| 1 | # |
| 2 | # General architecture dependent options |
| 3 | # |
| 4 | |
| 5 | config KEXEC_CORE |
| 6 | bool |
| 7 | |
| 8 | config OPROFILE |
| 9 | tristate "OProfile system profiling" |
| 10 | depends on PROFILING |
| 11 | depends on HAVE_OPROFILE |
| 12 | select RING_BUFFER |
| 13 | select RING_BUFFER_ALLOW_SWAP |
| 14 | help |
| 15 | OProfile is a profiling system capable of profiling the |
| 16 | whole system, include the kernel, kernel modules, libraries, |
| 17 | and applications. |
| 18 | |
| 19 | If unsure, say N. |
| 20 | |
| 21 | config OPROFILE_EVENT_MULTIPLEX |
| 22 | bool "OProfile multiplexing support (EXPERIMENTAL)" |
| 23 | default n |
| 24 | depends on OPROFILE && X86 |
| 25 | help |
| 26 | The number of hardware counters is limited. The multiplexing |
| 27 | feature enables OProfile to gather more events than counters |
| 28 | are provided by the hardware. This is realized by switching |
| 29 | between events at an user specified time interval. |
| 30 | |
| 31 | If unsure, say N. |
| 32 | |
| 33 | config HAVE_OPROFILE |
| 34 | bool |
| 35 | |
| 36 | config OPROFILE_NMI_TIMER |
| 37 | def_bool y |
| 38 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 |
| 39 | |
| 40 | config KPROBES |
| 41 | bool "Kprobes" |
| 42 | depends on MODULES |
| 43 | depends on HAVE_KPROBES |
| 44 | select KALLSYMS |
| 45 | help |
| 46 | Kprobes allows you to trap at almost any kernel address and |
| 47 | execute a callback function. register_kprobe() establishes |
| 48 | a probepoint and specifies the callback. Kprobes is useful |
| 49 | for kernel debugging, non-intrusive instrumentation and testing. |
| 50 | If in doubt, say "N". |
| 51 | |
| 52 | config JUMP_LABEL |
| 53 | bool "Optimize very unlikely/likely branches" |
| 54 | depends on HAVE_ARCH_JUMP_LABEL |
| 55 | help |
| 56 | This option enables a transparent branch optimization that |
| 57 | makes certain almost-always-true or almost-always-false branch |
| 58 | conditions even cheaper to execute within the kernel. |
| 59 | |
| 60 | Certain performance-sensitive kernel code, such as trace points, |
| 61 | scheduler functionality, networking code and KVM have such |
| 62 | branches and include support for this optimization technique. |
| 63 | |
| 64 | If it is detected that the compiler has support for "asm goto", |
| 65 | the kernel will compile such branches with just a nop |
| 66 | instruction. When the condition flag is toggled to true, the |
| 67 | nop will be converted to a jump instruction to execute the |
| 68 | conditional block of instructions. |
| 69 | |
| 70 | This technique lowers overhead and stress on the branch prediction |
| 71 | of the processor and generally makes the kernel faster. The update |
| 72 | of the condition is slower, but those are always very rare. |
| 73 | |
| 74 | ( On 32-bit x86, the necessary options added to the compiler |
| 75 | flags may increase the size of the kernel slightly. ) |
| 76 | |
| 77 | config STATIC_KEYS_SELFTEST |
| 78 | bool "Static key selftest" |
| 79 | depends on JUMP_LABEL |
| 80 | help |
| 81 | Boot time self-test of the branch patching code. |
| 82 | |
| 83 | config OPTPROBES |
| 84 | def_bool y |
| 85 | depends on KPROBES && HAVE_OPTPROBES |
| 86 | depends on !PREEMPT |
| 87 | |
| 88 | config KPROBES_ON_FTRACE |
| 89 | def_bool y |
| 90 | depends on KPROBES && HAVE_KPROBES_ON_FTRACE |
| 91 | depends on DYNAMIC_FTRACE_WITH_REGS |
| 92 | help |
| 93 | If function tracer is enabled and the arch supports full |
| 94 | passing of pt_regs to function tracing, then kprobes can |
| 95 | optimize on top of function tracing. |
