1 # SPDX-License-Identifier: GPL-2.0 1 # SPDX-License-Identifier: GPL-2.0
2 # 2 #
3 # General architecture dependent options 3 # General architecture dependent options
4 # 4 #
5 5
6 # 6 #
7 # Note: arch/$(SRCARCH)/Kconfig needs to be in 7 # Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can
8 # override the default values in this file. 8 # override the default values in this file.
9 # 9 #
10 source "arch/$(SRCARCH)/Kconfig" 10 source "arch/$(SRCARCH)/Kconfig"
11 11
12 config ARCH_CONFIGURES_CPU_MITIGATIONS <<
13 bool <<
14 <<
15 if !ARCH_CONFIGURES_CPU_MITIGATIONS <<
16 config CPU_MITIGATIONS <<
17 def_bool y <<
18 endif <<
19 <<
20 menu "General architecture-dependent options" 12 menu "General architecture-dependent options"
21 13
22 config ARCH_HAS_SUBPAGE_FAULTS !! 14 config CRASH_CORE
23 bool <<
24 help <<
25 Select if the architecture can check <<
26 granularity (e.g. arm64 MTE). The pr <<
27 must be implemented. <<
28 <<
29 config HOTPLUG_SMT <<
30 bool <<
31 <<
32 config SMT_NUM_THREADS_DYNAMIC <<
33 bool 15 bool
34 16
35 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU !! 17 config KEXEC_CORE
36 config HOTPLUG_CORE_SYNC !! 18 select CRASH_CORE
37 bool 19 bool
38 20
39 # Basic CPU dead synchronization selected by a !! 21 config KEXEC_ELF
40 config HOTPLUG_CORE_SYNC_DEAD <<
41 bool 22 bool
42 select HOTPLUG_CORE_SYNC <<
43 23
44 # Full CPU synchronization with alive state se !! 24 config HAVE_IMA_KEXEC
45 config HOTPLUG_CORE_SYNC_FULL <<
46 bool 25 bool
47 select HOTPLUG_CORE_SYNC_DEAD if HOTPL <<
48 select HOTPLUG_CORE_SYNC <<
49 26
50 config HOTPLUG_SPLIT_STARTUP !! 27 config ARCH_HAS_SUBPAGE_FAULTS
51 bool 28 bool
52 select HOTPLUG_CORE_SYNC_FULL !! 29 help
>> 30 Select if the architecture can check permissions at sub-page
>> 31 granularity (e.g. arm64 MTE). The probe_user_*() functions
>> 32 must be implemented.
53 33
54 config HOTPLUG_PARALLEL !! 34 config HOTPLUG_SMT
55 bool 35 bool
56 select HOTPLUG_SPLIT_STARTUP <<
57 36
58 config GENERIC_ENTRY 37 config GENERIC_ENTRY
59 bool !! 38 bool
60 39
61 config KPROBES 40 config KPROBES
62 bool "Kprobes" 41 bool "Kprobes"
>> 42 depends on MODULES
63 depends on HAVE_KPROBES 43 depends on HAVE_KPROBES
64 select KALLSYMS 44 select KALLSYMS
65 select EXECMEM !! 45 select TASKS_RCU if PREEMPTION
66 select NEED_TASKS_RCU <<
67 help 46 help
68 Kprobes allows you to trap at almost 47 Kprobes allows you to trap at almost any kernel address and
69 execute a callback function. regist 48 execute a callback function. register_kprobe() establishes
70 a probepoint and specifies the callb 49 a probepoint and specifies the callback. Kprobes is useful
71 for kernel debugging, non-intrusive 50 for kernel debugging, non-intrusive instrumentation and testing.
72 If in doubt, say "N". 51 If in doubt, say "N".
73 52
74 config JUMP_LABEL 53 config JUMP_LABEL
75 bool "Optimize very unlikely/likely br 54 bool "Optimize very unlikely/likely branches"
76 depends on HAVE_ARCH_JUMP_LABEL 55 depends on HAVE_ARCH_JUMP_LABEL
77 select OBJTOOL if HAVE_JUMP_LABEL_HACK 56 select OBJTOOL if HAVE_JUMP_LABEL_HACK
78 help 57 help
79 This option enables a transparent br !! 58 This option enables a transparent branch optimization that
80 makes certain almost-always-true or !! 59 makes certain almost-always-true or almost-always-false branch
81 conditions even cheaper to execute w !! 60 conditions even cheaper to execute within the kernel.
82 !! 61
83 Certain performance-sensitive kernel !! 62 Certain performance-sensitive kernel code, such as trace points,
84 scheduler functionality, networking !! 63 scheduler functionality, networking code and KVM have such
85 branches and include support for thi !! 64 branches and include support for this optimization technique.
86 !! 65
87 If it is detected that the compiler !! 66 If it is detected that the compiler has support for "asm goto",
88 the kernel will compile such branche !! 67 the kernel will compile such branches with just a nop
89 instruction. When the condition flag !! 68 instruction. When the condition flag is toggled to true, the
90 nop will be converted to a jump inst !! 69 nop will be converted to a jump instruction to execute the
91 conditional block of instructions. !! 70 conditional block of instructions.
92 !! 71
93 This technique lowers overhead and s !! 72 This technique lowers overhead and stress on the branch prediction
94 of the processor and generally makes !! 73 of the processor and generally makes the kernel faster. The update
95 of the condition is slower, but thos !! 74 of the condition is slower, but those are always very rare.
96 75
97 ( On 32-bit x86, the necessary optio !! 76 ( On 32-bit x86, the necessary options added to the compiler
98 flags may increase the size of the !! 77 flags may increase the size of the kernel slightly. )
99 78
100 config STATIC_KEYS_SELFTEST 79 config STATIC_KEYS_SELFTEST
101 bool "Static key selftest" 80 bool "Static key selftest"
102 depends on JUMP_LABEL 81 depends on JUMP_LABEL
103 help 82 help
104 Boot time self-test of the branch pa 83 Boot time self-test of the branch patching code.
105 84
106 config STATIC_CALL_SELFTEST 85 config STATIC_CALL_SELFTEST
107 bool "Static call selftest" 86 bool "Static call selftest"
108 depends on HAVE_STATIC_CALL 87 depends on HAVE_STATIC_CALL
109 help 88 help
110 Boot time self-test of the call patc 89 Boot time self-test of the call patching code.
111 90
112 config OPTPROBES 91 config OPTPROBES
113 def_bool y 92 def_bool y
114 depends on KPROBES && HAVE_OPTPROBES 93 depends on KPROBES && HAVE_OPTPROBES
115 select NEED_TASKS_RCU !! 94 select TASKS_RCU if PREEMPTION
116 95
117 config KPROBES_ON_FTRACE 96 config KPROBES_ON_FTRACE
118 def_bool y 97 def_bool y
119 depends on KPROBES && HAVE_KPROBES_ON_ 98 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
120 depends on DYNAMIC_FTRACE_WITH_REGS 99 depends on DYNAMIC_FTRACE_WITH_REGS
121 help 100 help
122 If function tracer is enabled and th !! 101 If function tracer is enabled and the arch supports full
123 passing of pt_regs to function traci !! 102 passing of pt_regs to function tracing, then kprobes can
124 optimize on top of function tracing. !! 103 optimize on top of function tracing.
125 104
126 config UPROBES 105 config UPROBES
127 def_bool n 106 def_bool n
128 depends on ARCH_SUPPORTS_UPROBES 107 depends on ARCH_SUPPORTS_UPROBES
129 help 108 help
130 Uprobes is the user-space counterpar 109 Uprobes is the user-space counterpart to kprobes: they
131 enable instrumentation applications 110 enable instrumentation applications (such as 'perf probe')
132 to establish unintrusive probes in u 111 to establish unintrusive probes in user-space binaries and
133 libraries, by executing handler func 112 libraries, by executing handler functions when the probes
134 are hit by user-space applications. 113 are hit by user-space applications.
135 114
136 ( These probes come in the form of s 115 ( These probes come in the form of single-byte breakpoints,
137 managed by the kernel and kept tra 116 managed by the kernel and kept transparent to the probed
138 application. ) 117 application. )
139 118
140 config HAVE_64BIT_ALIGNED_ACCESS 119 config HAVE_64BIT_ALIGNED_ACCESS
141 def_bool 64BIT && !HAVE_EFFICIENT_UNAL 120 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
142 help 121 help
143 Some architectures require 64 bit ac 122 Some architectures require 64 bit accesses to be 64 bit
144 aligned, which also requires structs 123 aligned, which also requires structs containing 64 bit values
145 to be 64 bit aligned too. This inclu 124 to be 64 bit aligned too. This includes some 32 bit
146 architectures which can do 64 bit ac 125 architectures which can do 64 bit accesses, as well as 64 bit
147 architectures without unaligned acce 126 architectures without unaligned access.
148 127
149 This symbol should be selected by an 128 This symbol should be selected by an architecture if 64 bit
150 accesses are required to be 64 bit a 129 accesses are required to be 64 bit aligned in this way even
151 though it is not a 64 bit architectu 130 though it is not a 64 bit architecture.
152 131
153 See Documentation/core-api/unaligned 132 See Documentation/core-api/unaligned-memory-access.rst for
154 more information on the topic of una 133 more information on the topic of unaligned memory accesses.
155 134
156 config HAVE_EFFICIENT_UNALIGNED_ACCESS 135 config HAVE_EFFICIENT_UNALIGNED_ACCESS
157 bool 136 bool
158 help 137 help
159 Some architectures are unable to per 138 Some architectures are unable to perform unaligned accesses
160 without the use of get_unaligned/put 139 without the use of get_unaligned/put_unaligned. Others are
161 unable to perform such accesses effi 140 unable to perform such accesses efficiently (e.g. trap on
162 unaligned access and require fixing 141 unaligned access and require fixing it up in the exception
163 handler.) 142 handler.)
164 143
165 This symbol should be selected by an 144 This symbol should be selected by an architecture if it can
166 perform unaligned accesses efficient 145 perform unaligned accesses efficiently to allow different
167 code paths to be selected for these 146 code paths to be selected for these cases. Some network
168 drivers, for example, could opt to n 147 drivers, for example, could opt to not fix up alignment
169 problems with received packets if do 148 problems with received packets if doing so would not help
170 much. 149 much.
171 150
172 See Documentation/core-api/unaligned 151 See Documentation/core-api/unaligned-memory-access.rst for more
173 information on the topic of unaligne 152 information on the topic of unaligned memory accesses.
174 153
175 config ARCH_USE_BUILTIN_BSWAP 154 config ARCH_USE_BUILTIN_BSWAP
176 bool 155 bool
177 help 156 help
178 Modern versions of GCC (since 4.4) h !! 157 Modern versions of GCC (since 4.4) have builtin functions
179 for handling byte-swapping. Using th !! 158 for handling byte-swapping. Using these, instead of the old
180 inline assembler that the architectu !! 159 inline assembler that the architecture code provides in the
181 __arch_bswapXX() macros, allows the !! 160 __arch_bswapXX() macros, allows the compiler to see what's
182 happening and offers more opportunit !! 161 happening and offers more opportunity for optimisation. In
183 particular, the compiler will be abl !! 162 particular, the compiler will be able to combine the byteswap
184 with a nearby load or store and use !! 163 with a nearby load or store and use load-and-swap or
185 store-and-swap instructions if the a !! 164 store-and-swap instructions if the architecture has them. It
186 should almost *never* result in code !! 165 should almost *never* result in code which is worse than the
187 hand-coded assembler in <asm/swab.h> !! 166 hand-coded assembler in <asm/swab.h>. But just in case it
188 does, the use of the builtins is opt !! 167 does, the use of the builtins is optional.
189 !! 168
190 Any architecture with load-and-swap !! 169 Any architecture with load-and-swap or store-and-swap
191 instructions should set this. And it !! 170 instructions should set this. And it shouldn't hurt to set it
192 on architectures that don't have suc !! 171 on architectures that don't have such instructions.
