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 15 bool 24 help << 25 Select if the architecture can check << 26 granularity (e.g. arm64 MTE). The pr << 27 must be implemented. << 28 16 29 config HOTPLUG_SMT !! 17 config KEXEC_CORE >> 18 select CRASH_CORE 30 bool 19 bool 31 20 32 config SMT_NUM_THREADS_DYNAMIC !! 21 config KEXEC_ELF 33 bool 22 bool 34 23 35 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU !! 24 config HAVE_IMA_KEXEC 36 config HOTPLUG_CORE_SYNC << 37 bool 25 bool 38 26 39 # Basic CPU dead synchronization selected by a !! 27 config HOTPLUG_SMT 40 config HOTPLUG_CORE_SYNC_DEAD << 41 bool 28 bool 42 select HOTPLUG_CORE_SYNC << 43 29 44 # Full CPU synchronization with alive state se !! 30 config OPROFILE 45 config HOTPLUG_CORE_SYNC_FULL !! 31 tristate "OProfile system profiling" 46 bool !! 32 depends on PROFILING 47 select HOTPLUG_CORE_SYNC_DEAD if HOTPL !! 33 depends on HAVE_OPROFILE 48 select HOTPLUG_CORE_SYNC !! 34 select RING_BUFFER >> 35 select RING_BUFFER_ALLOW_SWAP >> 36 help >> 37 OProfile is a profiling system capable of profiling the >> 38 whole system, include the kernel, kernel modules, libraries, >> 39 and applications. 49 40 50 config HOTPLUG_SPLIT_STARTUP !! 41 If unsure, say N. 51 bool << 52 select HOTPLUG_CORE_SYNC_FULL << 53 42 54 config HOTPLUG_PARALLEL !! 43 config OPROFILE_EVENT_MULTIPLEX 55 bool !! 44 bool "OProfile multiplexing support (EXPERIMENTAL)" 56 select HOTPLUG_SPLIT_STARTUP !! 45 default n >> 46 depends on OPROFILE && X86 >> 47 help >> 48 The number of hardware counters is limited. The multiplexing >> 49 feature enables OProfile to gather more events than counters >> 50 are provided by the hardware. This is realized by switching >> 51 between events at a user specified time interval. 57 52 58 config GENERIC_ENTRY !! 53 If unsure, say N. >> 54 >> 55 config HAVE_OPROFILE 59 bool 56 bool 60 57 >> 58 config OPROFILE_NMI_TIMER >> 59 def_bool y >> 60 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 >> 61 61 config KPROBES 62 config KPROBES 62 bool "Kprobes" 63 bool "Kprobes" >> 64 depends on MODULES 63 depends on HAVE_KPROBES 65 depends on HAVE_KPROBES 64 select KALLSYMS 66 select KALLSYMS 65 select EXECMEM << 66 select NEED_TASKS_RCU << 67 help 67 help 68 Kprobes allows you to trap at almost 68 Kprobes allows you to trap at almost any kernel address and 69 execute a callback function. regist 69 execute a callback function. register_kprobe() establishes 70 a probepoint and specifies the callb 70 a probepoint and specifies the callback. Kprobes is useful 71 for kernel debugging, non-intrusive 71 for kernel debugging, non-intrusive instrumentation and testing. 72 If in doubt, say "N". 72 If in doubt, say "N". 73 73 74 config JUMP_LABEL 74 config JUMP_LABEL 75 bool "Optimize very unlikely/likely br 75 bool "Optimize very unlikely/likely branches" 76 depends on HAVE_ARCH_JUMP_LABEL 76 depends on HAVE_ARCH_JUMP_LABEL 77 select OBJTOOL if HAVE_JUMP_LABEL_HACK !! 77 depends on CC_HAS_ASM_GOTO 78 help 78 help 79 This option enables a transparent br !! 79 This option enables a transparent branch optimization that 80 makes certain almost-always-true or !! 80 makes certain almost-always-true or almost-always-false branch 81 conditions even cheaper to execute w !! 81 conditions even cheaper to execute within the kernel. 82 !! 82 83 Certain performance-sensitive kernel !! 83 Certain performance-sensitive kernel code, such as trace points, 84 scheduler functionality, networking !! 84 scheduler functionality, networking code and KVM have such 85 branches and include support for thi !! 85 branches and include support for this optimization technique. 86 !! 86 87 If it is detected that the compiler !! 87 If it is detected that the compiler has support for "asm goto", 88 the kernel will compile such branche !! 88 the kernel will compile such branches with just a nop 89 instruction. When the condition flag !! 89 instruction. When the condition flag is toggled to true, the 90 nop will be converted to a jump inst !! 90 nop will be converted to a jump instruction to execute the 91 conditional block of instructions. !! 91 conditional block of instructions. 92 !! 92 93 This technique lowers overhead and s !! 93 This technique lowers overhead and stress on the branch prediction 94 of the processor and generally makes !! 94 of the processor and generally makes the kernel faster. The update 95 of the condition is slower, but thos !! 95 of the condition is slower, but those are always very rare. 96 96 97 ( On 32-bit x86, the necessary optio !! 97 ( On 32-bit x86, the necessary options added to the compiler 98 flags may increase the size of the !! 98 flags may increase the size of the kernel slightly. ) 99 99 100 config STATIC_KEYS_SELFTEST 100 config STATIC_KEYS_SELFTEST 101 bool "Static key selftest" 101 bool "Static key selftest" 102 depends on JUMP_LABEL 102 depends on JUMP_LABEL 103 help 103 help 104 Boot time self-test of the branch pa 104 Boot time self-test of the branch patching code. 105 105 106 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 106 config OPTPROBES 113 def_bool y 107 def_bool y 114 depends on KPROBES && HAVE_OPTPROBES 108 depends on KPROBES && HAVE_OPTPROBES 115 select NEED_TASKS_RCU !! 109 select TASKS_RCU if PREEMPTION 116 110 117 config KPROBES_ON_FTRACE 111 config KPROBES_ON_FTRACE 118 def_bool y 112 def_bool y 119 depends on KPROBES && HAVE_KPROBES_ON_ 113 depends on KPROBES && HAVE_KPROBES_ON_FTRACE 120 depends on DYNAMIC_FTRACE_WITH_REGS 114 depends on DYNAMIC_FTRACE_WITH_REGS 121 help 115 help 122 If function tracer is enabled and th !! 116 If function tracer is enabled and the arch supports full 123 passing of pt_regs to function traci !! 117 passing of pt_regs to function tracing, then kprobes can 124 optimize on top of function tracing. !! 118 optimize on top of function tracing. 125 119 126 config UPROBES 120 config UPROBES 127 def_bool n 121 def_bool n 128 depends on ARCH_SUPPORTS_UPROBES 122 depends on ARCH_SUPPORTS_UPROBES 129 help 123 help 130 Uprobes is the user-space counterpar 124 Uprobes is the user-space counterpart to kprobes: they 131 enable instrumentation applications 125 enable instrumentation applications (such as 'perf probe') 132 to establish unintrusive probes in u 126 to establish unintrusive probes in user-space binaries and 133 libraries, by executing handler func 127 libraries, by executing handler functions when the probes 134 are hit by user-space applications. 128 are hit by user-space applications. 