH_MMAP_RND_COMPAT_BITS 1005 config ARCH_MMAP_RND_COMPAT_BITS 1084 int "Number of bits to use for ASLR o 1006 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 1007 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 1086 default ARCH_MMAP_RND_COMPAT_BITS_DEF 1008 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1087 default ARCH_MMAP_RND_COMPAT_BITS_MIN 1009 default ARCH_MMAP_RND_COMPAT_BITS_MIN 1088 depends on HAVE_ARCH_MMAP_RND_COMPAT_ 1010 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 1089 help 1011 help 1090 This value can be used to select th 1012 This value can be used to select the number of bits to use to 1091 determine the random offset to the 1013 determine the random offset to the base address of vma regions 1092 resulting from mmap allocations for 1014 resulting from mmap allocations for compatible applications This 1093 value will be bounded by the archit 1015 value will be bounded by the architecture's minimum and maximum 1094 supported values. 1016 supported values. 1095 1017 1096 This value can be changed after boo 1018 This value can be changed after boot using the 1097 /proc/sys/vm/mmap_rnd_compat_bits t 1019 /proc/sys/vm/mmap_rnd_compat_bits tunable 1098 1020 1099 config HAVE_ARCH_COMPAT_MMAP_BASES 1021 config HAVE_ARCH_COMPAT_MMAP_BASES 1100 bool 1022 bool 1101 help 1023 help 1102 This allows 64bit applications to i 1024 This allows 64bit applications to invoke 32-bit mmap() syscall 1103 and vice-versa 32-bit applications 1025 and vice-versa 32-bit applications to call 64-bit mmap(). 1104 Required for applications doing dif 1026 Required for applications doing different bitness syscalls. 1105 1027 1106 config HAVE_PAGE_SIZE_4KB << 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 << 1117 << 1118 config HAVE_PAGE_SIZE_64KB << 1119 bool << 1120 << 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 1028 config PAGE_SIZE_LESS_THAN_64KB 1190 def_bool y 1029 def_bool y >> 1030 depends on !ARM64_64K_PAGES >> 1031 depends on !IA64_PAGE_SIZE_64KB 1191 depends on !PAGE_SIZE_64KB 1032 depends on !PAGE_SIZE_64KB >> 1033 depends on !PARISC_PAGE_SIZE_64KB 1192 depends on PAGE_SIZE_LESS_THAN_256KB 1034 depends on PAGE_SIZE_LESS_THAN_256KB 1193 1035 1194 config PAGE_SIZE_LESS_THAN_256KB 1036 config PAGE_SIZE_LESS_THAN_256KB 1195 def_bool y 1037 def_bool y 1196 depends on !PAGE_SIZE_256KB 1038 depends on !PAGE_SIZE_256KB 1197 1039 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 1040 # This allows to use a set of generic functions to determine mmap base 1208 # address by giving priority to top-down sche 1041 # address by giving priority to top-down scheme only if the process 1209 # is not in legacy mode (compat task, unlimit 1042 # is not in legacy mode (compat task, unlimited stack size or 1210 # sysctl_legacy_va_layout). 1043 # sysctl_legacy_va_layout). 1211 # Architecture that selects this option can p 1044 # Architecture that selects this option can provide its own version of: 1212 # - STACK_RND_MASK 1045 # - STACK_RND_MASK 1213 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 1046 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 1214 bool 1047 bool 1215 depends on MMU 1048 depends on MMU 1216 select ARCH_HAS_ELF_RANDOMIZE 1049 select ARCH_HAS_ELF_RANDOMIZE 1217 1050 1218 config HAVE_OBJTOOL 1051 config HAVE_OBJTOOL 1219 bool 1052 bool 1220 1053 1221 config HAVE_JUMP_LABEL_HACK 1054 config HAVE_JUMP_LABEL_HACK 1222 bool 1055 bool 1223 1056 1224 config HAVE_NOINSTR_HACK 1057 config HAVE_NOINSTR_HACK 1225 bool 1058 bool 1226 1059 1227 config HAVE_NOINSTR_VALIDATION 1060 config HAVE_NOINSTR_VALIDATION 1228 bool 1061 bool 1229 1062 1230 config HAVE_UACCESS_VALIDATION 1063 config HAVE_UACCESS_VALIDATION 1231 bool 1064 bool 1232 select OBJTOOL 1065 select OBJTOOL 1233 1066 1234 config HAVE_STACK_VALIDATION 1067 config HAVE_STACK_VALIDATION 1235 bool 1068 bool 1236 help 1069 help 1237 Architecture supports objtool compi 1070 Architecture supports objtool compile-time frame pointer rule 1238 validation. 