193 172
194 config KRETPROBES 173 config KRETPROBES
195 def_bool y 174 def_bool y
196 depends on KPROBES && (HAVE_KRETPROBES 175 depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK)
197 176
198 config KRETPROBE_ON_RETHOOK 177 config KRETPROBE_ON_RETHOOK
199 def_bool y 178 def_bool y
200 depends on HAVE_RETHOOK 179 depends on HAVE_RETHOOK
201 depends on KRETPROBES 180 depends on KRETPROBES
202 select RETHOOK 181 select RETHOOK
203 182
204 config USER_RETURN_NOTIFIER 183 config USER_RETURN_NOTIFIER
205 bool 184 bool
206 depends on HAVE_USER_RETURN_NOTIFIER 185 depends on HAVE_USER_RETURN_NOTIFIER
207 help 186 help
208 Provide a kernel-internal notificati 187 Provide a kernel-internal notification when a cpu is about to
209 switch to user mode. 188 switch to user mode.
210 189
211 config HAVE_IOREMAP_PROT 190 config HAVE_IOREMAP_PROT
212 bool 191 bool
213 192
214 config HAVE_KPROBES 193 config HAVE_KPROBES
215 bool 194 bool
216 195
217 config HAVE_KRETPROBES 196 config HAVE_KRETPROBES
218 bool 197 bool
219 198
220 config HAVE_OPTPROBES 199 config HAVE_OPTPROBES
221 bool 200 bool
222 201
223 config HAVE_KPROBES_ON_FTRACE 202 config HAVE_KPROBES_ON_FTRACE
224 bool 203 bool
225 204
226 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 205 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
227 bool 206 bool
228 help 207 help
229 Since kretprobes modifies return add 208 Since kretprobes modifies return address on the stack, the
230 stacktrace may see the kretprobe tra 209 stacktrace may see the kretprobe trampoline address instead
231 of correct one. If the architecture 210 of correct one. If the architecture stacktrace code and
232 unwinder can adjust such entries, se 211 unwinder can adjust such entries, select this configuration.
233 212
234 config HAVE_FUNCTION_ERROR_INJECTION 213 config HAVE_FUNCTION_ERROR_INJECTION
235 bool 214 bool
236 215
237 config HAVE_NMI 216 config HAVE_NMI
238 bool 217 bool
239 218
240 config HAVE_FUNCTION_DESCRIPTORS 219 config HAVE_FUNCTION_DESCRIPTORS
241 bool 220 bool
242 221
243 config TRACE_IRQFLAGS_SUPPORT 222 config TRACE_IRQFLAGS_SUPPORT
244 bool 223 bool
245 224
246 config TRACE_IRQFLAGS_NMI_SUPPORT 225 config TRACE_IRQFLAGS_NMI_SUPPORT
247 bool 226 bool
248 227
249 # 228 #
250 # An arch should select this if it provides al 229 # An arch should select this if it provides all these things:
251 # 230 #
252 # task_pt_regs() in asm/process 231 # task_pt_regs() in asm/processor.h or asm/ptrace.h
253 # arch_has_single_step() if there is ha 232 # arch_has_single_step() if there is hardware single-step support
254 # arch_has_block_step() if there is ha 233 # arch_has_block_step() if there is hardware block-step support
255 # asm/syscall.h supplying asm- 234 # asm/syscall.h supplying asm-generic/syscall.h interface
256 # linux/regset.h user_regset in 235 # linux/regset.h user_regset interfaces
257 # CORE_DUMP_USE_REGSET #define'd in l 236 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h
258 # TIF_SYSCALL_TRACE calls ptrace_r 237 # TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit}
259 # TIF_NOTIFY_RESUME calls resume_u 238 # TIF_NOTIFY_RESUME calls resume_user_mode_work()
260 # 239 #
261 config HAVE_ARCH_TRACEHOOK 240 config HAVE_ARCH_TRACEHOOK
262 bool 241 bool
263 242
264 config HAVE_DMA_CONTIGUOUS 243 config HAVE_DMA_CONTIGUOUS
265 bool 244 bool
266 245
267 config GENERIC_SMP_IDLE_THREAD 246 config GENERIC_SMP_IDLE_THREAD
268 bool 247 bool
269 248
270 config GENERIC_IDLE_POLL_SETUP 249 config GENERIC_IDLE_POLL_SETUP
271 bool 250 bool
272 251
273 config ARCH_HAS_FORTIFY_SOURCE 252 config ARCH_HAS_FORTIFY_SOURCE
274 bool 253 bool
275 help 254 help
276 An architecture should select this w 255 An architecture should select this when it can successfully
277 build and run with CONFIG_FORTIFY_SO 256 build and run with CONFIG_FORTIFY_SOURCE.
278 257
279 # 258 #
280 # Select if the arch provides a historic keepi 259 # Select if the arch provides a historic keepinit alias for the retain_initrd
281 # command line option 260 # command line option
282 # 261 #
283 config ARCH_HAS_KEEPINITRD 262 config ARCH_HAS_KEEPINITRD
284 bool 263 bool
285 264
286 # Select if arch has all set_memory_ro/rw/x/nx 265 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
287 config ARCH_HAS_SET_MEMORY 266 config ARCH_HAS_SET_MEMORY
288 bool 267 bool
289 268
290 # Select if arch has all set_direct_map_invali 269 # Select if arch has all set_direct_map_invalid/default() functions
291 config ARCH_HAS_SET_DIRECT_MAP 270 config ARCH_HAS_SET_DIRECT_MAP
292 bool 271 bool
293 272
294 # 273 #
295 # Select if the architecture provides the arch 274 # Select if the architecture provides the arch_dma_set_uncached symbol to
296 # either provide an uncached segment alias for 275 # either provide an uncached segment alias for a DMA allocation, or
297 # to remap the page tables in place. 276 # to remap the page tables in place.
298 # 277 #
299 config ARCH_HAS_DMA_SET_UNCACHED 278 config ARCH_HAS_DMA_SET_UNCACHED
300 bool 279 bool
301 280
302 # 281 #
303 # Select if the architectures provides the arc 282 # Select if the architectures provides the arch_dma_clear_uncached symbol
304 # to undo an in-place page table remap for unc 283 # to undo an in-place page table remap for uncached access.
305 # 284 #
306 config ARCH_HAS_DMA_CLEAR_UNCACHED 285 config ARCH_HAS_DMA_CLEAR_UNCACHED
307 bool 286 bool
308 287
309 config ARCH_HAS_CPU_FINALIZE_INIT !! 288 # Select if arch init_task must go in the __init_task_data section
>> 289 config ARCH_TASK_STRUCT_ON_STACK
310 bool 290 bool
311 291
312 # The architecture has a per-task state that i !! 292 # Select if arch has its private alloc_task_struct() function
313 config ARCH_HAS_CPU_PASID !! 293 config ARCH_TASK_STRUCT_ALLOCATOR
314 bool 294 bool
315 select IOMMU_MM_DATA <<
316 295
317 config HAVE_ARCH_THREAD_STRUCT_WHITELIST 296 config HAVE_ARCH_THREAD_STRUCT_WHITELIST
318 bool 297 bool
>> 298 depends on !ARCH_TASK_STRUCT_ALLOCATOR
319 help 299 help
320 An architecture should select this t 300 An architecture should select this to provide hardened usercopy
321 knowledge about what region of the t 301 knowledge about what region of the thread_struct should be
322 whitelisted for copying to userspace 302 whitelisted for copying to userspace. Normally this is only the
323 FPU registers. Specifically, arch_th 303 FPU registers. Specifically, arch_thread_struct_whitelist()
324 should be implemented. Without this, 304 should be implemented. Without this, the entire thread_struct
325 field in task_struct will be left wh 305 field in task_struct will be left whitelisted.
326 306
>> 307 # Select if arch has its private alloc_thread_stack() function
>> 308 config ARCH_THREAD_STACK_ALLOCATOR
>> 309 bool
>> 310
327 # Select if arch wants to size task_struct dyn 311 # Select if arch wants to size task_struct dynamically via arch_task_struct_size:
328 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 312 config ARCH_WANTS_DYNAMIC_TASK_STRUCT
329 bool 313 bool
330 314
331 config ARCH_WANTS_NO_INSTR 315 config ARCH_WANTS_NO_INSTR
332 bool 316 bool
333 help 317 help
334 An architecture should select this i 318 An architecture should select this if the noinstr macro is being used on
335 functions to denote that the toolcha 319 functions to denote that the toolchain should avoid instrumenting such
336 functions and is required for correc 320 functions and is required for correctness.
337 321
338 config ARCH_32BIT_OFF_T 322 config ARCH_32BIT_OFF_T
339 bool 323 bool
340 depends on !64BIT 324 depends on !64BIT
341 help 325 help
342 All new 32-bit architectures should 326 All new 32-bit architectures should have 64-bit off_t type on
343 userspace side which corresponds to 327 userspace side which corresponds to the loff_t kernel type. This
344 is the requirement for modern ABIs. 328 is the requirement for modern ABIs. Some existing architectures
345 still support 32-bit off_t. This opt 329 still support 32-bit off_t. This option is enabled for all such
346 architectures explicitly. 330 architectures explicitly.
347 331
348 # Selected by 64 bit architectures which have 332 # Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat
349 config ARCH_32BIT_USTAT_F_TINODE 333 config ARCH_32BIT_USTAT_F_TINODE
350 bool 334 bool
351 335
352 config HAVE_ASM_MODVERSIONS 336 config HAVE_ASM_MODVERSIONS
353 bool 337 bool
354 help 338 help
355 This symbol should be selected by an 339 This symbol should be selected by an architecture if it provides
356 <asm/asm-prototypes.h> to support th 340 <asm/asm-prototypes.h> to support the module versioning for symbols
357 exported from assembly code. 341 exported from assembly code.
358 342
359 config HAVE_REGS_AND_STACK_ACCESS_API 343 config HAVE_REGS_AND_STACK_ACCESS_API
360 bool 344 bool
361 help 345 help
362 This symbol should be selected by an 346 This symbol should be selected by an architecture if it supports
363 the API needed to access registers a 347 the API needed to access registers and stack entries from pt_regs,
364 declared in asm/ptrace.h 348 declared in asm/ptrace.h
365 For example the kprobes-based event 349 For example the kprobes-based event tracer needs this API.
366 350
367 config HAVE_RSEQ 351 config HAVE_RSEQ
368 bool 352 bool
369 depends on HAVE_REGS_AND_STACK_ACCESS_ 353 depends on HAVE_REGS_AND_STACK_ACCESS_API
370 help 354 help
371 This symbol should be selected by an 355 This symbol should be selected by an architecture if it
372 supports an implementation of restar 356 supports an implementation of restartable sequences.
373 357
374 config HAVE_RUST <<
375 bool <<
376 help <<
377 This symbol should be selected by an <<
378 supports Rust. <<
379 <<
380 config HAVE_FUNCTION_ARG_ACCESS_API 358 config HAVE_FUNCTION_ARG_ACCESS_API
381 bool 359 bool
382 help 360 help
383 This symbol should be selected by an 361 This symbol should be selected by an architecture if it supports
384 the API needed to access function ar 362 the API needed to access function arguments from pt_regs,
385 declared in asm/ptrace.h 363 declared in asm/ptrace.h
386 364
387 config HAVE_HW_BREAKPOINT 365 config HAVE_HW_BREAKPOINT
388 bool 366 bool
389 depends on PERF_EVENTS 367 depends on PERF_EVENTS
390 368
391 config HAVE_MIXED_BREAKPOINTS_REGS 369 config HAVE_MIXED_BREAKPOINTS_REGS
392 bool 370 bool
393 depends on HAVE_HW_BREAKPOINT 371 depends on HAVE_HW_BREAKPOINT
394 help 372 help
395 Depending on the arch implementation 373 Depending on the arch implementation of hardware breakpoints,
396 some of them have separate registers 374 some of them have separate registers for data and instruction
397 breakpoints addresses, others have m 375 breakpoints addresses, others have mixed registers to store
398 them but define the access type in a 376 them but define the access type in a control register.
399 Select this option if your arch impl 377 Select this option if your arch implements breakpoints under the
400 latter fashion. 378 latter fashion.