| 96 | |
| 97 | config UPROBES |
| 98 | def_bool n |
| 99 | help |
| 100 | Uprobes is the user-space counterpart to kprobes: they |
| 101 | enable instrumentation applications (such as 'perf probe') |
| 102 | to establish unintrusive probes in user-space binaries and |
| 103 | libraries, by executing handler functions when the probes |
| 104 | are hit by user-space applications. |
| 105 | |
| 106 | ( These probes come in the form of single-byte breakpoints, |
| 107 | managed by the kernel and kept transparent to the probed |
| 108 | application. ) |
| 109 | |
| 110 | config HAVE_64BIT_ALIGNED_ACCESS |
| 111 | def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS |
| 112 | help |
| 113 | Some architectures require 64 bit accesses to be 64 bit |
| 114 | aligned, which also requires structs containing 64 bit values |
| 115 | to be 64 bit aligned too. This includes some 32 bit |
| 116 | architectures which can do 64 bit accesses, as well as 64 bit |
| 117 | architectures without unaligned access. |
| 118 | |
| 119 | This symbol should be selected by an architecture if 64 bit |
| 120 | accesses are required to be 64 bit aligned in this way even |
| 121 | though it is not a 64 bit architecture. |
| 122 | |
| 123 | See Documentation/unaligned-memory-access.txt for more |
| 124 | information on the topic of unaligned memory accesses. |
| 125 | |
| 126 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
| 127 | bool |
| 128 | help |
| 129 | Some architectures are unable to perform unaligned accesses |
| 130 | without the use of get_unaligned/put_unaligned. Others are |
| 131 | unable to perform such accesses efficiently (e.g. trap on |
| 132 | unaligned access and require fixing it up in the exception |
| 133 | handler.) |
| 134 | |
| 135 | This symbol should be selected by an architecture if it can |
| 136 | perform unaligned accesses efficiently to allow different |
| 137 | code paths to be selected for these cases. Some network |
| 138 | drivers, for example, could opt to not fix up alignment |
| 139 | problems with received packets if doing so would not help |
| 140 | much. |
| 141 | |
| 142 | See Documentation/unaligned-memory-access.txt for more |
| 143 | information on the topic of unaligned memory accesses. |
| 144 | |
| 145 | config ARCH_USE_BUILTIN_BSWAP |
| 146 | bool |
| 147 | help |
| 148 | Modern versions of GCC (since 4.4) have builtin functions |
| 149 | for handling byte-swapping. Using these, instead of the old |
| 150 | inline assembler that the architecture code provides in the |
| 151 | __arch_bswapXX() macros, allows the compiler to see what's |
| 152 | happening and offers more opportunity for optimisation. In |
| 153 | particular, the compiler will be able to combine the byteswap |
| 154 | with a nearby load or store and use load-and-swap or |
| 155 | store-and-swap instructions if the architecture has them. It |
| 156 | should almost *never* result in code which is worse than the |
| 157 | hand-coded assembler in <asm/swab.h>. But just in case it |
| 158 | does, the use of the builtins is optional. |
| 159 | |
| 160 | Any architecture with load-and-swap or store-and-swap |
| 161 | instructions should set this. And it shouldn't hurt to set it |
| 162 | on architectures that don't have such instructions. |
| 163 | |
| 164 | config KRETPROBES |
| 165 | def_bool y |
| 166 | depends on KPROBES && HAVE_KRETPROBES |
| 167 | |
| 168 | config USER_RETURN_NOTIFIER |
| 169 | bool |
| 170 | depends on HAVE_USER_RETURN_NOTIFIER |
| 171 | help |
| 172 | Provide a kernel-internal notification when a cpu is about to |
