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 ARCH_HAS_SUBPAGE_FAULTS
40 config HOTPLUG_CORE_SYNC_DEAD <<
41 bool <<
42 select HOTPLUG_CORE_SYNC <<
43 <<
44 # Full CPU synchronization with alive state se <<
45 config HOTPLUG_CORE_SYNC_FULL <<
46 bool <<
47 select HOTPLUG_CORE_SYNC_DEAD if HOTPL <<
48 select HOTPLUG_CORE_SYNC <<
49 <<
50 config HOTPLUG_SPLIT_STARTUP <<
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 358 config HAVE_RUST
375 bool 359 bool
376 help 360 help
377 This symbol should be selected by an 361 This symbol should be selected by an architecture if it
378 supports Rust. 362 supports Rust.
379 363
380 config HAVE_FUNCTION_ARG_ACCESS_API 364 config HAVE_FUNCTION_ARG_ACCESS_API
381 bool 365 bool
382 help 366 help
383 This symbol should be selected by an 367 This symbol should be selected by an architecture if it supports
384 the API needed to access function ar 368 the API needed to access function arguments from pt_regs,
385 declared in asm/ptrace.h 369 declared in asm/ptrace.h
386 370
387 config HAVE_HW_BREAKPOINT 371 config HAVE_HW_BREAKPOINT
388 bool 372 bool
389 depends on PERF_EVENTS 373 depends on PERF_EVENTS
390 374
391 config HAVE_MIXED_BREAKPOINTS_REGS 375 config HAVE_MIXED_BREAKPOINTS_REGS
392 bool 376 bool
393 depends on HAVE_HW_BREAKPOINT 377 depends on HAVE_HW_BREAKPOINT
394 help 378 help
395 Depending on the arch implementation 379 Depending on the arch implementation of hardware breakpoints,
396 some of them have separate registers 380 some of them have separate registers for data and instruction
397 breakpoints addresses, others have m 381 breakpoints addresses, others have mixed registers to store
398 them but define the access type in a 382 them but define the access type in a control register.
399 Select this option if your arch impl 383 Select this option if your arch implements breakpoints under the
400 latter fashion. 384 latter fashion.
401 385
402 config HAVE_USER_RETURN_NOTIFIER 386 config HAVE_USER_RETURN_NOTIFIER
403 bool 387 bool
404 388
405 config HAVE_PERF_EVENTS_NMI 389 config HAVE_PERF_EVENTS_NMI
406 bool 390 bool
407 help 391 help
408 System hardware can generate an NMI 392 System hardware can generate an NMI using the perf event
409 subsystem. Also has support for cal 393 subsystem. Also has support for calculating CPU cycle events
410 to determine how many clock cycles i 394 to determine how many clock cycles in a given period.
411 395
412 config HAVE_HARDLOCKUP_DETECTOR_PERF 396 config HAVE_HARDLOCKUP_DETECTOR_PERF
413 bool 397 bool
414 depends on HAVE_PERF_EVENTS_NMI 398 depends on HAVE_PERF_EVENTS_NMI
415 help 399 help
416 The arch chooses to use the generic 400 The arch chooses to use the generic perf-NMI-based hardlockup
417 detector. Must define HAVE_PERF_EVEN 401 detector. Must define HAVE_PERF_EVENTS_NMI.
418 402
419 config HAVE_HARDLOCKUP_DETECTOR_ARCH !! 403 config HAVE_NMI_WATCHDOG
>> 404 depends on HAVE_NMI
420 bool 405 bool
421 help 406 help
422 The arch provides its own hardlockup !! 407 The arch provides a low level NMI watchdog. It provides
423 of the generic ones. !! 408 asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
424 409
425 It uses the same command line parame !! 410 config HAVE_HARDLOCKUP_DETECTOR_ARCH
426 as the generic hardlockup detectors. !! 411 bool
>> 412 select HAVE_NMI_WATCHDOG
>> 413 help
>> 414 The arch chooses to provide its own hardlockup detector, which is
>> 415 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
>> 416 interfaces and parameters provided by hardlockup detector subsystem.
427 417
428 config HAVE_PERF_REGS 418 config HAVE_PERF_REGS
429 bool 419 bool
430 help 420 help
431 Support selective register dumps for 421 Support selective register dumps for perf events. This includes
432 bit-mapping of each registers and a 422 bit-mapping of each registers and a unique architecture id.
433 423
434 config HAVE_PERF_USER_STACK_DUMP 424 config HAVE_PERF_USER_STACK_DUMP
435 bool 425 bool
436 help 426 help
437 Support user stack dumps for perf ev 427 Support user stack dumps for perf event samples. This needs
438 access to the user stack pointer whi 428 access to the user stack pointer which is not unified across
439 architectures. 429 architectures.
440 430
441 config HAVE_ARCH_JUMP_LABEL 431 config HAVE_ARCH_JUMP_LABEL
442 bool 432 bool
443 433
444 config HAVE_ARCH_JUMP_LABEL_RELATIVE 434 config HAVE_ARCH_JUMP_LABEL_RELATIVE
445 bool 435 bool
446 436
447 config MMU_GATHER_TABLE_FREE 437 config MMU_GATHER_TABLE_FREE
448 bool 438 bool
449 439
450 config MMU_GATHER_RCU_TABLE_FREE 440 config MMU_GATHER_RCU_TABLE_FREE
451 bool 441 bool
452 select MMU_GATHER_TABLE_FREE 442 select MMU_GATHER_TABLE_FREE
453 443
454 config MMU_GATHER_PAGE_SIZE 444 config MMU_GATHER_PAGE_SIZE
455 bool 445 bool
456 446
457 config MMU_GATHER_NO_RANGE 447 config MMU_GATHER_NO_RANGE
458 bool 448 bool
459 select MMU_GATHER_MERGE_VMAS 449 select MMU_GATHER_MERGE_VMAS
460 450
461 config MMU_GATHER_NO_FLUSH_CACHE 451 config MMU_GATHER_NO_FLUSH_CACHE
462 bool 452 bool
463 453
464 config MMU_GATHER_MERGE_VMAS 454 config MMU_GATHER_MERGE_VMAS
465 bool 455 bool
466 456
467 config MMU_GATHER_NO_GATHER 457 config MMU_GATHER_NO_GATHER
468 bool 458 bool
469 depends on MMU_GATHER_TABLE_FREE 459 depends on MMU_GATHER_TABLE_FREE
470 460
471 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM 461 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
472 bool 462 bool
473 help 463 help
474 Temporary select until all architect 464 Temporary select until all architectures can be converted to have
475 irqs disabled over activate_mm. Arch 465 irqs disabled over activate_mm. Architectures that do IPI based TLB
476 shootdowns should enable this. 466 shootdowns should enable this.
477 467
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 468 config ARCH_HAVE_NMI_SAFE_CMPXCHG
511 bool 469 bool
512 470
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 471 config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
523 bool 472 bool
524 473
525 config HAVE_ALIGNED_STRUCT_PAGE 474 config HAVE_ALIGNED_STRUCT_PAGE
526 bool 475 bool
527 help 476 help
528 This makes sure that struct pages ar 477 This makes sure that struct pages are double word aligned and that
529 e.g. the SLUB allocator can perform 478 e.g. the SLUB allocator can perform double word atomic operations
530 on a struct page for better performa 479 on a struct page for better performance. However selecting this
531 might increase the size of a struct 480 might increase the size of a struct page by a word.
