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 # <<
21 # Selected by architectures that need custom D <<
22 # IOMMUs not handled by dma-iommu. Drivers mu <<
23 # <<
24 config ARCH_HAS_DMA_OPS <<
25 depends on HAS_DMA <<
26 select DMA_OPS_HELPERS <<
27 bool <<
28 <<
29 menu "General architecture-dependent options" 12 menu "General architecture-dependent options"
30 13
31 config ARCH_HAS_SUBPAGE_FAULTS !! 14 config CRASH_CORE
32 bool 15 bool
33 help <<
34 Select if the architecture can check <<
35 granularity (e.g. arm64 MTE). The pr <<
36 must be implemented. <<
37 16
38 config HOTPLUG_SMT !! 17 config KEXEC_CORE
39 bool !! 18 select CRASH_CORE
40 <<
41 config SMT_NUM_THREADS_DYNAMIC <<
42 bool <<
43 <<
44 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU <<
45 config HOTPLUG_CORE_SYNC <<
46 bool <<
47 <<
48 # Basic CPU dead synchronization selected by a <<
49 config HOTPLUG_CORE_SYNC_DEAD <<
50 bool 19 bool
51 select HOTPLUG_CORE_SYNC <<
52 20
53 # Full CPU synchronization with alive state se !! 21 config KEXEC_ELF
54 config HOTPLUG_CORE_SYNC_FULL <<
55 bool 22 bool
56 select HOTPLUG_CORE_SYNC_DEAD if HOTPL <<
57 select HOTPLUG_CORE_SYNC <<
58 23
59 config HOTPLUG_SPLIT_STARTUP !! 24 config HAVE_IMA_KEXEC
60 bool 25 bool
61 select HOTPLUG_CORE_SYNC_FULL <<
62 26
63 config HOTPLUG_PARALLEL !! 27 config HOTPLUG_SMT
64 bool 28 bool
65 select HOTPLUG_SPLIT_STARTUP <<
66 29
67 config GENERIC_ENTRY 30 config GENERIC_ENTRY
68 bool !! 31 bool
69 32
70 config KPROBES 33 config KPROBES
71 bool "Kprobes" 34 bool "Kprobes"
>> 35 depends on MODULES
72 depends on HAVE_KPROBES 36 depends on HAVE_KPROBES
73 select KALLSYMS 37 select KALLSYMS
74 select EXECMEM <<
75 select NEED_TASKS_RCU <<
76 help 38 help
77 Kprobes allows you to trap at almost 39 Kprobes allows you to trap at almost any kernel address and
78 execute a callback function. regist 40 execute a callback function. register_kprobe() establishes
79 a probepoint and specifies the callb 41 a probepoint and specifies the callback. Kprobes is useful
80 for kernel debugging, non-intrusive 42 for kernel debugging, non-intrusive instrumentation and testing.
81 If in doubt, say "N". 43 If in doubt, say "N".
82 44
83 config JUMP_LABEL 45 config JUMP_LABEL
84 bool "Optimize very unlikely/likely br 46 bool "Optimize very unlikely/likely branches"
85 depends on HAVE_ARCH_JUMP_LABEL 47 depends on HAVE_ARCH_JUMP_LABEL
86 select OBJTOOL if HAVE_JUMP_LABEL_HACK !! 48 depends on CC_HAS_ASM_GOTO
87 help 49 help
88 This option enables a transparent br !! 50 This option enables a transparent branch optimization that
89 makes certain almost-always-true or !! 51 makes certain almost-always-true or almost-always-false branch
90 conditions even cheaper to execute w !! 52 conditions even cheaper to execute within the kernel.
91 !! 53
92 Certain performance-sensitive kernel !! 54 Certain performance-sensitive kernel code, such as trace points,
93 scheduler functionality, networking !! 55 scheduler functionality, networking code and KVM have such
94 branches and include support for thi !! 56 branches and include support for this optimization technique.
95 !! 57
96 If it is detected that the compiler !! 58 If it is detected that the compiler has support for "asm goto",
97 the kernel will compile such branche !! 59 the kernel will compile such branches with just a nop
98 instruction. When the condition flag !! 60 instruction. When the condition flag is toggled to true, the
99 nop will be converted to a jump inst !! 61 nop will be converted to a jump instruction to execute the
100 conditional block of instructions. !! 62 conditional block of instructions.
101 !! 63
102 This technique lowers overhead and s !! 64 This technique lowers overhead and stress on the branch prediction
103 of the processor and generally makes !! 65 of the processor and generally makes the kernel faster. The update
104 of the condition is slower, but thos !! 66 of the condition is slower, but those are always very rare.
105 67
106 ( On 32-bit x86, the necessary optio !! 68 ( On 32-bit x86, the necessary options added to the compiler
107 flags may increase the size of the !! 69 flags may increase the size of the kernel slightly. )
108 70
109 config STATIC_KEYS_SELFTEST 71 config STATIC_KEYS_SELFTEST
110 bool "Static key selftest" 72 bool "Static key selftest"
111 depends on JUMP_LABEL 73 depends on JUMP_LABEL
112 help 74 help
113 Boot time self-test of the branch pa 75 Boot time self-test of the branch patching code.
114 76
115 config STATIC_CALL_SELFTEST 77 config STATIC_CALL_SELFTEST
116 bool "Static call selftest" 78 bool "Static call selftest"
117 depends on HAVE_STATIC_CALL 79 depends on HAVE_STATIC_CALL
118 help 80 help
119 Boot time self-test of the call patc 81 Boot time self-test of the call patching code.
120 82
121 config OPTPROBES 83 config OPTPROBES
122 def_bool y 84 def_bool y
123 depends on KPROBES && HAVE_OPTPROBES 85 depends on KPROBES && HAVE_OPTPROBES
124 select NEED_TASKS_RCU !! 86 select TASKS_RCU if PREEMPTION
125 87
126 config KPROBES_ON_FTRACE 88 config KPROBES_ON_FTRACE
127 def_bool y 89 def_bool y
128 depends on KPROBES && HAVE_KPROBES_ON_ 90 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
129 depends on DYNAMIC_FTRACE_WITH_REGS 91 depends on DYNAMIC_FTRACE_WITH_REGS
130 help 92 help
131 If function tracer is enabled and th !! 93 If function tracer is enabled and the arch supports full
132 passing of pt_regs to function traci !! 94 passing of pt_regs to function tracing, then kprobes can
133 optimize on top of function tracing. !! 95 optimize on top of function tracing.
134 96
135 config UPROBES 97 config UPROBES
136 def_bool n 98 def_bool n
137 depends on ARCH_SUPPORTS_UPROBES 99 depends on ARCH_SUPPORTS_UPROBES
138 help 100 help
139 Uprobes is the user-space counterpar 101 Uprobes is the user-space counterpart to kprobes: they
140 enable instrumentation applications 102 enable instrumentation applications (such as 'perf probe')
141 to establish unintrusive probes in u 103 to establish unintrusive probes in user-space binaries and
142 libraries, by executing handler func 104 libraries, by executing handler functions when the probes
143 are hit by user-space applications. 105 are hit by user-space applications.
144 106
145 ( These probes come in the form of s 107 ( These probes come in the form of single-byte breakpoints,
146 managed by the kernel and kept tra 108 managed by the kernel and kept transparent to the probed
147 application. ) 109 application. )
148 110
149 config HAVE_64BIT_ALIGNED_ACCESS 111 config HAVE_64BIT_ALIGNED_ACCESS
150 def_bool 64BIT && !HAVE_EFFICIENT_UNAL 112 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
151 help 113 help
152 Some architectures require 64 bit ac 114 Some architectures require 64 bit accesses to be 64 bit
153 aligned, which also requires structs 115 aligned, which also requires structs containing 64 bit values
154 to be 64 bit aligned too. This inclu 116 to be 64 bit aligned too. This includes some 32 bit
155 architectures which can do 64 bit ac 117 architectures which can do 64 bit accesses, as well as 64 bit
156 architectures without unaligned acce 118 architectures without unaligned access.
157 119
158 This symbol should be selected by an 120 This symbol should be selected by an architecture if 64 bit
159 accesses are required to be 64 bit a 121 accesses are required to be 64 bit aligned in this way even
160 though it is not a 64 bit architectu 122 though it is not a 64 bit architecture.
161 123
162 See Documentation/core-api/unaligned 124 See Documentation/core-api/unaligned-memory-access.rst for
163 more information on the topic of una 125 more information on the topic of unaligned memory accesses.
164 126
165 config HAVE_EFFICIENT_UNALIGNED_ACCESS 127 config HAVE_EFFICIENT_UNALIGNED_ACCESS
166 bool 128 bool
167 help 129 help
168 Some architectures are unable to per 130 Some architectures are unable to perform unaligned accesses
169 without the use of get_unaligned/put 131 without the use of get_unaligned/put_unaligned. Others are
170 unable to perform such accesses effi 132 unable to perform such accesses efficiently (e.g. trap on
171 unaligned access and require fixing 133 unaligned access and require fixing it up in the exception
172 handler.) 134 handler.)
173 135
174 This symbol should be selected by an 136 This symbol should be selected by an architecture if it can
175 perform unaligned accesses efficient 137 perform unaligned accesses efficiently to allow different
176 code paths to be selected for these 138 code paths to be selected for these cases. Some network
177 drivers, for example, could opt to n 139 drivers, for example, could opt to not fix up alignment
178 problems with received packets if do 140 problems with received packets if doing so would not help
179 much. 141 much.
180 142
181 See Documentation/core-api/unaligned 143 See Documentation/core-api/unaligned-memory-access.rst for more
182 information on the topic of unaligne 144 information on the topic of unaligned memory accesses.
183 145
184 config ARCH_USE_BUILTIN_BSWAP 146 config ARCH_USE_BUILTIN_BSWAP
185 bool 147 bool
186 help 148 help
187 Modern versions of GCC (since 4.4) h !! 149 Modern versions of GCC (since 4.4) have builtin functions
188 for handling byte-swapping. Using th !! 150 for handling byte-swapping. Using these, instead of the old
189 inline assembler that the architectu !! 151 inline assembler that the architecture code provides in the
190 __arch_bswapXX() macros, allows the !! 152 __arch_bswapXX() macros, allows the compiler to see what's
191 happening and offers more opportunit !! 153 happening and offers more opportunity for optimisation. In
192 particular, the compiler will be abl !! 154 particular, the compiler will be able to combine the byteswap
193 with a nearby load or store and use !! 155 with a nearby load or store and use load-and-swap or
194 store-and-swap instructions if the a !! 156 store-and-swap instructions if the architecture has them. It
195 should almost *never* result in code !! 157 should almost *never* result in code which is worse than the
196 hand-coded assembler in <asm/swab.h> !! 158 hand-coded assembler in <asm/swab.h>. But just in case it
197 does, the use of the builtins is opt !! 159 does, the use of the builtins is optional.
198 !! 160
199 Any architecture with load-and-swap !! 161 Any architecture with load-and-swap or store-and-swap
200 instructions should set this. And it !! 162 instructions should set this. And it shouldn't hurt to set it
201 on architectures that don't have suc !! 163 on architectures that don't have such instructions.
202 164
203 config KRETPROBES 165 config KRETPROBES
204 def_bool y 166 def_bool y
205 depends on KPROBES && (HAVE_KRETPROBES 167 depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK)
206 168
207 config KRETPROBE_ON_RETHOOK 169 config KRETPROBE_ON_RETHOOK
208 def_bool y 170 def_bool y
209 depends on HAVE_RETHOOK 171 depends on HAVE_RETHOOK
210 depends on KRETPROBES 172 depends on KRETPROBES
211 select RETHOOK 173 select RETHOOK
212 174
213 config USER_RETURN_NOTIFIER 175 config USER_RETURN_NOTIFIER
214 bool 176 bool
215 depends on HAVE_USER_RETURN_NOTIFIER 177 depends on HAVE_USER_RETURN_NOTIFIER
216 help 178 help
217 Provide a kernel-internal notificati 179 Provide a kernel-internal notification when a cpu is about to
218 switch to user mode. 180 switch to user mode.