1071 validation. 1239 1072 1240 config HAVE_RELIABLE_STACKTRACE 1073 config HAVE_RELIABLE_STACKTRACE 1241 bool 1074 bool 1242 help 1075 help 1243 Architecture has either save_stack_ 1076 Architecture has either save_stack_trace_tsk_reliable() or 1244 arch_stack_walk_reliable() function 1077 arch_stack_walk_reliable() function which only returns a stack trace 1245 if it can guarantee the trace is re 1078 if it can guarantee the trace is reliable. 1246 1079 1247 config HAVE_ARCH_HASH 1080 config HAVE_ARCH_HASH 1248 bool 1081 bool 1249 default n 1082 default n 1250 help 1083 help 1251 If this is set, the architecture pr 1084 If this is set, the architecture provides an <asm/hash.h> 1252 file which provides platform-specif 1085 file which provides platform-specific implementations of some 1253 functions in <linux/hash.h> or fs/n 1086 functions in <linux/hash.h> or fs/namei.c. 1254 1087 1255 config HAVE_ARCH_NVRAM_OPS 1088 config HAVE_ARCH_NVRAM_OPS 1256 bool 1089 bool 1257 1090 1258 config ISA_BUS_API 1091 config ISA_BUS_API 1259 def_bool ISA 1092 def_bool ISA 1260 1093 1261 # 1094 # 1262 # ABI hall of shame 1095 # ABI hall of shame 1263 # 1096 # 1264 config CLONE_BACKWARDS 1097 config CLONE_BACKWARDS 1265 bool 1098 bool 1266 help 1099 help 1267 Architecture has tls passed as the 1100 Architecture has tls passed as the 4th argument of clone(2), 1268 not the 5th one. 1101 not the 5th one. 1269 1102 1270 config CLONE_BACKWARDS2 1103 config CLONE_BACKWARDS2 1271 bool 1104 bool 1272 help 1105 help 1273 Architecture has the first two argu 1106 Architecture has the first two arguments of clone(2) swapped. 1274 1107 1275 config CLONE_BACKWARDS3 1108 config CLONE_BACKWARDS3 1276 bool 1109 bool 1277 help 1110 help 1278 Architecture has tls passed as the 1111 Architecture has tls passed as the 3rd argument of clone(2), 1279 not the 5th one. 1112 not the 5th one. 1280 1113 1281 config ODD_RT_SIGACTION 1114 config ODD_RT_SIGACTION 1282 bool 1115 bool 1283 help 1116 help 1284 Architecture has unusual rt_sigacti 1117 Architecture has unusual rt_sigaction(2) arguments 1285 1118 1286 config OLD_SIGSUSPEND 1119 config OLD_SIGSUSPEND 1287 bool 1120 bool 1288 help 1121 help 1289 Architecture has old sigsuspend(2) 1122 Architecture has old sigsuspend(2) syscall, of one-argument variety 1290 1123 1291 config OLD_SIGSUSPEND3 1124 config OLD_SIGSUSPEND3 1292 bool 1125 bool 1293 help 1126 help 1294 Even weirder antique ABI - three-ar 1127 Even weirder antique ABI - three-argument sigsuspend(2) 1295 1128 1296 config OLD_SIGACTION 1129 config OLD_SIGACTION 1297 bool 1130 bool 1298 help 1131 help 1299 Architecture has old sigaction(2) s 1132 Architecture has old sigaction(2) syscall. Nope, not the same 1300 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 1133 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 1301 but fairly different variant of sig 1134 but fairly different variant of sigaction(2), thanks to OSF/1 1302 compatibility... 1135 compatibility... 