532 481
533 config HAVE_CMPXCHG_LOCAL 482 config HAVE_CMPXCHG_LOCAL
534 bool 483 bool
535 484
536 config HAVE_CMPXCHG_DOUBLE 485 config HAVE_CMPXCHG_DOUBLE
537 bool 486 bool
538 487
539 config ARCH_WEAK_RELEASE_ACQUIRE 488 config ARCH_WEAK_RELEASE_ACQUIRE
540 bool 489 bool
541 490
542 config ARCH_WANT_IPC_PARSE_VERSION 491 config ARCH_WANT_IPC_PARSE_VERSION
543 bool 492 bool
544 493
545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 494 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
546 bool 495 bool
547 496
548 config ARCH_WANT_OLD_COMPAT_IPC 497 config ARCH_WANT_OLD_COMPAT_IPC
549 select ARCH_WANT_COMPAT_IPC_PARSE_VERS 498 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
550 bool 499 bool
551 500
552 config HAVE_ARCH_SECCOMP 501 config HAVE_ARCH_SECCOMP
553 bool 502 bool
554 help 503 help
555 An arch should select this symbol to 504 An arch should select this symbol to support seccomp mode 1 (the fixed
556 syscall policy), and must provide an 505 syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
557 and compat syscalls if the asm-gener 506 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
558 - __NR_seccomp_read_32 507 - __NR_seccomp_read_32
559 - __NR_seccomp_write_32 508 - __NR_seccomp_write_32
560 - __NR_seccomp_exit_32 509 - __NR_seccomp_exit_32
561 - __NR_seccomp_sigreturn_32 510 - __NR_seccomp_sigreturn_32
562 511
563 config HAVE_ARCH_SECCOMP_FILTER 512 config HAVE_ARCH_SECCOMP_FILTER
564 bool 513 bool
565 select HAVE_ARCH_SECCOMP 514 select HAVE_ARCH_SECCOMP
566 help 515 help
567 An arch should select this symbol if 516 An arch should select this symbol if it provides all of these things:
568 - all the requirements for HAVE_ARCH 517 - all the requirements for HAVE_ARCH_SECCOMP
569 - syscall_get_arch() 518 - syscall_get_arch()
570 - syscall_get_arguments() 519 - syscall_get_arguments()
571 - syscall_rollback() 520 - syscall_rollback()
572 - syscall_set_return_value() 521 - syscall_set_return_value()
573 - SIGSYS siginfo_t support 522 - SIGSYS siginfo_t support
574 - secure_computing is called from a 523 - secure_computing is called from a ptrace_event()-safe context
575 - secure_computing return value is c 524 - secure_computing return value is checked and a return value of -1
576 results in the system call being s 525 results in the system call being skipped immediately.
577 - seccomp syscall wired up 526 - seccomp syscall wired up
578 - if !HAVE_SPARSE_SYSCALL_NR, have S 527 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
579 SECCOMP_ARCH_NATIVE_NR, SECCOMP_AR 528 SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
580 COMPAT is supported, have the SECC 529 COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
581 530
582 config SECCOMP 531 config SECCOMP
583 prompt "Enable seccomp to safely execu 532 prompt "Enable seccomp to safely execute untrusted bytecode"
584 def_bool y 533 def_bool y
585 depends on HAVE_ARCH_SECCOMP 534 depends on HAVE_ARCH_SECCOMP
586 help 535 help
587 This kernel feature is useful for nu 536 This kernel feature is useful for number crunching applications
588 that may need to handle untrusted by 537 that may need to handle untrusted bytecode during their
589 execution. By using pipes or other t 538 execution. By using pipes or other transports made available
590 to the process as file descriptors s 539 to the process as file descriptors supporting the read/write
591 syscalls, it's possible to isolate t 540 syscalls, it's possible to isolate those applications in their
592 own address space using seccomp. Onc 541 own address space using seccomp. Once seccomp is enabled via
593 prctl(PR_SET_SECCOMP) or the seccomp 542 prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be
594 disabled and the task is only allowe 543 disabled and the task is only allowed to execute a few safe
595 syscalls defined by each seccomp mod 544 syscalls defined by each seccomp mode.
596 545
597 If unsure, say Y. 546 If unsure, say Y.
598 547
599 config SECCOMP_FILTER 548 config SECCOMP_FILTER
600 def_bool y 549 def_bool y
601 depends on HAVE_ARCH_SECCOMP_FILTER && 550 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
602 help 551 help
603 Enable tasks to build secure computi 552 Enable tasks to build secure computing environments defined
604 in terms of Berkeley Packet Filter p 553 in terms of Berkeley Packet Filter programs which implement
605 task-defined system call filtering p 554 task-defined system call filtering polices.
606 555
607 See Documentation/userspace-api/secc 556 See Documentation/userspace-api/seccomp_filter.rst for details.
608 557
609 config SECCOMP_CACHE_DEBUG 558 config SECCOMP_CACHE_DEBUG
610 bool "Show seccomp filter cache status 559 bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
611 depends on SECCOMP_FILTER && !HAVE_SPA 560 depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
612 depends on PROC_FS 561 depends on PROC_FS
613 help 562 help
614 This enables the /proc/pid/seccomp_c 563 This enables the /proc/pid/seccomp_cache interface to monitor
615 seccomp cache data. The file format 564 seccomp cache data. The file format is subject to change. Reading
616 the file requires CAP_SYS_ADMIN. 565 the file requires CAP_SYS_ADMIN.
617 566
618 This option is for debugging only. E 567 This option is for debugging only. Enabling presents the risk that
619 an adversary may be able to infer th 568 an adversary may be able to infer the seccomp filter logic.
620 569
621 If unsure, say N. 570 If unsure, say N.
622 571
623 config HAVE_ARCH_STACKLEAK 572 config HAVE_ARCH_STACKLEAK
624 bool 573 bool
625 help 574 help
626 An architecture should select this i 575 An architecture should select this if it has the code which
627 fills the used part of the kernel st 576 fills the used part of the kernel stack with the STACKLEAK_POISON
628 value before returning from system c 577 value before returning from system calls.
629 578
630 config HAVE_STACKPROTECTOR 579 config HAVE_STACKPROTECTOR
631 bool 580 bool
632 help 581 help
633 An arch should select this symbol if 582 An arch should select this symbol if:
634 - it has implemented a stack canary 583 - it has implemented a stack canary (e.g. __stack_chk_guard)
635 584
636 config STACKPROTECTOR 585 config STACKPROTECTOR
637 bool "Stack Protector buffer overflow 586 bool "Stack Protector buffer overflow detection"
638 depends on HAVE_STACKPROTECTOR 587 depends on HAVE_STACKPROTECTOR
639 depends on $(cc-option,-fstack-protect 588 depends on $(cc-option,-fstack-protector)
640 default y 589 default y
641 help 590 help
642 This option turns on the "stack-prot 591 This option turns on the "stack-protector" GCC feature. This
643 feature puts, at the beginning of fu 592 feature puts, at the beginning of functions, a canary value on
644 the stack just before the return add 593 the stack just before the return address, and validates
645 the value just before actually retur 594 the value just before actually returning. Stack based buffer
646 overflows (that need to overwrite th 595 overflows (that need to overwrite this return address) now also
647 overwrite the canary, which gets det 596 overwrite the canary, which gets detected and the attack is then
648 neutralized via a kernel panic. 597 neutralized via a kernel panic.
649 598
650 Functions will have the stack-protec 599 Functions will have the stack-protector canary logic added if they
651 have an 8-byte or larger character a 600 have an 8-byte or larger character array on the stack.
652 601
653 This feature requires gcc version 4. 602 This feature requires gcc version 4.2 or above, or a distribution
654 gcc with the feature backported ("-f 603 gcc with the feature backported ("-fstack-protector").
655 604
656 On an x86 "defconfig" build, this fe 605 On an x86 "defconfig" build, this feature adds canary checks to
657 about 3% of all kernel functions, wh 606 about 3% of all kernel functions, which increases kernel code size
658 by about 0.3%. 607 by about 0.3%.
659 608
660 config STACKPROTECTOR_STRONG 609 config STACKPROTECTOR_STRONG
661 bool "Strong Stack Protector" 610 bool "Strong Stack Protector"
662 depends on STACKPROTECTOR 611 depends on STACKPROTECTOR
663 depends on $(cc-option,-fstack-protect 612 depends on $(cc-option,-fstack-protector-strong)
664 default y 613 default y
665 help 614 help
666 Functions will have the stack-protec 615 Functions will have the stack-protector canary logic added in any
667 of the following conditions: 616 of the following conditions:
668 617
669 - local variable's address used as p 618 - local variable's address used as part of the right hand side of an
670 assignment or function argument 619 assignment or function argument
671 - local variable is an array (or uni 620 - local variable is an array (or union containing an array),
672 regardless of array type or length 621 regardless of array type or length
673 - uses register local variables 622 - uses register local variables
674 623
675 This feature requires gcc version 4. 624 This feature requires gcc version 4.9 or above, or a distribution
676 gcc with the feature backported ("-f 625 gcc with the feature backported ("-fstack-protector-strong").
677 626
678 On an x86 "defconfig" build, this fe 627 On an x86 "defconfig" build, this feature adds canary checks to
679 about 20% of all kernel functions, w 628 about 20% of all kernel functions, which increases the kernel code
680 size by about 2%. 629 size by about 2%.
681 630
682 config ARCH_SUPPORTS_SHADOW_CALL_STACK 631 config ARCH_SUPPORTS_SHADOW_CALL_STACK
683 bool 632 bool
684 help 633 help
685 An architecture should select this i 634 An architecture should select this if it supports the compiler's
686 Shadow Call Stack and implements run 635 Shadow Call Stack and implements runtime support for shadow stack
687 switching. 636 switching.