219 181
220 config HAVE_IOREMAP_PROT 182 config HAVE_IOREMAP_PROT
221 bool 183 bool
222 184
223 config HAVE_KPROBES 185 config HAVE_KPROBES
224 bool 186 bool
225 187
226 config HAVE_KRETPROBES 188 config HAVE_KRETPROBES
227 bool 189 bool
228 190
229 config HAVE_OPTPROBES 191 config HAVE_OPTPROBES
230 bool 192 bool
231 193
232 config HAVE_KPROBES_ON_FTRACE 194 config HAVE_KPROBES_ON_FTRACE
233 bool 195 bool
234 196
235 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 197 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
236 bool 198 bool
237 help 199 help
238 Since kretprobes modifies return add 200 Since kretprobes modifies return address on the stack, the
239 stacktrace may see the kretprobe tra 201 stacktrace may see the kretprobe trampoline address instead
240 of correct one. If the architecture 202 of correct one. If the architecture stacktrace code and
241 unwinder can adjust such entries, se 203 unwinder can adjust such entries, select this configuration.
242 204
243 config HAVE_FUNCTION_ERROR_INJECTION 205 config HAVE_FUNCTION_ERROR_INJECTION
244 bool 206 bool
245 207
246 config HAVE_NMI 208 config HAVE_NMI
247 bool 209 bool
248 210
249 config HAVE_FUNCTION_DESCRIPTORS 211 config HAVE_FUNCTION_DESCRIPTORS
250 bool 212 bool
251 213
252 config TRACE_IRQFLAGS_SUPPORT 214 config TRACE_IRQFLAGS_SUPPORT
253 bool 215 bool
254 216
255 config TRACE_IRQFLAGS_NMI_SUPPORT 217 config TRACE_IRQFLAGS_NMI_SUPPORT
256 bool 218 bool
257 219
258 # 220 #
259 # An arch should select this if it provides al 221 # An arch should select this if it provides all these things:
260 # 222 #
261 # task_pt_regs() in asm/process 223 # task_pt_regs() in asm/processor.h or asm/ptrace.h
262 # arch_has_single_step() if there is ha 224 # arch_has_single_step() if there is hardware single-step support
263 # arch_has_block_step() if there is ha 225 # arch_has_block_step() if there is hardware block-step support
264 # asm/syscall.h supplying asm- 226 # asm/syscall.h supplying asm-generic/syscall.h interface
265 # linux/regset.h user_regset in 227 # linux/regset.h user_regset interfaces
266 # CORE_DUMP_USE_REGSET #define'd in l 228 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h
267 # TIF_SYSCALL_TRACE calls ptrace_r 229 # TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit}
268 # TIF_NOTIFY_RESUME calls resume_u 230 # TIF_NOTIFY_RESUME calls resume_user_mode_work()
269 # 231 #
270 config HAVE_ARCH_TRACEHOOK 232 config HAVE_ARCH_TRACEHOOK
271 bool 233 bool
272 234
273 config HAVE_DMA_CONTIGUOUS 235 config HAVE_DMA_CONTIGUOUS
274 bool 236 bool
275 237
276 config GENERIC_SMP_IDLE_THREAD 238 config GENERIC_SMP_IDLE_THREAD
277 bool 239 bool
278 240
279 config GENERIC_IDLE_POLL_SETUP 241 config GENERIC_IDLE_POLL_SETUP
280 bool 242 bool
281 243
282 config ARCH_HAS_FORTIFY_SOURCE 244 config ARCH_HAS_FORTIFY_SOURCE
283 bool 245 bool
284 help 246 help
285 An architecture should select this w 247 An architecture should select this when it can successfully
286 build and run with CONFIG_FORTIFY_SO 248 build and run with CONFIG_FORTIFY_SOURCE.
287 249
288 # 250 #
289 # Select if the arch provides a historic keepi 251 # Select if the arch provides a historic keepinit alias for the retain_initrd
290 # command line option 252 # command line option
291 # 253 #
292 config ARCH_HAS_KEEPINITRD 254 config ARCH_HAS_KEEPINITRD
293 bool 255 bool
294 256
295 # Select if arch has all set_memory_ro/rw/x/nx 257 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
296 config ARCH_HAS_SET_MEMORY 258 config ARCH_HAS_SET_MEMORY
297 bool 259 bool
298 260
299 # Select if arch has all set_direct_map_invali 261 # Select if arch has all set_direct_map_invalid/default() functions
300 config ARCH_HAS_SET_DIRECT_MAP 262 config ARCH_HAS_SET_DIRECT_MAP
301 bool 263 bool
302 264
303 # 265 #
304 # Select if the architecture provides the arch 266 # Select if the architecture provides the arch_dma_set_uncached symbol to
305 # either provide an uncached segment alias for 267 # either provide an uncached segment alias for a DMA allocation, or
306 # to remap the page tables in place. 268 # to remap the page tables in place.
307 # 269 #
308 config ARCH_HAS_DMA_SET_UNCACHED 270 config ARCH_HAS_DMA_SET_UNCACHED
309 bool 271 bool
310 272
311 # 273 #
312 # Select if the architectures provides the arc 274 # Select if the architectures provides the arch_dma_clear_uncached symbol
313 # to undo an in-place page table remap for unc 275 # to undo an in-place page table remap for uncached access.
314 # 276 #
315 config ARCH_HAS_DMA_CLEAR_UNCACHED 277 config ARCH_HAS_DMA_CLEAR_UNCACHED
316 bool 278 bool
317 279
318 config ARCH_HAS_CPU_FINALIZE_INIT !! 280 # Select if arch init_task must go in the __init_task_data section
>> 281 config ARCH_TASK_STRUCT_ON_STACK
319 bool 282 bool
320 283
321 # The architecture has a per-task state that i !! 284 # Select if arch has its private alloc_task_struct() function
322 config ARCH_HAS_CPU_PASID !! 285 config ARCH_TASK_STRUCT_ALLOCATOR
323 bool 286 bool
324 select IOMMU_MM_DATA <<
325 287
326 config HAVE_ARCH_THREAD_STRUCT_WHITELIST 288 config HAVE_ARCH_THREAD_STRUCT_WHITELIST
327 bool 289 bool
>> 290 depends on !ARCH_TASK_STRUCT_ALLOCATOR
328 help 291 help
329 An architecture should select this t 292 An architecture should select this to provide hardened usercopy
330 knowledge about what region of the t 293 knowledge about what region of the thread_struct should be
331 whitelisted for copying to userspace 294 whitelisted for copying to userspace. Normally this is only the
332 FPU registers. Specifically, arch_th 295 FPU registers. Specifically, arch_thread_struct_whitelist()
333 should be implemented. Without this, 296 should be implemented. Without this, the entire thread_struct
334 field in task_struct will be left wh 297 field in task_struct will be left whitelisted.
335 298
>> 299 # Select if arch has its private alloc_thread_stack() function
>> 300 config ARCH_THREAD_STACK_ALLOCATOR
>> 301 bool
>> 302
336 # Select if arch wants to size task_struct dyn 303 # Select if arch wants to size task_struct dynamically via arch_task_struct_size:
337 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 304 config ARCH_WANTS_DYNAMIC_TASK_STRUCT
338 bool 305 bool
339 306
340 config ARCH_WANTS_NO_INSTR 307 config ARCH_WANTS_NO_INSTR
341 bool 308 bool
342 help 309 help
343 An architecture should select this i 310 An architecture should select this if the noinstr macro is being used on
344 functions to denote that the toolcha 311 functions to denote that the toolchain should avoid instrumenting such
345 functions and is required for correc 312 functions and is required for correctness.
346 313
347 config ARCH_32BIT_OFF_T 314 config ARCH_32BIT_OFF_T
348 bool 315 bool
349 depends on !64BIT 316 depends on !64BIT
350 help 317 help
351 All new 32-bit architectures should 318 All new 32-bit architectures should have 64-bit off_t type on
352 userspace side which corresponds to 319 userspace side which corresponds to the loff_t kernel type. This
353 is the requirement for modern ABIs. 320 is the requirement for modern ABIs. Some existing architectures
354 still support 32-bit off_t. This opt 321 still support 32-bit off_t. This option is enabled for all such
355 architectures explicitly. 322 architectures explicitly.
356 323
357 # Selected by 64 bit architectures which have 324 # Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat
358 config ARCH_32BIT_USTAT_F_TINODE 325 config ARCH_32BIT_USTAT_F_TINODE
359 bool 326 bool
360 327
361 config HAVE_ASM_MODVERSIONS 328 config HAVE_ASM_MODVERSIONS
362 bool 329 bool
363 help 330 help
364 This symbol should be selected by an 331 This symbol should be selected by an architecture if it provides
365 <asm/asm-prototypes.h> to support th 332 <asm/asm-prototypes.h> to support the module versioning for symbols
366 exported from assembly code. 333 exported from assembly code.
367 334
368 config HAVE_REGS_AND_STACK_ACCESS_API 335 config HAVE_REGS_AND_STACK_ACCESS_API
369 bool 336 bool
370 help 337 help
371 This symbol should be selected by an 338 This symbol should be selected by an architecture if it supports
372 the API needed to access registers a 339 the API needed to access registers and stack entries from pt_regs,
373 declared in asm/ptrace.h 340 declared in asm/ptrace.h
374 For example the kprobes-based event 341 For example the kprobes-based event tracer needs this API.
375 342
376 config HAVE_RSEQ 343 config HAVE_RSEQ
377 bool 344 bool
378 depends on HAVE_REGS_AND_STACK_ACCESS_ 345 depends on HAVE_REGS_AND_STACK_ACCESS_API
379 help 346 help
380 This symbol should be selected by an 347 This symbol should be selected by an architecture if it
381 supports an implementation of restar 348 supports an implementation of restartable sequences.
382 349
383 config HAVE_RUST <<
384 bool <<
385 help <<
386 This symbol should be selected by an <<
387 supports Rust. <<
388 <<
389 config HAVE_FUNCTION_ARG_ACCESS_API 350 config HAVE_FUNCTION_ARG_ACCESS_API
390 bool 351 bool
391 help 352 help
392 This symbol should be selected by an 353 This symbol should be selected by an architecture if it supports
393 the API needed to access function ar 354 the API needed to access function arguments from pt_regs,
394 declared in asm/ptrace.h 355 declared in asm/ptrace.h
395 356
396 config HAVE_HW_BREAKPOINT 357 config HAVE_HW_BREAKPOINT
397 bool 358 bool
398 depends on PERF_EVENTS 359 depends on PERF_EVENTS
399 360
400 config HAVE_MIXED_BREAKPOINTS_REGS 361 config HAVE_MIXED_BREAKPOINTS_REGS
401 bool 362 bool
402 depends on HAVE_HW_BREAKPOINT 363 depends on HAVE_HW_BREAKPOINT
403 help 364 help
404 Depending on the arch implementation 365 Depending on the arch implementation of hardware breakpoints,
405 some of them have separate registers 366 some of them have separate registers for data and instruction
406 breakpoints addresses, others have m 367 breakpoints addresses, others have mixed registers to store
407 them but define the access type in a 368 them but define the access type in a control register.
408 Select this option if your arch impl 369 Select this option if your arch implements breakpoints under the
409 latter fashion. 370 latter fashion.
410 371
411 config HAVE_USER_RETURN_NOTIFIER 372 config HAVE_USER_RETURN_NOTIFIER
412 bool 373 bool
413 374
414 config HAVE_PERF_EVENTS_NMI 375 config HAVE_PERF_EVENTS_NMI
415 bool 376 bool
416 help 377 help
417 System hardware can generate an NMI 378 System hardware can generate an NMI using the perf event
418 subsystem. Also has support for cal 379 subsystem. Also has support for calculating CPU cycle events
419 to determine how many clock cycles i 380 to determine how many clock cycles in a given period.
420 381
421 config HAVE_HARDLOCKUP_DETECTOR_PERF 382 config HAVE_HARDLOCKUP_DETECTOR_PERF
422 bool 383 bool
423 depends on HAVE_PERF_EVENTS_NMI 384 depends on HAVE_PERF_EVENTS_NMI
424 help 385 help
425 The arch chooses to use the generic 386 The arch chooses to use the generic perf-NMI-based hardlockup
426 detector. Must define HAVE_PERF_EVEN 387 detector. Must define HAVE_PERF_EVENTS_NMI.
