arch/x86/Kconfig.debug

   1 menu "Kernel hacking"
   2
   3 config TRACE_IRQFLAGS_SUPPORT
   4         def_bool y
   5
   6 source "lib/Kconfig.debug"
   7
   8 config EARLY_PRINTK
   9         bool "Early printk" if EMBEDDED
  10         default y
  11         help
  12           Write kernel log output directly into the VGA buffer or to a serial
  13           port.
  14
  15           This is useful for kernel debugging when your machine crashes very
  16           early before the console code is initialized. For normal operation
  17           it is not recommended because it looks ugly and doesn't cooperate
  18           with klogd/syslogd or the X server. You should normally N here,
  19           unless you want to debug such a crash.
  20
  21 config DEBUG_STACKOVERFLOW
  22         bool "Check for stack overflows"
  23         depends on DEBUG_KERNEL
  24         help
  25           This option will cause messages to be printed if free stack space
  26           drops below a certain limit.
  27
  28 config DEBUG_STACK_USAGE
  29         bool "Stack utilization instrumentation"
  30         depends on DEBUG_KERNEL
  31         help
  32           Enables the display of the minimum amount of free stack which each
  33           task has ever had available in the sysrq-T and sysrq-P debug output.
  34
  35           This option will slow down process creation somewhat.
  36
  37 comment "Page alloc debug is incompatible with Software Suspend on i386"
  38         depends on DEBUG_KERNEL && HIBERNATION
  39         depends on X86_32
  40
  41 config DEBUG_PAGEALLOC
  42         bool "Debug page memory allocations"
  43         depends on DEBUG_KERNEL && X86_32
  44         help
  45           Unmap pages from the kernel linear mapping after free_pages().
  46           This results in a large slowdown, but helps to find certain types
  47           of memory corruptions.
  48
  49 config DEBUG_PER_CPU_MAPS
  50         bool "Debug access to per_cpu maps"
  51         depends on DEBUG_KERNEL
  52         depends on X86_64_SMP
  53         default n
  54         help
  55           Say Y to verify that the per_cpu map being accessed has
  56           been setup.  Adds a fair amount of code to kernel memory
  57           and decreases performance.
  58
  59           Say N if unsure.
  60
  61 config DEBUG_RODATA
  62         bool "Write protect kernel read-only data structures"
  63         default y
  64         depends on DEBUG_KERNEL
  65         help
  66           Mark the kernel read-only data as write-protected in the pagetables,
  67           in order to catch accidental (and incorrect) writes to such const
  68           data. This is recommended so that we can catch kernel bugs sooner.
  69           If in doubt, say "Y".
  70
  71 config DEBUG_RODATA_TEST
  72         bool "Testcase for the DEBUG_RODATA feature"
  73         depends on DEBUG_RODATA
  74         help
  75           This option enables a testcase for the DEBUG_RODATA
  76           feature as well as for the change_page_attr() infrastructure.
  77           If in doubt, say "N"
  78
  79 config DEBUG_NX_TEST
  80         tristate "Testcase for the NX non-executable stack feature"
  81         depends on DEBUG_KERNEL && m
  82         help
  83           This option enables a testcase for the CPU NX capability
  84           and the software setup of this feature.
  85           If in doubt, say "N"
  86
  87 config 4KSTACKS
  88         bool "Use 4Kb for kernel stacks instead of 8Kb"
  89         depends on DEBUG_KERNEL
  90         depends on X86_32
  91         help
  92           If you say Y here the kernel will use a 4Kb stacksize for the
  93           kernel stack attached to each process/thread. This facilitates
  94           running more threads on a system and also reduces the pressure
  95           on the VM subsystem for higher order allocations. This option
  96           will also use IRQ stacks to compensate for the reduced stackspace.