135 129 136 ( These probes come in the form of s 130 ( These probes come in the form of single-byte breakpoints, 137 managed by the kernel and kept tra 131 managed by the kernel and kept transparent to the probed 138 application. ) 132 application. ) 139 133 140 config HAVE_64BIT_ALIGNED_ACCESS << 141 def_bool 64BIT && !HAVE_EFFICIENT_UNAL << 142 help << 143 Some architectures require 64 bit ac << 144 aligned, which also requires structs << 145 to be 64 bit aligned too. This inclu << 146 architectures which can do 64 bit ac << 147 architectures without unaligned acce << 148 << 149 This symbol should be selected by an << 150 accesses are required to be 64 bit a << 151 though it is not a 64 bit architectu << 152 << 153 See Documentation/core-api/unaligned << 154 more information on the topic of una << 155 << 156 config HAVE_EFFICIENT_UNALIGNED_ACCESS 134 config HAVE_EFFICIENT_UNALIGNED_ACCESS 157 bool 135 bool 158 help 136 help 159 Some architectures are unable to per 137 Some architectures are unable to perform unaligned accesses 160 without the use of get_unaligned/put 138 without the use of get_unaligned/put_unaligned. Others are 161 unable to perform such accesses effi 139 unable to perform such accesses efficiently (e.g. trap on 162 unaligned access and require fixing 140 unaligned access and require fixing it up in the exception 163 handler.) 141 handler.) 164 142 165 This symbol should be selected by an 143 This symbol should be selected by an architecture if it can 166 perform unaligned accesses efficient 144 perform unaligned accesses efficiently to allow different 167 code paths to be selected for these 145 code paths to be selected for these cases. Some network 168 drivers, for example, could opt to n 146 drivers, for example, could opt to not fix up alignment 169 problems with received packets if do 147 problems with received packets if doing so would not help 170 much. 148 much. 171 149 172 See Documentation/core-api/unaligned !! 150 See Documentation/unaligned-memory-access.txt for more 173 information on the topic of unaligne 151 information on the topic of unaligned memory accesses. 174 152 175 config ARCH_USE_BUILTIN_BSWAP 153 config ARCH_USE_BUILTIN_BSWAP 176 bool 154 bool 177 help 155 help 178 Modern versions of GCC (since 4.4) h !! 156 Modern versions of GCC (since 4.4) have builtin functions 179 for handling byte-swapping. Using th !! 157 for handling byte-swapping. Using these, instead of the old 180 inline assembler that the architectu !! 158 inline assembler that the architecture code provides in the 181 __arch_bswapXX() macros, allows the !! 159 __arch_bswapXX() macros, allows the compiler to see what's 182 happening and offers more opportunit !! 160 happening and offers more opportunity for optimisation. In 183 particular, the compiler will be abl !! 161 particular, the compiler will be able to combine the byteswap 184 with a nearby load or store and use !! 162 with a nearby load or store and use load-and-swap or 185 store-and-swap instructions if the a !! 163 store-and-swap instructions if the architecture has them. It 186 should almost *never* result in code !! 164 should almost *never* result in code which is worse than the 187 hand-coded assembler in <asm/swab.h> !! 165 hand-coded assembler in <asm/swab.h>. But just in case it 188 does, the use of the builtins is opt !! 166 does, the use of the builtins is optional. 189 !! 167 190 Any architecture with load-and-swap !! 168 Any architecture with load-and-swap or store-and-swap 191 instructions should set this. And it !! 169 instructions should set this. And it shouldn't hurt to set it 192 on architectures that don't have suc !! 170 on architectures that don't have such instructions. 193 171 194 config KRETPROBES 172 config KRETPROBES 195 def_bool y 173 def_bool y 196 depends on KPROBES && (HAVE_KRETPROBES !! 174 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 << 203 175 204 config USER_RETURN_NOTIFIER 176 config USER_RETURN_NOTIFIER 205 bool 177 bool 206 depends on HAVE_USER_RETURN_NOTIFIER 178 depends on HAVE_USER_RETURN_NOTIFIER 207 help 179 help 208 Provide a kernel-internal notificati 180 Provide a kernel-internal notification when a cpu is about to 209 switch to user mode. 181 switch to user mode. 210 182 211 config HAVE_IOREMAP_PROT 183 config HAVE_IOREMAP_PROT 212 bool 184 bool 213 185 214 config HAVE_KPROBES 186 config HAVE_KPROBES 215 bool 187 bool 216 188 217 config HAVE_KRETPROBES 189 config HAVE_KRETPROBES 218 bool 190 bool 219 191 220 config HAVE_OPTPROBES 192 config HAVE_OPTPROBES 221 bool 193 bool 222 194 223 config HAVE_KPROBES_ON_FTRACE 195 config HAVE_KPROBES_ON_FTRACE 224 bool 196 bool 225 197 226 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 198 config HAVE_FUNCTION_ERROR_INJECTION 235 bool 199 bool 236 200 237 config HAVE_NMI 201 config HAVE_NMI 238 bool 202 bool 239 203 240 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 # 204 # 250 # An arch should select this if it provides al 205 # An arch should select this if it provides all these things: 251 # 206 # 252 # task_pt_regs() in asm/process 207 # task_pt_regs() in asm/processor.h or asm/ptrace.h 253 # arch_has_single_step() if there is ha 208 # arch_has_single_step() if there is hardware single-step support 254 # arch_has_block_step() if there is ha 209 # arch_has_block_step() if there is hardware block-step support 255 # asm/syscall.h supplying asm- 210 # asm/syscall.h supplying asm-generic/syscall.h interface 256 # linux/regset.h user_regset in 211 # linux/regset.h user_regset interfaces 257 # CORE_DUMP_USE_REGSET #define'd in l 212 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h 258 # TIF_SYSCALL_TRACE calls ptrace_r !! 213 # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 259 # TIF_NOTIFY_RESUME calls resume_u !! 214 # TIF_NOTIFY_RESUME calls tracehook_notify_resume() >> 215 # signal delivery calls tracehook_signal_handler() 260 # 216 # 261 config HAVE_ARCH_TRACEHOOK 217 config HAVE_ARCH_TRACEHOOK 262 bool 218 bool 263 219 264 config HAVE_DMA_CONTIGUOUS 220 config HAVE_DMA_CONTIGUOUS 265 bool 221 bool 266 222 267 config GENERIC_SMP_IDLE_THREAD 223 config GENERIC_SMP_IDLE_THREAD 268 bool 224 bool 269 225 270 config GENERIC_IDLE_POLL_SETUP 226 config GENERIC_IDLE_POLL_SETUP 271 bool 227 bool 272 228 273 config ARCH_HAS_FORTIFY_SOURCE 229 config ARCH_HAS_FORTIFY_SOURCE 274 bool 230 bool 275 help 231 help 276 An architecture should select this w 232 An architecture should select this when it can successfully 277 build and run with CONFIG_FORTIFY_SO 233 build and run with CONFIG_FORTIFY_SOURCE. 278 234 279 # 235 # 280 # Select if the arch provides a historic keepi 236 # Select if the arch provides a historic keepinit alias for the retain_initrd 281 # command line option 237 # command line option 282 # 238 # 283 config ARCH_HAS_KEEPINITRD 239 config ARCH_HAS_KEEPINITRD 284 bool 240 bool 285 241 286 # Select if arch has all set_memory_ro/rw/x/nx 242 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h 287 config ARCH_HAS_SET_MEMORY 243 config ARCH_HAS_SET_MEMORY 288 bool 244 bool 289 245 290 # Select if arch has all set_direct_map_invali 246 # Select if arch has all set_direct_map_invalid/default() functions 291 config ARCH_HAS_SET_DIRECT_MAP 247 config ARCH_HAS_SET_DIRECT_MAP 292 bool 248 bool 293 249 294 # 250 # 295 # Select if the architecture provides the arch !! 251 # Select if arch has an uncached kernel segment and provides the 296 # either provide an uncached segment alias for !! 