401 379
402 config HAVE_USER_RETURN_NOTIFIER 380 config HAVE_USER_RETURN_NOTIFIER
403 bool 381 bool
404 382
405 config HAVE_PERF_EVENTS_NMI 383 config HAVE_PERF_EVENTS_NMI
406 bool 384 bool
407 help 385 help
408 System hardware can generate an NMI 386 System hardware can generate an NMI using the perf event
409 subsystem. Also has support for cal 387 subsystem. Also has support for calculating CPU cycle events
410 to determine how many clock cycles i 388 to determine how many clock cycles in a given period.
411 389
412 config HAVE_HARDLOCKUP_DETECTOR_PERF 390 config HAVE_HARDLOCKUP_DETECTOR_PERF
413 bool 391 bool
414 depends on HAVE_PERF_EVENTS_NMI 392 depends on HAVE_PERF_EVENTS_NMI
415 help 393 help
416 The arch chooses to use the generic 394 The arch chooses to use the generic perf-NMI-based hardlockup
417 detector. Must define HAVE_PERF_EVEN 395 detector. Must define HAVE_PERF_EVENTS_NMI.
418 396
419 config HAVE_HARDLOCKUP_DETECTOR_ARCH !! 397 config HAVE_NMI_WATCHDOG
>> 398 depends on HAVE_NMI
420 bool 399 bool
421 help 400 help
422 The arch provides its own hardlockup !! 401 The arch provides a low level NMI watchdog. It provides
423 of the generic ones. !! 402 asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
424 403
425 It uses the same command line parame !! 404 config HAVE_HARDLOCKUP_DETECTOR_ARCH
426 as the generic hardlockup detectors. !! 405 bool
>> 406 select HAVE_NMI_WATCHDOG
>> 407 help
>> 408 The arch chooses to provide its own hardlockup detector, which is
>> 409 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
>> 410 interfaces and parameters provided by hardlockup detector subsystem.
427 411
428 config HAVE_PERF_REGS 412 config HAVE_PERF_REGS
429 bool 413 bool
430 help 414 help
431 Support selective register dumps for 415 Support selective register dumps for perf events. This includes
432 bit-mapping of each registers and a 416 bit-mapping of each registers and a unique architecture id.
433 417
434 config HAVE_PERF_USER_STACK_DUMP 418 config HAVE_PERF_USER_STACK_DUMP
435 bool 419 bool
436 help 420 help
437 Support user stack dumps for perf ev 421 Support user stack dumps for perf event samples. This needs
438 access to the user stack pointer whi 422 access to the user stack pointer which is not unified across
439 architectures. 423 architectures.
440 424
441 config HAVE_ARCH_JUMP_LABEL 425 config HAVE_ARCH_JUMP_LABEL
442 bool 426 bool
443 427
444 config HAVE_ARCH_JUMP_LABEL_RELATIVE 428 config HAVE_ARCH_JUMP_LABEL_RELATIVE
445 bool 429 bool
446 430
447 config MMU_GATHER_TABLE_FREE 431 config MMU_GATHER_TABLE_FREE
448 bool 432 bool
449 433
450 config MMU_GATHER_RCU_TABLE_FREE 434 config MMU_GATHER_RCU_TABLE_FREE
451 bool 435 bool
452 select MMU_GATHER_TABLE_FREE 436 select MMU_GATHER_TABLE_FREE
453 437
454 config MMU_GATHER_PAGE_SIZE 438 config MMU_GATHER_PAGE_SIZE
455 bool 439 bool
456 440
457 config MMU_GATHER_NO_RANGE 441 config MMU_GATHER_NO_RANGE
458 bool 442 bool
459 select MMU_GATHER_MERGE_VMAS 443 select MMU_GATHER_MERGE_VMAS
460 444
461 config MMU_GATHER_NO_FLUSH_CACHE 445 config MMU_GATHER_NO_FLUSH_CACHE
462 bool 446 bool
463 447
464 config MMU_GATHER_MERGE_VMAS 448 config MMU_GATHER_MERGE_VMAS
465 bool 449 bool
466 450
467 config MMU_GATHER_NO_GATHER 451 config MMU_GATHER_NO_GATHER
468 bool 452 bool
469 depends on MMU_GATHER_TABLE_FREE 453 depends on MMU_GATHER_TABLE_FREE
470 454
471 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM 455 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
472 bool 456 bool
473 help 457 help
474 Temporary select until all architect 458 Temporary select until all architectures can be converted to have
475 irqs disabled over activate_mm. Arch 459 irqs disabled over activate_mm. Architectures that do IPI based TLB
476 shootdowns should enable this. 460 shootdowns should enable this.
477 461
478 # Use normal mm refcounting for MMU_LAZY_TLB k <<
479 # MMU_LAZY_TLB_REFCOUNT=n can improve the scal <<
480 # to/from kernel threads when the same mm is r <<
481 # multi-threaded application), by reducing con <<
482 # <<
483 # This can be disabled if the architecture ens <<
484 # "lazy tlb" beyond its final refcount (i.e., <<
485 # or its kernel page tables). This could be ar <<
486 # final exit(2) TLB flush, for example. <<
487 # <<
488 # To implement this, an arch *must*: <<
489 # Ensure the _lazy_tlb variants of mmgrab/mmdr <<
490 # the lazy tlb reference of a kthread's ->acti <<
491 # converted already). <<
492 config MMU_LAZY_TLB_REFCOUNT <<
493 def_bool y <<
494 depends on !MMU_LAZY_TLB_SHOOTDOWN <<
495 <<
496 # This option allows MMU_LAZY_TLB_REFCOUNT=n. <<
497 # mm as a lazy tlb beyond its last reference c <<
498 # users before the mm is deallocated. __mmdrop <<
499 # be using the mm as a lazy tlb, so that they <<
500 # init_mm for their active mm. mm_cpumask(mm) <<
501 # may be using mm as a lazy tlb mm. <<
502 # <<
503 # To implement this, an arch *must*: <<
504 # - At the time of the final mmdrop of the mm, <<
505 # at least all possible CPUs in which the mm <<
506 # - It must meet the requirements for MMU_LAZY <<
507 config MMU_LAZY_TLB_SHOOTDOWN <<
508 bool <<
509 <<
510 config ARCH_HAVE_NMI_SAFE_CMPXCHG 462 config ARCH_HAVE_NMI_SAFE_CMPXCHG
511 bool 463 bool
512 464
513 config ARCH_HAVE_EXTRA_ELF_NOTES <<
514 bool <<
515 help <<
516 An architecture should select this i <<
517 arch-specific ELF note section to co <<
518 functions: elf_coredump_extra_notes_ <<
519 elf_coredump_extra_notes_write() whi <<
520 dumper. <<
521 <<
522 config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS <<
523 bool <<
524 <<
525 config HAVE_ALIGNED_STRUCT_PAGE 465 config HAVE_ALIGNED_STRUCT_PAGE
526 bool 466 bool
527 help 467 help
528 This makes sure that struct pages ar 468 This makes sure that struct pages are double word aligned and that
529 e.g. the SLUB allocator can perform 469 e.g. the SLUB allocator can perform double word atomic operations
530 on a struct page for better performa 470 on a struct page for better performance. However selecting this
531 might increase the size of a struct 471 might increase the size of a struct page by a word.
532 472
533 config HAVE_CMPXCHG_LOCAL 473 config HAVE_CMPXCHG_LOCAL
534 bool 474 bool
535 475
536 config HAVE_CMPXCHG_DOUBLE 476 config HAVE_CMPXCHG_DOUBLE
537 bool 477 bool
538 478
539 config ARCH_WEAK_RELEASE_ACQUIRE 479 config ARCH_WEAK_RELEASE_ACQUIRE
540 bool 480 bool
541 481
542 config ARCH_WANT_IPC_PARSE_VERSION 482 config ARCH_WANT_IPC_PARSE_VERSION
543 bool 483 bool
544 484
545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 485 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
546 bool 486 bool
547 487
548 config ARCH_WANT_OLD_COMPAT_IPC 488 config ARCH_WANT_OLD_COMPAT_IPC
549 select ARCH_WANT_COMPAT_IPC_PARSE_VERS 489 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
550 bool 490 bool
551 491
552 config HAVE_ARCH_SECCOMP 492 config HAVE_ARCH_SECCOMP
553 bool 493 bool
554 help 494 help
555 An arch should select this symbol to 495 An arch should select this symbol to support seccomp mode 1 (the fixed
556 syscall policy), and must provide an 496 syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
557 and compat syscalls if the asm-gener 497 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
558 - __NR_seccomp_read_32 498 - __NR_seccomp_read_32
559 - __NR_seccomp_write_32 499 - __NR_seccomp_write_32
560 - __NR_seccomp_exit_32 500 - __NR_seccomp_exit_32
561 - __NR_seccomp_sigreturn_32 501 - __NR_seccomp_sigreturn_32
562 502
563 config HAVE_ARCH_SECCOMP_FILTER 503 config HAVE_ARCH_SECCOMP_FILTER
564 bool 504 bool
565 select HAVE_ARCH_SECCOMP 505 select HAVE_ARCH_SECCOMP
566 help 506 help
567 An arch should select this symbol if 507 An arch should select this symbol if it provides all of these things:
568 - all the requirements for HAVE_ARCH 508 - all the requirements for HAVE_ARCH_SECCOMP
569 - syscall_get_arch() 509 - syscall_get_arch()
570 - syscall_get_arguments() 510 - syscall_get_arguments()
571 - syscall_rollback() 511 - syscall_rollback()
572 - syscall_set_return_value() 512 - syscall_set_return_value()
573 - SIGSYS siginfo_t support 513 - SIGSYS siginfo_t support
574 - secure_computing is called from a 514 - secure_computing is called from a ptrace_event()-safe context
575 - secure_computing return value is c 515 - secure_computing return value is checked and a return value of -1
576 results in the system call being s 516 results in the system call being skipped immediately.
577 - seccomp syscall wired up 517 - seccomp syscall wired up
578 - if !HAVE_SPARSE_SYSCALL_NR, have S 518 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
579 SECCOMP_ARCH_NATIVE_NR, SECCOMP_AR 519 SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
580 COMPAT is supported, have the SECC 520 COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
581 521
582 config SECCOMP 522 config SECCOMP
583 prompt "Enable seccomp to safely execu 523 prompt "Enable seccomp to safely execute untrusted bytecode"
584 def_bool y 524 def_bool y
585 depends on HAVE_ARCH_SECCOMP 525 depends on HAVE_ARCH_SECCOMP
586 help 526 help
587 This kernel feature is useful for nu 527 This kernel feature is useful for number crunching applications
588 that may need to handle untrusted by 528 that may need to handle untrusted bytecode during their
589 execution. By using pipes or other t 529 execution. By using pipes or other transports made available
590 to the process as file descriptors s 530 to the process as file descriptors supporting the read/write
591 syscalls, it's possible to isolate t 531 syscalls, it's possible to isolate those applications in their
592 own address space using seccomp. Onc 532 own address space using seccomp. Once seccomp is enabled via
593 prctl(PR_SET_SECCOMP) or the seccomp 533 prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be
594 disabled and the task is only allowe 534 disabled and the task is only allowed to execute a few safe
595 syscalls defined by each seccomp mod 535 syscalls defined by each seccomp mode.
596 536
597 If unsure, say Y. 537 If unsure, say Y.
598 538
599 config SECCOMP_FILTER 539 config SECCOMP_FILTER
600 def_bool y 540 def_bool y
601 depends on HAVE_ARCH_SECCOMP_FILTER && 541 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
602 help 542 help
603 Enable tasks to build secure computi 543 Enable tasks to build secure computing environments defined
604 in terms of Berkeley Packet Filter p 544 in terms of Berkeley Packet Filter programs which implement
605 task-defined system call filtering p 545 task-defined system call filtering polices.
606 546
607 See Documentation/userspace-api/secc 547 See Documentation/userspace-api/seccomp_filter.rst for details.
608 548
609 config SECCOMP_CACHE_DEBUG 549 config SECCOMP_CACHE_DEBUG
610 bool "Show seccomp filter cache status 550 bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
611 depends on SECCOMP_FILTER && !HAVE_SPA 551 depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
612 depends on PROC_FS 552 depends on PROC_FS
613 help 553 help
614 This enables the /proc/pid/seccomp_c 554 This enables the /proc/pid/seccomp_cache interface to monitor
615 seccomp cache data. The file format 555 seccomp cache data. The file format is subject to change. Reading
616 the file requires CAP_SYS_ADMIN. 556 the file requires CAP_SYS_ADMIN.