427 388
428 config HAVE_HARDLOCKUP_DETECTOR_ARCH !! 389 config HAVE_NMI_WATCHDOG
>> 390 depends on HAVE_NMI
429 bool 391 bool
430 help 392 help
431 The arch provides its own hardlockup !! 393 The arch provides a low level NMI watchdog. It provides
432 of the generic ones. !! 394 asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
433 395
434 It uses the same command line parame !! 396 config HAVE_HARDLOCKUP_DETECTOR_ARCH
435 as the generic hardlockup detectors. !! 397 bool
>> 398 select HAVE_NMI_WATCHDOG
>> 399 help
>> 400 The arch chooses to provide its own hardlockup detector, which is
>> 401 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
>> 402 interfaces and parameters provided by hardlockup detector subsystem.
436 403
437 config HAVE_PERF_REGS 404 config HAVE_PERF_REGS
438 bool 405 bool
439 help 406 help
440 Support selective register dumps for 407 Support selective register dumps for perf events. This includes
441 bit-mapping of each registers and a 408 bit-mapping of each registers and a unique architecture id.
442 409
443 config HAVE_PERF_USER_STACK_DUMP 410 config HAVE_PERF_USER_STACK_DUMP
444 bool 411 bool
445 help 412 help
446 Support user stack dumps for perf ev 413 Support user stack dumps for perf event samples. This needs
447 access to the user stack pointer whi 414 access to the user stack pointer which is not unified across
448 architectures. 415 architectures.
449 416
450 config HAVE_ARCH_JUMP_LABEL 417 config HAVE_ARCH_JUMP_LABEL
451 bool 418 bool
452 419
453 config HAVE_ARCH_JUMP_LABEL_RELATIVE 420 config HAVE_ARCH_JUMP_LABEL_RELATIVE
454 bool 421 bool
455 422
456 config MMU_GATHER_TABLE_FREE 423 config MMU_GATHER_TABLE_FREE
457 bool 424 bool
458 425
459 config MMU_GATHER_RCU_TABLE_FREE 426 config MMU_GATHER_RCU_TABLE_FREE
460 bool 427 bool
461 select MMU_GATHER_TABLE_FREE 428 select MMU_GATHER_TABLE_FREE
462 429
463 config MMU_GATHER_PAGE_SIZE 430 config MMU_GATHER_PAGE_SIZE
464 bool 431 bool
465 432
466 config MMU_GATHER_NO_RANGE 433 config MMU_GATHER_NO_RANGE
467 bool 434 bool
468 select MMU_GATHER_MERGE_VMAS <<
469 <<
470 config MMU_GATHER_NO_FLUSH_CACHE <<
471 bool <<
472 <<
473 config MMU_GATHER_MERGE_VMAS <<
474 bool <<
475 435
476 config MMU_GATHER_NO_GATHER 436 config MMU_GATHER_NO_GATHER
477 bool 437 bool
478 depends on MMU_GATHER_TABLE_FREE 438 depends on MMU_GATHER_TABLE_FREE
479 439
480 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM 440 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
481 bool 441 bool
482 help 442 help
483 Temporary select until all architect 443 Temporary select until all architectures can be converted to have
484 irqs disabled over activate_mm. Arch 444 irqs disabled over activate_mm. Architectures that do IPI based TLB
485 shootdowns should enable this. 445 shootdowns should enable this.
486 446
487 # Use normal mm refcounting for MMU_LAZY_TLB k <<
488 # MMU_LAZY_TLB_REFCOUNT=n can improve the scal <<
489 # to/from kernel threads when the same mm is r <<
490 # multi-threaded application), by reducing con <<
491 # <<
492 # This can be disabled if the architecture ens <<
493 # "lazy tlb" beyond its final refcount (i.e., <<
494 # or its kernel page tables). This could be ar <<
495 # final exit(2) TLB flush, for example. <<
496 # <<
497 # To implement this, an arch *must*: <<
498 # Ensure the _lazy_tlb variants of mmgrab/mmdr <<
499 # the lazy tlb reference of a kthread's ->acti <<
500 # converted already). <<
501 config MMU_LAZY_TLB_REFCOUNT <<
502 def_bool y <<
503 depends on !MMU_LAZY_TLB_SHOOTDOWN <<
504 <<
505 # This option allows MMU_LAZY_TLB_REFCOUNT=n. <<
506 # mm as a lazy tlb beyond its last reference c <<
507 # users before the mm is deallocated. __mmdrop <<
508 # be using the mm as a lazy tlb, so that they <<
509 # init_mm for their active mm. mm_cpumask(mm) <<
510 # may be using mm as a lazy tlb mm. <<
511 # <<
512 # To implement this, an arch *must*: <<
513 # - At the time of the final mmdrop of the mm, <<
514 # at least all possible CPUs in which the mm <<
515 # - It must meet the requirements for MMU_LAZY <<
516 config MMU_LAZY_TLB_SHOOTDOWN <<
517 bool <<
518 <<
519 config ARCH_HAVE_NMI_SAFE_CMPXCHG 447 config ARCH_HAVE_NMI_SAFE_CMPXCHG
520 bool 448 bool
521 449
522 config ARCH_HAVE_EXTRA_ELF_NOTES <<
523 bool <<
524 help <<
525 An architecture should select this i <<
526 arch-specific ELF note section to co <<
527 functions: elf_coredump_extra_notes_ <<
528 elf_coredump_extra_notes_write() whi <<
529 dumper. <<
530 <<
531 config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS <<
532 bool <<
533 <<
534 config HAVE_ALIGNED_STRUCT_PAGE 450 config HAVE_ALIGNED_STRUCT_PAGE
535 bool 451 bool
536 help 452 help
537 This makes sure that struct pages ar 453 This makes sure that struct pages are double word aligned and that
538 e.g. the SLUB allocator can perform 454 e.g. the SLUB allocator can perform double word atomic operations
539 on a struct page for better performa 455 on a struct page for better performance. However selecting this
540 might increase the size of a struct 456 might increase the size of a struct page by a word.
541 457
542 config HAVE_CMPXCHG_LOCAL 458 config HAVE_CMPXCHG_LOCAL
543 bool 459 bool
544 460
545 config HAVE_CMPXCHG_DOUBLE 461 config HAVE_CMPXCHG_DOUBLE
546 bool 462 bool
547 463
548 config ARCH_WEAK_RELEASE_ACQUIRE 464 config ARCH_WEAK_RELEASE_ACQUIRE
549 bool 465 bool
550 466
551 config ARCH_WANT_IPC_PARSE_VERSION 467 config ARCH_WANT_IPC_PARSE_VERSION
552 bool 468 bool
553 469
554 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 470 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
555 bool 471 bool
556 472
557 config ARCH_WANT_OLD_COMPAT_IPC 473 config ARCH_WANT_OLD_COMPAT_IPC
558 select ARCH_WANT_COMPAT_IPC_PARSE_VERS 474 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
559 bool 475 bool
560 476
561 config HAVE_ARCH_SECCOMP 477 config HAVE_ARCH_SECCOMP
562 bool 478 bool
563 help 479 help
564 An arch should select this symbol to 480 An arch should select this symbol to support seccomp mode 1 (the fixed
565 syscall policy), and must provide an 481 syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
566 and compat syscalls if the asm-gener 482 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
567 - __NR_seccomp_read_32 483 - __NR_seccomp_read_32
568 - __NR_seccomp_write_32 484 - __NR_seccomp_write_32
569 - __NR_seccomp_exit_32 485 - __NR_seccomp_exit_32
570 - __NR_seccomp_sigreturn_32 486 - __NR_seccomp_sigreturn_32
571 487
572 config HAVE_ARCH_SECCOMP_FILTER 488 config HAVE_ARCH_SECCOMP_FILTER
573 bool 489 bool
574 select HAVE_ARCH_SECCOMP 490 select HAVE_ARCH_SECCOMP
575 help 491 help
576 An arch should select this symbol if 492 An arch should select this symbol if it provides all of these things:
577 - all the requirements for HAVE_ARCH 493 - all the requirements for HAVE_ARCH_SECCOMP
578 - syscall_get_arch() 494 - syscall_get_arch()
579 - syscall_get_arguments() 495 - syscall_get_arguments()
580 - syscall_rollback() 496 - syscall_rollback()
581 - syscall_set_return_value() 497 - syscall_set_return_value()
582 - SIGSYS siginfo_t support 498 - SIGSYS siginfo_t support
583 - secure_computing is called from a 499 - secure_computing is called from a ptrace_event()-safe context
584 - secure_computing return value is c 500 - secure_computing return value is checked and a return value of -1
585 results in the system call being s 501 results in the system call being skipped immediately.
586 - seccomp syscall wired up 502 - seccomp syscall wired up
587 - if !HAVE_SPARSE_SYSCALL_NR, have S 503 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
588 SECCOMP_ARCH_NATIVE_NR, SECCOMP_AR 504 SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
589 COMPAT is supported, have the SECC 505 COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
590 506
591 config SECCOMP 507 config SECCOMP
592 prompt "Enable seccomp to safely execu 508 prompt "Enable seccomp to safely execute untrusted bytecode"
593 def_bool y 509 def_bool y
594 depends on HAVE_ARCH_SECCOMP 510 depends on HAVE_ARCH_SECCOMP
595 help 511 help
596 This kernel feature is useful for nu 512 This kernel feature is useful for number crunching applications
597 that may need to handle untrusted by 513 that may need to handle untrusted bytecode during their
598 execution. By using pipes or other t 514 execution. By using pipes or other transports made available
599 to the process as file descriptors s 515 to the process as file descriptors supporting the read/write
600 syscalls, it's possible to isolate t 516 syscalls, it's possible to isolate those applications in their
601 own address space using seccomp. Onc 517 own address space using seccomp. Once seccomp is enabled via
602 prctl(PR_SET_SECCOMP) or the seccomp 518 prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be
603 disabled and the task is only allowe 519 disabled and the task is only allowed to execute a few safe
604 syscalls defined by each seccomp mod 520 syscalls defined by each seccomp mode.
605 521
606 If unsure, say Y. 522 If unsure, say Y.
607 523
608 config SECCOMP_FILTER 524 config SECCOMP_FILTER
609 def_bool y 525 def_bool y
610 depends on HAVE_ARCH_SECCOMP_FILTER && 526 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
611 help 527 help
612 Enable tasks to build secure computi 528 Enable tasks to build secure computing environments defined
613 in terms of Berkeley Packet Filter p 529 in terms of Berkeley Packet Filter programs which implement
614 task-defined system call filtering p 530 task-defined system call filtering polices.
615 531
616 See Documentation/userspace-api/secc 532 See Documentation/userspace-api/seccomp_filter.rst for details.
617 533
618 config SECCOMP_CACHE_DEBUG 534 config SECCOMP_CACHE_DEBUG
619 bool "Show seccomp filter cache status 535 bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
620 depends on SECCOMP_FILTER && !HAVE_SPA 536 depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
621 depends on PROC_FS 537 depends on PROC_FS
622 help 538 help
623 This enables the /proc/pid/seccomp_c 539 This enables the /proc/pid/seccomp_cache interface to monitor
624 seccomp cache data. The file format 540 seccomp cache data. The file format is subject to change. Reading
625 the file requires CAP_SYS_ADMIN. 541 the file requires CAP_SYS_ADMIN.
626 542
627 This option is for debugging only. E 543 This option is for debugging only. Enabling presents the risk that
628 an adversary may be able to infer th 544 an adversary may be able to infer the seccomp filter logic.
629 545
630 If unsure, say N. 546 If unsure, say N.
631 547
632 config HAVE_ARCH_STACKLEAK 548 config HAVE_ARCH_STACKLEAK
633 bool 549 bool
634 help 550 help
635 An architecture should select this i 551 An architecture should select this if it has the code which
636 fills the used part of the kernel st 552 fills the used part of the kernel stack with the STACKLEAK_POISON
637 value before returning from system c 553 value before returning from system calls.