1303 1136 1304 config COMPAT_OLD_SIGACTION 1137 config COMPAT_OLD_SIGACTION 1305 bool 1138 bool 1306 1139 1307 config COMPAT_32BIT_TIME 1140 config COMPAT_32BIT_TIME 1308 bool "Provide system calls for 32-bit 1141 bool "Provide system calls for 32-bit time_t" 1309 default !64BIT || COMPAT 1142 default !64BIT || COMPAT 1310 help 1143 help 1311 This enables 32 bit time_t support 1144 This enables 32 bit time_t support in addition to 64 bit time_t support. 1312 This is relevant on all 32-bit arch 1145 This is relevant on all 32-bit architectures, and 64-bit architectures 1313 as part of compat syscall handling. 1146 as part of compat syscall handling. 1314 1147 1315 config ARCH_NO_PREEMPT 1148 config ARCH_NO_PREEMPT 1316 bool 1149 bool 1317 1150 >> 1151 config ARCH_EPHEMERAL_INODES >> 1152 def_bool n >> 1153 help >> 1154 An arch should select this symbol if it doesn't keep track of inode >> 1155 instances on its own, but instead relies on something else (e.g. the >> 1156 host kernel for an UML kernel). >> 1157 1318 config ARCH_SUPPORTS_RT 1158 config ARCH_SUPPORTS_RT 1319 bool 1159 bool 1320 1160 1321 config CPU_NO_EFFICIENT_FFS 1161 config CPU_NO_EFFICIENT_FFS 1322 def_bool n 1162 def_bool n 1323 1163 1324 config HAVE_ARCH_VMAP_STACK 1164 config HAVE_ARCH_VMAP_STACK 1325 def_bool n 1165 def_bool n 1326 help 1166 help 1327 An arch should select this symbol i 1167 An arch should select this symbol if it can support kernel stacks 1328 in vmalloc space. This means: 1168 in vmalloc space. This means: 1329 1169 1330 - vmalloc space must be large enoug 1170 - vmalloc space must be large enough to hold many kernel stacks. 1331 This may rule out many 32-bit arc 1171 This may rule out many 32-bit architectures. 1332 1172 1333 - Stacks in vmalloc space need to w 1173 - Stacks in vmalloc space need to work reliably. For example, if 1334 vmap page tables are created on d 1174 vmap page tables are created on demand, either this mechanism 1335 needs to work while the stack poi 1175 needs to work while the stack points to a virtual address with 1336 unpopulated page tables or arch c 1176 unpopulated page tables or arch code (switch_to() and switch_mm(), 1337 most likely) needs to ensure that 1177 most likely) needs to ensure that the stack's page table entries 1338 are populated before running on a 1178 are populated before running on a possibly unpopulated stack. 1339 1179 1340 - If the stack overflows into a gua 1180 - If the stack overflows into a guard page, something reasonable 1341 should happen. The definition of 1181 should happen. The definition of "reasonable" is flexible, but 1342 instantly rebooting without loggi 1182 instantly rebooting without logging anything would be unfriendly. 1343 1183 1344 config VMAP_STACK 1184 config VMAP_STACK 1345 default y 1185 default y 1346 bool "Use a virtually-mapped stack" 1186 bool "Use a virtually-mapped stack" 1347 depends on HAVE_ARCH_VMAP_STACK 1187 depends on HAVE_ARCH_VMAP_STACK 1348 depends on !KASAN || KASAN_HW_TAGS || 1188 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC 1349 help 1189 help 1350 Enable this if you want the use vir 1190 Enable this if you want the use virtually-mapped kernel stacks 1351 with guard pages. This causes kern 1191 with guard pages. This causes kernel stack overflows to be 1352 caught immediately rather than caus 1192 caught immediately rather than causing difficult-to-diagnose 1353 corruption. 1193 corruption. 