| 173 | switch to user mode. |
| 174 | |
| 175 | config HAVE_IOREMAP_PROT |
| 176 | bool |
| 177 | |
| 178 | config HAVE_KPROBES |
| 179 | bool |
| 180 | |
| 181 | config HAVE_KRETPROBES |
| 182 | bool |
| 183 | |
| 184 | config HAVE_OPTPROBES |
| 185 | bool |
| 186 | |
| 187 | config HAVE_KPROBES_ON_FTRACE |
| 188 | bool |
| 189 | |
| 190 | config HAVE_NMI |
| 191 | bool |
| 192 | |
| 193 | config HAVE_NMI_WATCHDOG |
| 194 | depends on HAVE_NMI |
| 195 | bool |
| 196 | # |
| 197 | # An arch should select this if it provides all these things: |
| 198 | # |
| 199 | # task_pt_regs() in asm/processor.h or asm/ptrace.h |
| 200 | # arch_has_single_step() if there is hardware single-step support |
| 201 | # arch_has_block_step() if there is hardware block-step support |
| 202 | # asm/syscall.h supplying asm-generic/syscall.h interface |
| 203 | # linux/regset.h user_regset interfaces |
| 204 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h |
| 205 | # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} |
| 206 | # TIF_NOTIFY_RESUME calls tracehook_notify_resume() |
| 207 | # signal delivery calls tracehook_signal_handler() |
| 208 | # |
| 209 | config HAVE_ARCH_TRACEHOOK |
| 210 | bool |
| 211 | |
| 212 | config HAVE_DMA_CONTIGUOUS |
| 213 | bool |
| 214 | |
| 215 | config GENERIC_SMP_IDLE_THREAD |
| 216 | bool |
| 217 | |
| 218 | config GENERIC_IDLE_POLL_SETUP |
| 219 | bool |
| 220 | |
| 221 | # Select if arch init_task initializer is different to init/init_task.c |
| 222 | config ARCH_INIT_TASK |
| 223 | bool |
| 224 | |
| 225 | # Select if arch has its private alloc_task_struct() function |
| 226 | config ARCH_TASK_STRUCT_ALLOCATOR |
| 227 | bool |
| 228 | |
| 229 | # Select if arch has its private alloc_thread_info() function |
| 230 | config ARCH_THREAD_INFO_ALLOCATOR |
| 231 | bool |
| 232 | |
| 233 | # Select if arch wants to size task_struct dynamically via arch_task_struct_size: |
| 234 | config ARCH_WANTS_DYNAMIC_TASK_STRUCT |
| 235 | bool |
| 236 | |
| 237 | config HAVE_REGS_AND_STACK_ACCESS_API |
| 238 | bool |
| 239 | help |
| 240 | This symbol should be selected by an architecure if it supports |
| 241 | the API needed to access registers and stack entries from pt_regs, |
| 242 | declared in asm/ptrace.h |
| 243 | For example the kprobes-based event tracer needs this API. |
| 244 | |
| 245 | config HAVE_CLK |
| 246 | bool |
| 247 | help |
| 248 | The <linux/clk.h> calls support software clock gating and |
| 249 | thus are a key power management tool on many systems. |
| 250 | |
| 251 | config HAVE_DMA_API_DEBUG |
| 252 | bool |
| 253 | |
| 254 | config HAVE_HW_BREAKPOINT |
| 255 | bool |
| 256 | depends on PERF_EVENTS |
| 257 | |
| 258 | config HAVE_MIXED_BREAKPOINTS_REGS |
| 259 | bool |
| 260 | depends on HAVE_HW_BREAKPOINT |
| 261 | help |
| 262 | Depending on the arch implementation of hardware breakpoints, |
| 263 | some of them have separate registers for data and instruction |
| 264 | breakpoints addresses, others have mixed registers to store |
| 265 | them but define the access type in a control register. |
| 266 | Select this option if your arch implements breakpoints under the |
| 267 | latter fashion. |
| 268 | |
| 269 | config HAVE_USER_RETURN_NOTIFIER |
| 270 | bool |
| 271 | |
| 272 | config HAVE_PERF_EVENTS_NMI |
| 273 | bool |
| 274 | help |
| 275 | System hardware can generate an NMI using the perf event |
| 276 | subsystem. Also has support for calculating CPU cycle events |
| 277 | to determine how many clock cycles in a given period. |
| 278 | |
| 279 | config HAVE_PERF_REGS |
| 280 | bool |
| 281 | help |