252 # uncached_kernel_address / cached_kernel_address symbols to use it 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 # 253 # 306 config ARCH_HAS_DMA_CLEAR_UNCACHED !! 254 config ARCH_HAS_UNCACHED_SEGMENT >> 255 select ARCH_HAS_DMA_PREP_COHERENT 307 bool 256 bool 308 257 309 config ARCH_HAS_CPU_FINALIZE_INIT !! 258 # Select if arch init_task must go in the __init_task_data section >> 259 config ARCH_TASK_STRUCT_ON_STACK 310 bool 260 bool 311 261 312 # The architecture has a per-task state that i !! 262 # Select if arch has its private alloc_task_struct() function 313 config ARCH_HAS_CPU_PASID !! 263 config ARCH_TASK_STRUCT_ALLOCATOR 314 bool 264 bool 315 select IOMMU_MM_DATA << 316 265 317 config HAVE_ARCH_THREAD_STRUCT_WHITELIST 266 config HAVE_ARCH_THREAD_STRUCT_WHITELIST 318 bool 267 bool >> 268 depends on !ARCH_TASK_STRUCT_ALLOCATOR 319 help 269 help 320 An architecture should select this t 270 An architecture should select this to provide hardened usercopy 321 knowledge about what region of the t 271 knowledge about what region of the thread_struct should be 322 whitelisted for copying to userspace 272 whitelisted for copying to userspace. Normally this is only the 323 FPU registers. Specifically, arch_th 273 FPU registers. Specifically, arch_thread_struct_whitelist() 324 should be implemented. Without this, 274 should be implemented. Without this, the entire thread_struct 325 field in task_struct will be left wh 275 field in task_struct will be left whitelisted. 326 276 >> 277 # Select if arch has its private alloc_thread_stack() function >> 278 config ARCH_THREAD_STACK_ALLOCATOR >> 279 bool >> 280 327 # Select if arch wants to size task_struct dyn 281 # Select if arch wants to size task_struct dynamically via arch_task_struct_size: 328 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 282 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 329 bool 283 bool 330 284 331 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 285 config ARCH_32BIT_OFF_T 339 bool 286 bool 340 depends on !64BIT 287 depends on !64BIT 341 help 288 help 342 All new 32-bit architectures should 289 All new 32-bit architectures should have 64-bit off_t type on 343 userspace side which corresponds to 290 userspace side which corresponds to the loff_t kernel type. This 344 is the requirement for modern ABIs. 291 is the requirement for modern ABIs. Some existing architectures 345 still support 32-bit off_t. This opt 292 still support 32-bit off_t. This option is enabled for all such 346 architectures explicitly. 293 architectures explicitly. 347 294 348 # Selected by 64 bit architectures which have << 349 config ARCH_32BIT_USTAT_F_TINODE << 350 bool << 351 << 352 config HAVE_ASM_MODVERSIONS 295 config HAVE_ASM_MODVERSIONS 353 bool 296 bool 354 help 297 help 355 This symbol should be selected by an !! 298 This symbol should be selected by an architecure if it provides 356 <asm/asm-prototypes.h> to support th 299 <asm/asm-prototypes.h> to support the module versioning for symbols 357 exported from assembly code. 300 exported from assembly code. 358 301 359 config HAVE_REGS_AND_STACK_ACCESS_API 302 config HAVE_REGS_AND_STACK_ACCESS_API 360 bool 303 bool 361 help 304 help 362 This symbol should be selected by an !! 305 This symbol should be selected by an architecure if it supports 363 the API needed to access registers a 306 the API needed to access registers and stack entries from pt_regs, 364 declared in asm/ptrace.h 307 declared in asm/ptrace.h 365 For example the kprobes-based event 308 For example the kprobes-based event tracer needs this API. 366 309 367 config HAVE_RSEQ 310 config HAVE_RSEQ 368 bool 311 bool 369 depends on HAVE_REGS_AND_STACK_ACCESS_ 312 depends on HAVE_REGS_AND_STACK_ACCESS_API 370 help 313 help 371 This symbol should be selected by an 314 This symbol should be selected by an architecture if it 372 supports an implementation of restar 315 supports an implementation of restartable sequences. 373 316 374 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 317 config HAVE_FUNCTION_ARG_ACCESS_API 381 bool 318 bool 382 help 319 help 383 This symbol should be selected by an !! 320 This symbol should be selected by an architecure if it supports 384 the API needed to access function ar 321 the API needed to access function arguments from pt_regs, 385 declared in asm/ptrace.h 322 declared in asm/ptrace.h 386 323 >> 324 config HAVE_CLK >> 325 bool >> 326 help >> 327 The <linux/clk.h> calls support software clock gating and >> 328 thus are a key power management tool on many systems. >> 329 387 config HAVE_HW_BREAKPOINT 330 config HAVE_HW_BREAKPOINT 388 bool 331 bool 389 depends on PERF_EVENTS 332 depends on PERF_EVENTS 390 333 391 config HAVE_MIXED_BREAKPOINTS_REGS 334 config HAVE_MIXED_BREAKPOINTS_REGS 392 bool 335 bool 393 depends on HAVE_HW_BREAKPOINT 336 depends on HAVE_HW_BREAKPOINT 394 help 337 help 395 Depending on the arch implementation 338 Depending on the arch implementation of hardware breakpoints, 396 some of them have separate registers 339 some of them have separate registers for data and instruction 397 breakpoints addresses, others have m 340 breakpoints addresses, others have mixed registers to store 398 them but define the access type in a 341 them but define the access type in a control register. 399 Select this option if your arch impl 342 Select this option if your arch implements breakpoints under the 400 latter fashion. 343 latter fashion. 401 344 402 config HAVE_USER_RETURN_NOTIFIER 345 config HAVE_USER_RETURN_NOTIFIER 403 bool 346 bool 404 347 405 config HAVE_PERF_EVENTS_NMI 348 config HAVE_PERF_EVENTS_NMI 406 bool 349 bool 407 help 350 help 408 System hardware can generate an NMI 351 System hardware can generate an NMI using the perf event 409 subsystem. Also has support for cal 352 subsystem. Also has support for calculating CPU cycle events 410 to determine how many clock cycles i 353 to determine how many clock cycles in a given period. 411 354 412 config HAVE_HARDLOCKUP_DETECTOR_PERF 355 config HAVE_HARDLOCKUP_DETECTOR_PERF 413 bool 356 bool 414 depends on HAVE_PERF_EVENTS_NMI 357 depends on HAVE_PERF_EVENTS_NMI 415 help 358 help 416 The arch chooses to use the generic 359 The arch chooses to use the generic perf-NMI-based hardlockup 417 detector. Must define HAVE_PERF_EVEN 360 detector. Must define HAVE_PERF_EVENTS_NMI. 418 361 419 config HAVE_HARDLOCKUP_DETECTOR_ARCH !! 362 config HAVE_NMI_WATCHDOG >> 363 depends on HAVE_NMI 420 bool 364 bool 421 help 365 help 422 The arch provides its own hardlockup !! 366 The arch provides a low level NMI watchdog. It provides 423 of the generic ones. !! 367 asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). 424 368 425 It uses the same command line parame !! 369 config HAVE_HARDLOCKUP_DETECTOR_ARCH 426 as the generic hardlockup detectors. !! 