1354 1194 1355 To use this with software KASAN mod 1195 To use this with software KASAN modes, the architecture must support 1356 backing virtual mappings with real 1196 backing virtual mappings with real shadow memory, and KASAN_VMALLOC 1357 must be enabled. 1197 must be enabled. 1358 1198 1359 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1199 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1360 def_bool n 1200 def_bool n 1361 help 1201 help 1362 An arch should select this symbol i 1202 An arch should select this symbol if it can support kernel stack 1363 offset randomization with calls to 1203 offset randomization with calls to add_random_kstack_offset() 1364 during syscall entry and choose_ran 1204 during syscall entry and choose_random_kstack_offset() during 1365 syscall exit. Careful removal of -f 1205 syscall exit. Careful removal of -fstack-protector-strong and 1366 -fstack-protector should also be ap 1206 -fstack-protector should also be applied to the entry code and 1367 closely examined, as the artificial 1207 closely examined, as the artificial stack bump looks like an array 1368 to the compiler, so it will attempt 1208 to the compiler, so it will attempt to add canary checks regardless 1369 of the static branch state. 1209 of the static branch state. 1370 1210 1371 config RANDOMIZE_KSTACK_OFFSET 1211 config RANDOMIZE_KSTACK_OFFSET 1372 bool "Support for randomizing kernel 1212 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT 1373 default y 1213 default y 1374 depends on HAVE_ARCH_RANDOMIZE_KSTACK 1214 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1375 depends on INIT_STACK_NONE || !CC_IS_ 1215 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000 1376 help 1216 help 1377 The kernel stack offset can be rand 1217 The kernel stack offset can be randomized (after pt_regs) by 1378 roughly 5 bits of entropy, frustrat 1218 roughly 5 bits of entropy, frustrating memory corruption 1379 attacks that depend on stack addres 1219 attacks that depend on stack address determinism or 1380 cross-syscall address exposures. 1220 cross-syscall address exposures. 1381 1221 1382 The feature is controlled via the " 1222 The feature is controlled via the "randomize_kstack_offset=on/off" 1383 kernel boot param, and if turned of 1223 kernel boot param, and if turned off has zero overhead due to its use 1384 of static branches (see JUMP_LABEL) 1224 of static branches (see JUMP_LABEL). 1385 1225 1386 If unsure, say Y. 1226 If unsure, say Y. 1387 1227 1388 config RANDOMIZE_KSTACK_OFFSET_DEFAULT 1228 config RANDOMIZE_KSTACK_OFFSET_DEFAULT 1389 bool "Default state of kernel stack o 1229 bool "Default state of kernel stack offset randomization" 1390 depends on RANDOMIZE_KSTACK_OFFSET 1230 depends on RANDOMIZE_KSTACK_OFFSET 1391 help 1231 help 1392 Kernel stack offset randomization i 1232 Kernel stack offset randomization is controlled by kernel boot param 1393 "randomize_kstack_offset=on/off", a 1233 "randomize_kstack_offset=on/off", and this config chooses the default 1394 boot state. 1234 boot state. 1395 1235 1396 config ARCH_OPTIONAL_KERNEL_RWX 1236 config ARCH_OPTIONAL_KERNEL_RWX 1397 def_bool n 1237 def_bool n 1398 1238 1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1239 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1400 def_bool n 1240 def_bool n 1401 1241 1402 config ARCH_HAS_STRICT_KERNEL_RWX 1242 config ARCH_HAS_STRICT_KERNEL_RWX 1403 def_bool n 1243 def_bool n 1404 1244 1405 config STRICT_KERNEL_RWX 1245 config STRICT_KERNEL_RWX 1406 bool "Make kernel text and rodata rea 1246 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 1407 depends on