1 # SPDX-License-Identifier: GPL-2.0 1 # SPDX-License-Identifier: GPL-2.0
2 # 2 #
3 # General architecture dependent options 3 # General architecture dependent options
4 # 4 #
5 5
6 # 6 #
7 # Note: arch/$(SRCARCH)/Kconfig needs to be in 7 # Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can
8 # override the default values in this file. 8 # override the default values in this file.
9 # 9 #
10 source "arch/$(SRCARCH)/Kconfig" 10 source "arch/$(SRCARCH)/Kconfig"
11 11
12 config ARCH_CONFIGURES_CPU_MITIGATIONS <<
13 bool <<
14 <<
15 if !ARCH_CONFIGURES_CPU_MITIGATIONS <<
16 config CPU_MITIGATIONS <<
17 def_bool y <<
18 endif <<
19 <<
20 menu "General architecture-dependent options" 12 menu "General architecture-dependent options"
21 13
22 config ARCH_HAS_SUBPAGE_FAULTS !! 14 config CRASH_CORE
23 bool 15 bool
24 help <<
25 Select if the architecture can check <<
26 granularity (e.g. arm64 MTE). The pr <<
27 must be implemented. <<
28 16
29 config HOTPLUG_SMT !! 17 config KEXEC_CORE
>> 18 select CRASH_CORE
30 bool 19 bool
31 20
32 config SMT_NUM_THREADS_DYNAMIC !! 21 config KEXEC_ELF
33 bool 22 bool
34 23
35 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLU !! 24 config HAVE_IMA_KEXEC
36 config HOTPLUG_CORE_SYNC <<
37 bool 25 bool
38 26
39 # Basic CPU dead synchronization selected by a !! 27 config HOTPLUG_SMT
40 config HOTPLUG_CORE_SYNC_DEAD <<
41 bool 28 bool
42 select HOTPLUG_CORE_SYNC <<
43 29
44 # Full CPU synchronization with alive state se !! 30 config OPROFILE
45 config HOTPLUG_CORE_SYNC_FULL !! 31 tristate "OProfile system profiling"
46 bool !! 32 depends on PROFILING
47 select HOTPLUG_CORE_SYNC_DEAD if HOTPL !! 33 depends on HAVE_OPROFILE
48 select HOTPLUG_CORE_SYNC !! 34 select RING_BUFFER
>> 35 select RING_BUFFER_ALLOW_SWAP
>> 36 help
>> 37 OProfile is a profiling system capable of profiling the
>> 38 whole system, include the kernel, kernel modules, libraries,
>> 39 and applications.
49 40
50 config HOTPLUG_SPLIT_STARTUP !! 41 If unsure, say N.
51 bool <<
52 select HOTPLUG_CORE_SYNC_FULL <<
53 42
54 config HOTPLUG_PARALLEL !! 43 config OPROFILE_EVENT_MULTIPLEX
55 bool !! 44 bool "OProfile multiplexing support (EXPERIMENTAL)"
56 select HOTPLUG_SPLIT_STARTUP !! 45 default n
>> 46 depends on OPROFILE && X86
>> 47 help
>> 48 The number of hardware counters is limited. The multiplexing
>> 49 feature enables OProfile to gather more events than counters
>> 50 are provided by the hardware. This is realized by switching
>> 51 between events at a user specified time interval.
57 52
58 config GENERIC_ENTRY !! 53 If unsure, say N.
>> 54
>> 55 config HAVE_OPROFILE
59 bool 56 bool
60 57
>> 58 config OPROFILE_NMI_TIMER
>> 59 def_bool y
>> 60 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
>> 61
61 config KPROBES 62 config KPROBES
62 bool "Kprobes" 63 bool "Kprobes"
>> 64 depends on MODULES
63 depends on HAVE_KPROBES 65 depends on HAVE_KPROBES
64 select KALLSYMS 66 select KALLSYMS
65 select EXECMEM <<
66 select NEED_TASKS_RCU <<
67 help 67 help
68 Kprobes allows you to trap at almost 68 Kprobes allows you to trap at almost any kernel address and
69 execute a callback function. regist 69 execute a callback function. register_kprobe() establishes
70 a probepoint and specifies the callb 70 a probepoint and specifies the callback. Kprobes is useful
71 for kernel debugging, non-intrusive 71 for kernel debugging, non-intrusive instrumentation and testing.
72 If in doubt, say "N". 72 If in doubt, say "N".
73 73
74 config JUMP_LABEL 74 config JUMP_LABEL
75 bool "Optimize very unlikely/likely br 75 bool "Optimize very unlikely/likely branches"
76 depends on HAVE_ARCH_JUMP_LABEL 76 depends on HAVE_ARCH_JUMP_LABEL
77 select OBJTOOL if HAVE_JUMP_LABEL_HACK !! 77 depends on CC_HAS_ASM_GOTO
78 help 78 help
79 This option enables a transparent br !! 79 This option enables a transparent branch optimization that
80 makes certain almost-always-true or !! 80 makes certain almost-always-true or almost-always-false branch
81 conditions even cheaper to execute w !! 81 conditions even cheaper to execute within the kernel.
82 !! 82
83 Certain performance-sensitive kernel !! 83 Certain performance-sensitive kernel code, such as trace points,
84 scheduler functionality, networking !! 84 scheduler functionality, networking code and KVM have such
85 branches and include support for thi !! 85 branches and include support for this optimization technique.
86 !! 86
87 If it is detected that the compiler !! 87 If it is detected that the compiler has support for "asm goto",
88 the kernel will compile such branche !! 88 the kernel will compile such branches with just a nop
89 instruction. When the condition flag !! 89 instruction. When the condition flag is toggled to true, the
90 nop will be converted to a jump inst !! 90 nop will be converted to a jump instruction to execute the
91 conditional block of instructions. !! 91 conditional block of instructions.
92 !! 92
93 This technique lowers overhead and s !! 93 This technique lowers overhead and stress on the branch prediction
94 of the processor and generally makes !! 94 of the processor and generally makes the kernel faster. The update
95 of the condition is slower, but thos !! 95 of the condition is slower, but those are always very rare.
96 96
97 ( On 32-bit x86, the necessary optio !! 97 ( On 32-bit x86, the necessary options added to the compiler
98 flags may increase the size of the !! 98 flags may increase the size of the kernel slightly. )
99 99
100 config STATIC_KEYS_SELFTEST 100 config STATIC_KEYS_SELFTEST
101 bool "Static key selftest" 101 bool "Static key selftest"
102 depends on JUMP_LABEL 102 depends on JUMP_LABEL
103 help 103 help
104 Boot time self-test of the branch pa 104 Boot time self-test of the branch patching code.
105 105
106 config STATIC_CALL_SELFTEST <<
107 bool "Static call selftest" <<
108 depends on HAVE_STATIC_CALL <<
109 help <<
110 Boot time self-test of the call patc <<
111 <<
112 config OPTPROBES 106 config OPTPROBES
113 def_bool y 107 def_bool y
114 depends on KPROBES && HAVE_OPTPROBES 108 depends on KPROBES && HAVE_OPTPROBES
115 select NEED_TASKS_RCU !! 109 select TASKS_RCU if PREEMPTION
116 110
117 config KPROBES_ON_FTRACE 111 config KPROBES_ON_FTRACE
118 def_bool y 112 def_bool y
119 depends on KPROBES && HAVE_KPROBES_ON_ 113 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
120 depends on DYNAMIC_FTRACE_WITH_REGS 114 depends on DYNAMIC_FTRACE_WITH_REGS
121 help 115 help
122 If function tracer is enabled and th !! 116 If function tracer is enabled and the arch supports full
123 passing of pt_regs to function traci !! 117 passing of pt_regs to function tracing, then kprobes can
124 optimize on top of function tracing. !! 118 optimize on top of function tracing.
125 119
126 config UPROBES 120 config UPROBES
127 def_bool n 121 def_bool n
128 depends on ARCH_SUPPORTS_UPROBES 122 depends on ARCH_SUPPORTS_UPROBES
129 help 123 help
130 Uprobes is the user-space counterpar 124 Uprobes is the user-space counterpart to kprobes: they
131 enable instrumentation applications 125 enable instrumentation applications (such as 'perf probe')
132 to establish unintrusive probes in u 126 to establish unintrusive probes in user-space binaries and
133 libraries, by executing handler func 127 libraries, by executing handler functions when the probes
134 are hit by user-space applications. 128 are hit by user-space applications.
135 129
136 ( These probes come in the form of s 130 ( These probes come in the form of single-byte breakpoints,
137 managed by the kernel and kept tra 131 managed by the kernel and kept transparent to the probed
138 application. ) 132 application. )
139 133
140 config HAVE_64BIT_ALIGNED_ACCESS <<
141 def_bool 64BIT && !HAVE_EFFICIENT_UNAL <<
142 help <<
143 Some architectures require 64 bit ac <<
144 aligned, which also requires structs <<
145 to be 64 bit aligned too. This inclu <<
146 architectures which can do 64 bit ac <<
147 architectures without unaligned acce <<
148 <<
149 This symbol should be selected by an <<
150 accesses are required to be 64 bit a <<
151 though it is not a 64 bit architectu <<
152 <<
153 See Documentation/core-api/unaligned <<
154 more information on the topic of una <<
155 <<
156 config HAVE_EFFICIENT_UNALIGNED_ACCESS 134 config HAVE_EFFICIENT_UNALIGNED_ACCESS
157 bool 135 bool
158 help 136 help
159 Some architectures are unable to per 137 Some architectures are unable to perform unaligned accesses
160 without the use of get_unaligned/put 138 without the use of get_unaligned/put_unaligned. Others are
161 unable to perform such accesses effi 139 unable to perform such accesses efficiently (e.g. trap on
162 unaligned access and require fixing 140 unaligned access and require fixing it up in the exception
163 handler.) 141 handler.)
164 142
165 This symbol should be selected by an 143 This symbol should be selected by an architecture if it can
166 perform unaligned accesses efficient 144 perform unaligned accesses efficiently to allow different
167 code paths to be selected for these 145 code paths to be selected for these cases. Some network
168 drivers, for example, could opt to n 146 drivers, for example, could opt to not fix up alignment
169 problems with received packets if do 147 problems with received packets if doing so would not help
170 much. 148 much.
171 149
172 See Documentation/core-api/unaligned !! 150 See Documentation/unaligned-memory-access.txt for more
173 information on the topic of unaligne 151 information on the topic of unaligned memory accesses.