638 554
639 config HAVE_STACKPROTECTOR 555 config HAVE_STACKPROTECTOR
640 bool 556 bool
641 help 557 help
642 An arch should select this symbol if 558 An arch should select this symbol if:
643 - it has implemented a stack canary 559 - it has implemented a stack canary (e.g. __stack_chk_guard)
644 560
645 config STACKPROTECTOR 561 config STACKPROTECTOR
646 bool "Stack Protector buffer overflow 562 bool "Stack Protector buffer overflow detection"
647 depends on HAVE_STACKPROTECTOR 563 depends on HAVE_STACKPROTECTOR
648 depends on $(cc-option,-fstack-protect 564 depends on $(cc-option,-fstack-protector)
649 default y 565 default y
650 help 566 help
651 This option turns on the "stack-prot 567 This option turns on the "stack-protector" GCC feature. This
652 feature puts, at the beginning of fu 568 feature puts, at the beginning of functions, a canary value on
653 the stack just before the return add 569 the stack just before the return address, and validates
654 the value just before actually retur 570 the value just before actually returning. Stack based buffer
655 overflows (that need to overwrite th 571 overflows (that need to overwrite this return address) now also
656 overwrite the canary, which gets det 572 overwrite the canary, which gets detected and the attack is then
657 neutralized via a kernel panic. 573 neutralized via a kernel panic.
658 574
659 Functions will have the stack-protec 575 Functions will have the stack-protector canary logic added if they
660 have an 8-byte or larger character a 576 have an 8-byte or larger character array on the stack.
661 577
662 This feature requires gcc version 4. 578 This feature requires gcc version 4.2 or above, or a distribution
663 gcc with the feature backported ("-f 579 gcc with the feature backported ("-fstack-protector").
664 580
665 On an x86 "defconfig" build, this fe 581 On an x86 "defconfig" build, this feature adds canary checks to
666 about 3% of all kernel functions, wh 582 about 3% of all kernel functions, which increases kernel code size
667 by about 0.3%. 583 by about 0.3%.
668 584
669 config STACKPROTECTOR_STRONG 585 config STACKPROTECTOR_STRONG
670 bool "Strong Stack Protector" 586 bool "Strong Stack Protector"
671 depends on STACKPROTECTOR 587 depends on STACKPROTECTOR
672 depends on $(cc-option,-fstack-protect 588 depends on $(cc-option,-fstack-protector-strong)
673 default y 589 default y
674 help 590 help
675 Functions will have the stack-protec 591 Functions will have the stack-protector canary logic added in any
676 of the following conditions: 592 of the following conditions:
677 593
678 - local variable's address used as p 594 - local variable's address used as part of the right hand side of an
679 assignment or function argument 595 assignment or function argument
680 - local variable is an array (or uni 596 - local variable is an array (or union containing an array),
681 regardless of array type or length 597 regardless of array type or length
682 - uses register local variables 598 - uses register local variables
683 599
684 This feature requires gcc version 4. 600 This feature requires gcc version 4.9 or above, or a distribution
685 gcc with the feature backported ("-f 601 gcc with the feature backported ("-fstack-protector-strong").
686 602
687 On an x86 "defconfig" build, this fe 603 On an x86 "defconfig" build, this feature adds canary checks to
688 about 20% of all kernel functions, w 604 about 20% of all kernel functions, which increases the kernel code
689 size by about 2%. 605 size by about 2%.
690 606
691 config ARCH_SUPPORTS_SHADOW_CALL_STACK 607 config ARCH_SUPPORTS_SHADOW_CALL_STACK
692 bool 608 bool
693 help 609 help
694 An architecture should select this i 610 An architecture should select this if it supports the compiler's
695 Shadow Call Stack and implements run 611 Shadow Call Stack and implements runtime support for shadow stack
696 switching. 612 switching.
697 613
698 config SHADOW_CALL_STACK 614 config SHADOW_CALL_STACK
699 bool "Shadow Call Stack" 615 bool "Shadow Call Stack"
700 depends on ARCH_SUPPORTS_SHADOW_CALL_S 616 depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
701 depends on DYNAMIC_FTRACE_WITH_ARGS || !! 617 depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
702 depends on MMU <<
703 help 618 help
704 This option enables the compiler's S 619 This option enables the compiler's Shadow Call Stack, which
705 uses a shadow stack to protect funct 620 uses a shadow stack to protect function return addresses from
706 being overwritten by an attacker. Mo 621 being overwritten by an attacker. More information can be found
707 in the compiler's documentation: 622 in the compiler's documentation:
708 623
709 - Clang: https://clang.llvm.org/docs 624 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
710 - GCC: https://gcc.gnu.org/onlinedoc 625 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
711 626
712 Note that security guarantees in the 627 Note that security guarantees in the kernel differ from the
713 ones documented for user space. The 628 ones documented for user space. The kernel must store addresses
714 of shadow stacks in memory, which me 629 of shadow stacks in memory, which means an attacker capable of
715 reading and writing arbitrary memory 630 reading and writing arbitrary memory may be able to locate them
716 and hijack control flow by modifying 631 and hijack control flow by modifying the stacks.
717 632
718 config DYNAMIC_SCS <<
719 bool <<
720 help <<
721 Set by the arch code if it relies on <<
722 shadow call stack push and pop instr <<
723 compiler. <<
724 <<
725 config LTO 633 config LTO
726 bool 634 bool
727 help 635 help
728 Selected if the kernel will be built 636 Selected if the kernel will be built using the compiler's LTO feature.
729 637
730 config LTO_CLANG 638 config LTO_CLANG
731 bool 639 bool
732 select LTO 640 select LTO
733 help 641 help
734 Selected if the kernel will be built 642 Selected if the kernel will be built using Clang's LTO feature.
735 643
736 config ARCH_SUPPORTS_LTO_CLANG 644 config ARCH_SUPPORTS_LTO_CLANG
737 bool 645 bool
738 help 646 help
739 An architecture should select this o 647 An architecture should select this option if it supports:
740 - compiling with Clang, 648 - compiling with Clang,
741 - compiling inline assembly with Cla 649 - compiling inline assembly with Clang's integrated assembler,
742 - and linking with LLD. 650 - and linking with LLD.
743 651
744 config ARCH_SUPPORTS_LTO_CLANG_THIN 652 config ARCH_SUPPORTS_LTO_CLANG_THIN
745 bool 653 bool
746 help 654 help
747 An architecture should select this o 655 An architecture should select this option if it can support Clang's
748 ThinLTO mode. 656 ThinLTO mode.
749 657
750 config HAS_LTO_CLANG 658 config HAS_LTO_CLANG
751 def_bool y 659 def_bool y
752 depends on CC_IS_CLANG && LD_IS_LLD && 660 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM
753 depends on $(success,$(NM) --help | he 661 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
754 depends on $(success,$(AR) --help | he 662 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
755 depends on ARCH_SUPPORTS_LTO_CLANG 663 depends on ARCH_SUPPORTS_LTO_CLANG
756 depends on !FTRACE_MCOUNT_USE_RECORDMC 664 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
757 # https://github.com/ClangBuiltLinux/l !! 665 depends on !KASAN || KASAN_HW_TAGS
758 depends on (!KASAN || KASAN_HW_TAGS || <<
759 depends on (!KCOV || CLANG_VERSION >= <<
760 depends on !GCOV_KERNEL 666 depends on !GCOV_KERNEL
761 help 667 help
762 The compiler and Kconfig options sup 668 The compiler and Kconfig options support building with Clang's
763 LTO. 669 LTO.
764 670
765 choice 671 choice
766 prompt "Link Time Optimization (LTO)" 672 prompt "Link Time Optimization (LTO)"
767 default LTO_NONE 673 default LTO_NONE
768 help 674 help
769 This option enables Link Time Optimi 675 This option enables Link Time Optimization (LTO), which allows the
770 compiler to optimize binaries global 676 compiler to optimize binaries globally.
771 677
772 If unsure, select LTO_NONE. Note tha 678 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
773 so it's disabled by default. 679 so it's disabled by default.
774 680
775 config LTO_NONE 681 config LTO_NONE
776 bool "None" 682 bool "None"
777 help 683 help
778 Build the kernel normally, without L 684 Build the kernel normally, without Link Time Optimization (LTO).
779 685
780 config LTO_CLANG_FULL 686 config LTO_CLANG_FULL
781 bool "Clang Full LTO (EXPERIMENTAL)" 687 bool "Clang Full LTO (EXPERIMENTAL)"
782 depends on HAS_LTO_CLANG 688 depends on HAS_LTO_CLANG
783 depends on !COMPILE_TEST 689 depends on !COMPILE_TEST
784 select LTO_CLANG 690 select LTO_CLANG
785 help 691 help
786 This option enables Clang's full Lin !! 692 This option enables Clang's full Link Time Optimization (LTO), which
787 allows the compiler to optimize the !! 693 allows the compiler to optimize the kernel globally. If you enable
788 this option, the compiler generates !! 694 this option, the compiler generates LLVM bitcode instead of ELF
789 object files, and the actual compila !! 695 object files, and the actual compilation from bitcode happens at
790 the LTO link step, which may take se !! 696 the LTO link step, which may take several minutes depending on the
791 kernel configuration. More informati !! 697 kernel configuration. More information can be found from LLVM's
792 documentation: !! 698 documentation:
793 699
794 https://llvm.org/docs/LinkTimeOpti 700 https://llvm.org/docs/LinkTimeOptimization.html
795 701
796 During link time, this option can us 702 During link time, this option can use a large amount of RAM, and
797 may take much longer than the ThinLT 703 may take much longer than the ThinLTO option.
798 704
799 config LTO_CLANG_THIN 705 config LTO_CLANG_THIN
800 bool "Clang ThinLTO (EXPERIMENTAL)" 706 bool "Clang ThinLTO (EXPERIMENTAL)"
801 depends on HAS_LTO_CLANG && ARCH_SUPPO 707 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
802 select LTO_CLANG 708 select LTO_CLANG
803 help 709 help
804 This option enables Clang's ThinLTO, 710 This option enables Clang's ThinLTO, which allows for parallel
805 optimization and faster incremental 711 optimization and faster incremental compiles compared to the
806 CONFIG_LTO_CLANG_FULL option. More i 712 CONFIG_LTO_CLANG_FULL option. More information can be found
807 from Clang's documentation: 713 from Clang's documentation:
808 714
809 https://clang.llvm.org/docs/ThinLT 715 https://clang.llvm.org/docs/ThinLTO.html
810 716
811 If unsure, say Y. 717 If unsure, say Y.
812 endchoice 718 endchoice
813 719
814 config ARCH_SUPPORTS_CFI_CLANG 720 config ARCH_SUPPORTS_CFI_CLANG
815 bool 721 bool
816 help 722 help
817 An architecture should select this o 723 An architecture should select this option if it can support Clang's
818 Control-Flow Integrity (CFI) checkin 724 Control-Flow Integrity (CFI) checking.
819 725
820 config ARCH_USES_CFI_TRAPS <<
821 bool <<
822 <<
823 config CFI_CLANG 726 config CFI_CLANG
824 bool "Use Clang's Control Flow Integri 727 bool "Use Clang's Control Flow Integrity (CFI)"
825 depends on ARCH_SUPPORTS_CFI_CLANG !! 728 depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG
826 depends on $(cc-option,-fsanitize=kcfi !! 729 # Clang >= 12:
>> 730 # - https://bugs.llvm.org/show_bug.cgi?id=46258
>> 731 # - https://bugs.llvm.org/show_bug.cgi?id=47479
>> 732 depends on CLANG_VERSION >= 120000
>> 733 select KALLSYMS
827 help 734 help
828 This option enables Clang's forward- !! 735 This option enables Clang’s forward-edge Control Flow Integrity
829 (CFI) checking, where the compiler i 736 (CFI) checking, where the compiler injects a runtime check to each
830 indirect function call to ensure the 737 indirect function call to ensure the target is a valid function with
831 the correct static type. This restri 738 the correct static type. This restricts possible call targets and
832 makes it more difficult for an attac 739 makes it more difficult for an attacker to exploit bugs that allow
833 the modification of stored function 740 the modification of stored function pointers. More information can be
834 found from Clang's documentation: 741 found from Clang's documentation:
835 742
836 https://clang.llvm.org/docs/Contro 743 https://clang.llvm.org/docs/ControlFlowIntegrity.html
837 744
838 config CFI_ICALL_NORMALIZE_INTEGERS !! 745 config CFI_CLANG_SHADOW
839 bool "Normalize CFI tags for integers" !! 746 bool "Use CFI shadow to speed up cross-module checks"
840 depends on CFI_CLANG !! 747 default y
841 depends on HAVE_CFI_ICALL_NORMALIZE_IN !! 748 depends on CFI_CLANG && MODULES
842 help 749 help
843 This option normalizes the CFI tags !! 750 If you select this option, the kernel builds a fast look-up table of
844 integer types of the same size and s !! 751 CFI check functions in loaded modules to reduce performance overhead.