ARCH_HAS_STRICT_KERNEL_RWX 1247 depends on ARCH_HAS_STRICT_KERNEL_RWX 1408 default !ARCH_OPTIONAL_KERNEL_RWX || 1248 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1409 help 1249 help 1410 If this is set, kernel text and rod 1250 If this is set, kernel text and rodata memory will be made read-only, 1411 and non-text memory will be made no 1251 and non-text memory will be made non-executable. This provides 1412 protection against certain security 1252 protection against certain security exploits (e.g. executing the heap 1413 or modifying text) 1253 or modifying text) 1414 1254 1415 These features are considered stand 1255 These features are considered standard security practice these days. 1416 You should say Y here in almost all 1256 You should say Y here in almost all cases. 1417 1257 1418 config ARCH_HAS_STRICT_MODULE_RWX 1258 config ARCH_HAS_STRICT_MODULE_RWX 1419 def_bool n 1259 def_bool n 1420 1260 1421 config STRICT_MODULE_RWX 1261 config STRICT_MODULE_RWX 1422 bool "Set loadable kernel module data 1262 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 1263 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 1424 default !ARCH_OPTIONAL_KERNEL_RWX || 1264 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1425 help 1265 help 1426 If this is set, module text and rod 1266 If this is set, module text and rodata memory will be made read-only, 1427 and non-text memory will be made no 1267 and non-text memory will be made non-executable. This provides 1428 protection against certain security 1268 protection against certain security exploits (e.g. writing to text) 1429 1269 1430 # select if the architecture provides an asm/ 1270 # select if the architecture provides an asm/dma-direct.h header 1431 config ARCH_HAS_PHYS_TO_DMA 1271 config ARCH_HAS_PHYS_TO_DMA 1432 bool 1272 bool 1433 1273 1434 config HAVE_ARCH_COMPILER_H 1274 config HAVE_ARCH_COMPILER_H 1435 bool 1275 bool 1436 help 1276 help 1437 An architecture can select this if 1277 An architecture can select this if it provides an 1438 asm/compiler.h header that should b 1278 asm/compiler.h header that should be included after 1439 linux/compiler-*.h in order to over 1279 linux/compiler-*.h in order to override macro definitions that those 1440 headers generally provide. 1280 headers generally provide. 1441 1281 1442 config HAVE_ARCH_PREL32_RELOCATIONS 1282 config HAVE_ARCH_PREL32_RELOCATIONS 1443 bool 1283 bool 1444 help 1284 help 1445 May be selected by an architecture 1285 May be selected by an architecture if it supports place-relative 1446 32-bit relocations, both in the too 1286 32-bit relocations, both in the toolchain and in the module loader, 1447 in which case relative references c 1287 in which case relative references can be used in special sections 1448 for PCI fixup, initcalls etc which 1288 for PCI fixup, initcalls etc which are only half the size on 64 bit 1449 architectures, and don't require ru 1289 architectures, and don't require runtime relocation on relocatable 1450 kernels. 1290 kernels. 1451 1291 1452 config ARCH_USE_MEMREMAP_PROT 1292 config ARCH_USE_MEMREMAP_PROT 1453 bool 1293 bool 1454 1294 1455 config LOCK_EVENT_COUNTS 1295 config LOCK_EVENT_COUNTS 1456 bool "Locking event counts collection 1296 bool "Locking event counts collection" 1457 depends on DEBUG_FS 1297 depends on DEBUG_FS 1458 help 1298 help 1459 Enable light-weight counting of var 1299 Enable light-weight counting of various locking related events 1460 in the system with minimal performa 1300 in the system with minimal performance impact. This reduces 1461 the chance of application behavior 1301 the chance of application behavior change because of timing 1462 differences. The counts are reporte 1302 differences. The counts are reported via debugfs. 