Kconfig.debug 8.1 KB

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  1. menu "Kernel hacking"
  2. config TRACE_IRQFLAGS_SUPPORT
  3. def_bool y
  4. source "lib/Kconfig.debug"
  5. config STRICT_DEVMEM
  6. bool "Filter access to /dev/mem"
  7. ---help---
  8. If this option is disabled, you allow userspace (root) access to all
  9. of memory, including kernel and userspace memory. Accidental
  10. access to this is obviously disastrous, but specific access can
  11. be used by people debugging the kernel. Note that with PAT support
  12. enabled, even in this case there are restrictions on /dev/mem
  13. use due to the cache aliasing requirements.
  14. If this option is switched on, the /dev/mem file only allows
  15. userspace access to PCI space and the BIOS code and data regions.
  16. This is sufficient for dosemu and X and all common users of
  17. /dev/mem.
  18. If in doubt, say Y.
  19. config X86_VERBOSE_BOOTUP
  20. bool "Enable verbose x86 bootup info messages"
  21. default y
  22. ---help---
  23. Enables the informational output from the decompression stage
  24. (e.g. bzImage) of the boot. If you disable this you will still
  25. see errors. Disable this if you want silent bootup.
  26. config EARLY_PRINTK
  27. bool "Early printk" if EMBEDDED
  28. default y
  29. ---help---
  30. Write kernel log output directly into the VGA buffer or to a serial
  31. port.
  32. This is useful for kernel debugging when your machine crashes very
  33. early before the console code is initialized. For normal operation
  34. it is not recommended because it looks ugly and doesn't cooperate
  35. with klogd/syslogd or the X server. You should normally N here,
  36. unless you want to debug such a crash.
  37. config EARLY_PRINTK_DBGP
  38. bool "Early printk via EHCI debug port"
  39. default n
  40. depends on EARLY_PRINTK && PCI
  41. ---help---
  42. Write kernel log output directly into the EHCI debug port.
  43. This is useful for kernel debugging when your machine crashes very
  44. early before the console code is initialized. For normal operation
  45. it is not recommended because it looks ugly and doesn't cooperate
  46. with klogd/syslogd or the X server. You should normally N here,
  47. unless you want to debug such a crash. You need usb debug device.
  48. config DEBUG_STACKOVERFLOW
  49. bool "Check for stack overflows"
  50. depends on DEBUG_KERNEL
  51. ---help---
  52. This option will cause messages to be printed if free stack space
  53. drops below a certain limit.
  54. config DEBUG_STACK_USAGE
  55. bool "Stack utilization instrumentation"
  56. depends on DEBUG_KERNEL
  57. ---help---
  58. Enables the display of the minimum amount of free stack which each
  59. task has ever had available in the sysrq-T and sysrq-P debug output.
  60. This option will slow down process creation somewhat.
  61. config DEBUG_PER_CPU_MAPS
  62. bool "Debug access to per_cpu maps"
  63. depends on DEBUG_KERNEL
  64. depends on SMP
  65. default n
  66. ---help---
  67. Say Y to verify that the per_cpu map being accessed has
  68. been setup. Adds a fair amount of code to kernel memory
  69. and decreases performance.
  70. Say N if unsure.
  71. config X86_PTDUMP
  72. bool "Export kernel pagetable layout to userspace via debugfs"
  73. depends on DEBUG_KERNEL
  74. select DEBUG_FS
  75. ---help---
  76. Say Y here if you want to show the kernel pagetable layout in a
  77. debugfs file. This information is only useful for kernel developers
  78. who are working in architecture specific areas of the kernel.
  79. It is probably not a good idea to enable this feature in a production
  80. kernel.
  81. If in doubt, say "N"
  82. config DEBUG_RODATA
  83. bool "Write protect kernel read-only data structures"
  84. default y
  85. depends on DEBUG_KERNEL
  86. ---help---
  87. Mark the kernel read-only data as write-protected in the pagetables,
  88. in order to catch accidental (and incorrect) writes to such const
  89. data. This is recommended so that we can catch kernel bugs sooner.
  90. If in doubt, say "Y".
  91. config DEBUG_RODATA_TEST
  92. bool "Testcase for the DEBUG_RODATA feature"
  93. depends on DEBUG_RODATA
  94. default y
  95. ---help---
  96. This option enables a testcase for the DEBUG_RODATA
  97. feature as well as for the change_page_attr() infrastructure.
  98. If in doubt, say "N"
  99. config DEBUG_NX_TEST
  100. tristate "Testcase for the NX non-executable stack feature"
  101. depends on DEBUG_KERNEL && m
  102. ---help---
  103. This option enables a testcase for the CPU NX capability
  104. and the software setup of this feature.
  105. If in doubt, say "N"
  106. config 4KSTACKS
  107. bool "Use 4Kb for kernel stacks instead of 8Kb"
  108. depends on X86_32
  109. ---help---
  110. If you say Y here the kernel will use a 4Kb stacksize for the
  111. kernel stack attached to each process/thread. This facilitates
  112. running more threads on a system and also reduces the pressure
  113. on the VM subsystem for higher order allocations. This option
  114. will also use IRQ stacks to compensate for the reduced stackspace.
