Kconfig 5.9 KB

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  1. #
  2. # General architecture dependent options
  3. #
  4. config OPROFILE
  5. tristate "OProfile system profiling"
  6. depends on PROFILING
  7. depends on HAVE_OPROFILE
  8. select RING_BUFFER
  9. select RING_BUFFER_ALLOW_SWAP
  10. help
  11. OProfile is a profiling system capable of profiling the
  12. whole system, include the kernel, kernel modules, libraries,
  13. and applications.
  14. If unsure, say N.
  15. config OPROFILE_EVENT_MULTIPLEX
  16. bool "OProfile multiplexing support (EXPERIMENTAL)"
  17. default n
  18. depends on OPROFILE && X86
  19. help
  20. The number of hardware counters is limited. The multiplexing
  21. feature enables OProfile to gather more events than counters
  22. are provided by the hardware. This is realized by switching
  23. between events at an user specified time interval.
  24. If unsure, say N.
  25. config HAVE_OPROFILE
  26. bool
  27. config OPROFILE_NMI_TIMER
  28. def_bool y
  29. depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
  30. config KPROBES
  31. bool "Kprobes"
  32. depends on MODULES
  33. depends on HAVE_KPROBES
  34. select KALLSYMS
  35. help
  36. Kprobes allows you to trap at almost any kernel address and
  37. execute a callback function. register_kprobe() establishes
  38. a probepoint and specifies the callback. Kprobes is useful
  39. for kernel debugging, non-intrusive instrumentation and testing.
  40. If in doubt, say "N".
  41. config JUMP_LABEL
  42. bool "Optimize very unlikely/likely branches"
  43. depends on HAVE_ARCH_JUMP_LABEL
  44. help
  45. This option enables a transparent branch optimization that
  46. makes certain almost-always-true or almost-always-false branch
  47. conditions even cheaper to execute within the kernel.
  48. Certain performance-sensitive kernel code, such as trace points,
  49. scheduler functionality, networking code and KVM have such
  50. branches and include support for this optimization technique.
  51. If it is detected that the compiler has support for "asm goto",
  52. the kernel will compile such branches with just a nop
  53. instruction. When the condition flag is toggled to true, the
  54. nop will be converted to a jump instruction to execute the
  55. conditional block of instructions.
  56. This technique lowers overhead and stress on the branch prediction
  57. of the processor and generally makes the kernel faster. The update
  58. of the condition is slower, but those are always very rare.
  59. ( On 32-bit x86, the necessary options added to the compiler
  60. flags may increase the size of the kernel slightly. )
  61. config OPTPROBES
  62. def_bool y
  63. depends on KPROBES && HAVE_OPTPROBES
  64. depends on !PREEMPT
  65. config HAVE_EFFICIENT_UNALIGNED_ACCESS
  66. bool
  67. help
  68. Some architectures are unable to perform unaligned accesses
  69. without the use of get_unaligned/put_unaligned. Others are
  70. unable to perform such accesses efficiently (e.g. trap on
  71. unaligned access and require fixing it up in the exception
  72. handler.)
  73. This symbol should be selected by an architecture if it can
  74. perform unaligned accesses efficiently to allow different
  75. code paths to be selected for these cases. Some network
  76. drivers, for example, could opt to not fix up alignment
  77. problems with received packets if doing so would not help
  78. much.
  79. See Documentation/unaligned-memory-access.txt for more
  80. information on the topic of unaligned memory accesses.
  81. config HAVE_SYSCALL_WRAPPERS
  82. bool
  83. config KRETPROBES
  84. def_bool y
  85. depends on KPROBES && HAVE_KRETPROBES
  86. config USER_RETURN_NOTIFIER
  87. bool
  88. depends on HAVE_USER_RETURN_NOTIFIER
  89. help
  90. Provide a kernel-internal notification when a cpu is about to
  91. switch to user mode.
  92. config HAVE_IOREMAP_PROT
  93. bool
  94. config HAVE_KPROBES
  95. bool
  96. config HAVE_KRETPROBES
  97. bool
  98. config HAVE_OPTPROBES
  99. bool
  100. #
  101. # An arch should select this if it provides all these things:
  102. #
  103. # task_pt_regs() in asm/processor.h or asm/ptrace.h
  104. # arch_has_single_step() if there is hardware single-step support
  105. # arch_has_block_step() if there is hardware block-step support
  106. # asm/syscall.h supplying asm-generic/syscall.h interface
  107. # linux/regset.h user_regset interfaces
  108. # CORE_DUMP_USE_REGSET #define'd in linux/elf.h
  109. # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
  110. # TIF_NOTIFY_RESUME calls tracehook_notify_resume()
  111. # signal delivery calls tracehook_signal_handler()
  112. #
  113. config HAVE_ARCH_TRACEHOOK
  114. bool
  115. config HAVE_DMA_ATTRS
  116. bool
  117. config USE_GENERIC_SMP_HELPERS
  118. bool
  119. config HAVE_REGS_AND_STACK_ACCESS_API
  120. bool
  121. help
  122. This symbol should be selected by an architecure if it supports
  123. the API needed to access registers and stack entries from pt_regs,
  124. declared in asm/ptrace.h
  125. For example the kprobes-based event tracer needs this API.
  126. config HAVE_CLK
  127. bool
  128. help
  129. The <linux/clk.h> calls support software clock gating and
  130. thus are a key power management tool on many systems.
  131. config HAVE_DMA_API_DEBUG
  132. bool
  133. config HAVE_HW_BREAKPOINT
  134. bool
  135. depends on PERF_EVENTS
  136. config HAVE_MIXED_BREAKPOINTS_REGS
  137. bool
  138. depends on HAVE_HW_BREAKPOINT
  139. help
  140. Depending on the arch implementation of hardware breakpoints,
  141. some of them have separate registers for data and instruction
  142. breakpoints addresses, others have mixed registers to store
  143. them but define the access type in a control register.
  144. Select this option if your arch implements breakpoints under the
  145. latter fashion.
  146. config HAVE_USER_RETURN_NOTIFIER
  147. bool
  148. config HAVE_PERF_EVENTS_NMI
  149. bool
  150. help
  151. System hardware can generate an NMI using the perf event
  152. subsystem. Also has support for calculating CPU cycle events
  153. to determine how many clock cycles in a given period.
  154. config HAVE_ARCH_JUMP_LABEL
  155. bool
  156. config HAVE_ARCH_MUTEX_CPU_RELAX
  157. bool
  158. config HAVE_RCU_TABLE_FREE
  159. bool
  160. config ARCH_HAVE_NMI_SAFE_CMPXCHG
  161. bool
  162. config HAVE_ALIGNED_STRUCT_PAGE
  163. bool
  164. help
  165. This makes sure that struct pages are double word aligned and that
  166. e.g. the SLUB allocator can perform double word atomic operations
  167. on a struct page for better performance. However selecting this
  168. might increase the size of a struct page by a word.
  169. config HAVE_CMPXCHG_LOCAL
  170. bool
  171. config HAVE_CMPXCHG_DOUBLE
  172. bool
  173. source "kernel/gcov/Kconfig"