174 152
175 config ARCH_USE_BUILTIN_BSWAP 153 config ARCH_USE_BUILTIN_BSWAP
176 bool 154 bool
177 help 155 help
178 Modern versions of GCC (since 4.4) h !! 156 Modern versions of GCC (since 4.4) have builtin functions
179 for handling byte-swapping. Using th !! 157 for handling byte-swapping. Using these, instead of the old
180 inline assembler that the architectu !! 158 inline assembler that the architecture code provides in the
181 __arch_bswapXX() macros, allows the !! 159 __arch_bswapXX() macros, allows the compiler to see what's
182 happening and offers more opportunit !! 160 happening and offers more opportunity for optimisation. In
183 particular, the compiler will be abl !! 161 particular, the compiler will be able to combine the byteswap
184 with a nearby load or store and use !! 162 with a nearby load or store and use load-and-swap or
185 store-and-swap instructions if the a !! 163 store-and-swap instructions if the architecture has them. It
186 should almost *never* result in code !! 164 should almost *never* result in code which is worse than the
187 hand-coded assembler in <asm/swab.h> !! 165 hand-coded assembler in <asm/swab.h>. But just in case it
188 does, the use of the builtins is opt !! 166 does, the use of the builtins is optional.
189 !! 167
190 Any architecture with load-and-swap !! 168 Any architecture with load-and-swap or store-and-swap
191 instructions should set this. And it !! 169 instructions should set this. And it shouldn't hurt to set it
192 on architectures that don't have suc !! 170 on architectures that don't have such instructions.
193 171
194 config KRETPROBES 172 config KRETPROBES
195 def_bool y 173 def_bool y
196 depends on KPROBES && (HAVE_KRETPROBES !! 174 depends on KPROBES && HAVE_KRETPROBES
197 <<
198 config KRETPROBE_ON_RETHOOK <<
199 def_bool y <<
200 depends on HAVE_RETHOOK <<
201 depends on KRETPROBES <<
202 select RETHOOK <<
203 175
204 config USER_RETURN_NOTIFIER 176 config USER_RETURN_NOTIFIER
205 bool 177 bool
206 depends on HAVE_USER_RETURN_NOTIFIER 178 depends on HAVE_USER_RETURN_NOTIFIER
207 help 179 help
208 Provide a kernel-internal notificati 180 Provide a kernel-internal notification when a cpu is about to
209 switch to user mode. 181 switch to user mode.
210 182
211 config HAVE_IOREMAP_PROT 183 config HAVE_IOREMAP_PROT
212 bool 184 bool
213 185
214 config HAVE_KPROBES 186 config HAVE_KPROBES
215 bool 187 bool
216 188
217 config HAVE_KRETPROBES 189 config HAVE_KRETPROBES
218 bool 190 bool
219 191
220 config HAVE_OPTPROBES 192 config HAVE_OPTPROBES
221 bool 193 bool
222 194
223 config HAVE_KPROBES_ON_FTRACE 195 config HAVE_KPROBES_ON_FTRACE
224 bool 196 bool
225 197
226 config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE <<
227 bool <<
228 help <<
229 Since kretprobes modifies return add <<
230 stacktrace may see the kretprobe tra <<
231 of correct one. If the architecture <<
232 unwinder can adjust such entries, se <<
233 <<
234 config HAVE_FUNCTION_ERROR_INJECTION 198 config HAVE_FUNCTION_ERROR_INJECTION
235 bool 199 bool
236 200
237 config HAVE_NMI 201 config HAVE_NMI
238 bool 202 bool
239 203
240 config HAVE_FUNCTION_DESCRIPTORS <<
241 bool <<
242 <<
243 config TRACE_IRQFLAGS_SUPPORT <<
244 bool <<
245 <<
246 config TRACE_IRQFLAGS_NMI_SUPPORT <<
247 bool <<
248 <<
249 # 204 #
250 # An arch should select this if it provides al 205 # An arch should select this if it provides all these things:
251 # 206 #
252 # task_pt_regs() in asm/process 207 # task_pt_regs() in asm/processor.h or asm/ptrace.h
253 # arch_has_single_step() if there is ha 208 # arch_has_single_step() if there is hardware single-step support
254 # arch_has_block_step() if there is ha 209 # arch_has_block_step() if there is hardware block-step support
255 # asm/syscall.h supplying asm- 210 # asm/syscall.h supplying asm-generic/syscall.h interface
256 # linux/regset.h user_regset in 211 # linux/regset.h user_regset interfaces
257 # CORE_DUMP_USE_REGSET #define'd in l 212 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h
258 # TIF_SYSCALL_TRACE calls ptrace_r !! 213 # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
259 # TIF_NOTIFY_RESUME calls resume_u !! 214 # TIF_NOTIFY_RESUME calls tracehook_notify_resume()
>> 215 # signal delivery calls tracehook_signal_handler()
260 # 216 #
261 config HAVE_ARCH_TRACEHOOK 217 config HAVE_ARCH_TRACEHOOK
262 bool 218 bool
263 219
264 config HAVE_DMA_CONTIGUOUS 220 config HAVE_DMA_CONTIGUOUS
265 bool 221 bool
266 222
267 config GENERIC_SMP_IDLE_THREAD 223 config GENERIC_SMP_IDLE_THREAD
268 bool 224 bool
269 225
270 config GENERIC_IDLE_POLL_SETUP 226 config GENERIC_IDLE_POLL_SETUP
271 bool 227 bool
272 228
273 config ARCH_HAS_FORTIFY_SOURCE 229 config ARCH_HAS_FORTIFY_SOURCE
274 bool 230 bool
275 help 231 help
276 An architecture should select this w 232 An architecture should select this when it can successfully
277 build and run with CONFIG_FORTIFY_SO 233 build and run with CONFIG_FORTIFY_SOURCE.
278 234
279 # 235 #
280 # Select if the arch provides a historic keepi 236 # Select if the arch provides a historic keepinit alias for the retain_initrd
281 # command line option 237 # command line option
282 # 238 #
283 config ARCH_HAS_KEEPINITRD 239 config ARCH_HAS_KEEPINITRD
284 bool 240 bool
285 241
286 # Select if arch has all set_memory_ro/rw/x/nx 242 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
287 config ARCH_HAS_SET_MEMORY 243 config ARCH_HAS_SET_MEMORY
288 bool 244 bool
289 245
290 # Select if arch has all set_direct_map_invali 246 # Select if arch has all set_direct_map_invalid/default() functions
291 config ARCH_HAS_SET_DIRECT_MAP 247 config ARCH_HAS_SET_DIRECT_MAP
292 bool 248 bool
293 249
294 # 250 #
295 # Select if the architecture provides the arch !! 251 # Select if arch has an uncached kernel segment and provides the
296 # either provide an uncached segment alias for !! 252 # uncached_kernel_address / cached_kernel_address symbols to use it
297 # to remap the page tables in place. <<
298 # <<
299 config ARCH_HAS_DMA_SET_UNCACHED <<
300 bool <<
301 <<
302 # <<
303 # Select if the architectures provides the arc <<
304 # to undo an in-place page table remap for unc <<
305 # 253 #
306 config ARCH_HAS_DMA_CLEAR_UNCACHED !! 254 config ARCH_HAS_UNCACHED_SEGMENT
>> 255 select ARCH_HAS_DMA_PREP_COHERENT
307 bool 256 bool
308 257
309 config ARCH_HAS_CPU_FINALIZE_INIT !! 258 # Select if arch init_task must go in the __init_task_data section
>> 259 config ARCH_TASK_STRUCT_ON_STACK
310 bool 260 bool
311 261
312 # The architecture has a per-task state that i !! 262 # Select if arch has its private alloc_task_struct() function
313 config ARCH_HAS_CPU_PASID !! 263 config ARCH_TASK_STRUCT_ALLOCATOR
314 bool 264 bool
315 select IOMMU_MM_DATA <<
316 265
317 config HAVE_ARCH_THREAD_STRUCT_WHITELIST 266 config HAVE_ARCH_THREAD_STRUCT_WHITELIST
318 bool 267 bool
>> 268 depends on !ARCH_TASK_STRUCT_ALLOCATOR
319 help 269 help
320 An architecture should select this t 270 An architecture should select this to provide hardened usercopy
321 knowledge about what region of the t 271 knowledge about what region of the thread_struct should be
322 whitelisted for copying to userspace 272 whitelisted for copying to userspace. Normally this is only the
323 FPU registers. Specifically, arch_th 273 FPU registers. Specifically, arch_thread_struct_whitelist()
324 should be implemented. Without this, 274 should be implemented. Without this, the entire thread_struct
325 field in task_struct will be left wh 275 field in task_struct will be left whitelisted.
326 276
>> 277 # Select if arch has its private alloc_thread_stack() function
>> 278 config ARCH_THREAD_STACK_ALLOCATOR
>> 279 bool
>> 280
327 # Select if arch wants to size task_struct dyn 281 # Select if arch wants to size task_struct dynamically via arch_task_struct_size:
328 config ARCH_WANTS_DYNAMIC_TASK_STRUCT 282 config ARCH_WANTS_DYNAMIC_TASK_STRUCT
329 bool 283 bool
330 284
331 config ARCH_WANTS_NO_INSTR <<
332 bool <<
333 help <<
334 An architecture should select this i <<
335 functions to denote that the toolcha <<
336 functions and is required for correc <<
337 <<
338 config ARCH_32BIT_OFF_T 285 config ARCH_32BIT_OFF_T
339 bool 286 bool
340 depends on !64BIT 287 depends on !64BIT
341 help 288 help
342 All new 32-bit architectures should 289 All new 32-bit architectures should have 64-bit off_t type on
343 userspace side which corresponds to 290 userspace side which corresponds to the loff_t kernel type. This
344 is the requirement for modern ABIs. 291 is the requirement for modern ABIs. Some existing architectures
345 still support 32-bit off_t. This opt 292 still support 32-bit off_t. This option is enabled for all such
346 architectures explicitly. 293 architectures explicitly.
347 294
348 # Selected by 64 bit architectures which have <<
349 config ARCH_32BIT_USTAT_F_TINODE <<
350 bool <<
351 <<
352 config HAVE_ASM_MODVERSIONS 295 config HAVE_ASM_MODVERSIONS
353 bool 296 bool
354 help 297 help
355 This symbol should be selected by an !! 298 This symbol should be selected by an architecure if it provides
356 <asm/asm-prototypes.h> to support th 299 <asm/asm-prototypes.h> to support the module versioning for symbols
357 exported from assembly code. 300 exported from assembly code.