| 282 | Support selective register dumps for perf events. This includes |
| 283 | bit-mapping of each registers and a unique architecture id. |
| 284 | |
| 285 | config HAVE_PERF_USER_STACK_DUMP |
| 286 | bool |
| 287 | help |
| 288 | Support user stack dumps for perf event samples. This needs |
| 289 | access to the user stack pointer which is not unified across |
| 290 | architectures. |
| 291 | |
| 292 | config HAVE_ARCH_JUMP_LABEL |
| 293 | bool |
| 294 | |
| 295 | config HAVE_RCU_TABLE_FREE |
| 296 | bool |
| 297 | |
| 298 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
| 299 | bool |
| 300 | |
| 301 | config HAVE_ALIGNED_STRUCT_PAGE |
| 302 | bool |
| 303 | help |
| 304 | This makes sure that struct pages are double word aligned and that |
| 305 | e.g. the SLUB allocator can perform double word atomic operations |
| 306 | on a struct page for better performance. However selecting this |
| 307 | might increase the size of a struct page by a word. |
| 308 | |
| 309 | config HAVE_CMPXCHG_LOCAL |
| 310 | bool |
| 311 | |
| 312 | config HAVE_CMPXCHG_DOUBLE |
| 313 | bool |
| 314 | |
| 315 | config ARCH_WANT_IPC_PARSE_VERSION |
| 316 | bool |
| 317 | |
| 318 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
| 319 | bool |
| 320 | |
| 321 | config ARCH_WANT_OLD_COMPAT_IPC |
| 322 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
| 323 | bool |
| 324 | |
| 325 | config HAVE_ARCH_SECCOMP_FILTER |
| 326 | bool |
| 327 | help |
| 328 | An arch should select this symbol if it provides all of these things: |
| 329 | - syscall_get_arch() |
| 330 | - syscall_get_arguments() |
| 331 | - syscall_rollback() |
| 332 | - syscall_set_return_value() |
| 333 | - SIGSYS siginfo_t support |
| 334 | - secure_computing is called from a ptrace_event()-safe context |
| 335 | - secure_computing return value is checked and a return value of -1 |
| 336 | results in the system call being skipped immediately. |
| 337 | - seccomp syscall wired up |
| 338 | |
| 339 | For best performance, an arch should use seccomp_phase1 and |
| 340 | seccomp_phase2 directly. It should call seccomp_phase1 for all |
| 341 | syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not |
| 342 | need to be called from a ptrace-safe context. It must then |
| 343 | call seccomp_phase2 if seccomp_phase1 returns anything other |
| 344 | than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP. |
| 345 | |
| 346 | As an additional optimization, an arch may provide seccomp_data |
| 347 | directly to seccomp_phase1; this avoids multiple calls |
| 348 | to the syscall_xyz helpers for every syscall. |
| 349 | |
| 350 | config SECCOMP_FILTER |
| 351 | def_bool y |
| 352 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET |
| 353 | help |
| 354 | Enable tasks to build secure computing environments defined |
| 355 | in terms of Berkeley Packet Filter programs which implement |
| 356 | task-defined system call filtering polices. |
| 357 | |
| 358 | See Documentation/prctl/seccomp_filter.txt for details. |
| 359 | |
| 360 | config HAVE_CC_STACKPROTECTOR |
| 361 | bool |
| 362 | help |
| 363 | An arch should select this symbol if: |
| 364 | - its compiler supports the -fstack-protector option |
| 365 | - it has implemented a stack canary (e.g. __stack_chk_guard) |
| 366 | |
| 367 | config CC_STACKPROTECTOR |
| 368 | def_bool n |
| 369 | help |
| 370 | Set when a stack-protector mode is enabled, so that the build |
| 371 | can enable kernel-side support for the GCC feature. |
| 372 | |
| 373 | choice |
| 374 | prompt "Stack Protector buffer overflow detection" |
