1# 2# General architecture dependent options 3# 4 5config OPROFILE 6 tristate "OProfile system profiling" 7 depends on PROFILING 8 depends on HAVE_OPROFILE 9 select RING_BUFFER 10 select RING_BUFFER_ALLOW_SWAP 11 help 12 OProfile is a profiling system capable of profiling the 13 whole system, include the kernel, kernel modules, libraries, 14 and applications. 15 16 If unsure, say N. 17 18config OPROFILE_EVENT_MULTIPLEX 19 bool "OProfile multiplexing support (EXPERIMENTAL)" 20 default n 21 depends on OPROFILE && X86 22 help 23 The number of hardware counters is limited. The multiplexing 24 feature enables OProfile to gather more events than counters 25 are provided by the hardware. This is realized by switching 26 between events at an user specified time interval. 27 28 If unsure, say N. 29 30config HAVE_OPROFILE 31 bool 32 33config OPROFILE_NMI_TIMER 34 def_bool y 35 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI 36 37config KPROBES 38 bool "Kprobes" 39 depends on MODULES 40 depends on HAVE_KPROBES 41 select KALLSYMS 42 help 43 Kprobes allows you to trap at almost any kernel address and 44 execute a callback function. register_kprobe() establishes 45 a probepoint and specifies the callback. Kprobes is useful 46 for kernel debugging, non-intrusive instrumentation and testing. 47 If in doubt, say "N". 48 49config JUMP_LABEL 50 bool "Optimize very unlikely/likely branches" 51 depends on HAVE_ARCH_JUMP_LABEL 52 help 53 This option enables a transparent branch optimization that 54 makes certain almost-always-true or almost-always-false branch 55 conditions even cheaper to execute within the kernel. 56 57 Certain performance-sensitive kernel code, such as trace points, 58 scheduler functionality, networking code and KVM have such 59 branches and include support for this optimization technique. 60 61 If it is detected that the compiler has support for "asm goto", 62 the kernel will compile such branches with just a nop 63 instruction. When the condition flag is toggled to true, the 64 nop will be converted to a jump instruction to execute the 65 conditional block of instructions. 66 67 This technique lowers overhead and stress on the branch prediction 68 of the processor and generally makes the kernel faster. The update 69 of the condition is slower, but those are always very rare. 70 71 ( On 32-bit x86, the necessary options added to the compiler 72 flags may increase the size of the kernel slightly. ) 73 74config OPTPROBES 75 def_bool y 76 depends on KPROBES && HAVE_OPTPROBES 77 depends on !PREEMPT 78 79config UPROBES 80 bool "Transparent user-space probes (EXPERIMENTAL)" 81 depends on UPROBE_EVENT && PERF_EVENTS 82 default n 83 help 84 Uprobes is the user-space counterpart to kprobes: they 85 enable instrumentation applications (such as 'perf probe') 86 to establish unintrusive probes in user-space binaries and 87 libraries, by executing handler functions when the probes 88 are hit by user-space applications. 89 90 ( These probes come in the form of single-byte breakpoints, 91 managed by the kernel and kept transparent to the probed 92 application. ) 93 94 If in doubt, say "N". 95 96config HAVE_EFFICIENT_UNALIGNED_ACCESS 97 bool 98 help 99 Some architectures are unable to perform unaligned accesses 100 without the use of get_unaligned/put_unaligned. Others are 101 unable to perform such accesses efficiently (e.g. trap on 102 unaligned access and require fixing it up in the exception 103 handler.) 104 105 This symbol should be selected by an architecture if it can 106 perform unaligned accesses efficiently to allow different 107 code paths to be selected for these cases. Some network 108 drivers, for example, could opt to not fix up alignment 109 problems with received packets if doing so would not help 110 much. 111 112 See Documentation/unaligned-memory-access.txt for more 113 information on the topic of unaligned memory accesses. 114 115config HAVE_SYSCALL_WRAPPERS 116 bool 117 118config KRETPROBES 119 def_bool y 120 depends on KPROBES && HAVE_KRETPROBES 121 122config USER_RETURN_NOTIFIER 123 bool 124 depends on HAVE_USER_RETURN_NOTIFIER 125 help 126 Provide a kernel-internal notification when a cpu is about to 127 switch to user mode. 128 129config HAVE_IOREMAP_PROT 130 bool 131 132config HAVE_KPROBES 133 bool 134 135config HAVE_KRETPROBES 136 bool 137 138config HAVE_OPTPROBES 139 bool 140 141config HAVE_NMI_WATCHDOG 142 bool 143# 144# An arch should select this if it provides all these things: 145# 146# task_pt_regs() in asm/processor.h or asm/ptrace.h 147# arch_has_single_step() if there is hardware single-step support 148# arch_has_block_step() if there is hardware block-step support 149# asm/syscall.h supplying asm-generic/syscall.h interface 150# linux/regset.h user_regset interfaces 151# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 152# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 153# TIF_NOTIFY_RESUME calls tracehook_notify_resume() 154# signal delivery calls tracehook_signal_handler() 155# 156config HAVE_ARCH_TRACEHOOK 157 bool 158 159config HAVE_DMA_ATTRS 160 bool 161 162config HAVE_DMA_CONTIGUOUS 163 bool 164 165config