845 tag. <<
846 <<
847 The option is separate from CONFIG_R <<
848 When working with build systems that <<
849 convenient to be able to turn on thi <<
850 turned on. <<
851 <<
852 This option is necessary for using C <<
853 <<
854 config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG <<
855 def_bool y <<
856 depends on $(cc-option,-fsanitize=kcfi <<
857 # With GCOV/KASAN we need this fix: ht <<
858 depends on CLANG_VERSION >= 190103 || <<
859 752
860 config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC !! 753 If unsure, say Y.
861 def_bool y <<
862 depends on HAVE_CFI_ICALL_NORMALIZE_IN <<
863 depends on RUSTC_VERSION >= 107900 <<
864 # With GCOV/KASAN we need this fix: ht <<
865 depends on (RUSTC_LLVM_VERSION >= 1901 <<
866 (!GCOV_KERNEL && !KASAN_GENERI <<
867 754
868 config CFI_PERMISSIVE 755 config CFI_PERMISSIVE
869 bool "Use CFI in permissive mode" 756 bool "Use CFI in permissive mode"
870 depends on CFI_CLANG 757 depends on CFI_CLANG
871 help 758 help
872 When selected, Control Flow Integrit 759 When selected, Control Flow Integrity (CFI) violations result in a
873 warning instead of a kernel panic. T 760 warning instead of a kernel panic. This option should only be used
874 for finding indirect call type misma 761 for finding indirect call type mismatches during development.
875 762
876 If unsure, say N. 763 If unsure, say N.
877 764
878 config HAVE_ARCH_WITHIN_STACK_FRAMES 765 config HAVE_ARCH_WITHIN_STACK_FRAMES
879 bool 766 bool
880 help 767 help
881 An architecture should select this i 768 An architecture should select this if it can walk the kernel stack
882 frames to determine if an object is 769 frames to determine if an object is part of either the arguments
883 or local variables (i.e. that it exc 770 or local variables (i.e. that it excludes saved return addresses,
884 and similar) by implementing an inli 771 and similar) by implementing an inline arch_within_stack_frames(),
885 which is used by CONFIG_HARDENED_USE 772 which is used by CONFIG_HARDENED_USERCOPY.
886 773
887 config HAVE_CONTEXT_TRACKING_USER !! 774 config HAVE_CONTEXT_TRACKING
888 bool 775 bool
889 help 776 help
890 Provide kernel/user boundaries probe 777 Provide kernel/user boundaries probes necessary for subsystems
891 that need it, such as userspace RCU 778 that need it, such as userspace RCU extended quiescent state.
892 Syscalls need to be wrapped inside u 779 Syscalls need to be wrapped inside user_exit()-user_enter(), either
893 optimized behind static key or throu 780 optimized behind static key or through the slow path using TIF_NOHZ
894 flag. Exceptions handlers must be wr 781 flag. Exceptions handlers must be wrapped as well. Irqs are already
895 protected inside ct_irq_enter/ct_irq !! 782 protected inside rcu_irq_enter/rcu_irq_exit() but preemption or signal
896 handling on irq exit still need to b 783 handling on irq exit still need to be protected.
897 784
898 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK !! 785 config HAVE_CONTEXT_TRACKING_OFFSTACK
899 bool 786 bool
900 help 787 help
901 Architecture neither relies on excep 788 Architecture neither relies on exception_enter()/exception_exit()
902 nor on schedule_user(). Also preempt 789 nor on schedule_user(). Also preempt_schedule_notrace() and
903 preempt_schedule_irq() can't be call 790 preempt_schedule_irq() can't be called in a preemptible section
904 while context tracking is CT_STATE_U !! 791 while context tracking is CONTEXT_USER. This feature reflects a sane
905 entry implementation where the follo 792 entry implementation where the following requirements are met on
906 critical entry code, ie: before user 793 critical entry code, ie: before user_exit() or after user_enter():
907 794
908 - Critical entry code isn't preempti 795 - Critical entry code isn't preemptible (or better yet:
909 not interruptible). 796 not interruptible).
910 - No use of RCU read side critical s !! 797 - No use of RCU read side critical sections, unless rcu_nmi_enter()
911 got called. 798 got called.
912 - No use of instrumentation, unless 799 - No use of instrumentation, unless instrumentation_begin() got
913 called. 800 called.
914 801
915 config HAVE_TIF_NOHZ 802 config HAVE_TIF_NOHZ
916 bool 803 bool
917 help 804 help
918 Arch relies on TIF_NOHZ and syscall 805 Arch relies on TIF_NOHZ and syscall slow path to implement context
919 tracking calls to user_enter()/user_ 806 tracking calls to user_enter()/user_exit().
920 807
921 config HAVE_VIRT_CPU_ACCOUNTING 808 config HAVE_VIRT_CPU_ACCOUNTING
922 bool 809 bool
923 810
924 config HAVE_VIRT_CPU_ACCOUNTING_IDLE 811 config HAVE_VIRT_CPU_ACCOUNTING_IDLE
925 bool 812 bool
926 help 813 help
927 Architecture has its own way to acco 814 Architecture has its own way to account idle CPU time and therefore
928 doesn't implement vtime_account_idle 815 doesn't implement vtime_account_idle().
929 816
930 config ARCH_HAS_SCALED_CPUTIME 817 config ARCH_HAS_SCALED_CPUTIME
931 bool 818 bool
932 819
933 config HAVE_VIRT_CPU_ACCOUNTING_GEN 820 config HAVE_VIRT_CPU_ACCOUNTING_GEN
934 bool 821 bool
935 default y if 64BIT 822 default y if 64BIT
936 help 823 help
937 With VIRT_CPU_ACCOUNTING_GEN, cputim 824 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
938 Before enabling this option, arch co 825 Before enabling this option, arch code must be audited
939 to ensure there are no races in conc 826 to ensure there are no races in concurrent read/write of
940 cputime_t. For example, reading/writ 827 cputime_t. For example, reading/writing 64-bit cputime_t on
941 some 32-bit arches may require multi 828 some 32-bit arches may require multiple accesses, so proper
942 locking is needed to protect against 829 locking is needed to protect against concurrent accesses.
943 830
944 config HAVE_IRQ_TIME_ACCOUNTING 831 config HAVE_IRQ_TIME_ACCOUNTING
945 bool 832 bool
946 help 833 help
947 Archs need to ensure they use a high 834 Archs need to ensure they use a high enough resolution clock to
948 support irq time accounting and then 835 support irq time accounting and then call enable_sched_clock_irqtime().
949 836
950 config HAVE_MOVE_PUD 837 config HAVE_MOVE_PUD
951 bool 838 bool
952 help 839 help
953 Architectures that select this are a 840 Architectures that select this are able to move page tables at the
954 PUD level. If there are only 3 page 841 PUD level. If there are only 3 page table levels, the move effectively
955 happens at the PGD level. 842 happens at the PGD level.
956 843
957 config HAVE_MOVE_PMD 844 config HAVE_MOVE_PMD
958 bool 845 bool
959 help 846 help
960 Archs that select this are able to m 847 Archs that select this are able to move page tables at the PMD level.
961 848
962 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 849 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
963 bool 850 bool
964 851
965 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 852 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
966 bool 853 bool
967 854
968 config HAVE_ARCH_HUGE_VMAP 855 config HAVE_ARCH_HUGE_VMAP
969 bool 856 bool
970 857
971 # 858 #
972 # Archs that select this would be capable of 859 # Archs that select this would be capable of PMD-sized vmaps (i.e.,
973 # arch_vmap_pmd_supported() returns true). Th 860 # arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag
974 # must be used to enable allocations to use h 861 # must be used to enable allocations to use hugepages.
975 # 862 #
976 config HAVE_ARCH_HUGE_VMALLOC 863 config HAVE_ARCH_HUGE_VMALLOC
977 depends on HAVE_ARCH_HUGE_VMAP 864 depends on HAVE_ARCH_HUGE_VMAP
978 bool 865 bool
979 866
980 config ARCH_WANT_HUGE_PMD_SHARE 867 config ARCH_WANT_HUGE_PMD_SHARE
981 bool 868 bool
982 869
983 # Archs that want to use pmd_mkwrite on kernel <<
984 # if there are no userspace memory management <<
985 config ARCH_WANT_KERNEL_PMD_MKWRITE <<
986 bool <<
987 <<
988 config ARCH_WANT_PMD_MKWRITE <<
989 def_bool TRANSPARENT_HUGEPAGE || ARCH_ <<
990 <<
991 config HAVE_ARCH_SOFT_DIRTY 870 config HAVE_ARCH_SOFT_DIRTY
992 bool 871 bool
993 872
994 config HAVE_MOD_ARCH_SPECIFIC 873 config HAVE_MOD_ARCH_SPECIFIC
995 bool 874 bool
996 help 875 help
997 The arch uses struct mod_arch_specif 876 The arch uses struct mod_arch_specific to store data. Many arches
998 just need a simple module loader wit 877 just need a simple module loader without arch specific data - those
999 should not enable this. 878 should not enable this.
1000 879
1001 config MODULES_USE_ELF_RELA 880 config MODULES_USE_ELF_RELA
1002 bool 881 bool
1003 help 882 help
1004 Modules only use ELF RELA relocatio 883 Modules only use ELF RELA relocations. Modules with ELF REL
1005 relocations will give an error. 884 relocations will give an error.
1006 885
1007 config MODULES_USE_ELF_REL 886 config MODULES_USE_ELF_REL
1008 bool 887 bool
1009 help 888 help
1010 Modules only use ELF REL relocation 889 Modules only use ELF REL relocations. Modules with ELF RELA
1011 relocations will give an error. 890 relocations will give an error.
1012 891
1013 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC <<
1014 bool <<
1015 help <<
1016 For architectures like powerpc/32 w <<
1017 allocation and need to allocate mod <<
1018 <<
1019 config ARCH_WANTS_EXECMEM_LATE <<
1020 bool <<
1021 help <<
1022 For architectures that do not alloc <<
1023 boot, but rather require its initia <<
1024 enough entropy for module space ran <<
1025 arm64. <<
1026 <<
1027 config HAVE_IRQ_EXIT_ON_IRQ_STACK 892 config HAVE_IRQ_EXIT_ON_IRQ_STACK
1028 bool 893 bool
1029 help 894 help
1030 Architecture doesn't only execute t 895 Architecture doesn't only execute the irq handler on the irq stack
1031 but also irq_exit(). This way we ca 896 but also irq_exit(). This way we can process softirqs on this irq
1032 stack instead of switching to a new 897 stack instead of switching to a new one when we call __do_softirq()
1033 in the end of an hardirq. 898 in the end of an hardirq.
1034 This spares a stack switch and impr 899 This spares a stack switch and improves cache usage on softirq
1035 processing. 900 processing.
1036 901
1037 config HAVE_SOFTIRQ_ON_OWN_STACK 902 config HAVE_SOFTIRQ_ON_OWN_STACK
1038 bool 903 bool
1039 help 904 help
1040 Architecture provides a function to 905 Architecture provides a function to run __do_softirq() on a
1041 separate stack. 906 separate stack.
1042 907
1043 config SOFTIRQ_ON_OWN_STACK <<
1044 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && <<
1045 <<
1046 config ALTERNATE_USER_ADDRESS_SPACE 908 config ALTERNATE_USER_ADDRESS_SPACE
1047 bool 909 bool
1048 help 910 help
1049 Architectures set this when the CPU 911 Architectures set this when the CPU uses separate address
1050 spaces for kernel and user space po 912 spaces for kernel and user space pointers. In this case, the
1051 access_ok() check on a __user point 913 access_ok() check on a __user pointer is skipped.