370 bool >> 371 select HAVE_NMI_WATCHDOG >> 372 help >> 373 The arch chooses to provide its own hardlockup detector, which is >> 374 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config >> 375 interfaces and parameters provided by hardlockup detector subsystem. 427 376 428 config HAVE_PERF_REGS 377 config HAVE_PERF_REGS 429 bool 378 bool 430 help 379 help 431 Support selective register dumps for 380 Support selective register dumps for perf events. This includes 432 bit-mapping of each registers and a 381 bit-mapping of each registers and a unique architecture id. 433 382 434 config HAVE_PERF_USER_STACK_DUMP 383 config HAVE_PERF_USER_STACK_DUMP 435 bool 384 bool 436 help 385 help 437 Support user stack dumps for perf ev 386 Support user stack dumps for perf event samples. This needs 438 access to the user stack pointer whi 387 access to the user stack pointer which is not unified across 439 architectures. 388 architectures. 440 389 441 config HAVE_ARCH_JUMP_LABEL 390 config HAVE_ARCH_JUMP_LABEL 442 bool 391 bool 443 392 444 config HAVE_ARCH_JUMP_LABEL_RELATIVE 393 config HAVE_ARCH_JUMP_LABEL_RELATIVE 445 bool 394 bool 446 395 447 config MMU_GATHER_TABLE_FREE 396 config MMU_GATHER_TABLE_FREE 448 bool 397 bool 449 398 450 config MMU_GATHER_RCU_TABLE_FREE 399 config MMU_GATHER_RCU_TABLE_FREE 451 bool 400 bool 452 select MMU_GATHER_TABLE_FREE 401 select MMU_GATHER_TABLE_FREE 453 402 454 config MMU_GATHER_PAGE_SIZE 403 config MMU_GATHER_PAGE_SIZE 455 bool 404 bool 456 405 457 config MMU_GATHER_NO_RANGE 406 config MMU_GATHER_NO_RANGE 458 bool 407 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 << 466 408 467 config MMU_GATHER_NO_GATHER 409 config MMU_GATHER_NO_GATHER 468 bool 410 bool 469 depends on MMU_GATHER_TABLE_FREE 411 depends on MMU_GATHER_TABLE_FREE 470 412 471 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 << 509 << 510 config ARCH_HAVE_NMI_SAFE_CMPXCHG 413 config ARCH_HAVE_NMI_SAFE_CMPXCHG 511 bool 414 bool 512 415 513 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 416 config HAVE_ALIGNED_STRUCT_PAGE 526 bool 417 bool 527 help 418 help 528 This makes sure that struct pages ar 419 This makes sure that struct pages are double word aligned and that 529 e.g. the SLUB allocator can perform 420 e.g. the SLUB allocator can perform double word atomic operations 530 on a struct page for better performa 421 on a struct page for better performance. However selecting this 531 might increase the size of a struct 422 might increase the size of a struct page by a word. 532 423 533 config HAVE_CMPXCHG_LOCAL 424 config HAVE_CMPXCHG_LOCAL 534 bool 425 bool 535 426 536 config HAVE_CMPXCHG_DOUBLE 427 config HAVE_CMPXCHG_DOUBLE 537 bool 428 bool 538 429 539 config ARCH_WEAK_RELEASE_ACQUIRE 430 config ARCH_WEAK_RELEASE_ACQUIRE 540 bool 431 bool 541 432 542 config ARCH_WANT_IPC_PARSE_VERSION 433 config ARCH_WANT_IPC_PARSE_VERSION 543 bool 434 bool 544 435 545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 436 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 546 bool 437 bool 547 438 548 config ARCH_WANT_OLD_COMPAT_IPC 439 config ARCH_WANT_OLD_COMPAT_IPC 549 select ARCH_WANT_COMPAT_IPC_PARSE_VERS 440 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 550 bool 441 bool 551 442 552 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 443 config HAVE_ARCH_SECCOMP_FILTER 564 bool 444 bool 565 select HAVE_ARCH_SECCOMP << 566 help 445 help 567 An arch should select this symbol if 446 An arch should select this symbol if it provides all of these things: 568 - all the requirements for HAVE_ARCH << 569 - syscall_get_arch() 447 - syscall_get_arch() 570 - syscall_get_arguments() 448 - syscall_get_arguments() 571 - syscall_rollback() 449 - syscall_rollback() 572 - syscall_set_return_value() 450 - syscall_set_return_value() 573 - SIGSYS siginfo_t support 451 - SIGSYS siginfo_t support 574 - secure_computing is called from a 452 - secure_computing is called from a ptrace_event()-safe context 575 - secure_computing return value is c 453 - secure_computing return value is checked and a return value of -1 576 results in the system call being s 454 results in the system call being skipped immediately. 577 - seccomp syscall wired up 455 - 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. << 598 456 599 config SECCOMP_FILTER 457 config SECCOMP_FILTER 600 def_bool y 458 def_bool y 601 depends on HAVE_ARCH_SECCOMP_FILTER && 459 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 602 help 460 help 603 Enable tasks to build secure computi 461 Enable tasks to build secure computing environments defined 604 in terms of Berkeley Packet Filter p 462 in terms of Berkeley Packet Filter programs which implement 605 task-defined system call filtering p 463 task-defined system call filtering polices. 606 464 607 See Documentation/userspace-api/secc 465 See Documentation/userspace-api/seccomp_filter.rst for details. 608 466 609 config SECCOMP_CACHE_DEBUG << 610 bool "Show seccomp filter cache status << 611 depends on SECCOMP_FILTER && !HAVE_SPA << 612 depends on PROC_FS << 613 help << 614 This enables the /proc/pid/seccomp_c << 615 seccomp cache data. The file format << 616 the file requires CAP_SYS_ADMIN. << 617 << 618 This option is for debugging only. E << 619 an adversary may be able to infer th << 620 << 621 If unsure, say N. << 622 << 623 config HAVE_ARCH_STACKLEAK 467 config HAVE_ARCH_STACKLEAK 624 bool 468 bool 625 help 469 help 626 An architecture should select this i 470 An architecture should select this if it has the code which 627 fills the used part of the kernel st 471 fills the used part of the kernel stack with the STACKLEAK_POISON 628 value before returning from system c 472 value before returning from system calls. 629 473 630 config HAVE_STACKPROTECTOR 474 config HAVE_STACKPROTECTOR 631 bool 475 bool 632 help 476 help 633 An arch should select this symbol if 477 An arch should select this symbol if: 634 - it has implemented a stack canary 478 - it has implemented a stack canary (e.g. __stack_chk_guard) 635 479 >> 480 config CC_HAS_STACKPROTECTOR_NONE >> 481 def_bool $(cc-option,-fno-stack-protector) >> 482 636 config STACKPROTECTOR 483 config STACKPROTECTOR 637 bool "Stack Protector buffer overflow 484 bool "Stack Protector buffer overflow detection" 638 depends on HAVE_STACKPROTECTOR 485 depends on HAVE_STACKPROTECTOR 639 depends on $(cc-option,-fstack-protect 486 depends on $(cc-option,-fstack-protector) 640 default y 487 default y 641 help 488 help 642 This option turns on the "stack-prot 489 This option turns on the "stack-protector" GCC feature. This 643 feature puts, at the beginning of fu 490 feature puts, at the beginning of functions, a canary value on 644 the stack just before the return add 491 the stack just before the return address, and validates 645 the value just before actually retur 492 the value just before actually returning. Stack based buffer 646 overflows (that need to overwrite th 493 overflows (that need to overwrite this return address) now also 647 overwrite the canary, which gets det 494 overwrite the canary, which gets detected and the attack is then 648 neutralized via a kernel panic. 