358 301
359 config HAVE_REGS_AND_STACK_ACCESS_API 302 config HAVE_REGS_AND_STACK_ACCESS_API
360 bool 303 bool
361 help 304 help
362 This symbol should be selected by an !! 305 This symbol should be selected by an architecure if it supports
363 the API needed to access registers a 306 the API needed to access registers and stack entries from pt_regs,
364 declared in asm/ptrace.h 307 declared in asm/ptrace.h
365 For example the kprobes-based event 308 For example the kprobes-based event tracer needs this API.
366 309
367 config HAVE_RSEQ 310 config HAVE_RSEQ
368 bool 311 bool
369 depends on HAVE_REGS_AND_STACK_ACCESS_ 312 depends on HAVE_REGS_AND_STACK_ACCESS_API
370 help 313 help
371 This symbol should be selected by an 314 This symbol should be selected by an architecture if it
372 supports an implementation of restar 315 supports an implementation of restartable sequences.
373 316
374 config HAVE_RUST <<
375 bool <<
376 help <<
377 This symbol should be selected by an <<
378 supports Rust. <<
379 <<
380 config HAVE_FUNCTION_ARG_ACCESS_API 317 config HAVE_FUNCTION_ARG_ACCESS_API
381 bool 318 bool
382 help 319 help
383 This symbol should be selected by an !! 320 This symbol should be selected by an architecure if it supports
384 the API needed to access function ar 321 the API needed to access function arguments from pt_regs,
385 declared in asm/ptrace.h 322 declared in asm/ptrace.h
386 323
>> 324 config HAVE_CLK
>> 325 bool
>> 326 help
>> 327 The <linux/clk.h> calls support software clock gating and
>> 328 thus are a key power management tool on many systems.
>> 329
387 config HAVE_HW_BREAKPOINT 330 config HAVE_HW_BREAKPOINT
388 bool 331 bool
389 depends on PERF_EVENTS 332 depends on PERF_EVENTS
390 333
391 config HAVE_MIXED_BREAKPOINTS_REGS 334 config HAVE_MIXED_BREAKPOINTS_REGS
392 bool 335 bool
393 depends on HAVE_HW_BREAKPOINT 336 depends on HAVE_HW_BREAKPOINT
394 help 337 help
395 Depending on the arch implementation 338 Depending on the arch implementation of hardware breakpoints,
396 some of them have separate registers 339 some of them have separate registers for data and instruction
397 breakpoints addresses, others have m 340 breakpoints addresses, others have mixed registers to store
398 them but define the access type in a 341 them but define the access type in a control register.
399 Select this option if your arch impl 342 Select this option if your arch implements breakpoints under the
400 latter fashion. 343 latter fashion.
401 344
402 config HAVE_USER_RETURN_NOTIFIER 345 config HAVE_USER_RETURN_NOTIFIER
403 bool 346 bool
404 347
405 config HAVE_PERF_EVENTS_NMI 348 config HAVE_PERF_EVENTS_NMI
406 bool 349 bool
407 help 350 help
408 System hardware can generate an NMI 351 System hardware can generate an NMI using the perf event
409 subsystem. Also has support for cal 352 subsystem. Also has support for calculating CPU cycle events
410 to determine how many clock cycles i 353 to determine how many clock cycles in a given period.
411 354
412 config HAVE_HARDLOCKUP_DETECTOR_PERF 355 config HAVE_HARDLOCKUP_DETECTOR_PERF
413 bool 356 bool
414 depends on HAVE_PERF_EVENTS_NMI 357 depends on HAVE_PERF_EVENTS_NMI
415 help 358 help
416 The arch chooses to use the generic 359 The arch chooses to use the generic perf-NMI-based hardlockup
417 detector. Must define HAVE_PERF_EVEN 360 detector. Must define HAVE_PERF_EVENTS_NMI.
418 361
419 config HAVE_HARDLOCKUP_DETECTOR_ARCH !! 362 config HAVE_NMI_WATCHDOG
>> 363 depends on HAVE_NMI
420 bool 364 bool
421 help 365 help
422 The arch provides its own hardlockup !! 366 The arch provides a low level NMI watchdog. It provides
423 of the generic ones. !! 367 asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
424 368
425 It uses the same command line parame !! 369 config HAVE_HARDLOCKUP_DETECTOR_ARCH
426 as the generic hardlockup detectors. !! 370 bool
>> 371 select HAVE_NMI_WATCHDOG
>> 372 help
>> 373 The arch chooses to provide its own hardlockup detector, which is
>> 374 a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
>> 375 interfaces and parameters provided by hardlockup detector subsystem.
427 376
428 config HAVE_PERF_REGS 377 config HAVE_PERF_REGS
429 bool 378 bool
430 help 379 help
431 Support selective register dumps for 380 Support selective register dumps for perf events. This includes
432 bit-mapping of each registers and a 381 bit-mapping of each registers and a unique architecture id.
433 382
434 config HAVE_PERF_USER_STACK_DUMP 383 config HAVE_PERF_USER_STACK_DUMP
435 bool 384 bool
436 help 385 help
437 Support user stack dumps for perf ev 386 Support user stack dumps for perf event samples. This needs
438 access to the user stack pointer whi 387 access to the user stack pointer which is not unified across
439 architectures. 388 architectures.
440 389
441 config HAVE_ARCH_JUMP_LABEL 390 config HAVE_ARCH_JUMP_LABEL
442 bool 391 bool
443 392
444 config HAVE_ARCH_JUMP_LABEL_RELATIVE 393 config HAVE_ARCH_JUMP_LABEL_RELATIVE
445 bool 394 bool
446 395
447 config MMU_GATHER_TABLE_FREE 396 config MMU_GATHER_TABLE_FREE
448 bool 397 bool
449 398
450 config MMU_GATHER_RCU_TABLE_FREE 399 config MMU_GATHER_RCU_TABLE_FREE
451 bool 400 bool
452 select MMU_GATHER_TABLE_FREE 401 select MMU_GATHER_TABLE_FREE
453 402
454 config MMU_GATHER_PAGE_SIZE 403 config MMU_GATHER_PAGE_SIZE
455 bool 404 bool
456 405
457 config MMU_GATHER_NO_RANGE 406 config MMU_GATHER_NO_RANGE
458 bool 407 bool
459 select MMU_GATHER_MERGE_VMAS <<
460 <<
461 config MMU_GATHER_NO_FLUSH_CACHE <<
462 bool <<
463 <<
464 config MMU_GATHER_MERGE_VMAS <<
465 bool <<
466 408
467 config MMU_GATHER_NO_GATHER 409 config MMU_GATHER_NO_GATHER
468 bool 410 bool
469 depends on MMU_GATHER_TABLE_FREE 411 depends on MMU_GATHER_TABLE_FREE
470 412
471 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM <<
472 bool <<
473 help <<
474 Temporary select until all architect <<
475 irqs disabled over activate_mm. Arch <<
476 shootdowns should enable this. <<
477 <<
478 # Use normal mm refcounting for MMU_LAZY_TLB k <<
479 # MMU_LAZY_TLB_REFCOUNT=n can improve the scal <<
480 # to/from kernel threads when the same mm is r <<
481 # multi-threaded application), by reducing con <<
482 # <<
483 # This can be disabled if the architecture ens <<
484 # "lazy tlb" beyond its final refcount (i.e., <<
485 # or its kernel page tables). This could be ar <<
486 # final exit(2) TLB flush, for example. <<
487 # <<
488 # To implement this, an arch *must*: <<
489 # Ensure the _lazy_tlb variants of mmgrab/mmdr <<
490 # the lazy tlb reference of a kthread's ->acti <<
491 # converted already). <<
492 config MMU_LAZY_TLB_REFCOUNT <<
493 def_bool y <<
494 depends on !MMU_LAZY_TLB_SHOOTDOWN <<
495 <<
496 # This option allows MMU_LAZY_TLB_REFCOUNT=n. <<
497 # mm as a lazy tlb beyond its last reference c <<
498 # users before the mm is deallocated. __mmdrop <<
499 # be using the mm as a lazy tlb, so that they <<
500 # init_mm for their active mm. mm_cpumask(mm) <<
501 # may be using mm as a lazy tlb mm. <<
502 # <<
503 # To implement this, an arch *must*: <<
504 # - At the time of the final mmdrop of the mm, <<
505 # at least all possible CPUs in which the mm <<
506 # - It must meet the requirements for MMU_LAZY <<
507 config MMU_LAZY_TLB_SHOOTDOWN <<
508 bool <<
509 <<
510 config ARCH_HAVE_NMI_SAFE_CMPXCHG 413 config ARCH_HAVE_NMI_SAFE_CMPXCHG
511 bool 414 bool
512 415
513 config ARCH_HAVE_EXTRA_ELF_NOTES <<
514 bool <<
515 help <<
516 An architecture should select this i <<
517 arch-specific ELF note section to co <<
518 functions: elf_coredump_extra_notes_ <<
519 elf_coredump_extra_notes_write() whi <<
520 dumper. <<
521 <<
522 config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS <<
523 bool <<
524 <<
525 config HAVE_ALIGNED_STRUCT_PAGE 416 config HAVE_ALIGNED_STRUCT_PAGE
526 bool 417 bool
527 help 418 help
528 This makes sure that struct pages ar 419 This makes sure that struct pages are double word aligned and that
529 e.g. the SLUB allocator can perform 420 e.g. the SLUB allocator can perform double word atomic operations
530 on a struct page for better performa 421 on a struct page for better performance. However selecting this
531 might increase the size of a struct 422 might increase the size of a struct page by a word.
532 423
533 config HAVE_CMPXCHG_LOCAL 424 config HAVE_CMPXCHG_LOCAL
534 bool 425 bool
535 426
536 config HAVE_CMPXCHG_DOUBLE 427 config HAVE_CMPXCHG_DOUBLE
537 bool 428 bool
538 429
539 config ARCH_WEAK_RELEASE_ACQUIRE 430 config ARCH_WEAK_RELEASE_ACQUIRE
540 bool 431 bool
541 432
542 config ARCH_WANT_IPC_PARSE_VERSION 433 config ARCH_WANT_IPC_PARSE_VERSION
543 bool 434 bool
544 435
545 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 436 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
546 bool 437 bool
547 438
548 config ARCH_WANT_OLD_COMPAT_IPC 439 config ARCH_WANT_OLD_COMPAT_IPC
549 select ARCH_WANT_COMPAT_IPC_PARSE_VERS 440 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
550 bool 441 bool
551 442
552 config HAVE_ARCH_SECCOMP <<
553 bool <<
554 help <<
555 An arch should select this symbol to <<
556 syscall policy), and must provide an <<
557 and compat syscalls if the asm-gener <<
558 - __NR_seccomp_read_32 <<
559 - __NR_seccomp_write_32 <<
560 - __NR_seccomp_exit_32 <<
561 - __NR_seccomp_sigreturn_32 <<
562 <<
563 config HAVE_ARCH_SECCOMP_FILTER 443 config HAVE_ARCH_SECCOMP_FILTER
564 bool 444 bool
565 select HAVE_ARCH_SECCOMP <<
566 help 445 help
567 An arch should select this symbol if 446 An arch should select this symbol if it provides all of these things:
568 - all the requirements for HAVE_ARCH <<
569 - syscall_get_arch() 447 - syscall_get_arch()
570 - syscall_get_arguments() 448 - syscall_get_arguments()
571 - syscall_rollback() 449 - syscall_rollback()
572 - syscall_set_return_value() 450 - syscall_set_return_value()
573 - SIGSYS siginfo_t support 451 - SIGSYS siginfo_t support
574 - secure_computing is called from a 452 - secure_computing is called from a ptrace_event()-safe context
575 - secure_computing return value is c 453 - secure_computing return value is checked and a return value of -1
576 results in the system call being s 454 results in the system call being skipped immediately.