1463 1303 1464 # Select if the architecture has support for 1304 # Select if the architecture has support for applying RELR relocations. 1465 config ARCH_HAS_RELR 1305 config ARCH_HAS_RELR 1466 bool 1306 bool 1467 1307 1468 config RELR 1308 config RELR 1469 bool "Use RELR relocation packing" 1309 bool "Use RELR relocation packing" 1470 depends on ARCH_HAS_RELR && TOOLS_SUP 1310 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR 1471 default y 1311 default y 1472 help 1312 help 1473 Store the kernel's dynamic relocati 1313 Store the kernel's dynamic relocations in the RELR relocation packing 1474 format. Requires a compatible linke 1314 format. Requires a compatible linker (LLD supports this feature), as 1475 well as compatible NM and OBJCOPY u 1315 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy 1476 are compatible). 1316 are compatible). 1477 1317 1478 config ARCH_HAS_MEM_ENCRYPT 1318 config ARCH_HAS_MEM_ENCRYPT 1479 bool 1319 bool 1480 1320 1481 config ARCH_HAS_CC_PLATFORM 1321 config ARCH_HAS_CC_PLATFORM 1482 bool 1322 bool 1483 1323 1484 config HAVE_SPARSE_SYSCALL_NR 1324 config HAVE_SPARSE_SYSCALL_NR 1485 bool !! 1325 bool 1486 help !! 1326 help 1487 An architecture should select this !! 1327 An architecture should select this if its syscall numbering is sparse 1488 to save space. For example, MIPS ar 1328 to save space. For example, MIPS architecture has a syscall array with 1489 entries at 4000, 5000 and 6000 loca 1329 entries at 4000, 5000 and 6000 locations. This option turns on syscall 1490 related optimizations for a given a 1330 related optimizations for a given architecture. 1491 1331 1492 config ARCH_HAS_VDSO_DATA 1332 config ARCH_HAS_VDSO_DATA 1493 bool 1333 bool 1494 1334 1495 config HAVE_STATIC_CALL 1335 config HAVE_STATIC_CALL 1496 bool 1336 bool 1497 1337 1498 config HAVE_STATIC_CALL_INLINE 1338 config HAVE_STATIC_CALL_INLINE 1499 bool 1339 bool 1500 depends on HAVE_STATIC_CALL 1340 depends on HAVE_STATIC_CALL 1501 select OBJTOOL 1341 select OBJTOOL 1502 1342 1503 config HAVE_PREEMPT_DYNAMIC 1343 config HAVE_PREEMPT_DYNAMIC 1504 bool 1344 bool 1505 1345 1506 config HAVE_PREEMPT_DYNAMIC_CALL 1346 config HAVE_PREEMPT_DYNAMIC_CALL 1507 bool 1347 bool 1508 depends on HAVE_STATIC_CALL 1348 depends on HAVE_STATIC_CALL 1509 select HAVE_PREEMPT_DYNAMIC 1349 select HAVE_PREEMPT_DYNAMIC 1510 help 1350 help 1511 An architecture should select this !! 1351 An architecture should select this if it can handle the preemption 1512 model being selected at boot time u !! 1352 model being selected at boot time using static calls. 1513 1353 1514 Where an architecture selects HAVE_ !! 1354 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a 1515 preemption function will be patched !! 1355 preemption function will be patched directly. 1516 1356 1517 Where an architecture does not sele !! 1357 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any 1518 call to a preemption function will !! 1358 call to a preemption function will go through a trampoline, and the 1519 trampoline will be patched. !! 1359 trampoline will be patched. 1520 1360 1521 It is strongly advised to support i !! 1361 It is strongly advised to support inline static call to avoid any 1522 overhead. !! 1362 overhead. 