  97
  98 config X86_FIND_SMP_CONFIG
  99         def_bool y
 100         depends on X86_LOCAL_APIC || X86_VOYAGER
 101         depends on X86_32
 102
 103 config X86_MPPARSE
 104         def_bool y
 105         depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) || X86_64
 106
 107 config DOUBLEFAULT
 108         default y
 109         bool "Enable doublefault exception handler" if EMBEDDED
 110         depends on X86_32
 111         help
 112           This option allows trapping of rare doublefault exceptions that
 113           would otherwise cause a system to silently reboot. Disabling this
 114           option saves about 4k and might cause you much additional grey
 115           hair.
 116
 117 config IOMMU_DEBUG
 118         bool "Enable IOMMU debugging"
 119         depends on GART_IOMMU && DEBUG_KERNEL
 120         depends on X86_64
 121         help
 122           Force the IOMMU to on even when you have less than 4GB of
 123           memory and add debugging code. On overflow always panic. And
 124           allow to enable IOMMU leak tracing. Can be disabled at boot
 125           time with iommu=noforce. This will also enable scatter gather
 126           list merging.  Currently not recommended for production
 127           code. When you use it make sure you have a big enough
 128           IOMMU/AGP aperture.  Most of the options enabled by this can
 129           be set more finegrained using the iommu= command line
 130           options. See Documentation/x86_64/boot-options.txt for more
 131           details.
 132
 133 config IOMMU_LEAK
 134         bool "IOMMU leak tracing"
 135         depends on DEBUG_KERNEL
 136         depends on IOMMU_DEBUG
 137         help
 138           Add a simple leak tracer to the IOMMU code. This is useful when you
 139           are debugging a buggy device driver that leaks IOMMU mappings.
 140
 141 #
 142 # IO delay types:
 143 #
 144
 145 config IO_DELAY_TYPE_0X80
 146         int
 147         default "0"
 148
 149 config IO_DELAY_TYPE_0XED
 150         int
 151         default "1"
 152
 153 config IO_DELAY_TYPE_UDELAY
 154         int
 155         default "2"
 156
 157 config IO_DELAY_TYPE_NONE
 158         int
 159         default "3"
 160
 161 choice
 162         prompt "IO delay type"
 163         default IO_DELAY_0XED
 164
 165 config IO_DELAY_0X80
 166         bool "port 0x80 based port-IO delay [recommended]"
 167         help
 168           This is the traditional Linux IO delay used for in/out_p.
 169           It is the most tested hence safest selection here.
 170
 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
 177 config IO_DELAY_UDELAY
 178         bool "udelay based port-IO delay"
 179         help
 180           Use udelay(2) as the IO delay method. This provides the delay
 181           while not having any side-effect on the IO port space.
 182
 183 config IO_DELAY_NONE
 184         bool "no port-IO delay"
 185         help
 186           No port-IO delay. Will break on old boxes that require port-IO
 187           delay for certain operations. Should work on most new machines.
 188
 189 endchoice
 190
 191 if IO_DELAY_0X80
 192 config DEFAULT_IO_DELAY_TYPE
 193         int
 194         default IO_DELAY_TYPE_0X80
 195 endif
 196
 197 if IO_DELAY_0XED
 198 config DEFAULT_IO_DELAY_TYPE
 199         int
 200         default IO_DELAY_TYPE_0XED
 201 endif
 202
 203 if IO_DELAY_UDELAY
 204 config DEFAULT_IO_DELAY_TYPE
 205         int
 206         default IO_DELAY_TYPE_UDELAY
 207 endif
 208
 209 if IO_DELAY_NONE
 210 config DEFAULT_IO_DELAY_TYPE
 211         int
 212         default IO_DELAY_TYPE_NONE
 213 endif
 214
 215 config DEBUG_BOOT_PARAMS
 216         bool "Debug boot parameters"
 217         depends on DEBUG_KERNEL
 218         depends on DEBUG_FS
 219         help
 220           This option will cause struct boot_params to be exported via debugfs.
 221
 222 config CPA_DEBUG
 223         bool "CPA self test code"
 224         depends on DEBUG_KERNEL
 225         help
 226           Do change_page_attr self tests at boot.
 227
 228 endmenu