577 - seccomp syscall wired up 455 - seccomp syscall wired up
578 - if !HAVE_SPARSE_SYSCALL_NR, have S <<
579 SECCOMP_ARCH_NATIVE_NR, SECCOMP_AR <<
580 COMPAT is supported, have the SECC <<
581 <<
582 config SECCOMP <<
583 prompt "Enable seccomp to safely execu <<
584 def_bool y <<
585 depends on HAVE_ARCH_SECCOMP <<
586 help <<
587 This kernel feature is useful for nu <<
588 that may need to handle untrusted by <<
589 execution. By using pipes or other t <<
590 to the process as file descriptors s <<
591 syscalls, it's possible to isolate t <<
592 own address space using seccomp. Onc <<
593 prctl(PR_SET_SECCOMP) or the seccomp <<
594 disabled and the task is only allowe <<
595 syscalls defined by each seccomp mod <<
596 <<
597 If unsure, say Y. <<
598 456
599 config SECCOMP_FILTER 457 config SECCOMP_FILTER
600 def_bool y 458 def_bool y
601 depends on HAVE_ARCH_SECCOMP_FILTER && 459 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
602 help 460 help
603 Enable tasks to build secure computi 461 Enable tasks to build secure computing environments defined
604 in terms of Berkeley Packet Filter p 462 in terms of Berkeley Packet Filter programs which implement
605 task-defined system call filtering p 463 task-defined system call filtering polices.
606 464
607 See Documentation/userspace-api/secc 465 See Documentation/userspace-api/seccomp_filter.rst for details.
608 466
609 config SECCOMP_CACHE_DEBUG <<
610 bool "Show seccomp filter cache status <<
611 depends on SECCOMP_FILTER && !HAVE_SPA <<
612 depends on PROC_FS <<
613 help <<
614 This enables the /proc/pid/seccomp_c <<
615 seccomp cache data. The file format <<
616 the file requires CAP_SYS_ADMIN. <<
617 <<
618 This option is for debugging only. E <<
619 an adversary may be able to infer th <<
620 <<
621 If unsure, say N. <<
622 <<
623 config HAVE_ARCH_STACKLEAK 467 config HAVE_ARCH_STACKLEAK
624 bool 468 bool
625 help 469 help
626 An architecture should select this i 470 An architecture should select this if it has the code which
627 fills the used part of the kernel st 471 fills the used part of the kernel stack with the STACKLEAK_POISON
628 value before returning from system c 472 value before returning from system calls.
629 473
630 config HAVE_STACKPROTECTOR 474 config HAVE_STACKPROTECTOR
631 bool 475 bool
632 help 476 help
633 An arch should select this symbol if 477 An arch should select this symbol if:
634 - it has implemented a stack canary 478 - it has implemented a stack canary (e.g. __stack_chk_guard)
635 479
>> 480 config CC_HAS_STACKPROTECTOR_NONE
>> 481 def_bool $(cc-option,-fno-stack-protector)
>> 482
636 config STACKPROTECTOR 483 config STACKPROTECTOR
637 bool "Stack Protector buffer overflow 484 bool "Stack Protector buffer overflow detection"
638 depends on HAVE_STACKPROTECTOR 485 depends on HAVE_STACKPROTECTOR
639 depends on $(cc-option,-fstack-protect 486 depends on $(cc-option,-fstack-protector)
640 default y 487 default y
641 help 488 help
642 This option turns on the "stack-prot 489 This option turns on the "stack-protector" GCC feature. This
643 feature puts, at the beginning of fu 490 feature puts, at the beginning of functions, a canary value on
644 the stack just before the return add 491 the stack just before the return address, and validates
645 the value just before actually retur 492 the value just before actually returning. Stack based buffer
646 overflows (that need to overwrite th 493 overflows (that need to overwrite this return address) now also
647 overwrite the canary, which gets det 494 overwrite the canary, which gets detected and the attack is then
648 neutralized via a kernel panic. 495 neutralized via a kernel panic.
649 496
650 Functions will have the stack-protec 497 Functions will have the stack-protector canary logic added if they
651 have an 8-byte or larger character a 498 have an 8-byte or larger character array on the stack.
652 499
653 This feature requires gcc version 4. 500 This feature requires gcc version 4.2 or above, or a distribution
654 gcc with the feature backported ("-f 501 gcc with the feature backported ("-fstack-protector").
655 502
656 On an x86 "defconfig" build, this fe 503 On an x86 "defconfig" build, this feature adds canary checks to
657 about 3% of all kernel functions, wh 504 about 3% of all kernel functions, which increases kernel code size
658 by about 0.3%. 505 by about 0.3%.
659 506
660 config STACKPROTECTOR_STRONG 507 config STACKPROTECTOR_STRONG
661 bool "Strong Stack Protector" 508 bool "Strong Stack Protector"
662 depends on STACKPROTECTOR 509 depends on STACKPROTECTOR
663 depends on $(cc-option,-fstack-protect 510 depends on $(cc-option,-fstack-protector-strong)
664 default y 511 default y
665 help 512 help
666 Functions will have the stack-protec 513 Functions will have the stack-protector canary logic added in any
667 of the following conditions: 514 of the following conditions:
668 515
669 - local variable's address used as p 516 - local variable's address used as part of the right hand side of an
670 assignment or function argument 517 assignment or function argument
671 - local variable is an array (or uni 518 - local variable is an array (or union containing an array),
672 regardless of array type or length 519 regardless of array type or length
673 - uses register local variables 520 - uses register local variables
674 521
675 This feature requires gcc version 4. 522 This feature requires gcc version 4.9 or above, or a distribution
676 gcc with the feature backported ("-f 523 gcc with the feature backported ("-fstack-protector-strong").
677 524
678 On an x86 "defconfig" build, this fe 525 On an x86 "defconfig" build, this feature adds canary checks to
679 about 20% of all kernel functions, w 526 about 20% of all kernel functions, which increases the kernel code
680 size by about 2%. 527 size by about 2%.
681 528
682 config ARCH_SUPPORTS_SHADOW_CALL_STACK <<
683 bool <<
684 help <<
685 An architecture should select this i <<
686 Shadow Call Stack and implements run <<
687 switching. <<
688 <<
689 config SHADOW_CALL_STACK <<
690 bool "Shadow Call Stack" <<
691 depends on ARCH_SUPPORTS_SHADOW_CALL_S <<
692 depends on DYNAMIC_FTRACE_WITH_ARGS || <<
693 depends on MMU <<
694 help <<
695 This option enables the compiler's S <<
696 uses a shadow stack to protect funct <<
697 being overwritten by an attacker. Mo <<
698 in the compiler's documentation: <<
699 <<
700 - Clang: https://clang.llvm.org/docs <<
701 - GCC: https://gcc.gnu.org/onlinedoc <<
702 <<
703 Note that security guarantees in the <<
704 ones documented for user space. The <<
705 of shadow stacks in memory, which me <<
706 reading and writing arbitrary memory <<
707 and hijack control flow by modifying <<
708 <<
709 config DYNAMIC_SCS <<
710 bool <<
711 help <<
712 Set by the arch code if it relies on <<
713 shadow call stack push and pop instr <<
714 compiler. <<
715 <<
716 config LTO <<
717 bool <<
718 help <<
719 Selected if the kernel will be built <<
720 <<
721 config LTO_CLANG <<
722 bool <<
723 select LTO <<
724 help <<
725 Selected if the kernel will be built <<
726 <<
727 config ARCH_SUPPORTS_LTO_CLANG <<
728 bool <<
729 help <<
730 An architecture should select this o <<
731 - compiling with Clang, <<
732 - compiling inline assembly with Cla <<
733 - and linking with LLD. <<
734 <<
735 config ARCH_SUPPORTS_LTO_CLANG_THIN <<
736 bool <<
737 help <<
738 An architecture should select this o <<
739 ThinLTO mode. <<
740 <<
741 config HAS_LTO_CLANG <<
742 def_bool y <<
743 depends on CC_IS_CLANG && LD_IS_LLD && <<
744 depends on $(success,$(NM) --help | he <<
745 depends on $(success,$(AR) --help | he <<
746 depends on ARCH_SUPPORTS_LTO_CLANG <<
747 depends on !FTRACE_MCOUNT_USE_RECORDMC <<
748 # https://github.com/ClangBuiltLinux/l <<
749 depends on (!KASAN || KASAN_HW_TAGS || <<
750 depends on (!KCOV || CLANG_VERSION >= <<
751 depends on !GCOV_KERNEL <<
752 help <<
753 The compiler and Kconfig options sup <<
754 LTO. <<
755 <<
756 choice <<
757 prompt "Link Time Optimization (LTO)" <<
758 default LTO_NONE <<
759 help <<
760 This option enables Link Time Optimi <<
761 compiler to optimize binaries global <<
762 <<
763 If unsure, select LTO_NONE. Note tha <<
764 so it's disabled by default. <<
765 <<
766 config LTO_NONE <<
767 bool "None" <<
768 help <<
769 Build the kernel normally, without L <<
770 <<
771 config LTO_CLANG_FULL <<
772 bool "Clang Full LTO (EXPERIMENTAL)" <<
773 depends on HAS_LTO_CLANG <<
774 depends on !COMPILE_TEST <<
775 select LTO_CLANG <<
776 help <<
777 This option enables Clang's full Lin <<
778 allows the compiler to optimize the <<
779 this option, the compiler generates <<
780 object files, and the actual compila <<
781 the LTO link step, which may take se <<
782 kernel configuration. More informati <<
783 documentation: <<
784 <<
785 https://llvm.org/docs/LinkTimeOpti <<
786 <<
787 During link time, this option can us <<
788 may take much longer than the ThinLT <<
789 <<
790 config LTO_CLANG_THIN <<
791 bool "Clang ThinLTO (EXPERIMENTAL)" <<
792 depends on HAS_LTO_CLANG && ARCH_SUPPO <<
793 select LTO_CLANG <<
794 help <<
795 This option enables Clang's ThinLTO, <<
796 optimization and faster incremental <<
797 CONFIG_LTO_CLANG_FULL option. More i <<
798 from Clang's documentation: <<
799 <<
800 https://clang.llvm.org/docs/ThinLT <<
801 <<
802 If unsure, say Y. <<
803 endchoice <<
804 <<
805 config ARCH_SUPPORTS_CFI_CLANG <<
806 bool <<
807 help <<
808 An architecture should select this o <<
809 Control-Flow Integrity (CFI) checkin <<
810 <<
811 config ARCH_USES_CFI_TRAPS <<
812 bool <<
813 <<
814 config CFI_CLANG <<
815 bool "Use Clang's Control Flow Integri <<
816 depends on ARCH_SUPPORTS_CFI_CLANG <<
817 depends on $(cc-option,-fsanitize=kcfi <<
818 help <<
819 This option enables Clang's forward- <<
820 (CFI) checking, where the compiler i <<
821 indirect function call to ensure the <<
822 the correct static type. This restri <<
823 makes it more difficult for an attac <<
824 the modification of stored function <<
825 found from Clang's documentation: <<
826 <<
827 https://clang.llvm.org/docs/Contro <<
828 <<
829 config CFI_PERMISSIVE <<
830 bool "Use CFI in permissive mode" <<
831 depends on CFI_CLANG <<
832 help <<
833 When selected, Control Flow Integrit <<
834 warning instead of a kernel panic. T <<
835 for finding indirect call type misma <<
836 <<
837 If unsure, say N. <<
838 <<
839 config HAVE_ARCH_WITHIN_STACK_FRAMES 529 config HAVE_ARCH_WITHIN_STACK_FRAMES
840 bool 530 bool
841 help 531 help
842 An architecture should select this i 532 An architecture should select this if it can walk the kernel stack
843 frames to determine if an object is 533 frames to determine if an object is part of either the arguments
844 or local variables (i.e. that it exc 534 or local variables (i.e. that it excludes saved return addresses,
845 and similar) by implementing an inli 535 and similar) by implementing an inline arch_within_stack_frames(),
846 which is used by CONFIG_HARDENED_USE 536 which is used by CONFIG_HARDENED_USERCOPY.