1523 1363 1524 config HAVE_PREEMPT_DYNAMIC_KEY 1364 config HAVE_PREEMPT_DYNAMIC_KEY 1525 bool 1365 bool 1526 depends on HAVE_ARCH_JUMP_LABEL 1366 depends on HAVE_ARCH_JUMP_LABEL 1527 select HAVE_PREEMPT_DYNAMIC 1367 select HAVE_PREEMPT_DYNAMIC 1528 help 1368 help 1529 An architecture should select this !! 1369 An architecture should select this if it can handle the preemption 1530 model being selected at boot time u !! 1370 model being selected at boot time using static keys. 1531 1371 1532 Each preemption function will be gi !! 1372 Each preemption function will be given an early return based on a 1533 static key. This should have slight !! 1373 static key. This should have slightly lower overhead than non-inline 1534 static calls, as this effectively i !! 1374 static calls, as this effectively inlines each trampoline into the 1535 start of its callee. This may avoid !! 1375 start of its callee. This may avoid redundant work, and may 1536 integrate better with CFI schemes. !! 1376 integrate better with CFI schemes. 1537 1377 1538 This will have greater overhead tha !! 1378 This will have greater overhead than using inline static calls as 1539 the call to the preemption function !! 1379 the call to the preemption function cannot be entirely elided. 1540 1380 1541 config ARCH_WANT_LD_ORPHAN_WARN 1381 config ARCH_WANT_LD_ORPHAN_WARN 1542 bool 1382 bool 1543 help 1383 help 1544 An arch should select this symbol o 1384 An arch should select this symbol once all linker sections are explicitly 1545 included, size-asserted, or discard 1385 included, size-asserted, or discarded in the linker scripts. This is 1546 important because we never want exp 1386 important because we never want expected sections to be placed heuristically 1547 by the linker, since the locations 1387 by the linker, since the locations of such sections can change between linker 1548 versions. 1388 versions. 1549 1389 1550 config HAVE_ARCH_PFN_VALID 1390 config HAVE_ARCH_PFN_VALID 1551 bool 1391 bool 1552 1392 1553 config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1393 config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1554 bool 1394 bool 1555 1395 1556 config ARCH_SUPPORTS_PAGE_TABLE_CHECK 1396 config ARCH_SUPPORTS_PAGE_TABLE_CHECK 1557 bool 1397 bool 1558 1398 1559 config ARCH_SPLIT_ARG64 1399 config ARCH_SPLIT_ARG64 1560 bool 1400 bool 1561 help 1401 help 1562 If a 32-bit architecture requires 6 !! 1402 If a 32-bit architecture requires 64-bit arguments to be split into 1563 pairs of 32-bit arguments, select t !! 1403 pairs of 32-bit arguments, select this option. 1564 1404 1565 config ARCH_HAS_ELFCORE_COMPAT 1405 config ARCH_HAS_ELFCORE_COMPAT 1566 bool 1406 bool 1567 1407 1568 config ARCH_HAS_PARANOID_L1D_FLUSH 1408 config ARCH_HAS_PARANOID_L1D_FLUSH 1569 bool 1409 bool 1570 1410 1571 config ARCH_HAVE_TRACE_MMIO_ACCESS 1411 config ARCH_HAVE_TRACE_MMIO_ACCESS 1572 bool 1412 bool 1573 1413 1574 config DYNAMIC_SIGFRAME 1414 config DYNAMIC_SIGFRAME 1575 bool 1415 bool 1576 1416 1577 # Select, if arch has a named attribute group 1417 # Select, if arch has a named attribute group bound to NUMA device nodes. 1578 config HAVE_ARCH_NODE_DEV_GROUP 1418 config HAVE_ARCH_NODE_DEV_GROUP 1579 bool 1419 bool 1580 1420 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 << 1603 source "kernel/gcov/Kconfig" 1421 source "kernel/gcov/Kconfig" 1604 1422 1605 source "scripts/gcc-plugins/Kconfig" 1423 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 1424 1646 endmenu 1425 endmenu
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