617 557
618 This option is for debugging only. E 558 This option is for debugging only. Enabling presents the risk that
619 an adversary may be able to infer th 559 an adversary may be able to infer the seccomp filter logic.
620 560
621 If unsure, say N. 561 If unsure, say N.
622 562
623 config HAVE_ARCH_STACKLEAK 563 config HAVE_ARCH_STACKLEAK
624 bool 564 bool
625 help 565 help
626 An architecture should select this i 566 An architecture should select this if it has the code which
627 fills the used part of the kernel st 567 fills the used part of the kernel stack with the STACKLEAK_POISON
628 value before returning from system c 568 value before returning from system calls.
629 569
630 config HAVE_STACKPROTECTOR 570 config HAVE_STACKPROTECTOR
631 bool 571 bool
632 help 572 help
633 An arch should select this symbol if 573 An arch should select this symbol if:
634 - it has implemented a stack canary 574 - it has implemented a stack canary (e.g. __stack_chk_guard)
635 575
636 config STACKPROTECTOR 576 config STACKPROTECTOR
637 bool "Stack Protector buffer overflow 577 bool "Stack Protector buffer overflow detection"
638 depends on HAVE_STACKPROTECTOR 578 depends on HAVE_STACKPROTECTOR
639 depends on $(cc-option,-fstack-protect 579 depends on $(cc-option,-fstack-protector)
640 default y 580 default y
641 help 581 help
642 This option turns on the "stack-prot 582 This option turns on the "stack-protector" GCC feature. This
643 feature puts, at the beginning of fu 583 feature puts, at the beginning of functions, a canary value on
644 the stack just before the return add 584 the stack just before the return address, and validates
645 the value just before actually retur 585 the value just before actually returning. Stack based buffer
646 overflows (that need to overwrite th 586 overflows (that need to overwrite this return address) now also
647 overwrite the canary, which gets det 587 overwrite the canary, which gets detected and the attack is then
648 neutralized via a kernel panic. 588 neutralized via a kernel panic.
649 589
650 Functions will have the stack-protec 590 Functions will have the stack-protector canary logic added if they
651 have an 8-byte or larger character a 591 have an 8-byte or larger character array on the stack.
652 592
653 This feature requires gcc version 4. 593 This feature requires gcc version 4.2 or above, or a distribution
654 gcc with the feature backported ("-f 594 gcc with the feature backported ("-fstack-protector").
655 595
656 On an x86 "defconfig" build, this fe 596 On an x86 "defconfig" build, this feature adds canary checks to
657 about 3% of all kernel functions, wh 597 about 3% of all kernel functions, which increases kernel code size
658 by about 0.3%. 598 by about 0.3%.
659 599
660 config STACKPROTECTOR_STRONG 600 config STACKPROTECTOR_STRONG
661 bool "Strong Stack Protector" 601 bool "Strong Stack Protector"
662 depends on STACKPROTECTOR 602 depends on STACKPROTECTOR
663 depends on $(cc-option,-fstack-protect 603 depends on $(cc-option,-fstack-protector-strong)
664 default y 604 default y
665 help 605 help
666 Functions will have the stack-protec 606 Functions will have the stack-protector canary logic added in any
667 of the following conditions: 607 of the following conditions:
668 608
669 - local variable's address used as p 609 - local variable's address used as part of the right hand side of an
670 assignment or function argument 610 assignment or function argument
671 - local variable is an array (or uni 611 - local variable is an array (or union containing an array),
672 regardless of array type or length 612 regardless of array type or length
673 - uses register local variables 613 - uses register local variables
674 614
675 This feature requires gcc version 4. 615 This feature requires gcc version 4.9 or above, or a distribution
676 gcc with the feature backported ("-f 616 gcc with the feature backported ("-fstack-protector-strong").
677 617
678 On an x86 "defconfig" build, this fe 618 On an x86 "defconfig" build, this feature adds canary checks to
679 about 20% of all kernel functions, w 619 about 20% of all kernel functions, which increases the kernel code
680 size by about 2%. 620 size by about 2%.
681 621
682 config ARCH_SUPPORTS_SHADOW_CALL_STACK 622 config ARCH_SUPPORTS_SHADOW_CALL_STACK
683 bool 623 bool
684 help 624 help
685 An architecture should select this i 625 An architecture should select this if it supports the compiler's
686 Shadow Call Stack and implements run 626 Shadow Call Stack and implements runtime support for shadow stack
687 switching. 627 switching.
688 628
689 config SHADOW_CALL_STACK 629 config SHADOW_CALL_STACK
690 bool "Shadow Call Stack" 630 bool "Shadow Call Stack"
691 depends on ARCH_SUPPORTS_SHADOW_CALL_S 631 depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
692 depends on DYNAMIC_FTRACE_WITH_ARGS || 632 depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
693 depends on MMU <<
694 help 633 help
695 This option enables the compiler's S 634 This option enables the compiler's Shadow Call Stack, which
696 uses a shadow stack to protect funct 635 uses a shadow stack to protect function return addresses from
697 being overwritten by an attacker. Mo 636 being overwritten by an attacker. More information can be found
698 in the compiler's documentation: 637 in the compiler's documentation:
699 638
700 - Clang: https://clang.llvm.org/docs 639 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
701 - GCC: https://gcc.gnu.org/onlinedoc 640 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
702 641
703 Note that security guarantees in the 642 Note that security guarantees in the kernel differ from the
704 ones documented for user space. The 643 ones documented for user space. The kernel must store addresses
705 of shadow stacks in memory, which me 644 of shadow stacks in memory, which means an attacker capable of
706 reading and writing arbitrary memory 645 reading and writing arbitrary memory may be able to locate them
707 and hijack control flow by modifying 646 and hijack control flow by modifying the stacks.
708 647
709 config DYNAMIC_SCS <<
710 bool <<
711 help <<
712 Set by the arch code if it relies on <<
713 shadow call stack push and pop instr <<
714 compiler. <<
715 <<
716 config LTO 648 config LTO
717 bool 649 bool
718 help 650 help
719 Selected if the kernel will be built 651 Selected if the kernel will be built using the compiler's LTO feature.
720 652
721 config LTO_CLANG 653 config LTO_CLANG
722 bool 654 bool
723 select LTO 655 select LTO
724 help 656 help
725 Selected if the kernel will be built 657 Selected if the kernel will be built using Clang's LTO feature.
726 658
727 config ARCH_SUPPORTS_LTO_CLANG 659 config ARCH_SUPPORTS_LTO_CLANG
728 bool 660 bool
729 help 661 help
730 An architecture should select this o 662 An architecture should select this option if it supports:
731 - compiling with Clang, 663 - compiling with Clang,
732 - compiling inline assembly with Cla 664 - compiling inline assembly with Clang's integrated assembler,
733 - and linking with LLD. 665 - and linking with LLD.
734 666
735 config ARCH_SUPPORTS_LTO_CLANG_THIN 667 config ARCH_SUPPORTS_LTO_CLANG_THIN
736 bool 668 bool
737 help 669 help
738 An architecture should select this o 670 An architecture should select this option if it can support Clang's
739 ThinLTO mode. 671 ThinLTO mode.
740 672
741 config HAS_LTO_CLANG 673 config HAS_LTO_CLANG
742 def_bool y 674 def_bool y
743 depends on CC_IS_CLANG && LD_IS_LLD && 675 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM
744 depends on $(success,$(NM) --help | he 676 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
745 depends on $(success,$(AR) --help | he 677 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
746 depends on ARCH_SUPPORTS_LTO_CLANG 678 depends on ARCH_SUPPORTS_LTO_CLANG
747 depends on !FTRACE_MCOUNT_USE_RECORDMC 679 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
748 # https://github.com/ClangBuiltLinux/l !! 680 depends on !KASAN || KASAN_HW_TAGS
749 depends on (!KASAN || KASAN_HW_TAGS || <<
750 depends on (!KCOV || CLANG_VERSION >= <<
751 depends on !GCOV_KERNEL 681 depends on !GCOV_KERNEL
752 help 682 help
753 The compiler and Kconfig options sup 683 The compiler and Kconfig options support building with Clang's
754 LTO. 684 LTO.
755 685
756 choice 686 choice
757 prompt "Link Time Optimization (LTO)" 687 prompt "Link Time Optimization (LTO)"
758 default LTO_NONE 688 default LTO_NONE
759 help 689 help
760 This option enables Link Time Optimi 690 This option enables Link Time Optimization (LTO), which allows the
761 compiler to optimize binaries global 691 compiler to optimize binaries globally.
762 692
763 If unsure, select LTO_NONE. Note tha 693 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
764 so it's disabled by default. 694 so it's disabled by default.
765 695
766 config LTO_NONE 696 config LTO_NONE
767 bool "None" 697 bool "None"
768 help 698 help
769 Build the kernel normally, without L 699 Build the kernel normally, without Link Time Optimization (LTO).
770 700
771 config LTO_CLANG_FULL 701 config LTO_CLANG_FULL
772 bool "Clang Full LTO (EXPERIMENTAL)" 702 bool "Clang Full LTO (EXPERIMENTAL)"
773 depends on HAS_LTO_CLANG 703 depends on HAS_LTO_CLANG
774 depends on !COMPILE_TEST 704 depends on !COMPILE_TEST
775 select LTO_CLANG 705 select LTO_CLANG
776 help 706 help
777 This option enables Clang's full Lin !! 707 This option enables Clang's full Link Time Optimization (LTO), which
778 allows the compiler to optimize the !! 708 allows the compiler to optimize the kernel globally. If you enable
779 this option, the compiler generates !! 709 this option, the compiler generates LLVM bitcode instead of ELF
780 object files, and the actual compila !! 710 object files, and the actual compilation from bitcode happens at
781 the LTO link step, which may take se !! 711 the LTO link step, which may take several minutes depending on the
782 kernel configuration. More informati !! 712 kernel configuration. More information can be found from LLVM's
783 documentation: !! 713 documentation:
784 714
785 https://llvm.org/docs/LinkTimeOpti 715 https://llvm.org/docs/LinkTimeOptimization.html
786 716
787 During link time, this option can us 717 During link time, this option can use a large amount of RAM, and
788 may take much longer than the ThinLT 718 may take much longer than the ThinLTO option.
789 719
790 config LTO_CLANG_THIN 720 config LTO_CLANG_THIN
791 bool "Clang ThinLTO (EXPERIMENTAL)" 721 bool "Clang ThinLTO (EXPERIMENTAL)"
792 depends on HAS_LTO_CLANG && ARCH_SUPPO 722 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
793 select LTO_CLANG 723 select LTO_CLANG
794 help 724 help
795 This option enables Clang's ThinLTO, 725 This option enables Clang's ThinLTO, which allows for parallel
796 optimization and faster incremental 726 optimization and faster incremental compiles compared to the
797 CONFIG_LTO_CLANG_FULL option. More i 727 CONFIG_LTO_CLANG_FULL option. More information can be found
798 from Clang's documentation: 728 from Clang's documentation:
799 729
800 https://clang.llvm.org/docs/ThinLT 730 https://clang.llvm.org/docs/ThinLTO.html
801 731
802 If unsure, say Y. 732 If unsure, say Y.
803 endchoice 733 endchoice
804 734
805 config ARCH_SUPPORTS_CFI_CLANG 735 config ARCH_SUPPORTS_CFI_CLANG
806 bool 736 bool
807 help 737 help
808 An architecture should select this o 738 An architecture should select this option if it can support Clang's
809 Control-Flow Integrity (CFI) checkin 739 Control-Flow Integrity (CFI) checking.
810 740
811 config ARCH_USES_CFI_TRAPS <<
812 bool <<
813 <<
814 config CFI_CLANG 741 config CFI_CLANG
815 bool "Use Clang's Control Flow Integri 742 bool "Use Clang's Control Flow Integrity (CFI)"
816 depends on ARCH_SUPPORTS_CFI_CLANG !! 743 depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG
817 depends on $(cc-option,-fsanitize=kcfi !! 744 depends on CLANG_VERSION >= 140000
>> 745 select KALLSYMS
818 help 746 help
819 This option enables Clang's forward- !! 747 This option enables Clang’s forward-edge Control Flow Integrity
820 (CFI) checking, where the compiler i 748 (CFI) checking, where the compiler injects a runtime check to each
821 indirect function call to ensure the 749 indirect function call to ensure the target is a valid function with
822 the correct static type. This restri 750 the correct static type. This restricts possible call targets and
823 makes it more difficult for an attac 751 makes it more difficult for an attacker to exploit bugs that allow
824 the modification of stored function 752 the modification of stored function pointers. More information can be
825 found from Clang's documentation: 753 found from Clang's documentation:
826 754
827 https://clang.llvm.org/docs/Contro 755 https://clang.llvm.org/docs/ControlFlowIntegrity.html
828 756
>> 757 config CFI_CLANG_SHADOW
>> 758 bool "Use CFI shadow to speed up cross-module checks"
>> 759 default y
>> 760 depends on CFI_CLANG && MODULES
>> 761 help
>> 762 If you select this option, the kernel builds a fast look-up table of
>> 763 CFI check functions in loaded modules to reduce performance overhead.