847 537
848 config HAVE_CONTEXT_TRACKING_USER !! 538 config HAVE_CONTEXT_TRACKING
849 bool 539 bool
850 help 540 help
851 Provide kernel/user boundaries probe 541 Provide kernel/user boundaries probes necessary for subsystems
852 that need it, such as userspace RCU 542 that need it, such as userspace RCU extended quiescent state.
853 Syscalls need to be wrapped inside u !! 543 Syscalls need to be wrapped inside user_exit()-user_enter() through
854 optimized behind static key or throu !! 544 the slow path using TIF_NOHZ flag. Exceptions handlers must be
855 flag. Exceptions handlers must be wr !! 545 wrapped as well. Irqs are already protected inside
856 protected inside ct_irq_enter/ct_irq !! 546 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
857 handling on irq exit still need to b !! 547 irq exit still need to be protected.
858 <<
859 config HAVE_CONTEXT_TRACKING_USER_OFFSTACK <<
860 bool <<
861 help <<
862 Architecture neither relies on excep <<
863 nor on schedule_user(). Also preempt <<
864 preempt_schedule_irq() can't be call <<
865 while context tracking is CONTEXT_US <<
866 entry implementation where the follo <<
867 critical entry code, ie: before user <<
868 <<
869 - Critical entry code isn't preempti <<
870 not interruptible). <<
871 - No use of RCU read side critical s <<
872 got called. <<
873 - No use of instrumentation, unless <<
874 called. <<
875 <<
876 config HAVE_TIF_NOHZ <<
877 bool <<
878 help <<
879 Arch relies on TIF_NOHZ and syscall <<
880 tracking calls to user_enter()/user_ <<
881 548
882 config HAVE_VIRT_CPU_ACCOUNTING 549 config HAVE_VIRT_CPU_ACCOUNTING
883 bool 550 bool
884 551
885 config HAVE_VIRT_CPU_ACCOUNTING_IDLE <<
886 bool <<
887 help <<
888 Architecture has its own way to acco <<
889 doesn't implement vtime_account_idle <<
890 <<
891 config ARCH_HAS_SCALED_CPUTIME 552 config ARCH_HAS_SCALED_CPUTIME
892 bool 553 bool
893 554
894 config HAVE_VIRT_CPU_ACCOUNTING_GEN 555 config HAVE_VIRT_CPU_ACCOUNTING_GEN
895 bool 556 bool
896 default y if 64BIT 557 default y if 64BIT
897 help 558 help
898 With VIRT_CPU_ACCOUNTING_GEN, cputim 559 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
899 Before enabling this option, arch co 560 Before enabling this option, arch code must be audited
900 to ensure there are no races in conc 561 to ensure there are no races in concurrent read/write of
901 cputime_t. For example, reading/writ 562 cputime_t. For example, reading/writing 64-bit cputime_t on
902 some 32-bit arches may require multi 563 some 32-bit arches may require multiple accesses, so proper
903 locking is needed to protect against 564 locking is needed to protect against concurrent accesses.
904 565
>> 566
905 config HAVE_IRQ_TIME_ACCOUNTING 567 config HAVE_IRQ_TIME_ACCOUNTING
906 bool 568 bool
907 help 569 help
908 Archs need to ensure they use a high 570 Archs need to ensure they use a high enough resolution clock to
909 support irq time accounting and then 571 support irq time accounting and then call enable_sched_clock_irqtime().
910 572
911 config HAVE_MOVE_PUD <<
912 bool <<
913 help <<
914 Architectures that select this are a <<
915 PUD level. If there are only 3 page <<
916 happens at the PGD level. <<
917 <<
918 config HAVE_MOVE_PMD 573 config HAVE_MOVE_PMD
919 bool 574 bool
920 help 575 help
921 Archs that select this are able to m 576 Archs that select this are able to move page tables at the PMD level.
922 577
923 config HAVE_ARCH_TRANSPARENT_HUGEPAGE 578 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
924 bool 579 bool
925 580
926 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 581 config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
927 bool 582 bool
928 583
929 config HAVE_ARCH_HUGE_VMAP 584 config HAVE_ARCH_HUGE_VMAP
930 bool 585 bool
931 586
932 # <<
933 # Archs that select this would be capable of <<
934 # arch_vmap_pmd_supported() returns true). Th <<
935 # must be used to enable allocations to use h <<
936 # <<
937 config HAVE_ARCH_HUGE_VMALLOC <<
938 depends on HAVE_ARCH_HUGE_VMAP <<
939 bool <<
940 <<
941 config ARCH_WANT_HUGE_PMD_SHARE 587 config ARCH_WANT_HUGE_PMD_SHARE
942 bool 588 bool
943 589
944 # Archs that want to use pmd_mkwrite on kernel <<
945 # if there are no userspace memory management <<
946 config ARCH_WANT_KERNEL_PMD_MKWRITE <<
947 bool <<
948 <<
949 config ARCH_WANT_PMD_MKWRITE <<
950 def_bool TRANSPARENT_HUGEPAGE || ARCH_ <<
951 <<
952 config HAVE_ARCH_SOFT_DIRTY 590 config HAVE_ARCH_SOFT_DIRTY
953 bool 591 bool
954 592
955 config HAVE_MOD_ARCH_SPECIFIC 593 config HAVE_MOD_ARCH_SPECIFIC
956 bool 594 bool
957 help 595 help
958 The arch uses struct mod_arch_specif 596 The arch uses struct mod_arch_specific to store data. Many arches
959 just need a simple module loader wit 597 just need a simple module loader without arch specific data - those
960 should not enable this. 598 should not enable this.
961 599
962 config MODULES_USE_ELF_RELA 600 config MODULES_USE_ELF_RELA
963 bool 601 bool
964 help 602 help
965 Modules only use ELF RELA relocation 603 Modules only use ELF RELA relocations. Modules with ELF REL
966 relocations will give an error. 604 relocations will give an error.
967 605
968 config MODULES_USE_ELF_REL 606 config MODULES_USE_ELF_REL
969 bool 607 bool
970 help 608 help
971 Modules only use ELF REL relocations 609 Modules only use ELF REL relocations. Modules with ELF RELA
972 relocations will give an error. 610 relocations will give an error.
973 611
974 config ARCH_WANTS_MODULES_DATA_IN_VMALLOC <<
975 bool <<
976 help <<
977 For architectures like powerpc/32 wh <<
978 allocation and need to allocate modu <<
979 <<
980 config ARCH_WANTS_EXECMEM_LATE <<
981 bool <<
982 help <<
983 For architectures that do not alloca <<
984 boot, but rather require its initial <<
985 enough entropy for module space rand <<
986 arm64. <<
987 <<
988 config HAVE_IRQ_EXIT_ON_IRQ_STACK 612 config HAVE_IRQ_EXIT_ON_IRQ_STACK
989 bool 613 bool
990 help 614 help
991 Architecture doesn't only execute th 615 Architecture doesn't only execute the irq handler on the irq stack
992 but also irq_exit(). This way we can 616 but also irq_exit(). This way we can process softirqs on this irq
993 stack instead of switching to a new 617 stack instead of switching to a new one when we call __do_softirq()
994 in the end of an hardirq. 618 in the end of an hardirq.
995 This spares a stack switch and impro 619 This spares a stack switch and improves cache usage on softirq
996 processing. 620 processing.