USE_GENERIC_SMP_HELPERS 166 bool 167 168config GENERIC_SMP_IDLE_THREAD 169 bool 170 171# Select if arch init_task initializer is different to init/init_task.c 172config ARCH_INIT_TASK 173 bool 174 175# Select if arch has its private alloc_task_struct() function 176config ARCH_TASK_STRUCT_ALLOCATOR 177 bool 178 179# Select if arch has its private alloc_thread_info() function 180config ARCH_THREAD_INFO_ALLOCATOR 181 bool 182 183config HAVE_REGS_AND_STACK_ACCESS_API 184 bool 185 help 186 This symbol should be selected by an architecure if it supports 187 the API needed to access registers and stack entries from pt_regs, 188 declared in asm/ptrace.h 189 For example the kprobes-based event tracer needs this API. 190 191config HAVE_CLK 192 bool 193 help 194 The <linux/clk.h> calls support software clock gating and 195 thus are a key power management tool on many systems. 196 197config HAVE_DMA_API_DEBUG 198 bool 199 200config HAVE_HW_BREAKPOINT 201 bool 202 depends on PERF_EVENTS 203 204config HAVE_MIXED_BREAKPOINTS_REGS 205 bool 206 depends on HAVE_HW_BREAKPOINT 207 help 208 Depending on the arch implementation of hardware breakpoints, 209 some of them have separate registers for data and instruction 210 breakpoints addresses, others have mixed registers to store 211 them but define the access type in a control register. 212 Select this option if your arch implements breakpoints under the 213 latter fashion. 214 215config HAVE_USER_RETURN_NOTIFIER 216 bool 217 218config HAVE_PERF_EVENTS_NMI 219 bool 220 help 221 System hardware can generate an NMI using the perf event 222 subsystem. Also has support for calculating CPU cycle events 223 to determine how many clock cycles in a given period. 224 225config HAVE_PERF_REGS 226 bool 227 help 228 Support selective register dumps for perf events. This includes 229 bit-mapping of each registers and a unique architecture id. 230 231config HAVE_PERF_USER_STACK_DUMP 232 bool 233 help 234 Support user stack dumps for perf event samples. This needs 235 access to the user stack pointer which is not unified across 236 architectures. 237 238config HAVE_ARCH_JUMP_LABEL 239 bool 240 241config HAVE_ARCH_MUTEX_CPU_RELAX 242 bool 243 244config HAVE_RCU_TABLE_FREE 245 bool 246 247config ARCH_HAVE_NMI_SAFE_CMPXCHG 248 bool 249 250config HAVE_ALIGNED_STRUCT_PAGE 251 bool 252 help 253 This makes sure that struct pages are double word aligned and that 254 e.g. the SLUB allocator can perform double word atomic operations 255 on a struct page for better performance. However selecting this 256 might increase the size of a struct page by a word. 257 258config HAVE_CMPXCHG_LOCAL 259 bool 260 261config HAVE_CMPXCHG_DOUBLE 262 bool 263 264config ARCH_WANT_IPC_PARSE_VERSION 265 bool 266 267config ARCH_WANT_COMPAT_IPC_PARSE_VERSION 268 bool 269 270config ARCH_WANT_OLD_COMPAT_IPC 271 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 272 bool 273 274config GENERIC_KERNEL_THREAD 275 bool 276 277config GENERIC_KERNEL_EXECVE 278 bool 279 280config HAVE_ARCH_SECCOMP_FILTER 281 bool 282 help 283 An arch should select this symbol if it provides all of these things: 284 - syscall_get_arch() 285 - syscall_get_arguments() 286 - syscall_rollback() 287 - syscall_set_return_value() 288 - SIGSYS siginfo_t support 289 - secure_computing is called from a ptrace_event()-safe context 290 - secure_computing return value is checked and a return value of -1 291 results in the system call being skipped immediately. 292 293config SECCOMP_FILTER 294 def_bool y 295 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 296 help 297 Enable tasks to build secure computing environments defined 298 in terms of Berkeley Packet Filter programs which implement 299 task-defined system call filtering polices. 300 301 See Documentation/prctl/seccomp_filter.txt for details. 302 303config HAVE_RCU_USER_QS 304 bool 305 help 306 Provide kernel entry/exit hooks necessary for userspace 307 RCU extended quiescent state. Syscalls need to be wrapped inside 308 rcu_user_exit()-rcu_user_enter() through the slow path using 309 TIF_NOHZ flag. Exceptions handlers must be wrapped as well. Irqs 310 are already protected inside rcu_irq_enter/rcu_irq_exit() but 311 preemption or signal handling on irq exit still need to be protected. 312 313config HAVE_VIRT_CPU_ACCOUNTING 314 bool 315 316config HAVE_IRQ_TIME_ACCOUNTING 317 bool 318 help 319 Archs need to ensure they use a high enough resolution clock to 320 support irq time accounting and then call enable_sched_clock_irqtime(). 321 322config HAVE_ARCH_TRANSPARENT_HUGEPAGE 323 bool 324 325config HAVE_MOD_ARCH_SPECIFIC 326 bool 327 help 328 The arch uses struct mod_arch_specific to store data. Many arches 329 just need a simple module loader without arch specific data - those 330 should not enable this. 331 332config MODULES_USE_ELF_RELA 333 bool 334 help 335 Modules only use ELF RELA relocations. Modules with ELF REL 336 relocations will give an error. 337 338config MODULES_USE_ELF_REL 339 bool 340 help 341 Modules only use ELF REL relocations. Modules with ELF RELA 342 relocations will give an error. 343 344source "kernel/gcov/Kconfig" 345