688 637
689 config SHADOW_CALL_STACK 638 config SHADOW_CALL_STACK
690 bool "Shadow Call Stack" 639 bool "Shadow Call Stack"
691 depends on ARCH_SUPPORTS_SHADOW_CALL_S 640 depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
692 depends on DYNAMIC_FTRACE_WITH_ARGS || 641 depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
693 depends on MMU <<
694 help 642 help
695 This option enables the compiler's S 643 This option enables the compiler's Shadow Call Stack, which
696 uses a shadow stack to protect funct 644 uses a shadow stack to protect function return addresses from
697 being overwritten by an attacker. Mo 645 being overwritten by an attacker. More information can be found
698 in the compiler's documentation: 646 in the compiler's documentation:
699 647
700 - Clang: https://clang.llvm.org/docs 648 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
701 - GCC: https://gcc.gnu.org/onlinedoc 649 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
702 650
703 Note that security guarantees in the 651 Note that security guarantees in the kernel differ from the
704 ones documented for user space. The 652 ones documented for user space. The kernel must store addresses
705 of shadow stacks in memory, which me 653 of shadow stacks in memory, which means an attacker capable of
706 reading and writing arbitrary memory 654 reading and writing arbitrary memory may be able to locate them
707 and hijack control flow by modifying 655 and hijack control flow by modifying the stacks.
708 656
709 config DYNAMIC_SCS 657 config DYNAMIC_SCS
710 bool 658 bool
711 help 659 help
712 Set by the arch code if it relies on 660 Set by the arch code if it relies on code patching to insert the
713 shadow call stack push and pop instr 661 shadow call stack push and pop instructions rather than on the
714 compiler. 662 compiler.
715 663
716 config LTO 664 config LTO
717 bool 665 bool
718 help 666 help
719 Selected if the kernel will be built 667 Selected if the kernel will be built using the compiler's LTO feature.
720 668
721 config LTO_CLANG 669 config LTO_CLANG
722 bool 670 bool
723 select LTO 671 select LTO
724 help 672 help
725 Selected if the kernel will be built 673 Selected if the kernel will be built using Clang's LTO feature.
726 674
727 config ARCH_SUPPORTS_LTO_CLANG 675 config ARCH_SUPPORTS_LTO_CLANG
728 bool 676 bool
729 help 677 help
730 An architecture should select this o 678 An architecture should select this option if it supports:
731 - compiling with Clang, 679 - compiling with Clang,
732 - compiling inline assembly with Cla 680 - compiling inline assembly with Clang's integrated assembler,
733 - and linking with LLD. 681 - and linking with LLD.
734 682
735 config ARCH_SUPPORTS_LTO_CLANG_THIN 683 config ARCH_SUPPORTS_LTO_CLANG_THIN
736 bool 684 bool
737 help 685 help
738 An architecture should select this o 686 An architecture should select this option if it can support Clang's
739 ThinLTO mode. 687 ThinLTO mode.
740 688
741 config HAS_LTO_CLANG 689 config HAS_LTO_CLANG
742 def_bool y 690 def_bool y
743 depends on CC_IS_CLANG && LD_IS_LLD && 691 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM
744 depends on $(success,$(NM) --help | he 692 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
745 depends on $(success,$(AR) --help | he 693 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
746 depends on ARCH_SUPPORTS_LTO_CLANG 694 depends on ARCH_SUPPORTS_LTO_CLANG
747 depends on !FTRACE_MCOUNT_USE_RECORDMC 695 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
748 # https://github.com/ClangBuiltLinux/l !! 696 depends on !KASAN || KASAN_HW_TAGS
749 depends on (!KASAN || KASAN_HW_TAGS || <<
750 depends on (!KCOV || CLANG_VERSION >= <<
751 depends on !GCOV_KERNEL 697 depends on !GCOV_KERNEL
752 help 698 help
753 The compiler and Kconfig options sup 699 The compiler and Kconfig options support building with Clang's
754 LTO. 700 LTO.
755 701
756 choice 702 choice
757 prompt "Link Time Optimization (LTO)" 703 prompt "Link Time Optimization (LTO)"
758 default LTO_NONE 704 default LTO_NONE
759 help 705 help
760 This option enables Link Time Optimi 706 This option enables Link Time Optimization (LTO), which allows the
761 compiler to optimize binaries global 707 compiler to optimize binaries globally.
762 708
763 If unsure, select LTO_NONE. Note tha 709 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
764 so it's disabled by default. 710 so it's disabled by default.
765 711
766 config LTO_NONE 712 config LTO_NONE
767 bool "None" 713 bool "None"
768 help 714 help
769 Build the kernel normally, without L 715 Build the kernel normally, without Link Time Optimization (LTO).
770 716
771 config LTO_CLANG_FULL 717 config LTO_CLANG_FULL
772 bool "Clang Full LTO (EXPERIMENTAL)" 718 bool "Clang Full LTO (EXPERIMENTAL)"
773 depends on HAS_LTO_CLANG 719 depends on HAS_LTO_CLANG
774 depends on !COMPILE_TEST 720 depends on !COMPILE_TEST
775 select LTO_CLANG 721 select LTO_CLANG
776 help 722 help
777 This option enables Clang's full Lin 723 This option enables Clang's full Link Time Optimization (LTO), which
778 allows the compiler to optimize the 724 allows the compiler to optimize the kernel globally. If you enable
779 this option, the compiler generates 725 this option, the compiler generates LLVM bitcode instead of ELF
780 object files, and the actual compila 726 object files, and the actual compilation from bitcode happens at
781 the LTO link step, which may take se 727 the LTO link step, which may take several minutes depending on the
782 kernel configuration. More informati 728 kernel configuration. More information can be found from LLVM's
783 documentation: 729 documentation:
784 730
785 https://llvm.org/docs/LinkTimeOpti 731 https://llvm.org/docs/LinkTimeOptimization.html
786 732
787 During link time, this option can us 733 During link time, this option can use a large amount of RAM, and
788 may take much longer than the ThinLT 734 may take much longer than the ThinLTO option.
789 735
790 config LTO_CLANG_THIN 736 config LTO_CLANG_THIN
791 bool "Clang ThinLTO (EXPERIMENTAL)" 737 bool "Clang ThinLTO (EXPERIMENTAL)"
792 depends on HAS_LTO_CLANG && ARCH_SUPPO 738 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
793 select LTO_CLANG 739 select LTO_CLANG
794 help 740 help
795 This option enables Clang's ThinLTO, 741 This option enables Clang's ThinLTO, which allows for parallel
796 optimization and faster incremental 742 optimization and faster incremental compiles compared to the
797 CONFIG_LTO_CLANG_FULL option. More i 743 CONFIG_LTO_CLANG_FULL option. More information can be found
798 from Clang's documentation: 744 from Clang's documentation:
799 745
800 https://clang.llvm.org/docs/ThinLT 746 https://clang.llvm.org/docs/ThinLTO.html
801 747
802 If unsure, say Y. 748 If unsure, say Y.
803 endchoice 749 endchoice
804 750
805 config ARCH_SUPPORTS_CFI_CLANG 751 config ARCH_SUPPORTS_CFI_CLANG
806 bool 752 bool
807 help 753 help
808 An architecture should select this o 754 An architecture should select this option if it can support Clang's
809 Control-Flow Integrity (CFI) checkin 755 Control-Flow Integrity (CFI) checking.
810 756
811 config ARCH_USES_CFI_TRAPS 757 config ARCH_USES_CFI_TRAPS
812 bool 758 bool
813 759
814 config CFI_CLANG 760 config CFI_CLANG
815 bool "Use Clang's Control Flow Integri 761 bool "Use Clang's Control Flow Integrity (CFI)"
816 depends on ARCH_SUPPORTS_CFI_CLANG 762 depends on ARCH_SUPPORTS_CFI_CLANG
817 depends on $(cc-option,-fsanitize=kcfi 763 depends on $(cc-option,-fsanitize=kcfi)
818 help 764 help
819 This option enables Clang's forward- !! 765 This option enables Clang’s forward-edge Control Flow Integrity
820 (CFI) checking, where the compiler i 766 (CFI) checking, where the compiler injects a runtime check to each
821 indirect function call to ensure the 767 indirect function call to ensure the target is a valid function with
822 the correct static type. This restri 768 the correct static type. This restricts possible call targets and
823 makes it more difficult for an attac 769 makes it more difficult for an attacker to exploit bugs that allow
824 the modification of stored function 770 the modification of stored function pointers. More information can be
825 found from Clang's documentation: 771 found from Clang's documentation:
826 772
827 https://clang.llvm.org/docs/Contro 773 https://clang.llvm.org/docs/ControlFlowIntegrity.html
828 774
829 config CFI_PERMISSIVE 775 config CFI_PERMISSIVE
830 bool "Use CFI in permissive mode" 776 bool "Use CFI in permissive mode"
831 depends on CFI_CLANG 777 depends on CFI_CLANG
832 help 778 help
833 When selected, Control Flow Integrit 779 When selected, Control Flow Integrity (CFI) violations result in a
834 warning instead of a kernel panic. T 780 warning instead of a kernel panic. This option should only be used
835 for finding indirect call type misma 781 for finding indirect call type mismatches during development.