997 621
998 config HAVE_SOFTIRQ_ON_OWN_STACK <<
999 bool <<
1000 help <<
1001 Architecture provides a function to <<
1002 separate stack. <<
1003 <<
1004 config SOFTIRQ_ON_OWN_STACK <<
1005 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && <<
1006 <<
1007 config ALTERNATE_USER_ADDRESS_SPACE <<
1008 bool <<
1009 help <<
1010 Architectures set this when the CPU <<
1011 spaces for kernel and user space po <<
1012 access_ok() check on a __user point <<
1013 <<
1014 config PGTABLE_LEVELS 622 config PGTABLE_LEVELS
1015 int 623 int
1016 default 2 624 default 2
1017 625
1018 config ARCH_HAS_ELF_RANDOMIZE 626 config ARCH_HAS_ELF_RANDOMIZE
1019 bool 627 bool
1020 help 628 help
1021 An architecture supports choosing r 629 An architecture supports choosing randomized locations for
1022 stack, mmap, brk, and ET_DYN. Defin 630 stack, mmap, brk, and ET_DYN. Defined functions:
1023 - arch_mmap_rnd() 631 - arch_mmap_rnd()
1024 - arch_randomize_brk() 632 - arch_randomize_brk()
1025 633
1026 config HAVE_ARCH_MMAP_RND_BITS 634 config HAVE_ARCH_MMAP_RND_BITS
1027 bool 635 bool
1028 help 636 help
1029 An arch should select this symbol i 637 An arch should select this symbol if it supports setting a variable
1030 number of bits for use in establish 638 number of bits for use in establishing the base address for mmap
1031 allocations, has MMU enabled and pr 639 allocations, has MMU enabled and provides values for both:
1032 - ARCH_MMAP_RND_BITS_MIN 640 - ARCH_MMAP_RND_BITS_MIN
1033 - ARCH_MMAP_RND_BITS_MAX 641 - ARCH_MMAP_RND_BITS_MAX
1034 642
1035 config HAVE_EXIT_THREAD 643 config HAVE_EXIT_THREAD
1036 bool 644 bool
1037 help 645 help
1038 An architecture implements exit_thr 646 An architecture implements exit_thread.
1039 647
1040 config ARCH_MMAP_RND_BITS_MIN 648 config ARCH_MMAP_RND_BITS_MIN
1041 int 649 int
1042 650
1043 config ARCH_MMAP_RND_BITS_MAX 651 config ARCH_MMAP_RND_BITS_MAX
1044 int 652 int
1045 653
1046 config ARCH_MMAP_RND_BITS_DEFAULT 654 config ARCH_MMAP_RND_BITS_DEFAULT
1047 int 655 int
1048 656
1049 config ARCH_MMAP_RND_BITS 657 config ARCH_MMAP_RND_BITS
1050 int "Number of bits to use for ASLR o 658 int "Number of bits to use for ASLR of mmap base address" if EXPERT
1051 range ARCH_MMAP_RND_BITS_MIN ARCH_MMA 659 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1052 default ARCH_MMAP_RND_BITS_DEFAULT if 660 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1053 default ARCH_MMAP_RND_BITS_MIN 661 default ARCH_MMAP_RND_BITS_MIN
1054 depends on HAVE_ARCH_MMAP_RND_BITS 662 depends on HAVE_ARCH_MMAP_RND_BITS
1055 help 663 help
1056 This value can be used to select th 664 This value can be used to select the number of bits to use to
1057 determine the random offset to the 665 determine the random offset to the base address of vma regions
1058 resulting from mmap allocations. Th 666 resulting from mmap allocations. This value will be bounded
1059 by the architecture's minimum and m 667 by the architecture's minimum and maximum supported values.
1060 668
1061 This value can be changed after boo 669 This value can be changed after boot using the
1062 /proc/sys/vm/mmap_rnd_bits tunable 670 /proc/sys/vm/mmap_rnd_bits tunable
1063 671
1064 config HAVE_ARCH_MMAP_RND_COMPAT_BITS 672 config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1065 bool 673 bool
1066 help 674 help
1067 An arch should select this symbol i 675 An arch should select this symbol if it supports running applications
1068 in compatibility mode, supports set 676 in compatibility mode, supports setting a variable number of bits for
1069 use in establishing the base addres 677 use in establishing the base address for mmap allocations, has MMU
1070 enabled and provides values for bot 678 enabled and provides values for both:
1071 - ARCH_MMAP_RND_COMPAT_BITS_MIN 679 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1072 - ARCH_MMAP_RND_COMPAT_BITS_MAX 680 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1073 681
1074 config ARCH_MMAP_RND_COMPAT_BITS_MIN 682 config ARCH_MMAP_RND_COMPAT_BITS_MIN
1075 int 683 int
1076 684
1077 config ARCH_MMAP_RND_COMPAT_BITS_MAX 685 config ARCH_MMAP_RND_COMPAT_BITS_MAX
1078 int 686 int
1079 687
1080 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 688 config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1081 int 689 int
1082 690
1083 config ARCH_MMAP_RND_COMPAT_BITS 691 config ARCH_MMAP_RND_COMPAT_BITS
1084 int "Number of bits to use for ASLR o 692 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
1085 range ARCH_MMAP_RND_COMPAT_BITS_MIN A 693 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1086 default ARCH_MMAP_RND_COMPAT_BITS_DEF 694 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1087 default ARCH_MMAP_RND_COMPAT_BITS_MIN 695 default ARCH_MMAP_RND_COMPAT_BITS_MIN
1088 depends on HAVE_ARCH_MMAP_RND_COMPAT_ 696 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1089 help 697 help
1090 This value can be used to select th 698 This value can be used to select the number of bits to use to
1091 determine the random offset to the 699 determine the random offset to the base address of vma regions
1092 resulting from mmap allocations for 700 resulting from mmap allocations for compatible applications This
1093 value will be bounded by the archit 701 value will be bounded by the architecture's minimum and maximum
1094 supported values. 702 supported values.
1095 703
1096 This value can be changed after boo 704 This value can be changed after boot using the
1097 /proc/sys/vm/mmap_rnd_compat_bits t 705 /proc/sys/vm/mmap_rnd_compat_bits tunable
1098 706
1099 config HAVE_ARCH_COMPAT_MMAP_BASES 707 config HAVE_ARCH_COMPAT_MMAP_BASES
1100 bool 708 bool
1101 help 709 help
1102 This allows 64bit applications to i 710 This allows 64bit applications to invoke 32-bit mmap() syscall
1103 and vice-versa 32-bit applications 711 and vice-versa 32-bit applications to call 64-bit mmap().
1104 Required for applications doing dif 712 Required for applications doing different bitness syscalls.
1105 713
1106 config HAVE_PAGE_SIZE_4KB <<
1107 bool <<
1108 <<
1109 config HAVE_PAGE_SIZE_8KB <<
1110 bool <<
1111 <<
1112 config HAVE_PAGE_SIZE_16KB <<
1113 bool <<
1114 <<
1115 config HAVE_PAGE_SIZE_32KB <<
1116 bool <<
1117 <<
1118 config HAVE_PAGE_SIZE_64KB <<
1119 bool <<
1120 <<
1121 config HAVE_PAGE_SIZE_256KB <<
1122 bool <<
1123 <<
1124 choice <<
1125 prompt "MMU page size" <<
1126 <<
1127 config PAGE_SIZE_4KB <<
1128 bool "4KiB pages" <<
1129 depends on HAVE_PAGE_SIZE_4KB <<
1130 help <<
1131 This option select the standard 4Ki <<
1132 available option on many architectu <<
1133 minimize memory consumption and is <<
1134 memory systems. <<
1135 Some software that is written for x <<
1136 assumptions about the page size and <<
1137 <<
1138 config PAGE_SIZE_8KB <<
1139 bool "8KiB pages" <<
1140 depends on HAVE_PAGE_SIZE_8KB <<
1141 help <<
1142 This option is the only supported p <<
1143 processors, and can be slightly fas <<
1144 <<
1145 config PAGE_SIZE_16KB <<
1146 bool "16KiB pages" <<
1147 depends on HAVE_PAGE_SIZE_16KB <<
1148 help <<
1149 This option is usually a good compr <<
1150 consumption and performance for typ <<
1151 workloads, often saving a level of <<
1152 to 4KB pages as well as reducing TL <<
1153 per-page operations in the kernel a <<
1154 page cache. <<
1155 <<
1156 config PAGE_SIZE_32KB <<
1157 bool "32KiB pages" <<
1158 depends on HAVE_PAGE_SIZE_32KB <<
1159 help <<
1160 Using 32KiB page size will result i <<
1161 kernel at the price of higher memor <<
1162 16KiB pages. This option is availa <<
1163 Note that you will need a suitable <<
1164 support this. <<
1165 <<
1166 config PAGE_SIZE_64KB <<
1167 bool "64KiB pages" <<
1168 depends on HAVE_PAGE_SIZE_64KB <<
1169 help <<
1170 Using 64KiB page size will result i <<
1171 kernel at the price of much higher <<
1172 4KiB or 16KiB pages. <<
1173 This is not suitable for general-pu <<
1174 better performance may be worth the <<
1175 supercomputing or database applicat <<
1176 large in-memory data rather than sm <<
1177 <<
1178 config PAGE_SIZE_256KB <<
1179 bool "256KiB pages" <<
1180 depends on HAVE_PAGE_SIZE_256KB <<
1181 help <<
1182 256KiB pages have little practical <<
1183 memory usage. The kernel will only <<
1184 that have been compiled with '-zmax <<
1185 (the default is 64KiB or 4KiB on mo <<
1186 <<
1187 endchoice <<
1188 <<
1189 config PAGE_SIZE_LESS_THAN_64KB <<
1190 def_bool y <<
1191 depends on !PAGE_SIZE_64KB <<
1192 depends on PAGE_SIZE_LESS_THAN_256KB <<
1193 <<
1194 config PAGE_SIZE_LESS_THAN_256KB <<
1195 def_bool y <<
1196 depends on !PAGE_SIZE_256KB <<
1197 <<
1198 config PAGE_SHIFT <<
1199 int <<
1200 default 12 if PAGE_SIZE_4KB <<
1201 default 13 if PAGE_SIZE_8KB <<
1202 default 14 if PAGE_SIZE_16KB <<
1203 default 15 if PAGE_SIZE_32KB <<
1204 default 16 if PAGE_SIZE_64KB <<
1205 default 18 if PAGE_SIZE_256KB <<
1206 <<
1207 # This allows to use a set of generic functio 714 # This allows to use a set of generic functions to determine mmap base
1208 # address by giving priority to top-down sche 715 # address by giving priority to top-down scheme only if the process
1209 # is not in legacy mode (compat task, unlimit 716 # is not in legacy mode (compat task, unlimited stack size or
1210 # sysctl_legacy_va_layout). 717 # sysctl_legacy_va_layout).
1211 # Architecture that selects this option can p 718 # Architecture that selects this option can provide its own version of:
1212 # - STACK_RND_MASK 719 # - STACK_RND_MASK
1213 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 720 config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
1214 bool 721 bool
1215 depends on MMU 722 depends on MMU
1216 select ARCH_HAS_ELF_RANDOMIZE 723 select ARCH_HAS_ELF_RANDOMIZE
1217 724
1218 config HAVE_OBJTOOL !! 725 config HAVE_COPY_THREAD_TLS
1219 bool 726 bool
1220 !! 727 help
1221 config HAVE_JUMP_LABEL_HACK !! 728 Architecture provides copy_thread_tls to accept tls argument via
1222 bool !! 729 normal C parameter passing, rather than extracting the syscall
1223 !! 730 argument from pt_regs.