495 neutralized via a kernel panic. 649 496 650 Functions will have the stack-protec 497 Functions will have the stack-protector canary logic added if they 651 have an 8-byte or larger character a 498 have an 8-byte or larger character array on the stack. 652 499 653 This feature requires gcc version 4. 500 This feature requires gcc version 4.2 or above, or a distribution 654 gcc with the feature backported ("-f 501 gcc with the feature backported ("-fstack-protector"). 655 502 656 On an x86 "defconfig" build, this fe 503 On an x86 "defconfig" build, this feature adds canary checks to 657 about 3% of all kernel functions, wh 504 about 3% of all kernel functions, which increases kernel code size 658 by about 0.3%. 505 by about 0.3%. 659 506 660 config STACKPROTECTOR_STRONG 507 config STACKPROTECTOR_STRONG 661 bool "Strong Stack Protector" 508 bool "Strong Stack Protector" 662 depends on STACKPROTECTOR 509 depends on STACKPROTECTOR 663 depends on $(cc-option,-fstack-protect 510 depends on $(cc-option,-fstack-protector-strong) 664 default y 511 default y 665 help 512 help 666 Functions will have the stack-protec 513 Functions will have the stack-protector canary logic added in any 667 of the following conditions: 514 of the following conditions: 668 515 669 - local variable's address used as p 516 - local variable's address used as part of the right hand side of an 670 assignment or function argument 517 assignment or function argument 671 - local variable is an array (or uni 518 - local variable is an array (or union containing an array), 672 regardless of array type or length 519 regardless of array type or length 673 - uses register local variables 520 - uses register local variables 674 521 675 This feature requires gcc version 4. 522 This feature requires gcc version 4.9 or above, or a distribution 676 gcc with the feature backported ("-f 523 gcc with the feature backported ("-fstack-protector-strong"). 677 524 678 On an x86 "defconfig" build, this fe 525 On an x86 "defconfig" build, this feature adds canary checks to 679 about 20% of all kernel functions, w 526 about 20% of all kernel functions, which increases the kernel code 680 size by about 2%. 527 size by about 2%. 681 528 682 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 << 804 << 805 config ARCH_SUPPORTS_CFI_CLANG << 806 bool << 807 help << 808 An architecture should select this o << 809 Control-Flow Integrity (CFI) checkin << 810 << 811 config ARCH_USES_CFI_TRAPS << 812 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 << 833 When selected, Control Flow Integrit << 834 warning instead of a kernel panic. T << 835 for finding indirect call type misma << 836 << 837 If unsure, say N. << 838 << 839 config HAVE_ARCH_WITHIN_STACK_FRAMES 529 config HAVE_ARCH_WITHIN_STACK_FRAMES 840 bool 530 bool 841 help 531 help 842 An architecture should select this i 532 An architecture should select this if it can walk the kernel stack 843 frames to determine if an object is 533 frames to determine if an object is part of either the arguments 844 or local variables (i.e. that it exc 534 or local variables (i.e. that it excludes saved return addresses, 845 and similar) by implementing an inli 535 and similar) by implementing an inline arch_within_stack_frames(), 846 which is used by CONFIG_HARDENED_USE 536 which is used by CONFIG_HARDENED_USERCOPY. 847 537 848 config HAVE_CONTEXT_TRACKING_USER !! 538 config HAVE_CONTEXT_TRACKING 849 bool 539 bool 850 help 540 help 851 Provide kernel/user boundaries probe 541 Provide kernel/user boundaries probes necessary for subsystems 852 that need it, such as userspace RCU 542 that need it, such as userspace RCU extended quiescent state. 853 Syscalls need to be wrapped inside u !! 543 Syscalls need to be wrapped inside user_exit()-user_enter() through 854 optimized behind static key or throu !! 544 the slow path using TIF_NOHZ flag. Exceptions handlers must be 855 flag. Exceptions handlers must be wr !! 545 wrapped as well. Irqs are already protected inside 856 protected inside ct_irq_enter/ct_irq !! 546 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on 857 handling on irq exit still need to b !! 547 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_ << 881 548 882 config HAVE_VIRT_CPU_ACCOUNTING 549 config HAVE_VIRT_CPU_ACCOUNTING 883 bool 550 bool 884 551 885 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 552 config ARCH_HAS_SCALED_CPUTIME 892 bool 553 bool 893 554 894 config HAVE_VIRT_CPU_ACCOUNTING_GEN 555 config HAVE_VIRT_CPU_ACCOUNTING_GEN 895 bool 556 bool 896 default y if 64BIT 557 default y if 64BIT 897 help 558 help 898 With VIRT_CPU_ACCOUNTING_GEN, cputim 559 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 899 Before enabling this option, arch co 560 Before enabling this option, arch code must be audited 900 to ensure there are no races in conc 561 to ensure there are no races in concurrent read/write of 901 cputime_t. For example, reading/writ 562 cputime_t. For example, reading/writing 64-bit cputime_t on 902 some 32-bit arches may require multi 563 some 32-bit arches may require multiple accesses, so proper 903 locking is needed to protect against 564 locking is needed to protect against concurrent accesses. 904 565 >> 566 905 config HAVE_IRQ_TIME_ACCOUNTING 567 config HAVE_IRQ_TIME_ACCOUNTING 906 bool 568 bool 907 help 569 help 908 Archs need to ensure they use a high 570 Archs need to ensure they use a high enough resolution clock to 909 support irq time accounting and then 571 support irq time accounting and then call enable_sched_clock_irqtime(). 910 572 911 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 573 config HAVE_MOVE_PMD 919 bool 574 bool 920 help 575 help 921 Archs that select this are able to m 576 Archs that select this are able to move page tables at the PMD level. 922 577 923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 578 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 924 bool 579 bool 925 580 926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 581 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 927 bool 582 bool 928 583 929 config HAVE_ARCH_HUGE_VMAP 584 config HAVE_ARCH_HUGE_VMAP 930 bool 585 bool 931 586 932 # << 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 587 config ARCH_WANT_HUGE_PMD_SHARE 942 bool 588 bool 943 589 944 # 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 590 config HAVE_ARCH_SOFT_DIRTY 953 bool 591 bool 954 592 955 config HAVE_MOD_ARCH_SPECIFIC 593 config HAVE_MOD_ARCH_SPECIFIC 956 bool 594 bool 957 help 595 help 958 The arch uses struct mod_arch_specif 596 The arch uses struct mod_arch_specific to store data. Many arches 959 just need a simple module loader wit 597 just need a simple module loader without arch specific data - those 960 should not enable this. 598 should not enable this. 961 599 962 config MODULES_USE_ELF_RELA 600 config MODULES_USE_ELF_RELA 963 bool 601 bool 964 help 602 help 965 Modules only use ELF RELA relocation 603 Modules only use ELF RELA relocations. Modules with ELF REL 966 relocations will give an error. 