836 782
837 If unsure, say N. 783 If unsure, say N.
838 784
839 config HAVE_ARCH_WITHIN_STACK_FRAMES 785 config HAVE_ARCH_WITHIN_STACK_FRAMES
840 bool 786 bool
841 help 787 help
842 An architecture should select this i 788 An architecture should select this if it can walk the kernel stack
843 frames to determine if an object is 789 frames to determine if an object is part of either the arguments
844 or local variables (i.e. that it exc 790 or local variables (i.e. that it excludes saved return addresses,
845 and similar) by implementing an inli 791 and similar) by implementing an inline arch_within_stack_frames(),
846 which is used by CONFIG_HARDENED_USE 792 which is used by CONFIG_HARDENED_USERCOPY.
847 793
848 config HAVE_CONTEXT_TRACKING_USER 794 config HAVE_CONTEXT_TRACKING_USER
849 bool 795 bool
850 help 796 help
851 Provide kernel/user boundaries probe 797 Provide kernel/user boundaries probes necessary for subsystems
852 that need it, such as userspace RCU 798 that need it, such as userspace RCU extended quiescent state.
853 Syscalls need to be wrapped inside u 799 Syscalls need to be wrapped inside user_exit()-user_enter(), either
854 optimized behind static key or throu 800 optimized behind static key or through the slow path using TIF_NOHZ
855 flag. Exceptions handlers must be wr 801 flag. Exceptions handlers must be wrapped as well. Irqs are already
856 protected inside ct_irq_enter/ct_irq 802 protected inside ct_irq_enter/ct_irq_exit() but preemption or signal
857 handling on irq exit still need to b 803 handling on irq exit still need to be protected.
858 804
859 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK 805 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK
860 bool 806 bool
861 help 807 help
862 Architecture neither relies on excep 808 Architecture neither relies on exception_enter()/exception_exit()
863 nor on schedule_user(). Also preempt 809 nor on schedule_user(). Also preempt_schedule_notrace() and
864 preempt_schedule_irq() can't be call 810 preempt_schedule_irq() can't be called in a preemptible section
865 while context tracking is CONTEXT_US 811 while context tracking is CONTEXT_USER. This feature reflects a sane
866 entry implementation where the follo 812 entry implementation where the following requirements are met on
867 critical entry code, ie: before user 813 critical entry code, ie: before user_exit() or after user_enter():
868 814
869 - Critical entry code isn't preempti 815 - Critical entry code isn't preemptible (or better yet:
870 not interruptible). 816 not interruptible).
871 - No use of RCU read side critical s 817 - No use of RCU read side critical sections, unless ct_nmi_enter()
872 got called. 818 got called.
873 - No use of instrumentation, unless 819 - No use of instrumentation, unless instrumentation_begin() got
874 called. 820 called.
875 821
876 config HAVE_TIF_NOHZ 822 config HAVE_TIF_NOHZ
877 bool 823 bool
878 help 824 help
879 Arch relies on TIF_NOHZ and syscall 825 Arch relies on TIF_NOHZ and syscall slow path to implement context
880 tracking calls to user_enter()/user_ 826 tracking calls to user_enter()/user_exit().
881 827
882 config HAVE_VIRT_CPU_ACCOUNTING 828 config HAVE_VIRT_CPU_ACCOUNTING
883 bool 829 bool
884 830
885 config HAVE_VIRT_CPU_ACCOUNTING_IDLE 831 config HAVE_VIRT_CPU_ACCOUNTING_IDLE
886 bool 832 bool
887 help 833 help
888 Architecture has its own way to acco 834 Architecture has its own way to account idle CPU time and therefore
889 doesn't implement vtime_account_idle 835 doesn't implement vtime_account_idle().
890 836
891 config ARCH_HAS_SCALED_CPUTIME 837 config ARCH_HAS_SCALED_CPUTIME
892 bool 838 bool
893 839
894 config HAVE_VIRT_CPU_ACCOUNTING_GEN 840 config HAVE_VIRT_CPU_ACCOUNTING_GEN
895 bool 841 bool
896 default y if 64BIT 842 default y if 64BIT
897 help 843 help
898 With VIRT_CPU_ACCOUNTING_GEN, cputim 844 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
899 Before enabling this option, arch co 845 Before enabling this option, arch code must be audited
900 to ensure there are no races in conc 846 to ensure there are no races in concurrent read/write of
901 cputime_t. For example, reading/writ 847 cputime_t. For example, reading/writing 64-bit cputime_t on
902 some 32-bit arches may require multi 848 some 32-bit arches may require multiple accesses, so proper
903 locking is needed to protect against 849 locking is needed to protect against concurrent accesses.
904 850
905 config HAVE_IRQ_TIME_ACCOUNTING 851 config HAVE_IRQ_TIME_ACCOUNTING
906 bool 852 bool
907 help 853 help
908 Archs need to ensure they use a high 854 Archs need to ensure they use a high enough resolution clock to
909 support irq time accounting and then 855 support irq time accounting and then call enable_sched_clock_irqtime().
910 856
911 config HAVE_MOVE_PUD 857 config HAVE_MOVE_PUD
912 bool 858 bool
913 help 859 help
914 Architectures that select this are a 860 Architectures that select this are able to move page tables at the
915 PUD level. If there are only 3 page 861 PUD level. If there are only 3 page table levels, the move effectively
916 happens at the PGD level. 862 happens at the PGD level.
917 863
918 config HAVE_MOVE_PMD 864 config HAVE_MOVE_PMD
919 bool 865 bool
920 help 866 help
921 Archs that select this are able to m 867 Archs that select this are able to move page tables at the PMD level.
922 868
923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 869 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
924 bool 870 bool
925 871
926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 872 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
927 bool 873 bool
928 874
929 config HAVE_ARCH_HUGE_VMAP 875 config HAVE_ARCH_HUGE_VMAP
930 bool 876 bool
931 877
932 # 878 #
933 # Archs that select this would be capable of 879 # Archs that select this would be capable of PMD-sized vmaps (i.e.,
934 # arch_vmap_pmd_supported() returns true). Th 880 # arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag
935 # must be used to enable allocations to use h 881 # must be used to enable allocations to use hugepages.
936 # 882 #
937 config HAVE_ARCH_HUGE_VMALLOC 883 config HAVE_ARCH_HUGE_VMALLOC
938 depends on HAVE_ARCH_HUGE_VMAP 884 depends on HAVE_ARCH_HUGE_VMAP
939 bool 885 bool
940 886
941 config ARCH_WANT_HUGE_PMD_SHARE 887 config ARCH_WANT_HUGE_PMD_SHARE
942 bool 888 bool
943 889
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 890 config HAVE_ARCH_SOFT_DIRTY
953 bool 891 bool
954 892
955 config HAVE_MOD_ARCH_SPECIFIC 893 config HAVE_MOD_ARCH_SPECIFIC
956 bool 894 bool
957 help 895 help
958 The arch uses struct mod_arch_specif 896 The arch uses struct mod_arch_specific to store data. Many arches
959 just need a simple module loader wit 897 just need a simple module loader without arch specific data - those
960 should not enable this. 898 should not enable this.
961 899
962 config MODULES_USE_ELF_RELA 900 config MODULES_USE_ELF_RELA
963 bool 901 bool
964 help 902 help
965 Modules only use ELF RELA relocation 903 Modules only use ELF RELA relocations. Modules with ELF REL
966 relocations will give an error. 904 relocations will give an error.
967 905
968 config MODULES_USE_ELF_REL 906 config MODULES_USE_ELF_REL
969 bool 907 bool
970 help 908 help
971 Modules only use ELF REL relocations 909 Modules only use ELF REL relocations. Modules with ELF RELA
972 relocations will give an error. 910 relocations will give an error.
973 911
974 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC 912 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC
975 bool 913 bool
976 help 914 help
977 For architectures like powerpc/32 wh 915 For architectures like powerpc/32 which have constraints on module
978 allocation and need to allocate modu 916 allocation and need to allocate module data outside of module area.