>> 764
>> 765 If unsure, say Y.
>> 766
829 config CFI_PERMISSIVE 767 config CFI_PERMISSIVE
830 bool "Use CFI in permissive mode" 768 bool "Use CFI in permissive mode"
831 depends on CFI_CLANG 769 depends on CFI_CLANG
832 help 770 help
833 When selected, Control Flow Integrit 771 When selected, Control Flow Integrity (CFI) violations result in a
834 warning instead of a kernel panic. T 772 warning instead of a kernel panic. This option should only be used
835 for finding indirect call type misma 773 for finding indirect call type mismatches during development.
836 774
837 If unsure, say N. 775 If unsure, say N.
838 776
839 config HAVE_ARCH_WITHIN_STACK_FRAMES 777 config HAVE_ARCH_WITHIN_STACK_FRAMES
840 bool 778 bool
841 help 779 help
842 An architecture should select this i 780 An architecture should select this if it can walk the kernel stack
843 frames to determine if an object is 781 frames to determine if an object is part of either the arguments
844 or local variables (i.e. that it exc 782 or local variables (i.e. that it excludes saved return addresses,
845 and similar) by implementing an inli 783 and similar) by implementing an inline arch_within_stack_frames(),
846 which is used by CONFIG_HARDENED_USE 784 which is used by CONFIG_HARDENED_USERCOPY.
847 785
848 config HAVE_CONTEXT_TRACKING_USER 786 config HAVE_CONTEXT_TRACKING_USER
849 bool 787 bool
850 help 788 help
851 Provide kernel/user boundaries probe 789 Provide kernel/user boundaries probes necessary for subsystems
852 that need it, such as userspace RCU 790 that need it, such as userspace RCU extended quiescent state.
853 Syscalls need to be wrapped inside u 791 Syscalls need to be wrapped inside user_exit()-user_enter(), either
854 optimized behind static key or throu 792 optimized behind static key or through the slow path using TIF_NOHZ
855 flag. Exceptions handlers must be wr 793 flag. Exceptions handlers must be wrapped as well. Irqs are already
856 protected inside ct_irq_enter/ct_irq 794 protected inside ct_irq_enter/ct_irq_exit() but preemption or signal
857 handling on irq exit still need to b 795 handling on irq exit still need to be protected.
858 796
859 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK 797 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK
860 bool 798 bool
861 help 799 help
862 Architecture neither relies on excep 800 Architecture neither relies on exception_enter()/exception_exit()
863 nor on schedule_user(). Also preempt 801 nor on schedule_user(). Also preempt_schedule_notrace() and
864 preempt_schedule_irq() can't be call 802 preempt_schedule_irq() can't be called in a preemptible section
865 while context tracking is CONTEXT_US 803 while context tracking is CONTEXT_USER. This feature reflects a sane
866 entry implementation where the follo 804 entry implementation where the following requirements are met on
867 critical entry code, ie: before user 805 critical entry code, ie: before user_exit() or after user_enter():
868 806
869 - Critical entry code isn't preempti 807 - Critical entry code isn't preemptible (or better yet:
870 not interruptible). 808 not interruptible).
871 - No use of RCU read side critical s 809 - No use of RCU read side critical sections, unless ct_nmi_enter()
872 got called. 810 got called.
873 - No use of instrumentation, unless 811 - No use of instrumentation, unless instrumentation_begin() got
874 called. 812 called.
875 813
876 config HAVE_TIF_NOHZ 814 config HAVE_TIF_NOHZ
877 bool 815 bool
878 help 816 help
879 Arch relies on TIF_NOHZ and syscall 817 Arch relies on TIF_NOHZ and syscall slow path to implement context
880 tracking calls to user_enter()/user_ 818 tracking calls to user_enter()/user_exit().
881 819
882 config HAVE_VIRT_CPU_ACCOUNTING 820 config HAVE_VIRT_CPU_ACCOUNTING
883 bool 821 bool
884 822
885 config HAVE_VIRT_CPU_ACCOUNTING_IDLE 823 config HAVE_VIRT_CPU_ACCOUNTING_IDLE
886 bool 824 bool
887 help 825 help
888 Architecture has its own way to acco 826 Architecture has its own way to account idle CPU time and therefore
889 doesn't implement vtime_account_idle 827 doesn't implement vtime_account_idle().
890 828
891 config ARCH_HAS_SCALED_CPUTIME 829 config ARCH_HAS_SCALED_CPUTIME
892 bool 830 bool
893 831
894 config HAVE_VIRT_CPU_ACCOUNTING_GEN 832 config HAVE_VIRT_CPU_ACCOUNTING_GEN
895 bool 833 bool
896 default y if 64BIT 834 default y if 64BIT
897 help 835 help
898 With VIRT_CPU_ACCOUNTING_GEN, cputim 836 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
899 Before enabling this option, arch co 837 Before enabling this option, arch code must be audited
900 to ensure there are no races in conc 838 to ensure there are no races in concurrent read/write of
901 cputime_t. For example, reading/writ 839 cputime_t. For example, reading/writing 64-bit cputime_t on
902 some 32-bit arches may require multi 840 some 32-bit arches may require multiple accesses, so proper
903 locking is needed to protect against 841 locking is needed to protect against concurrent accesses.
904 842
905 config HAVE_IRQ_TIME_ACCOUNTING 843 config HAVE_IRQ_TIME_ACCOUNTING
906 bool 844 bool
907 help 845 help
908 Archs need to ensure they use a high 846 Archs need to ensure they use a high enough resolution clock to
909 support irq time accounting and then 847 support irq time accounting and then call enable_sched_clock_irqtime().
910 848
911 config HAVE_MOVE_PUD 849 config HAVE_MOVE_PUD
912 bool 850 bool
913 help 851 help
914 Architectures that select this are a 852 Architectures that select this are able to move page tables at the
915 PUD level. If there are only 3 page 853 PUD level. If there are only 3 page table levels, the move effectively
916 happens at the PGD level. 854 happens at the PGD level.
917 855
918 config HAVE_MOVE_PMD 856 config HAVE_MOVE_PMD
919 bool 857 bool
920 help 858 help
921 Archs that select this are able to m 859 Archs that select this are able to move page tables at the PMD level.
922 860
923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 861 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
924 bool 862 bool
925 863
926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 864 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
927 bool 865 bool
928 866
929 config HAVE_ARCH_HUGE_VMAP 867 config HAVE_ARCH_HUGE_VMAP
930 bool 868 bool
931 869
932 # 870 #
933 # Archs that select this would be capable of 871 # Archs that select this would be capable of PMD-sized vmaps (i.e.,
934 # arch_vmap_pmd_supported() returns true). Th 872 # arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag
935 # must be used to enable allocations to use h 873 # must be used to enable allocations to use hugepages.
936 # 874 #
937 config HAVE_ARCH_HUGE_VMALLOC 875 config HAVE_ARCH_HUGE_VMALLOC
938 depends on HAVE_ARCH_HUGE_VMAP 876 depends on HAVE_ARCH_HUGE_VMAP
939 bool 877 bool
940 878
941 config ARCH_WANT_HUGE_PMD_SHARE 879 config ARCH_WANT_HUGE_PMD_SHARE
942 bool 880 bool
943 881
944 # Archs that want to use pmd_mkwrite on kernel <<
945 # if there are no userspace memory management <<
946 config ARCH_WANT_KERNEL_PMD_MKWRITE <<
947 bool <<
948 <<
949 config ARCH_WANT_PMD_MKWRITE <<
950 def_bool TRANSPARENT_HUGEPAGE || ARCH_ <<
951 <<
952 config HAVE_ARCH_SOFT_DIRTY 882 config HAVE_ARCH_SOFT_DIRTY
953 bool 883 bool
954 884
955 config HAVE_MOD_ARCH_SPECIFIC 885 config HAVE_MOD_ARCH_SPECIFIC
956 bool 886 bool
957 help 887 help
958 The arch uses struct mod_arch_specif 888 The arch uses struct mod_arch_specific to store data. Many arches
959 just need a simple module loader wit 889 just need a simple module loader without arch specific data - those
960 should not enable this. 890 should not enable this.
961 891
962 config MODULES_USE_ELF_RELA 892 config MODULES_USE_ELF_RELA
963 bool 893 bool
964 help 894 help
965 Modules only use ELF RELA relocation 895 Modules only use ELF RELA relocations. Modules with ELF REL
966 relocations will give an error. 896 relocations will give an error.
967 897
968 config MODULES_USE_ELF_REL 898 config MODULES_USE_ELF_REL
969 bool 899 bool
970 help 900 help
971 Modules only use ELF REL relocations 901 Modules only use ELF REL relocations. Modules with ELF RELA
972 relocations will give an error. 902 relocations will give an error.
973 903
974 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC 904 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC
975 bool 905 bool
976 help 906 help
977 For architectures like powerpc/32 wh 907 For architectures like powerpc/32 which have constraints on module
978 allocation and need to allocate modu 908 allocation and need to allocate module data outside of module area.
979 909
980 config ARCH_WANTS_EXECMEM_LATE <<
981 bool <<
982 help <<
983 For architectures that do not alloca <<
984 boot, but rather require its initial <<
985 enough entropy for module space rand <<
986 arm64. <<
987 <<
988 config HAVE_IRQ_EXIT_ON_IRQ_STACK 910 config HAVE_IRQ_EXIT_ON_IRQ_STACK
989 bool 911 bool
990 help 912 help
991 Architecture doesn't only execute th 913 Architecture doesn't only execute the irq handler on the irq stack
992 but also irq_exit(). This way we can 914 but also irq_exit(). This way we can process softirqs on this irq
993 stack instead of switching to a new 915 stack instead of switching to a new one when we call __do_softirq()
994 in the end of an hardirq. 916 in the end of an hardirq.
995 This spares a stack switch and impro 917 This spares a stack switch and improves cache usage on softirq
996 processing. 918 processing.
997 919
998 config HAVE_SOFTIRQ_ON_OWN_STACK 920 config HAVE_SOFTIRQ_ON_OWN_STACK
999 bool 921 bool
1000 help 922 help
1001 Architecture provides a function to 923 Architecture provides a function to run __do_softirq() on a
1002 separate stack. 924 separate stack.
1003 925
1004 config SOFTIRQ_ON_OWN_STACK 926 config SOFTIRQ_ON_OWN_STACK
1005 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && 927 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT
1006 928
1007 config ALTERNATE_USER_ADDRESS_SPACE 929 config ALTERNATE_USER_ADDRESS_SPACE
1008 bool 930 bool
1009 help 931 help
1010 Architectures set this when the CPU 932 Architectures set this when the CPU uses separate address
1011 spaces for kernel and user space po 933 spaces for kernel and user space pointers. In this case, the
1012 access_ok() check on a __user point 934 access_ok() check on a __user pointer is skipped.