| 375 | depends on HAVE_CC_STACKPROTECTOR |
| 376 | default CC_STACKPROTECTOR_NONE |
| 377 | help |
| 378 | This option turns on the "stack-protector" GCC feature. This |
| 379 | feature puts, at the beginning of functions, a canary value on |
| 380 | the stack just before the return address, and validates |
| 381 | the value just before actually returning. Stack based buffer |
| 382 | overflows (that need to overwrite this return address) now also |
| 383 | overwrite the canary, which gets detected and the attack is then |
| 384 | neutralized via a kernel panic. |
| 385 | |
| 386 | config CC_STACKPROTECTOR_NONE |
| 387 | bool "None" |
| 388 | help |
| 389 | Disable "stack-protector" GCC feature. |
| 390 | |
| 391 | config CC_STACKPROTECTOR_REGULAR |
| 392 | bool "Regular" |
| 393 | select CC_STACKPROTECTOR |
| 394 | help |
| 395 | Functions will have the stack-protector canary logic added if they |
| 396 | have an 8-byte or larger character array on the stack. |
| 397 | |
| 398 | This feature requires gcc version 4.2 or above, or a distribution |
| 399 | gcc with the feature backported ("-fstack-protector"). |
| 400 | |
| 401 | On an x86 "defconfig" build, this feature adds canary checks to |
| 402 | about 3% of all kernel functions, which increases kernel code size |
| 403 | by about 0.3%. |
| 404 | |
| 405 | config CC_STACKPROTECTOR_STRONG |
| 406 | bool "Strong" |
| 407 | select CC_STACKPROTECTOR |
| 408 | help |
| 409 | Functions will have the stack-protector canary logic added in any |
| 410 | of the following conditions: |
| 411 | |
| 412 | - local variable's address used as part of the right hand side of an |
| 413 | assignment or function argument |
| 414 | - local variable is an array (or union containing an array), |
| 415 | regardless of array type or length |
| 416 | - uses register local variables |
| 417 | |
| 418 | This feature requires gcc version 4.9 or above, or a distribution |
| 419 | gcc with the feature backported ("-fstack-protector-strong"). |
| 420 | |
| 421 | On an x86 "defconfig" build, this feature adds canary checks to |
| 422 | about 20% of all kernel functions, which increases the kernel code |
| 423 | size by about 2%. |
| 424 | |
| 425 | endchoice |
| 426 | |
| 427 | config HAVE_CONTEXT_TRACKING |
| 428 | bool |
| 429 | help |
| 430 | Provide kernel/user boundaries probes necessary for subsystems |
| 431 | that need it, such as userspace RCU extended quiescent state. |
| 432 | Syscalls need to be wrapped inside user_exit()-user_enter() through |
| 433 | the slow path using TIF_NOHZ flag. Exceptions handlers must be |
| 434 | wrapped as well. Irqs are already protected inside |
| 435 | rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on |
| 436 | irq exit still need to be protected. |
| 437 | |
| 438 | config HAVE_VIRT_CPU_ACCOUNTING |
| 439 | bool |
| 440 | |
| 441 | config HAVE_VIRT_CPU_ACCOUNTING_GEN |
| 442 | bool |
| 443 | default y if 64BIT |
| 444 | help |
| 445 | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. |
| 446 | Before enabling this option, arch code must be audited |
| 447 | to ensure there are no races in concurrent read/write of |
| 448 | cputime_t. For example, reading/writing 64-bit cputime_t on |
| 449 | some 32-bit arches may require multiple accesses, so proper |
| 450 | locking is needed to protect against concurrent accesses. |
| 451 | |
| 452 | |
| 453 | config HAVE_IRQ_TIME_ACCOUNTING |
| 454 | bool |
| 455 | help |
| 456 | Archs need to ensure they use a high enough resolution clock to |
| 457 | support irq time accounting and then call enable_sched_clock_irqtime(). |
| 458 | |