979 917
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 918 config HAVE_IRQ_EXIT_ON_IRQ_STACK
989 bool 919 bool
990 help 920 help
991 Architecture doesn't only execute th 921 Architecture doesn't only execute the irq handler on the irq stack
992 but also irq_exit(). This way we can 922 but also irq_exit(). This way we can process softirqs on this irq
993 stack instead of switching to a new 923 stack instead of switching to a new one when we call __do_softirq()
994 in the end of an hardirq. 924 in the end of an hardirq.
995 This spares a stack switch and impro 925 This spares a stack switch and improves cache usage on softirq
996 processing. 926 processing.
997 927
998 config HAVE_SOFTIRQ_ON_OWN_STACK 928 config HAVE_SOFTIRQ_ON_OWN_STACK
999 bool 929 bool
1000 help 930 help
1001 Architecture provides a function to 931 Architecture provides a function to run __do_softirq() on a
1002 separate stack. 932 separate stack.
1003 933
1004 config SOFTIRQ_ON_OWN_STACK 934 config SOFTIRQ_ON_OWN_STACK
1005 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && 935 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT
1006 936
1007 config ALTERNATE_USER_ADDRESS_SPACE 937 config ALTERNATE_USER_ADDRESS_SPACE
1008 bool 938 bool
1009 help 939 help
1010 Architectures set this when the CPU 940 Architectures set this when the CPU uses separate address
1011 spaces for kernel and user space po 941 spaces for kernel and user space pointers. In this case, the
1012 access_ok() check on a __user point 942 access_ok() check on a __user pointer is skipped.
1013 943
1014 config PGTABLE_LEVELS 944 config PGTABLE_LEVELS
1015 int 945 int
1016 default 2 946 default 2
1017 947
1018 config ARCH_HAS_ELF_RANDOMIZE 948 config ARCH_HAS_ELF_RANDOMIZE
1019 bool 949 bool
1020 help 950 help
1021 An architecture supports choosing r 951 An architecture supports choosing randomized locations for
1022 stack, mmap, brk, and ET_DYN. Defin 952 stack, mmap, brk, and ET_DYN. Defined functions:
1023 - arch_mmap_rnd() 953 - arch_mmap_rnd()
1024 - arch_randomize_brk() 954 - arch_randomize_brk()
1025 955
1026 config HAVE_ARCH_MMAP_RND_BITS 956 config HAVE_ARCH_MMAP_RND_BITS
1027 bool 957 bool
1028 help 958 help
1029 An arch should select this symbol i 959 An arch should select this symbol if it supports setting a variable
1030 number of bits for use in establish 960 number of bits for use in establishing the base address for mmap
1031 allocations, has MMU enabled and pr 961 allocations, has MMU enabled and provides values for both:
1032 - ARCH_MMAP_RND_BITS_MIN 962 - ARCH_MMAP_RND_BITS_MIN
1033 - ARCH_MMAP_RND_BITS_MAX 963 - ARCH_MMAP_RND_BITS_MAX
1034 964
1035 config HAVE_EXIT_THREAD 965 config HAVE_EXIT_THREAD
1036 bool 966 bool
1037 help 967 help
1038 An architecture implements exit_thr 968 An architecture implements exit_thread.
1039 969
1040 config ARCH_MMAP_RND_BITS_MIN 970 config ARCH_MMAP_RND_BITS_MIN
1041 int 971 int
1042 972
1043 config ARCH_MMAP_RND_BITS_MAX 973 config ARCH_MMAP_RND_BITS_MAX
1044 int 974 int
1045 975
1046 config ARCH_MMAP_RND_BITS_DEFAULT 976 config ARCH_MMAP_RND_BITS_DEFAULT
1047 int 977 int
1048 978
1049 config ARCH_MMAP_RND_BITS 979 config ARCH_MMAP_RND_BITS
1050 int "Number of bits to use for ASLR o 980 int "Number of bits to use for ASLR of mmap base address" if EXPERT
1051 range ARCH_MMAP_RND_BITS_MIN ARCH_MMA 981 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1052 default ARCH_MMAP_RND_BITS_DEFAULT if 982 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1053 default ARCH_MMAP_RND_BITS_MIN 983 default ARCH_MMAP_RND_BITS_MIN
1054 depends on HAVE_ARCH_MMAP_RND_BITS 984 depends on HAVE_ARCH_MMAP_RND_BITS
1055 help 985 help
1056 This value can be used to select th 986 This value can be used to select the number of bits to use to
1057 determine the random offset to the 987 determine the random offset to the base address of vma regions
1058 resulting from mmap allocations. Th 988 resulting from mmap allocations. This value will be bounded
1059 by the architecture's minimum and m 989 by the architecture's minimum and maximum supported values.
1060 990
1061 This value can be changed after boo 991 This value can be changed after boot using the
1062 /proc/sys/vm/mmap_rnd_bits tunable 992 /proc/sys/vm/mmap_rnd_bits tunable
1063 993
1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 994 config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1065 bool 995 bool
1066 help 996 help
1067 An arch should select this symbol i 997 An arch should select this symbol if it supports running applications
1068 in compatibility mode, supports set 998 in compatibility mode, supports setting a variable number of bits for
1069 use in establishing the base addres 999 use in establishing the base address for mmap allocations, has MMU
1070 enabled and provides values for bot 1000 enabled and provides values for both:
1071 - ARCH_MMAP_RND_COMPAT_BITS_MIN 1001 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1072 - ARCH_MMAP_RND_COMPAT_BITS_MAX 1002 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1073 1003
1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN 1004 config ARCH_MMAP_RND_COMPAT_BITS_MIN
1075 int 1005 int
1076 1006
1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX 1007 config ARCH_MMAP_RND_COMPAT_BITS_MAX
1078 int 1008 int
1079 1009
1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1010 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1081 int 1011 int
1082 1012
1083 config ARCH_MMAP_RND_COMPAT_BITS 1013 config ARCH_MMAP_RND_COMPAT_BITS
1084 int "Number of bits to use for ASLR o 1014 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 1015 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1086 default ARCH_MMAP_RND_COMPAT_BITS_DEF 1016 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1087 default ARCH_MMAP_RND_COMPAT_BITS_MIN 1017 default ARCH_MMAP_RND_COMPAT_BITS_MIN
1088 depends on HAVE_ARCH_MMAP_RND_COMPAT_ 1018 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1089 help 1019 help
1090 This value can be used to select th 1020 This value can be used to select the number of bits to use to
1091 determine the random offset to the 1021 determine the random offset to the base address of vma regions
1092 resulting from mmap allocations for 1022 resulting from mmap allocations for compatible applications This
1093 value will be bounded by the archit 1023 value will be bounded by the architecture's minimum and maximum
1094 supported values. 1024 supported values.
1095 1025
1096 This value can be changed after boo 1026 This value can be changed after boot using the
1097 /proc/sys/vm/mmap_rnd_compat_bits t 1027 /proc/sys/vm/mmap_rnd_compat_bits tunable
1098 1028
1099 config HAVE_ARCH_COMPAT_MMAP_BASES 1029 config HAVE_ARCH_COMPAT_MMAP_BASES
1100 bool 1030 bool
1101 help 1031 help
1102 This allows 64bit applications to i 1032 This allows 64bit applications to invoke 32-bit mmap() syscall
1103 and vice-versa 32-bit applications 1033 and vice-versa 32-bit applications to call 64-bit mmap().
1104 Required for applications doing dif 1034 Required for applications doing different bitness syscalls.
1105 1035
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 1036 config PAGE_SIZE_LESS_THAN_64KB
1190 def_bool y 1037 def_bool y
>> 1038 depends on !ARM64_64K_PAGES
>> 1039 depends on !IA64_PAGE_SIZE_64KB
1191 depends on !PAGE_SIZE_64KB 1040 depends on !PAGE_SIZE_64KB
>> 1041 depends on !PARISC_PAGE_SIZE_64KB
1192 depends on PAGE_SIZE_LESS_THAN_256KB 1042 depends on PAGE_SIZE_LESS_THAN_256KB
1193 1043
1194 config PAGE_SIZE_LESS_THAN_256KB 1044 config PAGE_SIZE_LESS_THAN_256KB
1195 def_bool y 1045 def_bool y
1196 depends on !PAGE_SIZE_256KB 1046 depends on !PAGE_SIZE_256KB
1197 1047
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 1048 # This allows to use a set of generic functions to determine mmap base
1208 # address by giving priority to top-down sche 1049 # address by giving priority to top-down scheme only if the process
1209 # is not in legacy mode (compat task, unlimit 1050 # is not in legacy mode (compat task, unlimited stack size or
1210 # sysctl_legacy_va_layout). 1051 # sysctl_legacy_va_layout).