1013 935
1014 config PGTABLE_LEVELS 936 config PGTABLE_LEVELS
1015 int 937 int
1016 default 2 938 default 2
1017 939
1018 config ARCH_HAS_ELF_RANDOMIZE 940 config ARCH_HAS_ELF_RANDOMIZE
1019 bool 941 bool
1020 help 942 help
1021 An architecture supports choosing r 943 An architecture supports choosing randomized locations for
1022 stack, mmap, brk, and ET_DYN. Defin 944 stack, mmap, brk, and ET_DYN. Defined functions:
1023 - arch_mmap_rnd() 945 - arch_mmap_rnd()
1024 - arch_randomize_brk() 946 - arch_randomize_brk()
1025 947
1026 config HAVE_ARCH_MMAP_RND_BITS 948 config HAVE_ARCH_MMAP_RND_BITS
1027 bool 949 bool
1028 help 950 help
1029 An arch should select this symbol i 951 An arch should select this symbol if it supports setting a variable
1030 number of bits for use in establish 952 number of bits for use in establishing the base address for mmap
1031 allocations, has MMU enabled and pr 953 allocations, has MMU enabled and provides values for both:
1032 - ARCH_MMAP_RND_BITS_MIN 954 - ARCH_MMAP_RND_BITS_MIN
1033 - ARCH_MMAP_RND_BITS_MAX 955 - ARCH_MMAP_RND_BITS_MAX
1034 956
1035 config HAVE_EXIT_THREAD 957 config HAVE_EXIT_THREAD
1036 bool 958 bool
1037 help 959 help
1038 An architecture implements exit_thr 960 An architecture implements exit_thread.
1039 961
1040 config ARCH_MMAP_RND_BITS_MIN 962 config ARCH_MMAP_RND_BITS_MIN
1041 int 963 int
1042 964
1043 config ARCH_MMAP_RND_BITS_MAX 965 config ARCH_MMAP_RND_BITS_MAX
1044 int 966 int
1045 967
1046 config ARCH_MMAP_RND_BITS_DEFAULT 968 config ARCH_MMAP_RND_BITS_DEFAULT
1047 int 969 int
1048 970
1049 config ARCH_MMAP_RND_BITS 971 config ARCH_MMAP_RND_BITS
1050 int "Number of bits to use for ASLR o 972 int "Number of bits to use for ASLR of mmap base address" if EXPERT
1051 range ARCH_MMAP_RND_BITS_MIN ARCH_MMA 973 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1052 default ARCH_MMAP_RND_BITS_DEFAULT if 974 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1053 default ARCH_MMAP_RND_BITS_MIN 975 default ARCH_MMAP_RND_BITS_MIN
1054 depends on HAVE_ARCH_MMAP_RND_BITS 976 depends on HAVE_ARCH_MMAP_RND_BITS
1055 help 977 help
1056 This value can be used to select th 978 This value can be used to select the number of bits to use to
1057 determine the random offset to the 979 determine the random offset to the base address of vma regions
1058 resulting from mmap allocations. Th 980 resulting from mmap allocations. This value will be bounded
1059 by the architecture's minimum and m 981 by the architecture's minimum and maximum supported values.
1060 982
1061 This value can be changed after boo 983 This value can be changed after boot using the
1062 /proc/sys/vm/mmap_rnd_bits tunable 984 /proc/sys/vm/mmap_rnd_bits tunable
1063 985
1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 986 config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1065 bool 987 bool
1066 help 988 help
1067 An arch should select this symbol i 989 An arch should select this symbol if it supports running applications
1068 in compatibility mode, supports set 990 in compatibility mode, supports setting a variable number of bits for
1069 use in establishing the base addres 991 use in establishing the base address for mmap allocations, has MMU
1070 enabled and provides values for bot 992 enabled and provides values for both:
1071 - ARCH_MMAP_RND_COMPAT_BITS_MIN 993 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1072 - ARCH_MMAP_RND_COMPAT_BITS_MAX 994 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1073 995
1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN 996 config ARCH_MMAP_RND_COMPAT_BITS_MIN
1075 int 997 int
1076 998
1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX 999 config ARCH_MMAP_RND_COMPAT_BITS_MAX
1078 int 1000 int
1079 1001
1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1002 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1081 int 1003 int
1082 1004
1083 config ARCH_MMAP_RND_COMPAT_BITS 1005 config ARCH_MMAP_RND_COMPAT_BITS
1084 int "Number of bits to use for ASLR o 1006 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
1085 range ARCH_MMAP_RND_COMPAT_BITS_MIN A 1007 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1086 default ARCH_MMAP_RND_COMPAT_BITS_DEF 1008 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1087 default ARCH_MMAP_RND_COMPAT_BITS_MIN 1009 default ARCH_MMAP_RND_COMPAT_BITS_MIN
1088 depends on HAVE_ARCH_MMAP_RND_COMPAT_ 1010 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1089 help 1011 help
1090 This value can be used to select th 1012 This value can be used to select the number of bits to use to
1091 determine the random offset to the 1013 determine the random offset to the base address of vma regions
1092 resulting from mmap allocations for 1014 resulting from mmap allocations for compatible applications This
1093 value will be bounded by the archit 1015 value will be bounded by the architecture's minimum and maximum
1094 supported values. 1016 supported values.
1095 1017
1096 This value can be changed after boo 1018 This value can be changed after boot using the
1097 /proc/sys/vm/mmap_rnd_compat_bits t 1019 /proc/sys/vm/mmap_rnd_compat_bits tunable
1098 1020
1099 config HAVE_ARCH_COMPAT_MMAP_BASES 1021 config HAVE_ARCH_COMPAT_MMAP_BASES
1100 bool 1022 bool
1101 help 1023 help
1102 This allows 64bit applications to i 1024 This allows 64bit applications to invoke 32-bit mmap() syscall
1103 and vice-versa 32-bit applications 1025 and vice-versa 32-bit applications to call 64-bit mmap().
1104 Required for applications doing dif 1026 Required for applications doing different bitness syscalls.
1105 1027
1106 config HAVE_PAGE_SIZE_4KB <<
1107 bool <<
1108 <<
1109 config HAVE_PAGE_SIZE_8KB <<
1110 bool <<
1111 <<
1112 config HAVE_PAGE_SIZE_16KB <<
1113 bool <<
1114 <<
1115 config HAVE_PAGE_SIZE_32KB <<
1116 bool <<
1117 <<
1118 config HAVE_PAGE_SIZE_64KB <<
1119 bool <<
1120 <<
1121 config HAVE_PAGE_SIZE_256KB <<
1122 bool <<
1123 <<
1124 choice <<
1125 prompt "MMU page size" <<
1126 <<
1127 config PAGE_SIZE_4KB <<
1128 bool "4KiB pages" <<
1129 depends on HAVE_PAGE_SIZE_4KB <<
1130 help <<
1131 This option select the standard 4Ki <<
1132 available option on many architectu <<
1133 minimize memory consumption and is <<
1134 memory systems. <<
1135 Some software that is written for x <<
1136 assumptions about the page size and <<
1137 <<
1138 config PAGE_SIZE_8KB <<
1139 bool "8KiB pages" <<
1140 depends on HAVE_PAGE_SIZE_8KB <<
1141 help <<
1142 This option is the only supported p <<
1143 processors, and can be slightly fas <<
1144 <<
1145 config PAGE_SIZE_16KB <<
1146 bool "16KiB pages" <<
1147 depends on HAVE_PAGE_SIZE_16KB <<
1148 help <<
1149 This option is usually a good compr <<
1150 consumption and performance for typ <<
1151 workloads, often saving a level of <<
1152 to 4KB pages as well as reducing TL <<
1153 per-page operations in the kernel a <<
1154 page cache. <<
1155 <<
1156 config PAGE_SIZE_32KB <<
1157 bool "32KiB pages" <<
1158 depends on HAVE_PAGE_SIZE_32KB <<
1159 help <<
1160 Using 32KiB page size will result i <<
1161 kernel at the price of higher memor <<
1162 16KiB pages. This option is availa <<
1163 Note that you will need a suitable <<
1164 support this. <<
1165 <<
1166 config PAGE_SIZE_64KB <<
1167 bool "64KiB pages" <<
1168 depends on HAVE_PAGE_SIZE_64KB <<
1169 help <<
1170 Using 64KiB page size will result i <<
1171 kernel at the price of much higher <<
1172 4KiB or 16KiB pages. <<
1173 This is not suitable for general-pu <<
1174 better performance may be worth the <<
1175 supercomputing or database applicat <<
1176 large in-memory data rather than sm <<
1177 <<
1178 config PAGE_SIZE_256KB <<
1179 bool "256KiB pages" <<
1180 depends on HAVE_PAGE_SIZE_256KB <<
1181 help <<
1182 256KiB pages have little practical <<
1183 memory usage. The kernel will only <<
1184 that have been compiled with '-zmax <<
1185 (the default is 64KiB or 4KiB on mo <<
1186 <<
1187 endchoice <<
1188 <<
1189 config PAGE_SIZE_LESS_THAN_64KB 1028 config PAGE_SIZE_LESS_THAN_64KB
1190 def_bool y 1029 def_bool y
>> 1030 depends on !ARM64_64K_PAGES
>> 1031 depends on !IA64_PAGE_SIZE_64KB
1191 depends on !PAGE_SIZE_64KB 1032 depends on !PAGE_SIZE_64KB
>> 1033 depends on !PARISC_PAGE_SIZE_64KB
1192 depends on PAGE_SIZE_LESS_THAN_256KB 1034 depends on PAGE_SIZE_LESS_THAN_256KB
1193 1035
1194 config PAGE_SIZE_LESS_THAN_256KB 1036 config PAGE_SIZE_LESS_THAN_256KB
1195 def_bool y 1037 def_bool y
1196 depends on !PAGE_SIZE_256KB 1038 depends on !PAGE_SIZE_256KB
1197 1039
1198 config PAGE_SHIFT <<
1199 int <<
1200 default 12 if PAGE_SIZE_4KB <<
1201 default 13 if PAGE_SIZE_8KB <<
1202 default 14 if PAGE_SIZE_16KB <<
1203 default 15 if PAGE_SIZE_32KB <<
1204 default 16 if PAGE_SIZE_64KB <<
1205 default 18 if PAGE_SIZE_256KB <<
1206 <<
1207 # This allows to use a set of generic functio 1040 # This allows to use a set of generic functions to determine mmap base
1208 # address by giving priority to top-down sche 1041 # address by giving priority to top-down scheme only if the process
1209 # is not in legacy mode (compat task, unlimit 1042 # is not in legacy mode (compat task, unlimited stack size or
1210 # sysctl_legacy_va_layout). 1043 # sysctl_legacy_va_layout).
1211 # Architecture that selects this option can p 1044 # Architecture that selects this option can provide its own version of:
1212 # - STACK_RND_MASK 1045 # - STACK_RND_MASK
1213 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 1046 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
1214 bool 1047 bool
1215 depends on MMU 1048 depends on MMU
1216 select ARCH_HAS_ELF_RANDOMIZE 1049 select ARCH_HAS_ELF_RANDOMIZE
1217 1050
1218 config HAVE_OBJTOOL 1051 config HAVE_OBJTOOL
1219 bool 1052 bool
1220 1053
1221 config HAVE_JUMP_LABEL_HACK 1054 config HAVE_JUMP_LABEL_HACK
1222 bool 1055 bool
1223 1056
1224 config HAVE_NOINSTR_HACK 1057 config HAVE_NOINSTR_HACK
1225 bool 1058 bool
1226 1059
1227 config HAVE_NOINSTR_VALIDATION 1060 config HAVE_NOINSTR_VALIDATION
1228 bool 1061 bool
1229 1062
1230 config HAVE_UACCESS_VALIDATION 1063 config HAVE_UACCESS_VALIDATION
1231 bool 1064 bool
1232 select OBJTOOL 1065 select OBJTOOL
1233 1066
1234 config HAVE_STACK_VALIDATION 1067 config HAVE_STACK_VALIDATION
1235 bool 1068 bool
1236 help 1069 help
1237 Architecture supports objtool compi 1070 Architecture supports objtool compile-time frame pointer rule
1238 validation. 1071 validation.
1239 1072
1240 config HAVE_RELIABLE_STACKTRACE 1073 config HAVE_RELIABLE_STACKTRACE
1241 bool 1074 bool
1242 help 1075 help
1243 Architecture has either save_stack_ 1076 Architecture has either save_stack_trace_tsk_reliable() or
1244 arch_stack_walk_reliable() function 1077 arch_stack_walk_reliable() function which only returns a stack trace
1245 if it can guarantee the trace is re 1078 if it can guarantee the trace is reliable.