1224 config HAVE_NOINSTR_HACK <<
1225 bool <<
1226 <<
1227 config HAVE_NOINSTR_VALIDATION <<
1228 bool <<
1229 <<
1230 config HAVE_UACCESS_VALIDATION <<
1231 bool <<
1232 select OBJTOOL <<
1233 731
1234 config HAVE_STACK_VALIDATION 732 config HAVE_STACK_VALIDATION
1235 bool 733 bool
1236 help 734 help
1237 Architecture supports objtool compi !! 735 Architecture supports the 'objtool check' host tool command, which
1238 validation. !! 736 performs compile-time stack metadata validation.
1239 737
1240 config HAVE_RELIABLE_STACKTRACE 738 config HAVE_RELIABLE_STACKTRACE
1241 bool 739 bool
1242 help 740 help
1243 Architecture has either save_stack_ 741 Architecture has either save_stack_trace_tsk_reliable() or
1244 arch_stack_walk_reliable() function 742 arch_stack_walk_reliable() function which only returns a stack trace
1245 if it can guarantee the trace is re 743 if it can guarantee the trace is reliable.
1246 744
1247 config HAVE_ARCH_HASH 745 config HAVE_ARCH_HASH
1248 bool 746 bool
1249 default n 747 default n
1250 help 748 help
1251 If this is set, the architecture pr 749 If this is set, the architecture provides an <asm/hash.h>
1252 file which provides platform-specif 750 file which provides platform-specific implementations of some
1253 functions in <linux/hash.h> or fs/n 751 functions in <linux/hash.h> or fs/namei.c.
1254 752
1255 config HAVE_ARCH_NVRAM_OPS 753 config HAVE_ARCH_NVRAM_OPS
1256 bool 754 bool
1257 755
1258 config ISA_BUS_API 756 config ISA_BUS_API
1259 def_bool ISA 757 def_bool ISA
1260 758
1261 # 759 #
1262 # ABI hall of shame 760 # ABI hall of shame
1263 # 761 #
1264 config CLONE_BACKWARDS 762 config CLONE_BACKWARDS
1265 bool 763 bool
1266 help 764 help
1267 Architecture has tls passed as the 765 Architecture has tls passed as the 4th argument of clone(2),
1268 not the 5th one. 766 not the 5th one.
1269 767
1270 config CLONE_BACKWARDS2 768 config CLONE_BACKWARDS2
1271 bool 769 bool
1272 help 770 help
1273 Architecture has the first two argu 771 Architecture has the first two arguments of clone(2) swapped.
1274 772
1275 config CLONE_BACKWARDS3 773 config CLONE_BACKWARDS3
1276 bool 774 bool
1277 help 775 help
1278 Architecture has tls passed as the 776 Architecture has tls passed as the 3rd argument of clone(2),
1279 not the 5th one. 777 not the 5th one.
1280 778
1281 config ODD_RT_SIGACTION 779 config ODD_RT_SIGACTION
1282 bool 780 bool
1283 help 781 help
1284 Architecture has unusual rt_sigacti 782 Architecture has unusual rt_sigaction(2) arguments
1285 783
1286 config OLD_SIGSUSPEND 784 config OLD_SIGSUSPEND
1287 bool 785 bool
1288 help 786 help
1289 Architecture has old sigsuspend(2) 787 Architecture has old sigsuspend(2) syscall, of one-argument variety
1290 788
1291 config OLD_SIGSUSPEND3 789 config OLD_SIGSUSPEND3
1292 bool 790 bool
1293 help 791 help
1294 Even weirder antique ABI - three-ar 792 Even weirder antique ABI - three-argument sigsuspend(2)
1295 793
1296 config OLD_SIGACTION 794 config OLD_SIGACTION
1297 bool 795 bool
1298 help 796 help
1299 Architecture has old sigaction(2) s 797 Architecture has old sigaction(2) syscall. Nope, not the same
1300 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 798 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1301 but fairly different variant of sig 799 but fairly different variant of sigaction(2), thanks to OSF/1
1302 compatibility... 800 compatibility...
1303 801
1304 config COMPAT_OLD_SIGACTION 802 config COMPAT_OLD_SIGACTION
1305 bool 803 bool
1306 804
1307 config COMPAT_32BIT_TIME 805 config COMPAT_32BIT_TIME
1308 bool "Provide system calls for 32-bit 806 bool "Provide system calls for 32-bit time_t"
1309 default !64BIT || COMPAT 807 default !64BIT || COMPAT
1310 help 808 help
1311 This enables 32 bit time_t support 809 This enables 32 bit time_t support in addition to 64 bit time_t support.
1312 This is relevant on all 32-bit arch 810 This is relevant on all 32-bit architectures, and 64-bit architectures
1313 as part of compat syscall handling. 811 as part of compat syscall handling.
1314 812
1315 config ARCH_NO_PREEMPT 813 config ARCH_NO_PREEMPT
1316 bool 814 bool
1317 815
1318 config ARCH_SUPPORTS_RT 816 config ARCH_SUPPORTS_RT
1319 bool 817 bool
1320 818
1321 config CPU_NO_EFFICIENT_FFS 819 config CPU_NO_EFFICIENT_FFS
1322 def_bool n 820 def_bool n
1323 821
1324 config HAVE_ARCH_VMAP_STACK 822 config HAVE_ARCH_VMAP_STACK
1325 def_bool n 823 def_bool n
1326 help 824 help
1327 An arch should select this symbol i 825 An arch should select this symbol if it can support kernel stacks
1328 in vmalloc space. This means: 826 in vmalloc space. This means:
1329 827
1330 - vmalloc space must be large enoug 828 - vmalloc space must be large enough to hold many kernel stacks.
1331 This may rule out many 32-bit arc 829 This may rule out many 32-bit architectures.
1332 830
1333 - Stacks in vmalloc space need to w 831 - Stacks in vmalloc space need to work reliably. For example, if
1334 vmap page tables are created on d 832 vmap page tables are created on demand, either this mechanism
1335 needs to work while the stack poi 833 needs to work while the stack points to a virtual address with
1336 unpopulated page tables or arch c 834 unpopulated page tables or arch code (switch_to() and switch_mm(),
1337 most likely) needs to ensure that 835 most likely) needs to ensure that the stack's page table entries
1338 are populated before running on a 836 are populated before running on a possibly unpopulated stack.
1339 837
1340 - If the stack overflows into a gua 838 - If the stack overflows into a guard page, something reasonable
1341 should happen. The definition of 839 should happen. The definition of "reasonable" is flexible, but
1342 instantly rebooting without loggi 840 instantly rebooting without logging anything would be unfriendly.
1343 841
1344 config VMAP_STACK 842 config VMAP_STACK
1345 default y 843 default y
1346 bool "Use a virtually-mapped stack" 844 bool "Use a virtually-mapped stack"
1347 depends on HAVE_ARCH_VMAP_STACK 845 depends on HAVE_ARCH_VMAP_STACK
1348 depends on !KASAN || KASAN_HW_TAGS || !! 846 depends on !KASAN || KASAN_VMALLOC
1349 help !! 847 ---help---
1350 Enable this if you want the use vir 848 Enable this if you want the use virtually-mapped kernel stacks
1351 with guard pages. This causes kern 849 with guard pages. This causes kernel stack overflows to be
1352 caught immediately rather than caus 850 caught immediately rather than causing difficult-to-diagnose
1353 corruption. 851 corruption.
1354 852
1355 To use this with software KASAN mod !! 853 To use this with KASAN, the architecture must support backing
1356 backing virtual mappings with real !! 854 virtual mappings with real shadow memory, and KASAN_VMALLOC must
1357 must be enabled. !! 855 be enabled.
1358 <<
1359 config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET <<
1360 def_bool n <<
1361 help <<
1362 An arch should select this symbol i <<
1363 offset randomization with calls to <<
1364 during syscall entry and choose_ran <<
1365 syscall exit. Careful removal of -f <<
1366 -fstack-protector should also be ap <<
1367 closely examined, as the artificial <<
1368 to the compiler, so it will attempt <<
1369 of the static branch state. <<
1370 <<
1371 config RANDOMIZE_KSTACK_OFFSET <<
1372 bool "Support for randomizing kernel <<
1373 default y <<
1374 depends on HAVE_ARCH_RANDOMIZE_KSTACK <<
1375 depends on INIT_STACK_NONE || !CC_IS_ <<
1376 help <<
1377 The kernel stack offset can be rand <<
1378 roughly 5 bits of entropy, frustrat <<
1379 attacks that depend on stack addres <<
1380 cross-syscall address exposures. <<
1381 <<
1382 The feature is controlled via the " <<
1383 kernel boot param, and if turned of <<
1384 of static branches (see JUMP_LABEL) <<
1385 <<
1386 If unsure, say Y. <<
1387 <<
1388 config RANDOMIZE_KSTACK_OFFSET_DEFAULT <<
1389 bool "Default state of kernel stack o <<
1390 depends on RANDOMIZE_KSTACK_OFFSET <<
1391 help <<
1392 Kernel stack offset randomization i <<
1393 "randomize_kstack_offset=on/off", a <<
1394 boot state. <<
1395 856
1396 config ARCH_OPTIONAL_KERNEL_RWX 857 config ARCH_OPTIONAL_KERNEL_RWX
1397 def_bool n 858 def_bool n
1398 859
1399 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 860 config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1400 def_bool n 861 def_bool n
1401 862
1402 config ARCH_HAS_STRICT_KERNEL_RWX 863 config ARCH_HAS_STRICT_KERNEL_RWX
1403 def_bool n 864 def_bool n
1404 865
1405 config STRICT_KERNEL_RWX 866 config STRICT_KERNEL_RWX
1406 bool "Make kernel text and rodata rea 867 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1407 depends on ARCH_HAS_STRICT_KERNEL_RWX 868 depends on ARCH_HAS_STRICT_KERNEL_RWX
1408 default !ARCH_OPTIONAL_KERNEL_RWX || 869 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1409 help 870 help
1410 If this is set, kernel text and rod 871 If this is set, kernel text and rodata memory will be made read-only,
1411 and non-text memory will be made no 872 and non-text memory will be made non-executable. This provides
1412 protection against certain security 873 protection against certain security exploits (e.g. executing the heap
1413 or modifying text) 874 or modifying text)
