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 HAVE_EFFICIENT_UNALIGNED_ACCESS 80 bool 81 help 82 Some architectures are unable to perform unaligned accesses 83 without the use of get_unaligned/put_unaligned. Others are 84 unable to perform such accesses efficiently (e.g. trap on 85 unaligned access and require fixing it up in the exception 86 handler.) 87 88 This symbol should be selected by an architecture if it can 89 perform unaligned accesses efficiently to allow different 90 code paths to be selected for these cases. Some network 91 drivers, for example, could opt to not fix up alignment 92 problems with received packets if doing so would not help 93 much. 94 95 See Documentation/unaligned-memory-access.txt for more 96 information on the topic of unaligned memory accesses. 97 98config HAVE_SYSCALL_WRAPPERS 99 bool 100 101config KRETPROBES 102 def_bool y 103 depends on KPROBES && HAVE_KRETPROBES 104 105config USER_RETURN_NOTIFIER 106 bool 107 depends on HAVE_USER_RETURN_NOTIFIER 108 help 109 Provide a kernel-internal notification when a cpu is about to 110 switch to user mode. 111 112config HAVE_IOREMAP_PROT 113 bool 114 115config HAVE_KPROBES 116 bool 117 118config HAVE_KRETPROBES 119 bool 120 121config HAVE_OPTPROBES 122 bool 123 124config HAVE_NMI_WATCHDOG 125 bool 126# 127# An arch should select this if it provides all these things: 128# 129# task_pt_regs() in asm/processor.h or asm/ptrace.h 130# arch_has_single_step() if there is hardware single-step support 131# arch_has_block_step() if there is hardware block-step support 132# asm/syscall.h supplying asm-generic/syscall.h interface 133# linux/regset.h user_regset interfaces 134# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 135# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 136# TIF_NOTIFY_RESUME calls tracehook_notify_resume() 137# signal delivery calls tracehook_signal_handler() 138# 139config HAVE_ARCH_TRACEHOOK 140 bool 141 142config HAVE_DMA_ATTRS 143 bool 144 145config USE_GENERIC_SMP_HELPERS 146 bool 147 148config GENERIC_SMP_IDLE_THREAD 149 bool 150 151# Select if arch init_task initializer is different to init/init_task.c 152config ARCH_INIT_TASK 153 bool 154 155# Select if arch has its private alloc_task_struct() function 156config ARCH_TASK_STRUCT_ALLOCATOR 157 bool 158 159# Select if arch has its private alloc_thread_info() function 160config ARCH_THREAD_INFO_ALLOCATOR 161 bool 162 163config HAVE_REGS_AND_STACK_ACCESS_API 164 bool 165 help 166 This symbol should be selected by an architecure if it supports 167 the API needed to access registers and stack entries from pt_regs, 168 declared in asm/ptrace.h 169 For example the kprobes-based event tracer needs this API. 170 171config HAVE_CLK 172 bool 173 help 174 The <linux/clk.h> calls support software clock gating and 175 thus are a key power management tool on many systems. 176 177config HAVE_DMA_API_DEBUG 178 bool 179 180config HAVE_HW_BREAKPOINT 181 bool 182 depends on PERF_EVENTS 183 184config HAVE_MIXED_BREAKPOINTS_REGS 185 bool 186 depends on HAVE_HW_BREAKPOINT 187 help 188 Depending on the arch implementation of hardware breakpoints, 189 some of them have separate registers for data and instruction 190 breakpoints addresses, others have mixed registers to store 191 them but define the access type in a control register. 192 Select this option if your arch implements breakpoints under the 193 latter fashion. 194 195config HAVE_USER_RETURN_NOTIFIER 196 bool 197 198config HAVE_PERF_EVENTS_NMI 199 bool 200 help 201 System hardware can generate an NMI using the perf event 202 subsystem. Also has support for calculating CPU cycle events 203 to determine how many clock cycles in a given period. 204 205config HAVE_ARCH_JUMP_LABEL 206 bool 207 208config HAVE_ARCH_MUTEX_CPU_RELAX 209 bool 210 211config HAVE_RCU_TABLE_FREE 212 bool 213 214config ARCH_HAVE_NMI_SAFE_CMPXCHG 215 bool 216 217config HAVE_ALIGNED_STRUCT_PAGE 218 bool 219 help 220 This makes sure that struct pages are double word aligned and that 221 e.g. the SLUB allocator can perform double word atomic operations 222 on a struct page for better performance. However selecting this 223 might increase the size of a struct page by a word. 224 225config HAVE_CMPXCHG_LOCAL 226 bool 227 228config HAVE_CMPXCHG_DOUBLE 229 bool 230 231config ARCH_WANT_OLD_COMPAT_IPC 232 bool 233 234config HAVE_ARCH_SECCOMP_FILTER 235 bool 236 help 237 An arch should select this symbol if it provides all of these things: 238 - syscall_get_arch() 239 - syscall_get_arguments() 240 - syscall_rollback() 241 - syscall_set_return_value() 242 - SIGSYS siginfo_t support 243 - secure_computing is called from a ptrace_event()-safe context 244 - secure_computing return value is checked and a return value of -1 245 results in the system call being skipped immediately. 246 247config SECCOMP_FILTER 248 def_bool y 249 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 250 help 251 Enable tasks to build secure computing environments defined 252 in terms of Berkeley Packet Filter programs which implement 253 task-defined system call filtering polices. 254 255 See Documentation/prctl/seccomp_filter.txt for details. 256 257source "kernel/gcov/Kconfig" 258