1211 # Architecture that selects this option can p 1052 # Architecture that selects this option can provide its own version of:
1212 # - STACK_RND_MASK 1053 # - STACK_RND_MASK
1213 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 1054 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
1214 bool 1055 bool
1215 depends on MMU 1056 depends on MMU
1216 select ARCH_HAS_ELF_RANDOMIZE 1057 select ARCH_HAS_ELF_RANDOMIZE
1217 1058
1218 config HAVE_OBJTOOL 1059 config HAVE_OBJTOOL
1219 bool 1060 bool
1220 1061
1221 config HAVE_JUMP_LABEL_HACK 1062 config HAVE_JUMP_LABEL_HACK
1222 bool 1063 bool
1223 1064
1224 config HAVE_NOINSTR_HACK 1065 config HAVE_NOINSTR_HACK
1225 bool 1066 bool
1226 1067
1227 config HAVE_NOINSTR_VALIDATION 1068 config HAVE_NOINSTR_VALIDATION
1228 bool 1069 bool
1229 1070
1230 config HAVE_UACCESS_VALIDATION 1071 config HAVE_UACCESS_VALIDATION
1231 bool 1072 bool
1232 select OBJTOOL 1073 select OBJTOOL
1233 1074
1234 config HAVE_STACK_VALIDATION 1075 config HAVE_STACK_VALIDATION
1235 bool 1076 bool
1236 help 1077 help
1237 Architecture supports objtool compi 1078 Architecture supports objtool compile-time frame pointer rule
1238 validation. 1079 validation.
1239 1080
1240 config HAVE_RELIABLE_STACKTRACE 1081 config HAVE_RELIABLE_STACKTRACE
1241 bool 1082 bool
1242 help 1083 help
1243 Architecture has either save_stack_ 1084 Architecture has either save_stack_trace_tsk_reliable() or
1244 arch_stack_walk_reliable() function 1085 arch_stack_walk_reliable() function which only returns a stack trace
1245 if it can guarantee the trace is re 1086 if it can guarantee the trace is reliable.
1246 1087
1247 config HAVE_ARCH_HASH 1088 config HAVE_ARCH_HASH
1248 bool 1089 bool
1249 default n 1090 default n
1250 help 1091 help
1251 If this is set, the architecture pr 1092 If this is set, the architecture provides an <asm/hash.h>
1252 file which provides platform-specif 1093 file which provides platform-specific implementations of some
1253 functions in <linux/hash.h> or fs/n 1094 functions in <linux/hash.h> or fs/namei.c.
1254 1095
1255 config HAVE_ARCH_NVRAM_OPS 1096 config HAVE_ARCH_NVRAM_OPS
1256 bool 1097 bool
1257 1098
1258 config ISA_BUS_API 1099 config ISA_BUS_API
1259 def_bool ISA 1100 def_bool ISA
1260 1101
1261 # 1102 #
1262 # ABI hall of shame 1103 # ABI hall of shame
1263 # 1104 #
1264 config CLONE_BACKWARDS 1105 config CLONE_BACKWARDS
1265 bool 1106 bool
1266 help 1107 help
1267 Architecture has tls passed as the 1108 Architecture has tls passed as the 4th argument of clone(2),
1268 not the 5th one. 1109 not the 5th one.
1269 1110
1270 config CLONE_BACKWARDS2 1111 config CLONE_BACKWARDS2
1271 bool 1112 bool
1272 help 1113 help
1273 Architecture has the first two argu 1114 Architecture has the first two arguments of clone(2) swapped.
1274 1115
1275 config CLONE_BACKWARDS3 1116 config CLONE_BACKWARDS3
1276 bool 1117 bool
1277 help 1118 help
1278 Architecture has tls passed as the 1119 Architecture has tls passed as the 3rd argument of clone(2),
1279 not the 5th one. 1120 not the 5th one.
1280 1121
1281 config ODD_RT_SIGACTION 1122 config ODD_RT_SIGACTION
1282 bool 1123 bool
1283 help 1124 help
1284 Architecture has unusual rt_sigacti 1125 Architecture has unusual rt_sigaction(2) arguments
1285 1126
1286 config OLD_SIGSUSPEND 1127 config OLD_SIGSUSPEND
1287 bool 1128 bool
1288 help 1129 help
1289 Architecture has old sigsuspend(2) 1130 Architecture has old sigsuspend(2) syscall, of one-argument variety
1290 1131
1291 config OLD_SIGSUSPEND3 1132 config OLD_SIGSUSPEND3
1292 bool 1133 bool
1293 help 1134 help
1294 Even weirder antique ABI - three-ar 1135 Even weirder antique ABI - three-argument sigsuspend(2)
1295 1136
1296 config OLD_SIGACTION 1137 config OLD_SIGACTION
1297 bool 1138 bool
1298 help 1139 help
1299 Architecture has old sigaction(2) s 1140 Architecture has old sigaction(2) syscall. Nope, not the same
1300 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 1141 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1301 but fairly different variant of sig 1142 but fairly different variant of sigaction(2), thanks to OSF/1
1302 compatibility... 1143 compatibility...
1303 1144
1304 config COMPAT_OLD_SIGACTION 1145 config COMPAT_OLD_SIGACTION
1305 bool 1146 bool
1306 1147
1307 config COMPAT_32BIT_TIME 1148 config COMPAT_32BIT_TIME
1308 bool "Provide system calls for 32-bit 1149 bool "Provide system calls for 32-bit time_t"
1309 default !64BIT || COMPAT 1150 default !64BIT || COMPAT
1310 help 1151 help
1311 This enables 32 bit time_t support 1152 This enables 32 bit time_t support in addition to 64 bit time_t support.
1312 This is relevant on all 32-bit arch 1153 This is relevant on all 32-bit architectures, and 64-bit architectures
1313 as part of compat syscall handling. 1154 as part of compat syscall handling.
1314 1155
1315 config ARCH_NO_PREEMPT 1156 config ARCH_NO_PREEMPT
1316 bool 1157 bool
1317 1158
>> 1159 config ARCH_EPHEMERAL_INODES
>> 1160 def_bool n
>> 1161 help
>> 1162 An arch should select this symbol if it doesn't keep track of inode
>> 1163 instances on its own, but instead relies on something else (e.g. the
>> 1164 host kernel for an UML kernel).
>> 1165
1318 config ARCH_SUPPORTS_RT 1166 config ARCH_SUPPORTS_RT
1319 bool 1167 bool
1320 1168
1321 config CPU_NO_EFFICIENT_FFS 1169 config CPU_NO_EFFICIENT_FFS
1322 def_bool n 1170 def_bool n
1323 1171
1324 config HAVE_ARCH_VMAP_STACK 1172 config HAVE_ARCH_VMAP_STACK
1325 def_bool n 1173 def_bool n
1326 help 1174 help
1327 An arch should select this symbol i 1175 An arch should select this symbol if it can support kernel stacks
1328 in vmalloc space. This means: 1176 in vmalloc space. This means:
1329 1177
1330 - vmalloc space must be large enoug 1178 - vmalloc space must be large enough to hold many kernel stacks.
1331 This may rule out many 32-bit arc 1179 This may rule out many 32-bit architectures.
1332 1180
1333 - Stacks in vmalloc space need to w 1181 - Stacks in vmalloc space need to work reliably. For example, if
1334 vmap page tables are created on d 1182 vmap page tables are created on demand, either this mechanism
1335 needs to work while the stack poi 1183 needs to work while the stack points to a virtual address with
1336 unpopulated page tables or arch c 1184 unpopulated page tables or arch code (switch_to() and switch_mm(),
1337 most likely) needs to ensure that 1185 most likely) needs to ensure that the stack's page table entries
1338 are populated before running on a 1186 are populated before running on a possibly unpopulated stack.
1339 1187
1340 - If the stack overflows into a gua 1188 - If the stack overflows into a guard page, something reasonable
1341 should happen. The definition of 1189 should happen. The definition of "reasonable" is flexible, but
1342 instantly rebooting without loggi 1190 instantly rebooting without logging anything would be unfriendly.
1343 1191
1344 config VMAP_STACK 1192 config VMAP_STACK
1345 default y 1193 default y
1346 bool "Use a virtually-mapped stack" 1194 bool "Use a virtually-mapped stack"
1347 depends on HAVE_ARCH_VMAP_STACK 1195 depends on HAVE_ARCH_VMAP_STACK
1348 depends on !KASAN || KASAN_HW_TAGS || 1196 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
1349 help 1197 help
1350 Enable this if you want the use vir 1198 Enable this if you want the use virtually-mapped kernel stacks
1351 with guard pages. This causes kern 1199 with guard pages. This causes kernel stack overflows to be
1352 caught immediately rather than caus 1200 caught immediately rather than causing difficult-to-diagnose
1353 corruption. 1201 corruption.