604 relocations will give an error. 967 605 968 config MODULES_USE_ELF_REL 606 config MODULES_USE_ELF_REL 969 bool 607 bool 970 help 608 help 971 Modules only use ELF REL relocations 609 Modules only use ELF REL relocations. Modules with ELF RELA 972 relocations will give an error. 610 relocations will give an error. 973 611 974 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC << 975 bool << 976 help << 977 For architectures like powerpc/32 wh << 978 allocation and need to allocate modu << 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 << 988 config HAVE_IRQ_EXIT_ON_IRQ_STACK 612 config HAVE_IRQ_EXIT_ON_IRQ_STACK 989 bool 613 bool 990 help 614 help 991 Architecture doesn't only execute th 615 Architecture doesn't only execute the irq handler on the irq stack 992 but also irq_exit(). This way we can 616 but also irq_exit(). This way we can process softirqs on this irq 993 stack instead of switching to a new 617 stack instead of switching to a new one when we call __do_softirq() 994 in the end of an hardirq. 618 in the end of an hardirq. 995 This spares a stack switch and impro 619 This spares a stack switch and improves cache usage on softirq 996 processing. 620 processing. 997 621 998 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 622 config PGTABLE_LEVELS 1015 int 623 int 1016 default 2 624 default 2 1017 625 1018 config ARCH_HAS_ELF_RANDOMIZE 626 config ARCH_HAS_ELF_RANDOMIZE 1019 bool 627 bool 1020 help 628 help 1021 An architecture supports choosing r 629 An architecture supports choosing randomized locations for 1022 stack, mmap, brk, and ET_DYN. Defin 630 stack, mmap, brk, and ET_DYN. Defined functions: 1023 - arch_mmap_rnd() 631 - arch_mmap_rnd() 1024 - arch_randomize_brk() 632 - arch_randomize_brk() 1025 633 1026 config HAVE_ARCH_MMAP_RND_BITS 634 config HAVE_ARCH_MMAP_RND_BITS 1027 bool 635 bool 1028 help 636 help 1029 An arch should select this symbol i 637 An arch should select this symbol if it supports setting a variable 1030 number of bits for use in establish 638 number of bits for use in establishing the base address for mmap 1031 allocations, has MMU enabled and pr 639 allocations, has MMU enabled and provides values for both: 1032 - ARCH_MMAP_RND_BITS_MIN 640 - ARCH_MMAP_RND_BITS_MIN 1033 - ARCH_MMAP_RND_BITS_MAX 641 - ARCH_MMAP_RND_BITS_MAX 1034 642 1035 config HAVE_EXIT_THREAD 643 config HAVE_EXIT_THREAD 1036 bool 644 bool 1037 help 645 help 1038 An architecture implements exit_thr 646 An architecture implements exit_thread. 1039 647 1040 config ARCH_MMAP_RND_BITS_MIN 648 config ARCH_MMAP_RND_BITS_MIN 1041 int 649 int 1042 650 1043 config ARCH_MMAP_RND_BITS_MAX 651 config ARCH_MMAP_RND_BITS_MAX 1044 int 652 int 1045 653 1046 config ARCH_MMAP_RND_BITS_DEFAULT 654 config ARCH_MMAP_RND_BITS_DEFAULT 1047 int 655 int 1048 656 1049 config ARCH_MMAP_RND_BITS 657 config ARCH_MMAP_RND_BITS 1050 int "Number of bits to use for ASLR o 658 int "Number of bits to use for ASLR of mmap base address" if EXPERT 1051 range ARCH_MMAP_RND_BITS_MIN ARCH_MMA 659 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 1052 default ARCH_MMAP_RND_BITS_DEFAULT if 660 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 1053 default ARCH_MMAP_RND_BITS_MIN 661 default ARCH_MMAP_RND_BITS_MIN 1054 depends on HAVE_ARCH_MMAP_RND_BITS 662 depends on HAVE_ARCH_MMAP_RND_BITS 1055 help 663 help 1056 This value can be used to select th 664 This value can be used to select the number of bits to use to 1057 determine the random offset to the 665 determine the random offset to the base address of vma regions 1058 resulting from mmap allocations. Th 666 resulting from mmap allocations. This value will be bounded 1059 by the architecture's minimum and m 667 by the architecture's minimum and maximum supported values. 1060 668 1061 This value can be changed after boo 669 This value can be changed after boot using the 1062 /proc/sys/vm/mmap_rnd_bits tunable 670 /proc/sys/vm/mmap_rnd_bits tunable 1063 671 1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 672 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 1065 bool 673 bool 1066 help 674 help 1067 An arch should select this symbol i 675 An arch should select this symbol if it supports running applications 1068 in compatibility mode, supports set 676 in compatibility mode, supports setting a variable number of bits for 1069 use in establishing the base addres 677 use in establishing the base address for mmap allocations, has MMU 1070 enabled and provides values for bot 678 enabled and provides values for both: 1071 - ARCH_MMAP_RND_COMPAT_BITS_MIN 679 - ARCH_MMAP_RND_COMPAT_BITS_MIN 1072 - ARCH_MMAP_RND_COMPAT_BITS_MAX 680 - ARCH_MMAP_RND_COMPAT_BITS_MAX 1073 681 1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN 682 config ARCH_MMAP_RND_COMPAT_BITS_MIN 1075 int 683 int 1076 684 1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX 685 config ARCH_MMAP_RND_COMPAT_BITS_MAX 1078 int 686 int 1079 687 1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 688 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1081 int 689 int 1082 690 1083 config ARCH_MMAP_RND_COMPAT_BITS 691 config ARCH_MMAP_RND_COMPAT_BITS 1084 int "Number of bits to use for ASLR o 692 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 693 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 1086 default ARCH_MMAP_RND_COMPAT_BITS_DEF 694 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1087 default ARCH_MMAP_RND_COMPAT_BITS_MIN 695 default ARCH_MMAP_RND_COMPAT_BITS_MIN 1088 depends on HAVE_ARCH_MMAP_RND_COMPAT_ 696 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 1089 help 697 help 1090 This value can be used to select th 698 This value can be used to select the number of bits to use to 1091 determine the random offset to the 699 determine the random offset to the base address of vma regions 1092 resulting from mmap allocations for 700 resulting from mmap allocations for compatible applications This 1093 value will be bounded by the archit 701 value will be bounded by the architecture's minimum and maximum 1094 supported values. 702 supported values. 1095 703 1096 This value can be changed after boo 704 This value can be changed after boot using the 1097 /proc/sys/vm/mmap_rnd_compat_bits t 705 /proc/sys/vm/mmap_rnd_compat_bits tunable 1098 706 1099 config HAVE_ARCH_COMPAT_MMAP_BASES 707 config HAVE_ARCH_COMPAT_MMAP_BASES 1100 bool 708 bool 1101 help 709 help 1102 This allows 64bit applications to i 710 This allows 64bit applications to invoke 32-bit mmap() syscall 1103 and vice-versa 32-bit applications 711 and vice-versa 32-bit applications to call 64-bit mmap(). 1104 Required for applications doing dif 712 Required for applications doing different bitness syscalls. 