1414 875
1415 These features are considered stand 876 These features are considered standard security practice these days.
1416 You should say Y here in almost all 877 You should say Y here in almost all cases.
1417 878
1418 config ARCH_HAS_STRICT_MODULE_RWX 879 config ARCH_HAS_STRICT_MODULE_RWX
1419 def_bool n 880 def_bool n
1420 881
1421 config STRICT_MODULE_RWX 882 config STRICT_MODULE_RWX
1422 bool "Set loadable kernel module data 883 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
1423 depends on ARCH_HAS_STRICT_MODULE_RWX 884 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1424 default !ARCH_OPTIONAL_KERNEL_RWX || 885 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1425 help 886 help
1426 If this is set, module text and rod 887 If this is set, module text and rodata memory will be made read-only,
1427 and non-text memory will be made no 888 and non-text memory will be made non-executable. This provides
1428 protection against certain security 889 protection against certain security exploits (e.g. writing to text)
1429 890
1430 # select if the architecture provides an asm/ 891 # select if the architecture provides an asm/dma-direct.h header
1431 config ARCH_HAS_PHYS_TO_DMA 892 config ARCH_HAS_PHYS_TO_DMA
1432 bool 893 bool
1433 894
1434 config HAVE_ARCH_COMPILER_H 895 config HAVE_ARCH_COMPILER_H
1435 bool 896 bool
1436 help 897 help
1437 An architecture can select this if 898 An architecture can select this if it provides an
1438 asm/compiler.h header that should b 899 asm/compiler.h header that should be included after
1439 linux/compiler-*.h in order to over 900 linux/compiler-*.h in order to override macro definitions that those
1440 headers generally provide. 901 headers generally provide.
1441 902
1442 config HAVE_ARCH_PREL32_RELOCATIONS 903 config HAVE_ARCH_PREL32_RELOCATIONS
1443 bool 904 bool
1444 help 905 help
1445 May be selected by an architecture 906 May be selected by an architecture if it supports place-relative
1446 32-bit relocations, both in the too 907 32-bit relocations, both in the toolchain and in the module loader,
1447 in which case relative references c 908 in which case relative references can be used in special sections
1448 for PCI fixup, initcalls etc which 909 for PCI fixup, initcalls etc which are only half the size on 64 bit
1449 architectures, and don't require ru 910 architectures, and don't require runtime relocation on relocatable
1450 kernels. 911 kernels.
1451 912
1452 config ARCH_USE_MEMREMAP_PROT 913 config ARCH_USE_MEMREMAP_PROT
1453 bool 914 bool
1454 915
1455 config LOCK_EVENT_COUNTS 916 config LOCK_EVENT_COUNTS
1456 bool "Locking event counts collection 917 bool "Locking event counts collection"
1457 depends on DEBUG_FS 918 depends on DEBUG_FS
1458 help !! 919 ---help---
1459 Enable light-weight counting of var 920 Enable light-weight counting of various locking related events
1460 in the system with minimal performa 921 in the system with minimal performance impact. This reduces
1461 the chance of application behavior 922 the chance of application behavior change because of timing
1462 differences. The counts are reporte 923 differences. The counts are reported via debugfs.
1463 924
1464 # Select if the architecture has support for 925 # Select if the architecture has support for applying RELR relocations.
1465 config ARCH_HAS_RELR 926 config ARCH_HAS_RELR
1466 bool 927 bool
1467 928
1468 config RELR 929 config RELR
1469 bool "Use RELR relocation packing" 930 bool "Use RELR relocation packing"
1470 depends on ARCH_HAS_RELR && TOOLS_SUP 931 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
1471 default y 932 default y
1472 help 933 help
1473 Store the kernel's dynamic relocati 934 Store the kernel's dynamic relocations in the RELR relocation packing
1474 format. Requires a compatible linke 935 format. Requires a compatible linker (LLD supports this feature), as
1475 well as compatible NM and OBJCOPY u 936 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1476 are compatible). 937 are compatible).
1477 938
1478 config ARCH_HAS_MEM_ENCRYPT 939 config ARCH_HAS_MEM_ENCRYPT
1479 bool 940 bool
1480 941
1481 config ARCH_HAS_CC_PLATFORM <<
1482 bool <<
1483 <<
1484 config HAVE_SPARSE_SYSCALL_NR 942 config HAVE_SPARSE_SYSCALL_NR
1485 bool !! 943 bool
1486 help !! 944 help
1487 An architecture should select this !! 945 An architecture should select this if its syscall numbering is sparse
1488 to save space. For example, MIPS ar 946 to save space. For example, MIPS architecture has a syscall array with
1489 entries at 4000, 5000 and 6000 loca 947 entries at 4000, 5000 and 6000 locations. This option turns on syscall
1490 related optimizations for a given a 948 related optimizations for a given architecture.
1491 949
1492 config ARCH_HAS_VDSO_DATA <<
1493 bool <<
1494 <<
1495 config HAVE_STATIC_CALL <<
1496 bool <<
1497 <<
1498 config HAVE_STATIC_CALL_INLINE <<
1499 bool <<
1500 depends on HAVE_STATIC_CALL <<
1501 select OBJTOOL <<
1502 <<
1503 config HAVE_PREEMPT_DYNAMIC <<
1504 bool <<
1505 <<
1506 config HAVE_PREEMPT_DYNAMIC_CALL <<
1507 bool <<
1508 depends on HAVE_STATIC_CALL <<
1509 select HAVE_PREEMPT_DYNAMIC <<
1510 help <<
1511 An architecture should select this <<
1512 model being selected at boot time u <<
1513 <<
1514 Where an architecture selects HAVE_ <<
1515 preemption function will be patched <<
1516 <<
1517 Where an architecture does not sele <<
1518 call to a preemption function will <<
1519 trampoline will be patched. <<
1520 <<
1521 It is strongly advised to support i <<
1522 overhead. <<
1523 <<
1524 config HAVE_PREEMPT_DYNAMIC_KEY <<
1525 bool <<
1526 depends on HAVE_ARCH_JUMP_LABEL <<
1527 select HAVE_PREEMPT_DYNAMIC <<
1528 help <<
1529 An architecture should select this <<
1530 model being selected at boot time u <<
1531 <<
1532 Each preemption function will be gi <<
1533 static key. This should have slight <<
1534 static calls, as this effectively i <<
1535 start of its callee. This may avoid <<
1536 integrate better with CFI schemes. <<
1537 <<
1538 This will have greater overhead tha <<
1539 the call to the preemption function <<
1540 <<
1541 config ARCH_WANT_LD_ORPHAN_WARN <<
1542 bool <<
1543 help <<
1544 An arch should select this symbol o <<
1545 included, size-asserted, or discard <<
1546 important because we never want exp <<
1547 by the linker, since the locations <<
1548 versions. <<
1549 <<
1550 config HAVE_ARCH_PFN_VALID <<
1551 bool <<
1552 <<
1553 config ARCH_SUPPORTS_DEBUG_PAGEALLOC <<
1554 bool <<
1555 <<
1556 config ARCH_SUPPORTS_PAGE_TABLE_CHECK <<
1557 bool <<
1558 <<
1559 config ARCH_SPLIT_ARG64 <<
1560 bool <<
1561 help <<
1562 If a 32-bit architecture requires 6 <<
1563 pairs of 32-bit arguments, select t <<
1564 <<
1565 config ARCH_HAS_ELFCORE_COMPAT <<
1566 bool <<
1567 <<
1568 config ARCH_HAS_PARANOID_L1D_FLUSH <<
1569 bool <<
1570 <<
1571 config ARCH_HAVE_TRACE_MMIO_ACCESS <<
1572 bool <<
1573 <<
1574 config DYNAMIC_SIGFRAME <<
1575 bool <<
1576 <<
1577 # Select, if arch has a named attribute group <<
1578 config HAVE_ARCH_NODE_DEV_GROUP <<
1579 bool <<
1580 <<
1581 config ARCH_HAS_HW_PTE_YOUNG <<
1582 bool <<
1583 help <<
1584 Architectures that select this opti <<
1585 accessed bit in PTE entries when us <<
1586 translations. Architectures that re <<
1587 this option and override arch_has_h <<
1588 <<
1589 config ARCH_HAS_NONLEAF_PMD_YOUNG <<
1590 bool <<
1591 help <<
1592 Architectures that select this opti <<
1593 accessed bit in non-leaf PMD entrie <<
1594 address translations. Page table wa <<
1595 may use this capability to reduce t <<
1596 <<
1597 config ARCH_HAS_KERNEL_FPU_SUPPORT <<
1598 bool <<
1599 help <<
1600 Architectures that select this opti <<
1601 the kernel, as described in Documen <<
1602 <<
1603 source "kernel/gcov/Kconfig" 950 source "kernel/gcov/Kconfig"
1604 951
1605 source "scripts/gcc-plugins/Kconfig" 952 source "scripts/gcc-plugins/Kconfig"
1606 <<
1607 config FUNCTION_ALIGNMENT_4B <<
1608 bool <<
1609 <<
1610 config FUNCTION_ALIGNMENT_8B <<
1611 bool <<
1612 <<
1613 config FUNCTION_ALIGNMENT_16B <<
1614 bool <<
1615 <<
1616 config FUNCTION_ALIGNMENT_32B <<
1617 bool <<
1618 <<
1619 config FUNCTION_ALIGNMENT_64B <<
1620 bool <<
1621 <<
1622 config FUNCTION_ALIGNMENT <<
1623 int <<
1624 default 64 if FUNCTION_ALIGNMENT_64B <<
1625 default 32 if FUNCTION_ALIGNMENT_32B <<
1626 default 16 if FUNCTION_ALIGNMENT_16B <<
1627 default 8 if FUNCTION_ALIGNMENT_8B <<
1628 default 4 if FUNCTION_ALIGNMENT_4B <<
1629 default 0 <<
1630 <<
1631 config CC_HAS_MIN_FUNCTION_ALIGNMENT <<
1632 # Detect availability of the GCC opti <<
1633 # guarantees minimal alignment for al <<
1634 # -falign-functions which the compile <<
1635 def_bool $(cc-option, -fmin-function- <<
1636 <<
1637 config CC_HAS_SANE_FUNCTION_ALIGNMENT <<
1638 # Set if the guaranteed alignment wit <<
1639 # available or extra care is required <<
1640 # strict alignment always, even with <<
1641 def_bool CC_HAS_MIN_FUNCTION_ALIGNMEN <<
1642 <<
1643 config ARCH_NEED_CMPXCHG_1_EMU <<
1644 bool <<
1645 953
1646 endmenu 954 endmenu
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