1354 1202
1355 To use this with software KASAN mod 1203 To use this with software KASAN modes, the architecture must support
1356 backing virtual mappings with real 1204 backing virtual mappings with real shadow memory, and KASAN_VMALLOC
1357 must be enabled. 1205 must be enabled.
1358 1206
1359 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1207 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1360 def_bool n 1208 def_bool n
1361 help 1209 help
1362 An arch should select this symbol i 1210 An arch should select this symbol if it can support kernel stack
1363 offset randomization with calls to 1211 offset randomization with calls to add_random_kstack_offset()
1364 during syscall entry and choose_ran 1212 during syscall entry and choose_random_kstack_offset() during
1365 syscall exit. Careful removal of -f 1213 syscall exit. Careful removal of -fstack-protector-strong and
1366 -fstack-protector should also be ap 1214 -fstack-protector should also be applied to the entry code and
1367 closely examined, as the artificial 1215 closely examined, as the artificial stack bump looks like an array
1368 to the compiler, so it will attempt 1216 to the compiler, so it will attempt to add canary checks regardless
1369 of the static branch state. 1217 of the static branch state.
1370 1218
1371 config RANDOMIZE_KSTACK_OFFSET 1219 config RANDOMIZE_KSTACK_OFFSET
1372 bool "Support for randomizing kernel 1220 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT
1373 default y 1221 default y
1374 depends on HAVE_ARCH_RANDOMIZE_KSTACK 1222 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1375 depends on INIT_STACK_NONE || !CC_IS_ 1223 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
1376 help 1224 help
1377 The kernel stack offset can be rand 1225 The kernel stack offset can be randomized (after pt_regs) by
1378 roughly 5 bits of entropy, frustrat 1226 roughly 5 bits of entropy, frustrating memory corruption
1379 attacks that depend on stack addres 1227 attacks that depend on stack address determinism or
1380 cross-syscall address exposures. 1228 cross-syscall address exposures.
1381 1229
1382 The feature is controlled via the " 1230 The feature is controlled via the "randomize_kstack_offset=on/off"
1383 kernel boot param, and if turned of 1231 kernel boot param, and if turned off has zero overhead due to its use
1384 of static branches (see JUMP_LABEL) 1232 of static branches (see JUMP_LABEL).
1385 1233
1386 If unsure, say Y. 1234 If unsure, say Y.
1387 1235
1388 config RANDOMIZE_KSTACK_OFFSET_DEFAULT 1236 config RANDOMIZE_KSTACK_OFFSET_DEFAULT
1389 bool "Default state of kernel stack o 1237 bool "Default state of kernel stack offset randomization"
1390 depends on RANDOMIZE_KSTACK_OFFSET 1238 depends on RANDOMIZE_KSTACK_OFFSET
1391 help 1239 help
1392 Kernel stack offset randomization i 1240 Kernel stack offset randomization is controlled by kernel boot param
1393 "randomize_kstack_offset=on/off", a 1241 "randomize_kstack_offset=on/off", and this config chooses the default
1394 boot state. 1242 boot state.
1395 1243
1396 config ARCH_OPTIONAL_KERNEL_RWX 1244 config ARCH_OPTIONAL_KERNEL_RWX
1397 def_bool n 1245 def_bool n
1398 1246
1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1247 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1400 def_bool n 1248 def_bool n
1401 1249
1402 config ARCH_HAS_STRICT_KERNEL_RWX 1250 config ARCH_HAS_STRICT_KERNEL_RWX
1403 def_bool n 1251 def_bool n
1404 1252
1405 config STRICT_KERNEL_RWX 1253 config STRICT_KERNEL_RWX
1406 bool "Make kernel text and rodata rea 1254 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1407 depends on ARCH_HAS_STRICT_KERNEL_RWX 1255 depends on ARCH_HAS_STRICT_KERNEL_RWX
1408 default !ARCH_OPTIONAL_KERNEL_RWX || 1256 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1409 help 1257 help
1410 If this is set, kernel text and rod 1258 If this is set, kernel text and rodata memory will be made read-only,
1411 and non-text memory will be made no 1259 and non-text memory will be made non-executable. This provides
1412 protection against certain security 1260 protection against certain security exploits (e.g. executing the heap
1413 or modifying text) 1261 or modifying text)
1414 1262
1415 These features are considered stand 1263 These features are considered standard security practice these days.
1416 You should say Y here in almost all 1264 You should say Y here in almost all cases.
1417 1265
1418 config ARCH_HAS_STRICT_MODULE_RWX 1266 config ARCH_HAS_STRICT_MODULE_RWX
1419 def_bool n 1267 def_bool n
1420 1268
1421 config STRICT_MODULE_RWX 1269 config STRICT_MODULE_RWX
1422 bool "Set loadable kernel module data 1270 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 1271 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1424 default !ARCH_OPTIONAL_KERNEL_RWX || 1272 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1425 help 1273 help
1426 If this is set, module text and rod 1274 If this is set, module text and rodata memory will be made read-only,
1427 and non-text memory will be made no 1275 and non-text memory will be made non-executable. This provides
1428 protection against certain security 1276 protection against certain security exploits (e.g. writing to text)
1429 1277
1430 # select if the architecture provides an asm/ 1278 # select if the architecture provides an asm/dma-direct.h header
1431 config ARCH_HAS_PHYS_TO_DMA 1279 config ARCH_HAS_PHYS_TO_DMA
1432 bool 1280 bool
1433 1281
1434 config HAVE_ARCH_COMPILER_H 1282 config HAVE_ARCH_COMPILER_H
1435 bool 1283 bool
1436 help 1284 help
1437 An architecture can select this if 1285 An architecture can select this if it provides an
1438 asm/compiler.h header that should b 1286 asm/compiler.h header that should be included after
1439 linux/compiler-*.h in order to over 1287 linux/compiler-*.h in order to override macro definitions that those
1440 headers generally provide. 1288 headers generally provide.
1441 1289
1442 config HAVE_ARCH_PREL32_RELOCATIONS 1290 config HAVE_ARCH_PREL32_RELOCATIONS
1443 bool 1291 bool
1444 help 1292 help
1445 May be selected by an architecture 1293 May be selected by an architecture if it supports place-relative
1446 32-bit relocations, both in the too 1294 32-bit relocations, both in the toolchain and in the module loader,
1447 in which case relative references c 1295 in which case relative references can be used in special sections
1448 for PCI fixup, initcalls etc which 1296 for PCI fixup, initcalls etc which are only half the size on 64 bit
1449 architectures, and don't require ru 1297 architectures, and don't require runtime relocation on relocatable
1450 kernels. 1298 kernels.
1451 1299
1452 config ARCH_USE_MEMREMAP_PROT 1300 config ARCH_USE_MEMREMAP_PROT
1453 bool 1301 bool
1454 1302
1455 config LOCK_EVENT_COUNTS 1303 config LOCK_EVENT_COUNTS
1456 bool "Locking event counts collection 1304 bool "Locking event counts collection"
1457 depends on DEBUG_FS 1305 depends on DEBUG_FS
1458 help 1306 help
1459 Enable light-weight counting of var 1307 Enable light-weight counting of various locking related events
1460 in the system with minimal performa 1308 in the system with minimal performance impact. This reduces
1461 the chance of application behavior 1309 the chance of application behavior change because of timing
1462 differences. The counts are reporte 1310 differences. The counts are reported via debugfs.
1463 1311
1464 # Select if the architecture has support for 1312 # Select if the architecture has support for applying RELR relocations.
1465 config ARCH_HAS_RELR 1313 config ARCH_HAS_RELR
1466 bool 1314 bool
1467 1315
1468 config RELR 1316 config RELR
1469 bool "Use RELR relocation packing" 1317 bool "Use RELR relocation packing"
1470 depends on ARCH_HAS_RELR && TOOLS_SUP 1318 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
1471 default y 1319 default y
1472 help 1320 help
1473 Store the kernel's dynamic relocati 1321 Store the kernel's dynamic relocations in the RELR relocation packing
1474 format. Requires a compatible linke 1322 format. Requires a compatible linker (LLD supports this feature), as
1475 well as compatible NM and OBJCOPY u 1323 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1476 are compatible). 1324 are compatible).