  115. config DOUBLEFAULT
  116. default y
  117. bool "Enable doublefault exception handler" if EMBEDDED
  118. depends on X86_32
  119. ---help---
  120. This option allows trapping of rare doublefault exceptions that
  121. would otherwise cause a system to silently reboot. Disabling this
  122. option saves about 4k and might cause you much additional grey
  123. hair.
  124. config IOMMU_DEBUG
  125. bool "Enable IOMMU debugging"
  126. depends on GART_IOMMU && DEBUG_KERNEL
  127. depends on X86_64
  128. ---help---
  129. Force the IOMMU to on even when you have less than 4GB of
  130. memory and add debugging code. On overflow always panic. And
  131. allow to enable IOMMU leak tracing. Can be disabled at boot
  132. time with iommu=noforce. This will also enable scatter gather
  133. list merging. Currently not recommended for production
  134. code. When you use it make sure you have a big enough
  135. IOMMU/AGP aperture. Most of the options enabled by this can
  136. be set more finegrained using the iommu= command line
  137. options. See Documentation/x86_64/boot-options.txt for more
  138. details.
  139. config IOMMU_LEAK
  140. bool "IOMMU leak tracing"
  141. depends on DEBUG_KERNEL
  142. depends on IOMMU_DEBUG
  143. ---help---
  144. Add a simple leak tracer to the IOMMU code. This is useful when you
  145. are debugging a buggy device driver that leaks IOMMU mappings.
  146. config HAVE_MMIOTRACE_SUPPORT
  147. def_bool y
  148. #
  149. # IO delay types:
  150. #
  151. config IO_DELAY_TYPE_0X80
  152. int
  153. default "0"
  154. config IO_DELAY_TYPE_0XED
  155. int
  156. default "1"
  157. config IO_DELAY_TYPE_UDELAY
  158. int
  159. default "2"
  160. config IO_DELAY_TYPE_NONE
  161. int
  162. default "3"
  163. choice
  164. prompt "IO delay type"
  165. default IO_DELAY_0X80
  166. config IO_DELAY_0X80
  167. bool "port 0x80 based port-IO delay [recommended]"
  168. ---help---
  169. This is the traditional Linux IO delay used for in/out_p.
  170. It is the most tested hence safest selection here.
  171. config IO_DELAY_0XED
  172. bool "port 0xed based port-IO delay"
  173. ---help---
  174. Use port 0xed as the IO delay. This frees up port 0x80 which is
  175. often used as a hardware-debug port.
  176. config IO_DELAY_UDELAY
  177. bool "udelay based port-IO delay"
  178. ---help---
  179. Use udelay(2) as the IO delay method. This provides the delay
  180. while not having any side-effect on the IO port space.
  181. config IO_DELAY_NONE
  182. bool "no port-IO delay"
  183. ---help---
  184. No port-IO delay. Will break on old boxes that require port-IO
  185. delay for certain operations. Should work on most new machines.
  186. endchoice
  187. if IO_DELAY_0X80
  188. config DEFAULT_IO_DELAY_TYPE
  189. int
  190. default IO_DELAY_TYPE_0X80
  191. endif
  192. if IO_DELAY_0XED
  193. config DEFAULT_IO_DELAY_TYPE
  194. int
  195. default IO_DELAY_TYPE_0XED
  196. endif
  197. if IO_DELAY_UDELAY
  198. config DEFAULT_IO_DELAY_TYPE
  199. int
  200. default IO_DELAY_TYPE_UDELAY
  201. endif
  202. if IO_DELAY_NONE
  203. config DEFAULT_IO_DELAY_TYPE
  204. int
  205. default IO_DELAY_TYPE_NONE
  206. endif
  207. config DEBUG_BOOT_PARAMS
  208. bool "Debug boot parameters"
  209. depends on DEBUG_KERNEL
  210. depends on DEBUG_FS
  211. ---help---
  212. This option will cause struct boot_params to be exported via debugfs.
  213. config CPA_DEBUG
  214. bool "CPA self-test code"
  215. depends on DEBUG_KERNEL
  216. ---help---
  217. Do change_page_attr() self-tests every 30 seconds.
  218. config OPTIMIZE_INLINING
  219. bool "Allow gcc to uninline functions marked 'inline'"
  220. ---help---
  221. This option determines if the kernel forces gcc to inline the functions
  222. developers have marked 'inline'. Doing so takes away freedom from gcc to
  223. do what it thinks is best, which is desirable for the gcc 3.x series of
  224. compilers. The gcc 4.x series have a rewritten inlining algorithm and
  225. enabling this option will generate a smaller kernel there. Hopefully
  226. this algorithm is so good that allowing gcc 4.x and above to make the
  227. decision will become the default in the future. Until then this option
  228. is there to test gcc for this.
  229. If unsure, say N.
  230. endmenu