1246 1079
1247 config HAVE_ARCH_HASH 1080 config HAVE_ARCH_HASH
1248 bool 1081 bool
1249 default n 1082 default n
1250 help 1083 help
1251 If this is set, the architecture pr 1084 If this is set, the architecture provides an <asm/hash.h>
1252 file which provides platform-specif 1085 file which provides platform-specific implementations of some
1253 functions in <linux/hash.h> or fs/n 1086 functions in <linux/hash.h> or fs/namei.c.
1254 1087
1255 config HAVE_ARCH_NVRAM_OPS 1088 config HAVE_ARCH_NVRAM_OPS
1256 bool 1089 bool
1257 1090
1258 config ISA_BUS_API 1091 config ISA_BUS_API
1259 def_bool ISA 1092 def_bool ISA
1260 1093
1261 # 1094 #
1262 # ABI hall of shame 1095 # ABI hall of shame
1263 # 1096 #
1264 config CLONE_BACKWARDS 1097 config CLONE_BACKWARDS
1265 bool 1098 bool
1266 help 1099 help
1267 Architecture has tls passed as the 1100 Architecture has tls passed as the 4th argument of clone(2),
1268 not the 5th one. 1101 not the 5th one.
1269 1102
1270 config CLONE_BACKWARDS2 1103 config CLONE_BACKWARDS2
1271 bool 1104 bool
1272 help 1105 help
1273 Architecture has the first two argu 1106 Architecture has the first two arguments of clone(2) swapped.
1274 1107
1275 config CLONE_BACKWARDS3 1108 config CLONE_BACKWARDS3
1276 bool 1109 bool
1277 help 1110 help
1278 Architecture has tls passed as the 1111 Architecture has tls passed as the 3rd argument of clone(2),
1279 not the 5th one. 1112 not the 5th one.
1280 1113
1281 config ODD_RT_SIGACTION 1114 config ODD_RT_SIGACTION
1282 bool 1115 bool
1283 help 1116 help
1284 Architecture has unusual rt_sigacti 1117 Architecture has unusual rt_sigaction(2) arguments
1285 1118
1286 config OLD_SIGSUSPEND 1119 config OLD_SIGSUSPEND
1287 bool 1120 bool
1288 help 1121 help
1289 Architecture has old sigsuspend(2) 1122 Architecture has old sigsuspend(2) syscall, of one-argument variety
1290 1123
1291 config OLD_SIGSUSPEND3 1124 config OLD_SIGSUSPEND3
1292 bool 1125 bool
1293 help 1126 help
1294 Even weirder antique ABI - three-ar 1127 Even weirder antique ABI - three-argument sigsuspend(2)
1295 1128
1296 config OLD_SIGACTION 1129 config OLD_SIGACTION
1297 bool 1130 bool
1298 help 1131 help
1299 Architecture has old sigaction(2) s 1132 Architecture has old sigaction(2) syscall. Nope, not the same
1300 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 1133 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1301 but fairly different variant of sig 1134 but fairly different variant of sigaction(2), thanks to OSF/1
1302 compatibility... 1135 compatibility...
1303 1136
1304 config COMPAT_OLD_SIGACTION 1137 config COMPAT_OLD_SIGACTION
1305 bool 1138 bool
1306 1139
1307 config COMPAT_32BIT_TIME 1140 config COMPAT_32BIT_TIME
1308 bool "Provide system calls for 32-bit 1141 bool "Provide system calls for 32-bit time_t"
1309 default !64BIT || COMPAT 1142 default !64BIT || COMPAT
1310 help 1143 help
1311 This enables 32 bit time_t support 1144 This enables 32 bit time_t support in addition to 64 bit time_t support.
1312 This is relevant on all 32-bit arch 1145 This is relevant on all 32-bit architectures, and 64-bit architectures
1313 as part of compat syscall handling. 1146 as part of compat syscall handling.
1314 1147
1315 config ARCH_NO_PREEMPT 1148 config ARCH_NO_PREEMPT
1316 bool 1149 bool
1317 1150
>> 1151 config ARCH_EPHEMERAL_INODES
>> 1152 def_bool n
>> 1153 help
>> 1154 An arch should select this symbol if it doesn't keep track of inode
>> 1155 instances on its own, but instead relies on something else (e.g. the
>> 1156 host kernel for an UML kernel).
>> 1157
1318 config ARCH_SUPPORTS_RT 1158 config ARCH_SUPPORTS_RT
1319 bool 1159 bool
1320 1160
1321 config CPU_NO_EFFICIENT_FFS 1161 config CPU_NO_EFFICIENT_FFS
1322 def_bool n 1162 def_bool n
1323 1163
1324 config HAVE_ARCH_VMAP_STACK 1164 config HAVE_ARCH_VMAP_STACK
1325 def_bool n 1165 def_bool n
1326 help 1166 help
1327 An arch should select this symbol i 1167 An arch should select this symbol if it can support kernel stacks
1328 in vmalloc space. This means: 1168 in vmalloc space. This means:
1329 1169
1330 - vmalloc space must be large enoug 1170 - vmalloc space must be large enough to hold many kernel stacks.
1331 This may rule out many 32-bit arc 1171 This may rule out many 32-bit architectures.
1332 1172
1333 - Stacks in vmalloc space need to w 1173 - Stacks in vmalloc space need to work reliably. For example, if
1334 vmap page tables are created on d 1174 vmap page tables are created on demand, either this mechanism
1335 needs to work while the stack poi 1175 needs to work while the stack points to a virtual address with
1336 unpopulated page tables or arch c 1176 unpopulated page tables or arch code (switch_to() and switch_mm(),
1337 most likely) needs to ensure that 1177 most likely) needs to ensure that the stack's page table entries
1338 are populated before running on a 1178 are populated before running on a possibly unpopulated stack.
1339 1179
1340 - If the stack overflows into a gua 1180 - If the stack overflows into a guard page, something reasonable
1341 should happen. The definition of 1181 should happen. The definition of "reasonable" is flexible, but
1342 instantly rebooting without loggi 1182 instantly rebooting without logging anything would be unfriendly.
1343 1183
1344 config VMAP_STACK 1184 config VMAP_STACK
1345 default y 1185 default y
1346 bool "Use a virtually-mapped stack" 1186 bool "Use a virtually-mapped stack"
1347 depends on HAVE_ARCH_VMAP_STACK 1187 depends on HAVE_ARCH_VMAP_STACK
1348 depends on !KASAN || KASAN_HW_TAGS || 1188 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
1349 help 1189 help
1350 Enable this if you want the use vir 1190 Enable this if you want the use virtually-mapped kernel stacks
1351 with guard pages. This causes kern 1191 with guard pages. This causes kernel stack overflows to be
1352 caught immediately rather than caus 1192 caught immediately rather than causing difficult-to-diagnose
1353 corruption. 1193 corruption.
1354 1194
1355 To use this with software KASAN mod 1195 To use this with software KASAN modes, the architecture must support
1356 backing virtual mappings with real 1196 backing virtual mappings with real shadow memory, and KASAN_VMALLOC
1357 must be enabled. 1197 must be enabled.
1358 1198
1359 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1199 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1360 def_bool n 1200 def_bool n
1361 help 1201 help
1362 An arch should select this symbol i 1202 An arch should select this symbol if it can support kernel stack
1363 offset randomization with calls to 1203 offset randomization with calls to add_random_kstack_offset()
1364 during syscall entry and choose_ran 1204 during syscall entry and choose_random_kstack_offset() during
1365 syscall exit. Careful removal of -f 1205 syscall exit. Careful removal of -fstack-protector-strong and
1366 -fstack-protector should also be ap 1206 -fstack-protector should also be applied to the entry code and
1367 closely examined, as the artificial 1207 closely examined, as the artificial stack bump looks like an array
1368 to the compiler, so it will attempt 1208 to the compiler, so it will attempt to add canary checks regardless
1369 of the static branch state. 1209 of the static branch state.
1370 1210
1371 config RANDOMIZE_KSTACK_OFFSET 1211 config RANDOMIZE_KSTACK_OFFSET
1372 bool "Support for randomizing kernel 1212 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT
1373 default y 1213 default y
1374 depends on HAVE_ARCH_RANDOMIZE_KSTACK 1214 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1375 depends on INIT_STACK_NONE || !CC_IS_ 1215 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
1376 help 1216 help
1377 The kernel stack offset can be rand 1217 The kernel stack offset can be randomized (after pt_regs) by
1378 roughly 5 bits of entropy, frustrat 1218 roughly 5 bits of entropy, frustrating memory corruption
1379 attacks that depend on stack addres 1219 attacks that depend on stack address determinism or
1380 cross-syscall address exposures. 1220 cross-syscall address exposures.
1381 1221
1382 The feature is controlled via the " 1222 The feature is controlled via the "randomize_kstack_offset=on/off"
1383 kernel boot param, and if turned of 1223 kernel boot param, and if turned off has zero overhead due to its use
1384 of static branches (see JUMP_LABEL) 1224 of static branches (see JUMP_LABEL).
1385 1225
1386 If unsure, say Y. 1226 If unsure, say Y.
1387 1227
1388 config RANDOMIZE_KSTACK_OFFSET_DEFAULT 1228 config RANDOMIZE_KSTACK_OFFSET_DEFAULT
1389 bool "Default state of kernel stack o 1229 bool "Default state of kernel stack offset randomization"
1390 depends on RANDOMIZE_KSTACK_OFFSET 1230 depends on RANDOMIZE_KSTACK_OFFSET
1391 help 1231 help
1392 Kernel stack offset randomization i 1232 Kernel stack offset randomization is controlled by kernel boot param
1393 "randomize_kstack_offset=on/off", a 1233 "randomize_kstack_offset=on/off", and this config chooses the default
1394 boot state. 1234 boot state.
1395 1235
1396 config ARCH_OPTIONAL_KERNEL_RWX 1236 config ARCH_OPTIONAL_KERNEL_RWX
1397 def_bool n 1237 def_bool n
1398 1238
1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1239 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1400 def_bool n 1240 def_bool n
1401 1241
1402 config ARCH_HAS_STRICT_KERNEL_RWX 1242 config ARCH_HAS_STRICT_KERNEL_RWX
1403 def_bool n 1243 def_bool n
1404 1244
1405 config STRICT_KERNEL_RWX 1245 config STRICT_KERNEL_RWX
1406 bool "Make kernel text and rodata rea 1246 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1407 depends on ARCH_HAS_STRICT_KERNEL_RWX 1247 depends on ARCH_HAS_STRICT_KERNEL_RWX
1408 default !ARCH_OPTIONAL_KERNEL_RWX || 1248 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1409 help 1249 help
1410 If this is set, kernel text and rod 1250 If this is set, kernel text and rodata memory will be made read-only,
1411 and non-text memory will be made no 1251 and non-text memory will be made non-executable. This provides
1412 protection against certain security 1252 protection against certain security exploits (e.g. executing the heap
1413 or modifying text) 1253 or modifying text)
1414 1254
1415 These features are considered stand 1255 These features are considered standard security practice these days.
1416 You should say Y here in almost all 1256 You should say Y here in almost all cases.
1417 1257
1418 config ARCH_HAS_STRICT_MODULE_RWX 1258 config ARCH_HAS_STRICT_MODULE_RWX
1419 def_bool n 1259 def_bool n
1420 1260
1421 config STRICT_MODULE_RWX 1261 config STRICT_MODULE_RWX
1422 bool "Set loadable kernel module data 1262 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
1423 depends on ARCH_HAS_STRICT_MODULE_RWX 1263 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1424 default !ARCH_OPTIONAL_KERNEL_RWX || 1264 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1425 help 1265 help
1426 If this is set, module text and rod 1266 If this is set, module text and rodata memory will be made read-only,
1427 and non-text memory will be made no 1267 and non-text memory will be made non-executable. This provides
1428 protection against certain security 1268 protection against certain security exploits (e.g. writing to text)
1429 1269
1430 # select if the architecture provides an asm/ 1270 # select if the architecture provides an asm/dma-direct.h header
1431 config ARCH_HAS_PHYS_TO_DMA 1271 config ARCH_HAS_PHYS_TO_DMA
1432 bool 1272 bool
1433 1273
1434 config HAVE_ARCH_COMPILER_H 1274 config HAVE_ARCH_COMPILER_H
1435 bool 1275 bool
1436 help 1276 help
1437 An architecture can select this if 1277 An architecture can select this if it provides an
1438 asm/compiler.h header that should b 1278 asm/compiler.h header that should be included after
1439 linux/compiler-*.h in order to over 1279 linux/compiler-*.h in order to override macro definitions that those
1440 headers generally provide. 1280 headers generally provide.