1477 1325
1478 config ARCH_HAS_MEM_ENCRYPT 1326 config ARCH_HAS_MEM_ENCRYPT
1479 bool 1327 bool
1480 1328
1481 config ARCH_HAS_CC_PLATFORM 1329 config ARCH_HAS_CC_PLATFORM
1482 bool 1330 bool
1483 1331
1484 config HAVE_SPARSE_SYSCALL_NR 1332 config HAVE_SPARSE_SYSCALL_NR
1485 bool 1333 bool
1486 help 1334 help
1487 An architecture should select this 1335 An architecture should select this if its syscall numbering is sparse
1488 to save space. For example, MIPS ar 1336 to save space. For example, MIPS architecture has a syscall array with
1489 entries at 4000, 5000 and 6000 loca 1337 entries at 4000, 5000 and 6000 locations. This option turns on syscall
1490 related optimizations for a given a 1338 related optimizations for a given architecture.
1491 1339
1492 config ARCH_HAS_VDSO_DATA 1340 config ARCH_HAS_VDSO_DATA
1493 bool 1341 bool
1494 1342
1495 config HAVE_STATIC_CALL 1343 config HAVE_STATIC_CALL
1496 bool 1344 bool
1497 1345
1498 config HAVE_STATIC_CALL_INLINE 1346 config HAVE_STATIC_CALL_INLINE
1499 bool 1347 bool
1500 depends on HAVE_STATIC_CALL 1348 depends on HAVE_STATIC_CALL
1501 select OBJTOOL 1349 select OBJTOOL
1502 1350
1503 config HAVE_PREEMPT_DYNAMIC 1351 config HAVE_PREEMPT_DYNAMIC
1504 bool 1352 bool
1505 1353
1506 config HAVE_PREEMPT_DYNAMIC_CALL 1354 config HAVE_PREEMPT_DYNAMIC_CALL
1507 bool 1355 bool
1508 depends on HAVE_STATIC_CALL 1356 depends on HAVE_STATIC_CALL
1509 select HAVE_PREEMPT_DYNAMIC 1357 select HAVE_PREEMPT_DYNAMIC
1510 help 1358 help
1511 An architecture should select this 1359 An architecture should select this if it can handle the preemption
1512 model being selected at boot time u 1360 model being selected at boot time using static calls.
1513 1361
1514 Where an architecture selects HAVE_ 1362 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a
1515 preemption function will be patched 1363 preemption function will be patched directly.
1516 1364
1517 Where an architecture does not sele 1365 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any
1518 call to a preemption function will 1366 call to a preemption function will go through a trampoline, and the
1519 trampoline will be patched. 1367 trampoline will be patched.
1520 1368
1521 It is strongly advised to support i 1369 It is strongly advised to support inline static call to avoid any
1522 overhead. 1370 overhead.
1523 1371
1524 config HAVE_PREEMPT_DYNAMIC_KEY 1372 config HAVE_PREEMPT_DYNAMIC_KEY
1525 bool 1373 bool
1526 depends on HAVE_ARCH_JUMP_LABEL 1374 depends on HAVE_ARCH_JUMP_LABEL
1527 select HAVE_PREEMPT_DYNAMIC 1375 select HAVE_PREEMPT_DYNAMIC
1528 help 1376 help
1529 An architecture should select this 1377 An architecture should select this if it can handle the preemption
1530 model being selected at boot time u 1378 model being selected at boot time using static keys.
1531 1379
1532 Each preemption function will be gi 1380 Each preemption function will be given an early return based on a
1533 static key. This should have slight 1381 static key. This should have slightly lower overhead than non-inline
1534 static calls, as this effectively i 1382 static calls, as this effectively inlines each trampoline into the
1535 start of its callee. This may avoid 1383 start of its callee. This may avoid redundant work, and may
1536 integrate better with CFI schemes. 1384 integrate better with CFI schemes.
1537 1385
1538 This will have greater overhead tha 1386 This will have greater overhead than using inline static calls as
1539 the call to the preemption function 1387 the call to the preemption function cannot be entirely elided.
1540 1388
1541 config ARCH_WANT_LD_ORPHAN_WARN 1389 config ARCH_WANT_LD_ORPHAN_WARN
1542 bool 1390 bool
1543 help 1391 help
1544 An arch should select this symbol o 1392 An arch should select this symbol once all linker sections are explicitly
1545 included, size-asserted, or discard 1393 included, size-asserted, or discarded in the linker scripts. This is
1546 important because we never want exp 1394 important because we never want expected sections to be placed heuristically
1547 by the linker, since the locations 1395 by the linker, since the locations of such sections can change between linker
1548 versions. 1396 versions.
1549 1397
1550 config HAVE_ARCH_PFN_VALID 1398 config HAVE_ARCH_PFN_VALID
1551 bool 1399 bool
1552 1400
1553 config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1401 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1554 bool 1402 bool
1555 1403
1556 config ARCH_SUPPORTS_PAGE_TABLE_CHECK 1404 config ARCH_SUPPORTS_PAGE_TABLE_CHECK
1557 bool 1405 bool
1558 1406
1559 config ARCH_SPLIT_ARG64 1407 config ARCH_SPLIT_ARG64
1560 bool 1408 bool
1561 help 1409 help
1562 If a 32-bit architecture requires 6 1410 If a 32-bit architecture requires 64-bit arguments to be split into
1563 pairs of 32-bit arguments, select t 1411 pairs of 32-bit arguments, select this option.
1564 1412
1565 config ARCH_HAS_ELFCORE_COMPAT 1413 config ARCH_HAS_ELFCORE_COMPAT
1566 bool 1414 bool
1567 1415
1568 config ARCH_HAS_PARANOID_L1D_FLUSH 1416 config ARCH_HAS_PARANOID_L1D_FLUSH
1569 bool 1417 bool
1570 1418
1571 config ARCH_HAVE_TRACE_MMIO_ACCESS 1419 config ARCH_HAVE_TRACE_MMIO_ACCESS
1572 bool 1420 bool
1573 1421
1574 config DYNAMIC_SIGFRAME 1422 config DYNAMIC_SIGFRAME
1575 bool 1423 bool
1576 1424
1577 # Select, if arch has a named attribute group 1425 # Select, if arch has a named attribute group bound to NUMA device nodes.
1578 config HAVE_ARCH_NODE_DEV_GROUP 1426 config HAVE_ARCH_NODE_DEV_GROUP
1579 bool 1427 bool
1580 1428
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 1429 config ARCH_HAS_NONLEAF_PMD_YOUNG
1590 bool 1430 bool
1591 help 1431 help
1592 Architectures that select this opti 1432 Architectures that select this option are capable of setting the
1593 accessed bit in non-leaf PMD entrie 1433 accessed bit in non-leaf PMD entries when using them as part of linear
1594 address translations. Page table wa 1434 address translations. Page table walkers that clear the accessed bit
1595 may use this capability to reduce t 1435 may use this capability to reduce their search space.
1596 1436
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" 1437 source "kernel/gcov/Kconfig"
1604 1438
1605 source "scripts/gcc-plugins/Kconfig" 1439 source "scripts/gcc-plugins/Kconfig"
1606 1440
1607 config FUNCTION_ALIGNMENT_4B 1441 config FUNCTION_ALIGNMENT_4B
1608 bool 1442 bool
1609 1443
1610 config FUNCTION_ALIGNMENT_8B 1444 config FUNCTION_ALIGNMENT_8B
1611 bool 1445 bool
1612 1446
1613 config FUNCTION_ALIGNMENT_16B 1447 config FUNCTION_ALIGNMENT_16B
1614 bool 1448 bool
1615 1449
1616 config FUNCTION_ALIGNMENT_32B 1450 config FUNCTION_ALIGNMENT_32B
1617 bool 1451 bool
1618 1452
1619 config FUNCTION_ALIGNMENT_64B 1453 config FUNCTION_ALIGNMENT_64B
1620 bool 1454 bool
1621 1455
1622 config FUNCTION_ALIGNMENT 1456 config FUNCTION_ALIGNMENT
1623 int 1457 int
1624 default 64 if FUNCTION_ALIGNMENT_64B 1458 default 64 if FUNCTION_ALIGNMENT_64B
1625 default 32 if FUNCTION_ALIGNMENT_32B 1459 default 32 if FUNCTION_ALIGNMENT_32B
1626 default 16 if FUNCTION_ALIGNMENT_16B 1460 default 16 if FUNCTION_ALIGNMENT_16B
1627 default 8 if FUNCTION_ALIGNMENT_8B 1461 default 8 if FUNCTION_ALIGNMENT_8B
1628 default 4 if FUNCTION_ALIGNMENT_4B 1462 default 4 if FUNCTION_ALIGNMENT_4B
1629 default 0 1463 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 1464
1646 endmenu 1465 endmenu
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