| 459 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
| 460 | bool |
| 461 | |
| 462 | config HAVE_ARCH_HUGE_VMAP |
| 463 | bool |
| 464 | |
| 465 | config HAVE_ARCH_SOFT_DIRTY |
| 466 | bool |
| 467 | |
| 468 | config HAVE_MOD_ARCH_SPECIFIC |
| 469 | bool |
| 470 | help |
| 471 | The arch uses struct mod_arch_specific to store data. Many arches |
| 472 | just need a simple module loader without arch specific data - those |
| 473 | should not enable this. |
| 474 | |
| 475 | config MODULES_USE_ELF_RELA |
| 476 | bool |
| 477 | help |
| 478 | Modules only use ELF RELA relocations. Modules with ELF REL |
| 479 | relocations will give an error. |
| 480 | |
| 481 | config MODULES_USE_ELF_REL |
| 482 | bool |
| 483 | help |
| 484 | Modules only use ELF REL relocations. Modules with ELF RELA |
| 485 | relocations will give an error. |
| 486 | |
| 487 | config HAVE_UNDERSCORE_SYMBOL_PREFIX |
| 488 | bool |
| 489 | help |
| 490 | Some architectures generate an _ in front of C symbols; things like |
| 491 | module loading and assembly files need to know about this. |
| 492 | |
| 493 | config HAVE_IRQ_EXIT_ON_IRQ_STACK |
| 494 | bool |
| 495 | help |
| 496 | Architecture doesn't only execute the irq handler on the irq stack |
| 497 | but also irq_exit(). This way we can process softirqs on this irq |
| 498 | stack instead of switching to a new one when we call __do_softirq() |
| 499 | in the end of an hardirq. |
| 500 | This spares a stack switch and improves cache usage on softirq |
| 501 | processing. |
| 502 | |
| 503 | config PGTABLE_LEVELS |
| 504 | int |
| 505 | default 2 |
| 506 | |
| 507 | config ARCH_HAS_ELF_RANDOMIZE |
| 508 | bool |
| 509 | help |
| 510 | An architecture supports choosing randomized locations for |
| 511 | stack, mmap, brk, and ET_DYN. Defined functions: |
| 512 | - arch_mmap_rnd() |
| 513 | - arch_randomize_brk() |
| 514 | |
| 515 | config HAVE_ARCH_MMAP_RND_BITS |
| 516 | bool |
| 517 | help |
| 518 | An arch should select this symbol if it supports setting a variable |
| 519 | number of bits for use in establishing the base address for mmap |
| 520 | allocations, has MMU enabled and provides values for both: |
| 521 | - ARCH_MMAP_RND_BITS_MIN |
| 522 | - ARCH_MMAP_RND_BITS_MAX |
| 523 | |
| 524 | config HAVE_EXIT_THREAD |
| 525 | bool |
| 526 | help |
| 527 | An architecture implements exit_thread. |
| 528 | |
| 529 | config ARCH_MMAP_RND_BITS_MIN |
| 530 | int |
| 531 | |
| 532 | config ARCH_MMAP_RND_BITS_MAX |
| 533 | int |
| 534 | |
| 535 | config ARCH_MMAP_RND_BITS_DEFAULT |
| 536 | int |
| 537 | |
| 538 | config ARCH_MMAP_RND_BITS |
| 539 | int "Number of bits to use for ASLR of mmap base address" if EXPERT |
| 540 | range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX |
| 541 | default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT |
| 542 | default ARCH_MMAP_RND_BITS_MIN |
| 543 | depends on HAVE_ARCH_MMAP_RND_BITS |
| 544 | help |
| 545 | This value can be used to select the number of bits to use to |
| 546 | determine the random offset to the base address of vma regions |
| 547 | resulting from mmap allocations. This value will be bounded |
| 548 | by the architecture's minimum and maximum supported values. |
| 549 | |
| 550 | This value can be changed after boot using the |
| 551 | /proc/sys/vm/mmap_rnd_bits tunable |
| 552 | |
| 553 | config HAVE_ARCH_MMAP_RND_COMPAT_BITS |
| 554 | bool |
| 555 | help |
| 556 | An arch should select this symbol if it supports running applications |
| 557 | in compatibility mode, supports setting a variable number of bits for |