1052 914
1053 config PGTABLE_LEVELS 915 config PGTABLE_LEVELS
1054 int 916 int
1055 default 2 917 default 2
1056 918
1057 config ARCH_HAS_ELF_RANDOMIZE 919 config ARCH_HAS_ELF_RANDOMIZE
1058 bool 920 bool
1059 help 921 help
1060 An architecture supports choosing r 922 An architecture supports choosing randomized locations for
1061 stack, mmap, brk, and ET_DYN. Defin 923 stack, mmap, brk, and ET_DYN. Defined functions:
1062 - arch_mmap_rnd() 924 - arch_mmap_rnd()
1063 - arch_randomize_brk() 925 - arch_randomize_brk()
1064 926
1065 config HAVE_ARCH_MMAP_RND_BITS 927 config HAVE_ARCH_MMAP_RND_BITS
1066 bool 928 bool
1067 help 929 help
1068 An arch should select this symbol i 930 An arch should select this symbol if it supports setting a variable
1069 number of bits for use in establish 931 number of bits for use in establishing the base address for mmap
1070 allocations, has MMU enabled and pr 932 allocations, has MMU enabled and provides values for both:
1071 - ARCH_MMAP_RND_BITS_MIN 933 - ARCH_MMAP_RND_BITS_MIN
1072 - ARCH_MMAP_RND_BITS_MAX 934 - ARCH_MMAP_RND_BITS_MAX
1073 935
1074 config HAVE_EXIT_THREAD 936 config HAVE_EXIT_THREAD
1075 bool 937 bool
1076 help 938 help
1077 An architecture implements exit_thr 939 An architecture implements exit_thread.
1078 940
1079 config ARCH_MMAP_RND_BITS_MIN 941 config ARCH_MMAP_RND_BITS_MIN
1080 int 942 int
1081 943
1082 config ARCH_MMAP_RND_BITS_MAX 944 config ARCH_MMAP_RND_BITS_MAX
1083 int 945 int
1084 946
1085 config ARCH_MMAP_RND_BITS_DEFAULT 947 config ARCH_MMAP_RND_BITS_DEFAULT
1086 int 948 int
1087 949
1088 config ARCH_MMAP_RND_BITS 950 config ARCH_MMAP_RND_BITS
1089 int "Number of bits to use for ASLR o 951 int "Number of bits to use for ASLR of mmap base address" if EXPERT
1090 range ARCH_MMAP_RND_BITS_MIN ARCH_MMA 952 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1091 default ARCH_MMAP_RND_BITS_DEFAULT if 953 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1092 default ARCH_MMAP_RND_BITS_MIN 954 default ARCH_MMAP_RND_BITS_MIN
1093 depends on HAVE_ARCH_MMAP_RND_BITS 955 depends on HAVE_ARCH_MMAP_RND_BITS
1094 help 956 help
1095 This value can be used to select th 957 This value can be used to select the number of bits to use to
1096 determine the random offset to the 958 determine the random offset to the base address of vma regions
1097 resulting from mmap allocations. Th 959 resulting from mmap allocations. This value will be bounded
1098 by the architecture's minimum and m 960 by the architecture's minimum and maximum supported values.
1099 961
1100 This value can be changed after boo 962 This value can be changed after boot using the
1101 /proc/sys/vm/mmap_rnd_bits tunable 963 /proc/sys/vm/mmap_rnd_bits tunable
1102 964
1103 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 965 config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1104 bool 966 bool
1105 help 967 help
1106 An arch should select this symbol i 968 An arch should select this symbol if it supports running applications
1107 in compatibility mode, supports set 969 in compatibility mode, supports setting a variable number of bits for
1108 use in establishing the base addres 970 use in establishing the base address for mmap allocations, has MMU
1109 enabled and provides values for bot 971 enabled and provides values for both:
1110 - ARCH_MMAP_RND_COMPAT_BITS_MIN 972 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1111 - ARCH_MMAP_RND_COMPAT_BITS_MAX 973 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1112 974
1113 config ARCH_MMAP_RND_COMPAT_BITS_MIN 975 config ARCH_MMAP_RND_COMPAT_BITS_MIN
1114 int 976 int
1115 977
1116 config ARCH_MMAP_RND_COMPAT_BITS_MAX 978 config ARCH_MMAP_RND_COMPAT_BITS_MAX
1117 int 979 int
1118 980
1119 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 981 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1120 int 982 int
1121 983
1122 config ARCH_MMAP_RND_COMPAT_BITS 984 config ARCH_MMAP_RND_COMPAT_BITS
1123 int "Number of bits to use for ASLR o 985 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
1124 range ARCH_MMAP_RND_COMPAT_BITS_MIN A 986 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1125 default ARCH_MMAP_RND_COMPAT_BITS_DEF 987 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1126 default ARCH_MMAP_RND_COMPAT_BITS_MIN 988 default ARCH_MMAP_RND_COMPAT_BITS_MIN
1127 depends on HAVE_ARCH_MMAP_RND_COMPAT_ 989 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1128 help 990 help
1129 This value can be used to select th 991 This value can be used to select the number of bits to use to
1130 determine the random offset to the 992 determine the random offset to the base address of vma regions
1131 resulting from mmap allocations for 993 resulting from mmap allocations for compatible applications This
1132 value will be bounded by the archit 994 value will be bounded by the architecture's minimum and maximum
1133 supported values. 995 supported values.
1134 996
1135 This value can be changed after boo 997 This value can be changed after boot using the
1136 /proc/sys/vm/mmap_rnd_compat_bits t 998 /proc/sys/vm/mmap_rnd_compat_bits tunable
1137 999
1138 config HAVE_ARCH_COMPAT_MMAP_BASES 1000 config HAVE_ARCH_COMPAT_MMAP_BASES
1139 bool 1001 bool
1140 help 1002 help
1141 This allows 64bit applications to i 1003 This allows 64bit applications to invoke 32-bit mmap() syscall
1142 and vice-versa 32-bit applications 1004 and vice-versa 32-bit applications to call 64-bit mmap().
1143 Required for applications doing dif 1005 Required for applications doing different bitness syscalls.
1144 1006
1145 config HAVE_PAGE_SIZE_4KB <<
1146 bool <<
1147 <<
1148 config HAVE_PAGE_SIZE_8KB <<
1149 bool <<
1150 <<
1151 config HAVE_PAGE_SIZE_16KB <<
1152 bool <<
1153 <<
1154 config HAVE_PAGE_SIZE_32KB <<
1155 bool <<
1156 <<
1157 config HAVE_PAGE_SIZE_64KB <<
1158 bool <<
1159 <<
1160 config HAVE_PAGE_SIZE_256KB <<
1161 bool <<
1162 <<
1163 choice <<
1164 prompt "MMU page size" <<
1165 <<
1166 config PAGE_SIZE_4KB <<
1167 bool "4KiB pages" <<
1168 depends on HAVE_PAGE_SIZE_4KB <<
1169 help <<
1170 This option select the standard 4Ki <<
1171 available option on many architectu <<
1172 minimize memory consumption and is <<
1173 memory systems. <<
1174 Some software that is written for x <<
1175 assumptions about the page size and <<
1176 <<
1177 config PAGE_SIZE_8KB <<
1178 bool "8KiB pages" <<
1179 depends on HAVE_PAGE_SIZE_8KB <<
1180 help <<
1181 This option is the only supported p <<
1182 processors, and can be slightly fas <<
1183 <<
1184 config PAGE_SIZE_16KB <<
1185 bool "16KiB pages" <<
1186 depends on HAVE_PAGE_SIZE_16KB <<
1187 help <<
1188 This option is usually a good compr <<
1189 consumption and performance for typ <<
1190 workloads, often saving a level of <<
1191 to 4KB pages as well as reducing TL <<
1192 per-page operations in the kernel a <<
1193 page cache. <<
1194 <<
1195 config PAGE_SIZE_32KB <<
1196 bool "32KiB pages" <<
1197 depends on HAVE_PAGE_SIZE_32KB <<
1198 help <<
1199 Using 32KiB page size will result i <<
1200 kernel at the price of higher memor <<
1201 16KiB pages. This option is availa <<
1202 Note that you will need a suitable <<
1203 support this. <<
1204 <<
1205 config PAGE_SIZE_64KB <<
1206 bool "64KiB pages" <<
1207 depends on HAVE_PAGE_SIZE_64KB <<
1208 help <<
1209 Using 64KiB page size will result i <<
1210 kernel at the price of much higher <<
1211 4KiB or 16KiB pages. <<
1212 This is not suitable for general-pu <<
1213 better performance may be worth the <<
1214 supercomputing or database applicat <<
1215 large in-memory data rather than sm <<
1216 <<
1217 config PAGE_SIZE_256KB <<
1218 bool "256KiB pages" <<
1219 depends on HAVE_PAGE_SIZE_256KB <<
1220 help <<
1221 256KiB pages have little practical <<
1222 memory usage. The kernel will only <<
1223 that have been compiled with '-zmax <<
1224 (the default is 64KiB or 4KiB on mo <<
1225 <<
1226 endchoice <<
1227 <<
1228 config PAGE_SIZE_LESS_THAN_64KB 1007 config PAGE_SIZE_LESS_THAN_64KB
1229 def_bool y 1008 def_bool y
>> 1009 depends on !ARM64_64K_PAGES
>> 1010 depends on !IA64_PAGE_SIZE_64KB
1230 depends on !PAGE_SIZE_64KB 1011 depends on !PAGE_SIZE_64KB
>> 1012 depends on !PARISC_PAGE_SIZE_64KB
>> 1013 depends on !PPC_64K_PAGES
1231 depends on PAGE_SIZE_LESS_THAN_256KB 1014 depends on PAGE_SIZE_LESS_THAN_256KB
1232 1015
1233 config PAGE_SIZE_LESS_THAN_256KB 1016 config PAGE_SIZE_LESS_THAN_256KB
1234 def_bool y 1017 def_bool y
>> 1018 depends on !PPC_256K_PAGES
1235 depends on !PAGE_SIZE_256KB 1019 depends on !PAGE_SIZE_256KB
1236 1020
1237 config PAGE_SHIFT <<
1238 int <<
1239 default 12 if PAGE_SIZE_4KB <<
1240 default 13 if PAGE_SIZE_8KB <<
1241 default 14 if PAGE_SIZE_16KB <<
1242 default 15 if PAGE_SIZE_32KB <<
1243 default 16 if PAGE_SIZE_64KB <<
1244 default 18 if PAGE_SIZE_256KB <<
1245 <<
1246 # This allows to use a set of generic functio 1021 # This allows to use a set of generic functions to determine mmap base
1247 # address by giving priority to top-down sche 1022 # address by giving priority to top-down scheme only if the process
1248 # is not in legacy mode (compat task, unlimit 1023 # is not in legacy mode (compat task, unlimited stack size or
1249 # sysctl_legacy_va_layout). 1024 # sysctl_legacy_va_layout).
1250 # Architecture that selects this option can p 1025 # Architecture that selects this option can provide its own version of:
1251 # - STACK_RND_MASK 1026 # - STACK_RND_MASK
1252 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 1027 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
1253 bool 1028 bool
1254 depends on MMU 1029 depends on MMU
1255 select ARCH_HAS_ELF_RANDOMIZE 1030 select ARCH_HAS_ELF_RANDOMIZE
1256 1031
1257 config HAVE_OBJTOOL <<
1258 bool <<
1259 <<
1260 config HAVE_JUMP_LABEL_HACK <<
1261 bool <<
1262 <<
1263 config HAVE_NOINSTR_HACK <<
1264 bool <<
1265 <<
1266 config HAVE_NOINSTR_VALIDATION <<
1267 bool <<
1268 <<
1269 config HAVE_UACCESS_VALIDATION <<
1270 bool <<
1271 select OBJTOOL <<
1272 <<
1273 config HAVE_STACK_VALIDATION 1032 config HAVE_STACK_VALIDATION
1274 bool 1033 bool
1275 help 1034 help
1276 Architecture supports objtool compi !! 1035 Architecture supports the 'objtool check' host tool command, which
1277 validation. !! 1036 performs compile-time stack metadata validation.