1105 713 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 << 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 714 # This allows to use a set of generic functions to determine mmap base 1208 # address by giving priority to top-down sche 715 # address by giving priority to top-down scheme only if the process 1209 # is not in legacy mode (compat task, unlimit 716 # is not in legacy mode (compat task, unlimited stack size or 1210 # sysctl_legacy_va_layout). 717 # sysctl_legacy_va_layout). 1211 # Architecture that selects this option can p 718 # Architecture that selects this option can provide its own version of: 1212 # - STACK_RND_MASK 719 # - STACK_RND_MASK 1213 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 720 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 1214 bool 721 bool 1215 depends on MMU 722 depends on MMU 1216 select ARCH_HAS_ELF_RANDOMIZE 723 select ARCH_HAS_ELF_RANDOMIZE 1217 724 1218 config HAVE_OBJTOOL !! 725 config HAVE_COPY_THREAD_TLS 1219 bool 726 bool 1220 !! 727 help 1221 config HAVE_JUMP_LABEL_HACK !! 728 Architecture provides copy_thread_tls to accept tls argument via 1222 bool !! 729 normal C parameter passing, rather than extracting the syscall 1223 !! 730 argument from pt_regs. 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 731 1234 config HAVE_STACK_VALIDATION 732 config HAVE_STACK_VALIDATION 1235 bool 733 bool 1236 help 734 help 1237 Architecture supports objtool compi !! 735 Architecture supports the 'objtool check' host tool command, which 1238 validation. !! 736 performs compile-time stack metadata validation. 1239 737 1240 config HAVE_RELIABLE_STACKTRACE 738 config HAVE_RELIABLE_STACKTRACE 1241 bool 739 bool 1242 help 740 help 1243 Architecture has either save_stack_ 741 Architecture has either save_stack_trace_tsk_reliable() or 1244 arch_stack_walk_reliable() function 742 arch_stack_walk_reliable() function which only returns a stack trace 1245 if it can guarantee the trace is re 743 if it can guarantee the trace is reliable. 1246 744 1247 config HAVE_ARCH_HASH 745 config HAVE_ARCH_HASH 1248 bool 746 bool 1249 default n 747 default n 1250 help 748 help 1251 If this is set, the architecture pr 749 If this is set, the architecture provides an <asm/hash.h> 1252 file which provides platform-specif 750 file which provides platform-specific implementations of some 1253 functions in <linux/hash.h> or fs/n 751 functions in <linux/hash.h> or fs/namei.c. 1254 752 1255 config HAVE_ARCH_NVRAM_OPS 753 config HAVE_ARCH_NVRAM_OPS 1256 bool 754 bool 1257 755 1258 config ISA_BUS_API 756 config ISA_BUS_API 1259 def_bool ISA 757 def_bool ISA 1260 758 1261 # 759 # 1262 # ABI hall of shame 760 # ABI hall of shame 1263 # 761 # 1264 config CLONE_BACKWARDS 762 config CLONE_BACKWARDS 1265 bool 763 bool 1266 help 764 help 1267 Architecture has tls passed as the 765 Architecture has tls passed as the 4th argument of clone(2), 1268 not the 5th one. 766 not the 5th one. 1269 767 1270 config CLONE_BACKWARDS2 768 config CLONE_BACKWARDS2 1271 bool 769 bool 1272 help 770 help 1273 Architecture has the first two argu 771 Architecture has the first two arguments of clone(2) swapped. 1274 772 1275 config CLONE_BACKWARDS3 773 config CLONE_BACKWARDS3 1276 bool 774 bool 1277 help 775 help 1278 Architecture has tls passed as the 776 Architecture has tls passed as the 3rd argument of clone(2), 1279 not the 5th one. 777 not the 5th one. 1280 778 1281 config ODD_RT_SIGACTION 779 config ODD_RT_SIGACTION 1282 bool 780 bool 1283 help 781 help 1284 Architecture has unusual rt_sigacti 782 Architecture has unusual rt_sigaction(2) arguments 1285 783 1286 config OLD_SIGSUSPEND 784 config OLD_SIGSUSPEND 1287 bool 785 bool 1288 help 786 help 1289 Architecture has old sigsuspend(2) 787 Architecture has old sigsuspend(2) syscall, of one-argument variety 1290 788 1291 config OLD_SIGSUSPEND3 789 config OLD_SIGSUSPEND3 1292 bool 790 bool 1293 help 791 help 1294 Even weirder antique ABI - three-ar 792 Even weirder antique ABI - three-argument sigsuspend(2) 1295 793 1296 config OLD_SIGACTION 794 config OLD_SIGACTION 1297 bool 795 bool 1298 help 796 help 1299 Architecture has old sigaction(2) s 797 Architecture has old sigaction(2) syscall. Nope, not the same 1300 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 798 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 1301 but fairly different variant of sig 799 but fairly different variant of sigaction(2), thanks to OSF/1 1302 compatibility... 800 compatibility... 1303 801 1304 config COMPAT_OLD_SIGACTION 802 config COMPAT_OLD_SIGACTION 1305 bool 803 bool 1306 804 1307 config COMPAT_32BIT_TIME 805 config COMPAT_32BIT_TIME 1308 bool "Provide system calls for 32-bit 806 bool "Provide system calls for 32-bit time_t" 1309 default !64BIT || COMPAT 807 default !64BIT || COMPAT 1310 help 808 help 1311 This enables 32 bit time_t support 809 This enables 32 bit time_t support in addition to 64 bit time_t support. 1312 This is relevant on all 32-bit arch 810 This is relevant on all 32-bit architectures, and 64-bit architectures 1313 as part of compat syscall handling. 811 as part of compat syscall handling. 1314 812 1315 config ARCH_NO_PREEMPT 813 config ARCH_NO_PREEMPT 1316 bool 814 bool 1317 815 1318 config ARCH_SUPPORTS_RT 816 config ARCH_SUPPORTS_RT 1319 bool 817 bool 1320 818 1321 config CPU_NO_EFFICIENT_FFS 819 config CPU_NO_EFFICIENT_FFS 1322 def_bool n 820 def_bool n 1323 821 1324 config HAVE_ARCH_VMAP_STACK 822 config HAVE_ARCH_VMAP_STACK 1325 def_bool n 823 def_bool n 1326 help 824 help 1327 An arch should select this symbol i 825 An arch should select this symbol if it can support kernel stacks 1328 in vmalloc space. This means: 826 in vmalloc space. This means: 1329 827 1330 - vmalloc space must be large enoug 828 - vmalloc space must be large enough to hold many kernel stacks. 1331 This may rule out many 32-bit arc 829 This may rule out many 32-bit architectures. 1332 830 1333 - Stacks in vmalloc space need to w 831 - Stacks in vmalloc space need to work reliably. For example, if 1334 vmap page tables are created on d 832 vmap page tables are created on demand, either this mechanism 1335 needs to work while the stack poi 833 needs to work while the stack points to a virtual address with 1336 unpopulated page tables or arch c 834 unpopulated page tables or arch code (switch_to() and switch_mm(), 1337 most likely) needs to ensure that 835 most likely) needs to ensure that the stack's page table entries 1338 are populated before running on a 836 are populated before running on a possibly unpopulated stack. 1339 837 1340 - If the stack overflows into a gua 838 - If the stack overflows into a guard page, something reasonable 1341 should happen. The definition of 839 should happen. The definition of "reasonable" is flexible, but 1342 instantly rebooting without loggi 840 instantly rebooting without logging anything would be unfriendly. 1343 841 1344 config VMAP_STACK 842 config VMAP_STACK 1345 default y 843 default y 1346 bool "Use a virtually-mapped stack" 844 bool "Use a virtually-mapped stack" 1347 depends on HAVE_ARCH_VMAP_STACK 845 depends on HAVE_ARCH_VMAP_STACK 1348 depends on !KASAN || KASAN_HW_TAGS || !! 