| 558 | use in establishing the base address for mmap allocations, has MMU |
| 559 | enabled and provides values for both: |
| 560 | - ARCH_MMAP_RND_COMPAT_BITS_MIN |
| 561 | - ARCH_MMAP_RND_COMPAT_BITS_MAX |
| 562 | |
| 563 | config ARCH_MMAP_RND_COMPAT_BITS_MIN |
| 564 | int |
| 565 | |
| 566 | config ARCH_MMAP_RND_COMPAT_BITS_MAX |
| 567 | int |
| 568 | |
| 569 | config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT |
| 570 | int |
| 571 | |
| 572 | config ARCH_MMAP_RND_COMPAT_BITS |
| 573 | int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT |
| 574 | range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX |
| 575 | default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT |
| 576 | default ARCH_MMAP_RND_COMPAT_BITS_MIN |
| 577 | depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS |
| 578 | help |
| 579 | This value can be used to select the number of bits to use to |
| 580 | determine the random offset to the base address of vma regions |
| 581 | resulting from mmap allocations for compatible applications This |
| 582 | value will be bounded by the architecture's minimum and maximum |
| 583 | supported values. |
| 584 | |
| 585 | This value can be changed after boot using the |
| 586 | /proc/sys/vm/mmap_rnd_compat_bits tunable |
| 587 | |
| 588 | config HAVE_COPY_THREAD_TLS |
| 589 | bool |
| 590 | help |
| 591 | Architecture provides copy_thread_tls to accept tls argument via |
| 592 | normal C parameter passing, rather than extracting the syscall |
| 593 | argument from pt_regs. |
| 594 | |
| 595 | config HAVE_STACK_VALIDATION |
| 596 | bool |
| 597 | help |
| 598 | Architecture supports the 'objtool check' host tool command, which |
| 599 | performs compile-time stack metadata validation. |
| 600 | |
| 601 | config HAVE_ARCH_HASH |
| 602 | bool |
| 603 | default n |
| 604 | help |
| 605 | If this is set, the architecture provides an <asm/hash.h> |
| 606 | file which provides platform-specific implementations of some |
| 607 | functions in <linux/hash.h> or fs/namei.c. |
| 608 | |
| 609 | config ISA_BUS_API |
| 610 | def_bool ISA |
| 611 | |
| 612 | # |
| 613 | # ABI hall of shame |
| 614 | # |
| 615 | config CLONE_BACKWARDS |
| 616 | bool |
| 617 | help |
| 618 | Architecture has tls passed as the 4th argument of clone(2), |
| 619 | not the 5th one. |
| 620 | |
| 621 | config CLONE_BACKWARDS2 |
| 622 | bool |
| 623 | help |
| 624 | Architecture has the first two arguments of clone(2) swapped. |
| 625 | |
| 626 | config CLONE_BACKWARDS3 |
| 627 | bool |
| 628 | help |
| 629 | Architecture has tls passed as the 3rd argument of clone(2), |
| 630 | not the 5th one. |
| 631 | |
| 632 | config ODD_RT_SIGACTION |
| 633 | bool |
| 634 | help |
| 635 | Architecture has unusual rt_sigaction(2) arguments |
| 636 | |
| 637 | config OLD_SIGSUSPEND |
| 638 | bool |
| 639 | help |
| 640 | Architecture has old sigsuspend(2) syscall, of one-argument variety |
| 641 | |
| 642 | config OLD_SIGSUSPEND3 |
| 643 | bool |
| 644 | help |
| 645 | Even weirder antique ABI - three-argument sigsuspend(2) |
| 646 | |
| 647 | config OLD_SIGACTION |
| 648 | bool |
| 649 | help |
| 650 | Architecture has old sigaction(2) syscall. Nope, not the same |
| 651 | as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), |
| 652 | but fairly different variant of sigaction(2), thanks to OSF/1 |
| 653 | compatibility... |
| 654 | |
| 655 | config COMPAT_OLD_SIGACTION |
| 656 | bool |
| 657 | |
| 658 | config ARCH_NO_COHERENT_DMA_MMAP |
| 659 | bool |
| 660 | |
| 661 | config CPU_NO_EFFICIENT_FFS |
| 662 | def_bool n |
| 663 | |
| 664 | source "kernel/gcov/Kconfig" |