1278 1037
1279 config HAVE_RELIABLE_STACKTRACE 1038 config HAVE_RELIABLE_STACKTRACE
1280 bool 1039 bool
1281 help 1040 help
1282 Architecture has either save_stack_ 1041 Architecture has either save_stack_trace_tsk_reliable() or
1283 arch_stack_walk_reliable() function 1042 arch_stack_walk_reliable() function which only returns a stack trace
1284 if it can guarantee the trace is re 1043 if it can guarantee the trace is reliable.
1285 1044
1286 config HAVE_ARCH_HASH 1045 config HAVE_ARCH_HASH
1287 bool 1046 bool
1288 default n 1047 default n
1289 help 1048 help
1290 If this is set, the architecture pr 1049 If this is set, the architecture provides an <asm/hash.h>
1291 file which provides platform-specif 1050 file which provides platform-specific implementations of some
1292 functions in <linux/hash.h> or fs/n 1051 functions in <linux/hash.h> or fs/namei.c.
1293 1052
1294 config HAVE_ARCH_NVRAM_OPS 1053 config HAVE_ARCH_NVRAM_OPS
1295 bool 1054 bool
1296 1055
1297 config ISA_BUS_API 1056 config ISA_BUS_API
1298 def_bool ISA 1057 def_bool ISA
1299 1058
1300 # 1059 #
1301 # ABI hall of shame 1060 # ABI hall of shame
1302 # 1061 #
1303 config CLONE_BACKWARDS 1062 config CLONE_BACKWARDS
1304 bool 1063 bool
1305 help 1064 help
1306 Architecture has tls passed as the 1065 Architecture has tls passed as the 4th argument of clone(2),
1307 not the 5th one. 1066 not the 5th one.
1308 1067
1309 config CLONE_BACKWARDS2 1068 config CLONE_BACKWARDS2
1310 bool 1069 bool
1311 help 1070 help
1312 Architecture has the first two argu 1071 Architecture has the first two arguments of clone(2) swapped.
1313 1072
1314 config CLONE_BACKWARDS3 1073 config CLONE_BACKWARDS3
1315 bool 1074 bool
1316 help 1075 help
1317 Architecture has tls passed as the 1076 Architecture has tls passed as the 3rd argument of clone(2),
1318 not the 5th one. 1077 not the 5th one.
1319 1078
1320 config ODD_RT_SIGACTION 1079 config ODD_RT_SIGACTION
1321 bool 1080 bool
1322 help 1081 help
1323 Architecture has unusual rt_sigacti 1082 Architecture has unusual rt_sigaction(2) arguments
1324 1083
1325 config OLD_SIGSUSPEND 1084 config OLD_SIGSUSPEND
1326 bool 1085 bool
1327 help 1086 help
1328 Architecture has old sigsuspend(2) 1087 Architecture has old sigsuspend(2) syscall, of one-argument variety
1329 1088
1330 config OLD_SIGSUSPEND3 1089 config OLD_SIGSUSPEND3
1331 bool 1090 bool
1332 help 1091 help
1333 Even weirder antique ABI - three-ar 1092 Even weirder antique ABI - three-argument sigsuspend(2)
1334 1093
1335 config OLD_SIGACTION 1094 config OLD_SIGACTION
1336 bool 1095 bool
1337 help 1096 help
1338 Architecture has old sigaction(2) s 1097 Architecture has old sigaction(2) syscall. Nope, not the same
1339 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 1098 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1340 but fairly different variant of sig 1099 but fairly different variant of sigaction(2), thanks to OSF/1
1341 compatibility... 1100 compatibility...
1342 1101
1343 config COMPAT_OLD_SIGACTION 1102 config COMPAT_OLD_SIGACTION
1344 bool 1103 bool
1345 1104
1346 config COMPAT_32BIT_TIME 1105 config COMPAT_32BIT_TIME
1347 bool "Provide system calls for 32-bit 1106 bool "Provide system calls for 32-bit time_t"
1348 default !64BIT || COMPAT 1107 default !64BIT || COMPAT
1349 help 1108 help
1350 This enables 32 bit time_t support 1109 This enables 32 bit time_t support in addition to 64 bit time_t support.
1351 This is relevant on all 32-bit arch 1110 This is relevant on all 32-bit architectures, and 64-bit architectures
1352 as part of compat syscall handling. 1111 as part of compat syscall handling.
1353 1112
1354 config ARCH_NO_PREEMPT 1113 config ARCH_NO_PREEMPT
1355 bool 1114 bool
1356 1115
>> 1116 config ARCH_EPHEMERAL_INODES
>> 1117 def_bool n
>> 1118 help
>> 1119 An arch should select this symbol if it doesn't keep track of inode
>> 1120 instances on its own, but instead relies on something else (e.g. the
>> 1121 host kernel for an UML kernel).
>> 1122
1357 config ARCH_SUPPORTS_RT 1123 config ARCH_SUPPORTS_RT
1358 bool 1124 bool
1359 1125
1360 config CPU_NO_EFFICIENT_FFS 1126 config CPU_NO_EFFICIENT_FFS
1361 def_bool n 1127 def_bool n
1362 1128
1363 config HAVE_ARCH_VMAP_STACK 1129 config HAVE_ARCH_VMAP_STACK
1364 def_bool n 1130 def_bool n
1365 help 1131 help
1366 An arch should select this symbol i 1132 An arch should select this symbol if it can support kernel stacks
1367 in vmalloc space. This means: 1133 in vmalloc space. This means:
1368 1134
1369 - vmalloc space must be large enoug 1135 - vmalloc space must be large enough to hold many kernel stacks.
1370 This may rule out many 32-bit arc 1136 This may rule out many 32-bit architectures.
1371 1137
1372 - Stacks in vmalloc space need to w 1138 - Stacks in vmalloc space need to work reliably. For example, if
1373 vmap page tables are created on d 1139 vmap page tables are created on demand, either this mechanism
1374 needs to work while the stack poi 1140 needs to work while the stack points to a virtual address with
1375 unpopulated page tables or arch c 1141 unpopulated page tables or arch code (switch_to() and switch_mm(),
1376 most likely) needs to ensure that 1142 most likely) needs to ensure that the stack's page table entries
1377 are populated before running on a 1143 are populated before running on a possibly unpopulated stack.
1378 1144
1379 - If the stack overflows into a gua 1145 - If the stack overflows into a guard page, something reasonable
1380 should happen. The definition of 1146 should happen. The definition of "reasonable" is flexible, but
1381 instantly rebooting without loggi 1147 instantly rebooting without logging anything would be unfriendly.
1382 1148
1383 config VMAP_STACK 1149 config VMAP_STACK
1384 default y 1150 default y
1385 bool "Use a virtually-mapped stack" 1151 bool "Use a virtually-mapped stack"
1386 depends on HAVE_ARCH_VMAP_STACK 1152 depends on HAVE_ARCH_VMAP_STACK
1387 depends on !KASAN || KASAN_HW_TAGS || 1153 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
1388 help 1154 help
1389 Enable this if you want the use vir 1155 Enable this if you want the use virtually-mapped kernel stacks
1390 with guard pages. This causes kern 1156 with guard pages. This causes kernel stack overflows to be
1391 caught immediately rather than caus 1157 caught immediately rather than causing difficult-to-diagnose
1392 corruption. 1158 corruption.
1393 1159
1394 To use this with software KASAN mod 1160 To use this with software KASAN modes, the architecture must support
1395 backing virtual mappings with real 1161 backing virtual mappings with real shadow memory, and KASAN_VMALLOC
1396 must be enabled. 1162 must be enabled.
1397 1163
1398 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1164 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1399 def_bool n 1165 def_bool n
1400 help 1166 help
1401 An arch should select this symbol i 1167 An arch should select this symbol if it can support kernel stack
1402 offset randomization with calls to 1168 offset randomization with calls to add_random_kstack_offset()
1403 during syscall entry and choose_ran 1169 during syscall entry and choose_random_kstack_offset() during
1404 syscall exit. Careful removal of -f 1170 syscall exit. Careful removal of -fstack-protector-strong and
1405 -fstack-protector should also be ap 1171 -fstack-protector should also be applied to the entry code and
1406 closely examined, as the artificial 1172 closely examined, as the artificial stack bump looks like an array
1407 to the compiler, so it will attempt 1173 to the compiler, so it will attempt to add canary checks regardless
1408 of the static branch state. 1174 of the static branch state.
1409 1175
1410 config RANDOMIZE_KSTACK_OFFSET 1176 config RANDOMIZE_KSTACK_OFFSET
1411 bool "Support for randomizing kernel 1177 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT
1412 default y 1178 default y
1413 depends on HAVE_ARCH_RANDOMIZE_KSTACK 1179 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1414 depends on INIT_STACK_NONE || !CC_IS_ 1180 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
1415 help 1181 help
1416 The kernel stack offset can be rand 1182 The kernel stack offset can be randomized (after pt_regs) by
1417 roughly 5 bits of entropy, frustrat 1183 roughly 5 bits of entropy, frustrating memory corruption
1418 attacks that depend on stack addres 1184 attacks that depend on stack address determinism or
1419 cross-syscall address exposures. 1185 cross-syscall address exposures.
1420 1186
1421 The feature is controlled via the " 1187 The feature is controlled via the "randomize_kstack_offset=on/off"
1422 kernel boot param, and if turned of 1188 kernel boot param, and if turned off has zero overhead due to its use
1423 of static branches (see JUMP_LABEL) 1189 of static branches (see JUMP_LABEL).
1424 1190
1425 If unsure, say Y. 1191 If unsure, say Y.
1426 1192
1427 config RANDOMIZE_KSTACK_OFFSET_DEFAULT 1193 config RANDOMIZE_KSTACK_OFFSET_DEFAULT
1428 bool "Default state of kernel stack o 1194 bool "Default state of kernel stack offset randomization"
1429 depends on RANDOMIZE_KSTACK_OFFSET 1195 depends on RANDOMIZE_KSTACK_OFFSET
1430 help 1196 help
1431 Kernel stack offset randomization i 1197 Kernel stack offset randomization is controlled by kernel boot param
1432 "randomize_kstack_offset=on/off", a 1198 "randomize_kstack_offset=on/off", and this config chooses the default
1433 boot state. 1199 boot state.
1434 1200
1435 config ARCH_OPTIONAL_KERNEL_RWX 1201 config ARCH_OPTIONAL_KERNEL_RWX
1436 def_bool n 1202 def_bool n
1437 1203
1438 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1204 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1439 def_bool n 1205 def_bool n
1440 1206
1441 config ARCH_HAS_STRICT_KERNEL_RWX 1207 config ARCH_HAS_STRICT_KERNEL_RWX
1442 def_bool n 1208 def_bool n
1443 1209
1444 config STRICT_KERNEL_RWX 1210 config STRICT_KERNEL_RWX
1445 bool "Make kernel text and rodata rea 1211 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1446 depends on ARCH_HAS_STRICT_KERNEL_RWX 1212 depends on ARCH_HAS_STRICT_KERNEL_RWX
1447 default !ARCH_OPTIONAL_KERNEL_RWX || 1213 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1448 help 1214 help
1449 If this is set, kernel text and rod 1215 If this is set, kernel text and rodata memory will be made read-only,
1450 and non-text memory will be made no 1216 and non-text memory will be made non-executable. This provides
1451 protection against certain security 1217 protection against certain security exploits (e.g. executing the heap
1452 or modifying text) 1218 or modifying text)
1453 1219
1454 These features are considered stand 1220 These features are considered standard security practice these days.
1455 You should say Y here in almost all 1221 You should say Y here in almost all cases.
1456 1222
1457 config ARCH_HAS_STRICT_MODULE_RWX 1223 config ARCH_HAS_STRICT_MODULE_RWX
1458 def_bool n 1224 def_bool n
1459 1225
1460 config STRICT_MODULE_RWX 1226 config STRICT_MODULE_RWX
1461 bool "Set loadable kernel module data 1227 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
1462 depends on ARCH_HAS_STRICT_MODULE_RWX 1228 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1463 default !ARCH_OPTIONAL_KERNEL_RWX || 1229 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1464 help 1230 help
1465 If this is set, module text and rod 1231 If this is set, module text and rodata memory will be made read-only,
1466 and non-text memory will be made no 1232 and non-text memory will be made non-executable. This provides
1467 protection against certain security 1233 protection against certain security exploits (e.g. writing to text)
1468 1234
1469 # select if the architecture provides an asm/ 1235 # select if the architecture provides an asm/dma-direct.h header
1470 config ARCH_HAS_PHYS_TO_DMA 1236 config ARCH_HAS_PHYS_TO_DMA
1471 bool 1237 bool
1472 1238
1473 config HAVE_ARCH_COMPILER_H 1239 config HAVE_ARCH_COMPILER_H
1474 bool 1240 bool
1475 help 1241 help
1476 An architecture can select this if 1242 An architecture can select this if it provides an
1477 asm/compiler.h header that should b 1243 asm/compiler.h header that should be included after
1478 linux/compiler-*.h in order to over 1244 linux/compiler-*.h in order to override macro definitions that those
1479 headers generally provide. 1245 headers generally provide.