1441 1281
1442 config HAVE_ARCH_PREL32_RELOCATIONS 1282 config HAVE_ARCH_PREL32_RELOCATIONS
1443 bool 1283 bool
1444 help 1284 help
1445 May be selected by an architecture 1285 May be selected by an architecture if it supports place-relative
1446 32-bit relocations, both in the too 1286 32-bit relocations, both in the toolchain and in the module loader,
1447 in which case relative references c 1287 in which case relative references can be used in special sections
1448 for PCI fixup, initcalls etc which 1288 for PCI fixup, initcalls etc which are only half the size on 64 bit
1449 architectures, and don't require ru 1289 architectures, and don't require runtime relocation on relocatable
1450 kernels. 1290 kernels.
1451 1291
1452 config ARCH_USE_MEMREMAP_PROT 1292 config ARCH_USE_MEMREMAP_PROT
1453 bool 1293 bool
1454 1294
1455 config LOCK_EVENT_COUNTS 1295 config LOCK_EVENT_COUNTS
1456 bool "Locking event counts collection 1296 bool "Locking event counts collection"
1457 depends on DEBUG_FS 1297 depends on DEBUG_FS
1458 help 1298 help
1459 Enable light-weight counting of var 1299 Enable light-weight counting of various locking related events
1460 in the system with minimal performa 1300 in the system with minimal performance impact. This reduces
1461 the chance of application behavior 1301 the chance of application behavior change because of timing
1462 differences. The counts are reporte 1302 differences. The counts are reported via debugfs.
1463 1303
1464 # Select if the architecture has support for 1304 # Select if the architecture has support for applying RELR relocations.
1465 config ARCH_HAS_RELR 1305 config ARCH_HAS_RELR
1466 bool 1306 bool
1467 1307
1468 config RELR 1308 config RELR
1469 bool "Use RELR relocation packing" 1309 bool "Use RELR relocation packing"
1470 depends on ARCH_HAS_RELR && TOOLS_SUP 1310 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
1471 default y 1311 default y
1472 help 1312 help
1473 Store the kernel's dynamic relocati 1313 Store the kernel's dynamic relocations in the RELR relocation packing
1474 format. Requires a compatible linke 1314 format. Requires a compatible linker (LLD supports this feature), as
1475 well as compatible NM and OBJCOPY u 1315 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1476 are compatible). 1316 are compatible).
1477 1317
1478 config ARCH_HAS_MEM_ENCRYPT 1318 config ARCH_HAS_MEM_ENCRYPT
1479 bool 1319 bool
1480 1320
1481 config ARCH_HAS_CC_PLATFORM 1321 config ARCH_HAS_CC_PLATFORM
1482 bool 1322 bool
1483 1323
1484 config HAVE_SPARSE_SYSCALL_NR 1324 config HAVE_SPARSE_SYSCALL_NR
1485 bool !! 1325 bool
1486 help !! 1326 help
1487 An architecture should select this !! 1327 An architecture should select this if its syscall numbering is sparse
1488 to save space. For example, MIPS ar 1328 to save space. For example, MIPS architecture has a syscall array with
1489 entries at 4000, 5000 and 6000 loca 1329 entries at 4000, 5000 and 6000 locations. This option turns on syscall
1490 related optimizations for a given a 1330 related optimizations for a given architecture.
1491 1331
1492 config ARCH_HAS_VDSO_DATA 1332 config ARCH_HAS_VDSO_DATA
1493 bool 1333 bool
1494 1334
1495 config HAVE_STATIC_CALL 1335 config HAVE_STATIC_CALL
1496 bool 1336 bool
1497 1337
1498 config HAVE_STATIC_CALL_INLINE 1338 config HAVE_STATIC_CALL_INLINE
1499 bool 1339 bool
1500 depends on HAVE_STATIC_CALL 1340 depends on HAVE_STATIC_CALL
1501 select OBJTOOL 1341 select OBJTOOL
1502 1342
1503 config HAVE_PREEMPT_DYNAMIC 1343 config HAVE_PREEMPT_DYNAMIC
1504 bool 1344 bool
1505 1345
1506 config HAVE_PREEMPT_DYNAMIC_CALL 1346 config HAVE_PREEMPT_DYNAMIC_CALL
1507 bool 1347 bool
1508 depends on HAVE_STATIC_CALL 1348 depends on HAVE_STATIC_CALL
1509 select HAVE_PREEMPT_DYNAMIC 1349 select HAVE_PREEMPT_DYNAMIC
1510 help 1350 help
1511 An architecture should select this !! 1351 An architecture should select this if it can handle the preemption
1512 model being selected at boot time u !! 1352 model being selected at boot time using static calls.
1513 1353
1514 Where an architecture selects HAVE_ !! 1354 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a
1515 preemption function will be patched !! 1355 preemption function will be patched directly.
1516 1356
1517 Where an architecture does not sele !! 1357 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any
1518 call to a preemption function will !! 1358 call to a preemption function will go through a trampoline, and the
1519 trampoline will be patched. !! 1359 trampoline will be patched.
1520 1360
1521 It is strongly advised to support i !! 1361 It is strongly advised to support inline static call to avoid any
1522 overhead. !! 1362 overhead.
1523 1363
1524 config HAVE_PREEMPT_DYNAMIC_KEY 1364 config HAVE_PREEMPT_DYNAMIC_KEY
1525 bool 1365 bool
1526 depends on HAVE_ARCH_JUMP_LABEL 1366 depends on HAVE_ARCH_JUMP_LABEL
1527 select HAVE_PREEMPT_DYNAMIC 1367 select HAVE_PREEMPT_DYNAMIC
1528 help 1368 help
1529 An architecture should select this !! 1369 An architecture should select this if it can handle the preemption
1530 model being selected at boot time u !! 1370 model being selected at boot time using static keys.
1531 1371
1532 Each preemption function will be gi !! 1372 Each preemption function will be given an early return based on a
1533 static key. This should have slight !! 1373 static key. This should have slightly lower overhead than non-inline
1534 static calls, as this effectively i !! 1374 static calls, as this effectively inlines each trampoline into the
1535 start of its callee. This may avoid !! 1375 start of its callee. This may avoid redundant work, and may
1536 integrate better with CFI schemes. !! 1376 integrate better with CFI schemes.
1537 1377
1538 This will have greater overhead tha !! 1378 This will have greater overhead than using inline static calls as
1539 the call to the preemption function !! 1379 the call to the preemption function cannot be entirely elided.
1540 1380
1541 config ARCH_WANT_LD_ORPHAN_WARN 1381 config ARCH_WANT_LD_ORPHAN_WARN
1542 bool 1382 bool
1543 help 1383 help
1544 An arch should select this symbol o 1384 An arch should select this symbol once all linker sections are explicitly
1545 included, size-asserted, or discard 1385 included, size-asserted, or discarded in the linker scripts. This is
1546 important because we never want exp 1386 important because we never want expected sections to be placed heuristically
1547 by the linker, since the locations 1387 by the linker, since the locations of such sections can change between linker
1548 versions. 1388 versions.
1549 1389
1550 config HAVE_ARCH_PFN_VALID 1390 config HAVE_ARCH_PFN_VALID
1551 bool 1391 bool
1552 1392
1553 config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1393 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1554 bool 1394 bool
1555 1395
1556 config ARCH_SUPPORTS_PAGE_TABLE_CHECK 1396 config ARCH_SUPPORTS_PAGE_TABLE_CHECK
1557 bool 1397 bool
1558 1398
1559 config ARCH_SPLIT_ARG64 1399 config ARCH_SPLIT_ARG64
1560 bool 1400 bool
1561 help 1401 help
1562 If a 32-bit architecture requires 6 !! 1402 If a 32-bit architecture requires 64-bit arguments to be split into
1563 pairs of 32-bit arguments, select t !! 1403 pairs of 32-bit arguments, select this option.
1564 1404
1565 config ARCH_HAS_ELFCORE_COMPAT 1405 config ARCH_HAS_ELFCORE_COMPAT
1566 bool 1406 bool
1567 1407
1568 config ARCH_HAS_PARANOID_L1D_FLUSH 1408 config ARCH_HAS_PARANOID_L1D_FLUSH
1569 bool 1409 bool
1570 1410
1571 config ARCH_HAVE_TRACE_MMIO_ACCESS 1411 config ARCH_HAVE_TRACE_MMIO_ACCESS
1572 bool 1412 bool
1573 1413
1574 config DYNAMIC_SIGFRAME 1414 config DYNAMIC_SIGFRAME
1575 bool 1415 bool
1576 1416
1577 # Select, if arch has a named attribute group 1417 # Select, if arch has a named attribute group bound to NUMA device nodes.
1578 config HAVE_ARCH_NODE_DEV_GROUP 1418 config HAVE_ARCH_NODE_DEV_GROUP
1579 bool 1419 bool
1580 1420
1581 config ARCH_HAS_HW_PTE_YOUNG <<
1582 bool <<
1583 help <<
1584 Architectures that select this opti <<
1585 accessed bit in PTE entries when us <<
1586 translations. Architectures that re <<
1587 this option and override arch_has_h <<
1588 <<
1589 config ARCH_HAS_NONLEAF_PMD_YOUNG <<
1590 bool <<
1591 help <<
1592 Architectures that select this opti <<
1593 accessed bit in non-leaf PMD entrie <<
1594 address translations. Page table wa <<
1595 may use this capability to reduce t <<
1596 <<
1597 config ARCH_HAS_KERNEL_FPU_SUPPORT <<
1598 bool <<
1599 help <<
1600 Architectures that select this opti <<
1601 the kernel, as described in Documen <<
1602 <<
1603 source "kernel/gcov/Kconfig" 1421 source "kernel/gcov/Kconfig"
1604 1422
1605 source "scripts/gcc-plugins/Kconfig" 1423 source "scripts/gcc-plugins/Kconfig"
1606 <<
1607 config FUNCTION_ALIGNMENT_4B <<
1608 bool <<
1609 <<
1610 config FUNCTION_ALIGNMENT_8B <<
1611 bool <<
1612 <<
1613 config FUNCTION_ALIGNMENT_16B <<
1614 bool <<
1615 <<
1616 config FUNCTION_ALIGNMENT_32B <<
1617 bool <<
1618 <<
1619 config FUNCTION_ALIGNMENT_64B <<
1620 bool <<
1621 <<
1622 config FUNCTION_ALIGNMENT <<
1623 int <<
1624 default 64 if FUNCTION_ALIGNMENT_64B <<
1625 default 32 if FUNCTION_ALIGNMENT_32B <<
1626 default 16 if FUNCTION_ALIGNMENT_16B <<
1627 default 8 if FUNCTION_ALIGNMENT_8B <<
1628 default 4 if FUNCTION_ALIGNMENT_4B <<
1629 default 0 <<
1630 <<
1631 config CC_HAS_MIN_FUNCTION_ALIGNMENT <<
1632 # Detect availability of the GCC opti <<
1633 # guarantees minimal alignment for al <<
1634 # -falign-functions which the compile <<
1635 def_bool $(cc-option, -fmin-function- <<
1636 <<
1637 config CC_HAS_SANE_FUNCTION_ALIGNMENT <<
1638 # Set if the guaranteed alignment wit <<
1639 # available or extra care is required <<
1640 # strict alignment always, even with <<
1641 def_bool CC_HAS_MIN_FUNCTION_ALIGNMEN <<
1642 <<
1643 config ARCH_NEED_CMPXCHG_1_EMU <<
1644 bool <<
1645 1424
1646 endmenu 1425 endmenu
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