846 depends on !KASAN || KASAN_VMALLOC 1349 help !! 847 ---help--- 1350 Enable this if you want the use vir 848 Enable this if you want the use virtually-mapped kernel stacks 1351 with guard pages. This causes kern 849 with guard pages. This causes kernel stack overflows to be 1352 caught immediately rather than caus 850 caught immediately rather than causing difficult-to-diagnose 1353 corruption. 851 corruption. 1354 852 1355 To use this with software KASAN mod !! 853 To use this with KASAN, the architecture must support backing 1356 backing virtual mappings with real !! 854 virtual mappings with real shadow memory, and KASAN_VMALLOC must 1357 must be enabled. !! 855 be enabled. 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 856 1396 config ARCH_OPTIONAL_KERNEL_RWX 857 config ARCH_OPTIONAL_KERNEL_RWX 1397 def_bool n 858 def_bool n 1398 859 1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 860 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1400 def_bool n 861 def_bool n 1401 862 1402 config ARCH_HAS_STRICT_KERNEL_RWX 863 config ARCH_HAS_STRICT_KERNEL_RWX 1403 def_bool n 864 def_bool n 1404 865 1405 config STRICT_KERNEL_RWX 866 config STRICT_KERNEL_RWX 1406 bool "Make kernel text and rodata rea 867 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 1407 depends on ARCH_HAS_STRICT_KERNEL_RWX 868 depends on ARCH_HAS_STRICT_KERNEL_RWX 1408 default !ARCH_OPTIONAL_KERNEL_RWX || 869 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1409 help 870 help 1410 If this is set, kernel text and rod 871 If this is set, kernel text and rodata memory will be made read-only, 1411 and non-text memory will be made no 872 and non-text memory will be made non-executable. This provides 1412 protection against certain security 873 protection against certain security exploits (e.g. executing the heap 1413 or modifying text) 874 or modifying text) 1414 875 1415 These features are considered stand 876 These features are considered standard security practice these days. 1416 You should say Y here in almost all 877 You should say Y here in almost all cases. 1417 878 1418 config ARCH_HAS_STRICT_MODULE_RWX 879 config ARCH_HAS_STRICT_MODULE_RWX 1419 def_bool n 880 def_bool n 1420 881 1421 config STRICT_MODULE_RWX 882 config STRICT_MODULE_RWX 1422 bool "Set loadable kernel module data 883 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 884 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 1424 default !ARCH_OPTIONAL_KERNEL_RWX || 885 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1425 help 886 help 1426 If this is set, module text and rod 887 If this is set, module text and rodata memory will be made read-only, 1427 and non-text memory will be made no 888 and non-text memory will be made non-executable. This provides 1428 protection against certain security 889 protection against certain security exploits (e.g. writing to text) 1429 890 1430 # select if the architecture provides an asm/ 891 # select if the architecture provides an asm/dma-direct.h header 1431 config ARCH_HAS_PHYS_TO_DMA 892 config ARCH_HAS_PHYS_TO_DMA 1432 bool 893 bool 1433 894 1434 config HAVE_ARCH_COMPILER_H 895 config HAVE_ARCH_COMPILER_H 1435 bool 896 bool 1436 help 897 help 1437 An architecture can select this if 898 An architecture can select this if it provides an 1438 asm/compiler.h header that should b 899 asm/compiler.h header that should be included after 1439 linux/compiler-*.h in order to over 900 linux/compiler-*.h in order to override macro definitions that those 1440 headers generally provide. 901 headers generally provide. 1441 902 1442 config HAVE_ARCH_PREL32_RELOCATIONS 903 config HAVE_ARCH_PREL32_RELOCATIONS 1443 bool 904 bool 1444 help 905 help 1445 May be selected by an architecture 906 May be selected by an architecture if it supports place-relative 1446 32-bit relocations, both in the too 907 32-bit relocations, both in the toolchain and in the module loader, 1447 in which case relative references c 908 in which case relative references can be used in special sections 1448 for PCI fixup, initcalls etc which 909 for PCI fixup, initcalls etc which are only half the size on 64 bit 1449 architectures, and don't require ru 910 architectures, and don't require runtime relocation on relocatable 1450 kernels. 911 kernels. 1451 912 1452 config ARCH_USE_MEMREMAP_PROT 913 config ARCH_USE_MEMREMAP_PROT 1453 bool 914 bool 1454 915 1455 config LOCK_EVENT_COUNTS 916 config LOCK_EVENT_COUNTS 1456 bool "Locking event counts collection 917 bool "Locking event counts collection" 1457 depends on DEBUG_FS 918 depends on DEBUG_FS 1458 help !! 919 ---help--- 1459 Enable light-weight counting of var 920 Enable light-weight counting of various locking related events 1460 in the system with minimal performa 921 in the system with minimal performance impact. This reduces 1461 the chance of application behavior 922 the chance of application behavior change because of timing 1462 differences. The counts are reporte 923 differences. The counts are reported via debugfs. 1463 924 1464 # Select if the architecture has support for 925 # Select if the architecture has support for applying RELR relocations. 1465 config ARCH_HAS_RELR 926 config ARCH_HAS_RELR 1466 bool 927 bool 1467 928 1468 config RELR 929 config RELR 1469 bool "Use RELR relocation packing" 930 bool "Use RELR relocation packing" 1470 depends on ARCH_HAS_RELR && TOOLS_SUP 931 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR 1471 default y 932 default y 1472 help 933 help 1473 Store the kernel's dynamic relocati 934 Store the kernel's dynamic relocations in the RELR relocation packing 1474 format. Requires a compatible linke 935 format. Requires a compatible linker (LLD supports this feature), as 1475 well as compatible NM and OBJCOPY u 936 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy 1476 are compatible). 937 are compatible). 1477 938 1478 config ARCH_HAS_MEM_ENCRYPT 939 config ARCH_HAS_MEM_ENCRYPT 1479 bool 940 bool 1480 941 1481 config ARCH_HAS_CC_PLATFORM << 1482 bool << 1483 << 1484 config HAVE_SPARSE_SYSCALL_NR 942 config HAVE_SPARSE_SYSCALL_NR 1485 bool !! 943 bool 1486 help !! 944 help 1487 An architecture should select this !! 945 An architecture should select this if its syscall numbering is sparse 1488 to save space. For example, MIPS ar 946 to save space. For example, MIPS architecture has a syscall array with 1489 entries at 4000, 5000 and 6000 loca 947 entries at 4000, 5000 and 6000 locations. This option turns on syscall 1490 related optimizations for a given a 948 related optimizations for a given architecture. 1491 949 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 << 1603 source "kernel/gcov/Kconfig" 950 source "kernel/gcov/Kconfig" 1604 951 1605 source "scripts/gcc-plugins/Kconfig" 952 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 953 1646 endmenu 954 endmenu
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