1480 1246
1481 config HAVE_ARCH_PREL32_RELOCATIONS 1247 config HAVE_ARCH_PREL32_RELOCATIONS
1482 bool 1248 bool
1483 help 1249 help
1484 May be selected by an architecture 1250 May be selected by an architecture if it supports place-relative
1485 32-bit relocations, both in the too 1251 32-bit relocations, both in the toolchain and in the module loader,
1486 in which case relative references c 1252 in which case relative references can be used in special sections
1487 for PCI fixup, initcalls etc which 1253 for PCI fixup, initcalls etc which are only half the size on 64 bit
1488 architectures, and don't require ru 1254 architectures, and don't require runtime relocation on relocatable
1489 kernels. 1255 kernels.
1490 1256
1491 config ARCH_USE_MEMREMAP_PROT 1257 config ARCH_USE_MEMREMAP_PROT
1492 bool 1258 bool
1493 1259
1494 config LOCK_EVENT_COUNTS 1260 config LOCK_EVENT_COUNTS
1495 bool "Locking event counts collection 1261 bool "Locking event counts collection"
1496 depends on DEBUG_FS 1262 depends on DEBUG_FS
1497 help 1263 help
1498 Enable light-weight counting of var 1264 Enable light-weight counting of various locking related events
1499 in the system with minimal performa 1265 in the system with minimal performance impact. This reduces
1500 the chance of application behavior 1266 the chance of application behavior change because of timing
1501 differences. The counts are reporte 1267 differences. The counts are reported via debugfs.
1502 1268
1503 # Select if the architecture has support for 1269 # Select if the architecture has support for applying RELR relocations.
1504 config ARCH_HAS_RELR 1270 config ARCH_HAS_RELR
1505 bool 1271 bool
1506 1272
1507 config RELR 1273 config RELR
1508 bool "Use RELR relocation packing" 1274 bool "Use RELR relocation packing"
1509 depends on ARCH_HAS_RELR && TOOLS_SUP 1275 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
1510 default y 1276 default y
1511 help 1277 help
1512 Store the kernel's dynamic relocati 1278 Store the kernel's dynamic relocations in the RELR relocation packing
1513 format. Requires a compatible linke 1279 format. Requires a compatible linker (LLD supports this feature), as
1514 well as compatible NM and OBJCOPY u 1280 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1515 are compatible). 1281 are compatible).
1516 1282
1517 config ARCH_HAS_MEM_ENCRYPT 1283 config ARCH_HAS_MEM_ENCRYPT
1518 bool 1284 bool
1519 1285
1520 config ARCH_HAS_CC_PLATFORM 1286 config ARCH_HAS_CC_PLATFORM
1521 bool 1287 bool
1522 1288
1523 config HAVE_SPARSE_SYSCALL_NR 1289 config HAVE_SPARSE_SYSCALL_NR
1524 bool !! 1290 bool
1525 help !! 1291 help
1526 An architecture should select this !! 1292 An architecture should select this if its syscall numbering is sparse
1527 to save space. For example, MIPS ar 1293 to save space. For example, MIPS architecture has a syscall array with
1528 entries at 4000, 5000 and 6000 loca 1294 entries at 4000, 5000 and 6000 locations. This option turns on syscall
1529 related optimizations for a given a 1295 related optimizations for a given architecture.
1530 1296
1531 config ARCH_HAS_VDSO_DATA 1297 config ARCH_HAS_VDSO_DATA
1532 bool 1298 bool
1533 1299
1534 config HAVE_STATIC_CALL 1300 config HAVE_STATIC_CALL
1535 bool 1301 bool
1536 1302
1537 config HAVE_STATIC_CALL_INLINE 1303 config HAVE_STATIC_CALL_INLINE
1538 bool 1304 bool
1539 depends on HAVE_STATIC_CALL 1305 depends on HAVE_STATIC_CALL
1540 select OBJTOOL <<
1541 1306
1542 config HAVE_PREEMPT_DYNAMIC 1307 config HAVE_PREEMPT_DYNAMIC
1543 bool 1308 bool
1544 1309
1545 config HAVE_PREEMPT_DYNAMIC_CALL 1310 config HAVE_PREEMPT_DYNAMIC_CALL
1546 bool 1311 bool
1547 depends on HAVE_STATIC_CALL 1312 depends on HAVE_STATIC_CALL
1548 select HAVE_PREEMPT_DYNAMIC 1313 select HAVE_PREEMPT_DYNAMIC
1549 help 1314 help
1550 An architecture should select this !! 1315 An architecture should select this if it can handle the preemption
1551 model being selected at boot time u !! 1316 model being selected at boot time using static calls.
1552 1317
1553 Where an architecture selects HAVE_ !! 1318 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a
1554 preemption function will be patched !! 1319 preemption function will be patched directly.
1555 1320
1556 Where an architecture does not sele !! 1321 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any
1557 call to a preemption function will !! 1322 call to a preemption function will go through a trampoline, and the
1558 trampoline will be patched. !! 1323 trampoline will be patched.
1559 1324
1560 It is strongly advised to support i !! 1325 It is strongly advised to support inline static call to avoid any
1561 overhead. !! 1326 overhead.
1562 1327
1563 config HAVE_PREEMPT_DYNAMIC_KEY 1328 config HAVE_PREEMPT_DYNAMIC_KEY
1564 bool 1329 bool
1565 depends on HAVE_ARCH_JUMP_LABEL !! 1330 depends on HAVE_ARCH_JUMP_LABEL && CC_HAS_ASM_GOTO
1566 select HAVE_PREEMPT_DYNAMIC 1331 select HAVE_PREEMPT_DYNAMIC
1567 help 1332 help
1568 An architecture should select this !! 1333 An architecture should select this if it can handle the preemption
1569 model being selected at boot time u !! 1334 model being selected at boot time using static keys.
1570 1335
1571 Each preemption function will be gi !! 1336 Each preemption function will be given an early return based on a
1572 static key. This should have slight !! 1337 static key. This should have slightly lower overhead than non-inline
1573 static calls, as this effectively i !! 1338 static calls, as this effectively inlines each trampoline into the
1574 start of its callee. This may avoid !! 1339 start of its callee. This may avoid redundant work, and may
1575 integrate better with CFI schemes. !! 1340 integrate better with CFI schemes.
1576 1341
1577 This will have greater overhead tha !! 1342 This will have greater overhead than using inline static calls as
1578 the call to the preemption function !! 1343 the call to the preemption function cannot be entirely elided.
1579 1344
1580 config ARCH_WANT_LD_ORPHAN_WARN 1345 config ARCH_WANT_LD_ORPHAN_WARN
1581 bool 1346 bool
1582 help 1347 help
1583 An arch should select this symbol o 1348 An arch should select this symbol once all linker sections are explicitly
1584 included, size-asserted, or discard 1349 included, size-asserted, or discarded in the linker scripts. This is
1585 important because we never want exp 1350 important because we never want expected sections to be placed heuristically
1586 by the linker, since the locations 1351 by the linker, since the locations of such sections can change between linker
1587 versions. 1352 versions.
1588 1353
1589 config HAVE_ARCH_PFN_VALID 1354 config HAVE_ARCH_PFN_VALID
1590 bool 1355 bool
1591 1356
1592 config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1357 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1593 bool 1358 bool
1594 1359
1595 config ARCH_SUPPORTS_PAGE_TABLE_CHECK 1360 config ARCH_SUPPORTS_PAGE_TABLE_CHECK
1596 bool 1361 bool
1597 1362
1598 config ARCH_SPLIT_ARG64 1363 config ARCH_SPLIT_ARG64
1599 bool 1364 bool
1600 help 1365 help
1601 If a 32-bit architecture requires 6 !! 1366 If a 32-bit architecture requires 64-bit arguments to be split into
1602 pairs of 32-bit arguments, select t !! 1367 pairs of 32-bit arguments, select this option.
1603 1368
1604 config ARCH_HAS_ELFCORE_COMPAT 1369 config ARCH_HAS_ELFCORE_COMPAT
1605 bool 1370 bool
1606 1371
1607 config ARCH_HAS_PARANOID_L1D_FLUSH 1372 config ARCH_HAS_PARANOID_L1D_FLUSH
1608 bool 1373 bool
1609 1374
1610 config ARCH_HAVE_TRACE_MMIO_ACCESS <<
1611 bool <<
1612 <<
1613 config DYNAMIC_SIGFRAME 1375 config DYNAMIC_SIGFRAME
1614 bool 1376 bool
1615 1377
1616 # Select, if arch has a named attribute group 1378 # Select, if arch has a named attribute group bound to NUMA device nodes.
1617 config HAVE_ARCH_NODE_DEV_GROUP 1379 config HAVE_ARCH_NODE_DEV_GROUP
1618 bool 1380 bool
1619 1381
1620 config ARCH_HAS_HW_PTE_YOUNG <<
1621 bool <<
1622 help <<
1623 Architectures that select this opti <<
1624 accessed bit in PTE entries when us <<
1625 translations. Architectures that re <<
1626 this option and override arch_has_h <<
1627 <<
1628 config ARCH_HAS_NONLEAF_PMD_YOUNG <<
1629 bool <<
1630 help <<
1631 Architectures that select this opti <<
1632 accessed bit in non-leaf PMD entrie <<
1633 address translations. Page table wa <<
1634 may use this capability to reduce t <<
1635 <<
1636 config ARCH_HAS_KERNEL_FPU_SUPPORT <<
1637 bool <<
1638 help <<
1639 Architectures that select this opti <<
1640 the kernel, as described in Documen <<
1641 <<
1642 source "kernel/gcov/Kconfig" 1382 source "kernel/gcov/Kconfig"
1643 1383
1644 source "scripts/gcc-plugins/Kconfig" 1384 source "scripts/gcc-plugins/Kconfig"
1645 <<
1646 config FUNCTION_ALIGNMENT_4B <<
1647 bool <<
1648 <<
1649 config FUNCTION_ALIGNMENT_8B <<
1650 bool <<
1651 <<
1652 config FUNCTION_ALIGNMENT_16B <<
1653 bool <<
1654 <<
1655 config FUNCTION_ALIGNMENT_32B <<
1656 bool <<
1657 <<
1658 config FUNCTION_ALIGNMENT_64B <<
1659 bool <<
1660 <<
1661 config FUNCTION_ALIGNMENT <<
1662 int <<
1663 default 64 if FUNCTION_ALIGNMENT_64B <<
1664 default 32 if FUNCTION_ALIGNMENT_32B <<
1665 default 16 if FUNCTION_ALIGNMENT_16B <<
1666 default 8 if FUNCTION_ALIGNMENT_8B <<
1667 default 4 if FUNCTION_ALIGNMENT_4B <<
1668 default 0 <<
1669 <<
1670 config CC_HAS_MIN_FUNCTION_ALIGNMENT <<
1671 # Detect availability of the GCC opti <<
1672 # guarantees minimal alignment for al <<
1673 # -falign-functions which the compile <<
1674 def_bool $(cc-option, -fmin-function- <<
1675 <<
1676 config CC_HAS_SANE_FUNCTION_ALIGNMENT <<
1677 # Set if the guaranteed alignment wit <<
1678 # available or extra care is required <<
1679 # strict alignment always, even with <<
1680 def_bool CC_HAS_MIN_FUNCTION_ALIGNMEN <<
1681 <<
1682 config ARCH_NEED_CMPXCHG_1_EMU <<
1683 bool <<
1684 1385
1685 endmenu 1386 endmenu
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