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 && DEBUG_KERNEL
  10         default y
  11         depends on X86_32
  12         help
  13           Write kernel log output directly into the VGA buffer or to a serial
  14           port.
  15
  16           This is useful for kernel debugging when your machine crashes very
  17           early before the console code is initialized. For normal operation
  18           it is not recommended because it looks ugly and doesn't cooperate
  19           with klogd/syslogd or the X server. You should normally N here,
  20           unless you want to debug such a crash.
  21
  22 config DEBUG_STACKOVERFLOW
  23         bool "Check for stack overflows"
  24         depends on DEBUG_KERNEL
  25         help
  26           This option will cause messages to be printed if free stack space
  27           drops below a certain limit.
  28
  29 config DEBUG_STACK_USAGE
  30         bool "Stack utilization instrumentation"
  31         depends on DEBUG_KERNEL
  32         help
  33           Enables the display of the minimum amount of free stack which each
  34           task has ever had available in the sysrq-T and sysrq-P debug output.
  35
  36           This option will slow down process creation somewhat.
  37
  38 comment "Page alloc debug is incompatible with Software Suspend on i386"
  39         depends on DEBUG_KERNEL && HIBERNATION
  40         depends on X86_32
  41
  42 config DEBUG_PAGEALLOC
  43         bool "Debug page memory allocations"
  44         depends on DEBUG_KERNEL && !HIBERNATION && !HUGETLBFS
  45         depends on X86_32
  46         help
  47           Unmap pages from the kernel linear mapping after free_pages().
  48           This results in a large slowdown, but helps to find certain types
  49           of memory corruptions.
  50
  51 config DEBUG_RODATA
  52         bool "Write protect kernel read-only data structures"
  53         depends on DEBUG_KERNEL
  54         help
  55           Mark the kernel read-only data as write-protected in the pagetables,
  56           in order to catch accidental (and incorrect) writes to such const
  57           data. This option may have a slight performance impact because a
  58           portion of the kernel code won't be covered by a 2MB TLB anymore.
  59           If in doubt, say "N".
  60
  61 config 4KSTACKS
  62         bool "Use 4Kb for kernel stacks instead of 8Kb"
  63         depends on DEBUG_KERNEL
  64         depends on X86_32
  65         help
  66           If you say Y here the kernel will use a 4Kb stacksize for the
  67           kernel stack attached to each process/thread. This facilitates
  68           running more threads on a system and also reduces the pressure
  69           on the VM subsystem for higher order allocations. This option
  70           will also use IRQ stacks to compensate for the reduced stackspace.
  71
  72 config X86_FIND_SMP_CONFIG
  73         def_bool y
  74         depends on X86_LOCAL_APIC || X86_VOYAGER
  75         depends on X86_32
  76
  77 config X86_MPPARSE
  78         def_bool y
  79         depends on X86_LOCAL_APIC && !X86_VISWS
  80         depends on X86_32
  81
  82 config DOUBLEFAULT
  83         default y
  84         bool "Enable doublefault exception handler" if EMBEDDED
  85         depends on X86_32
  86         help
  87           This option allows trapping of rare doublefault exceptions that
  88           would otherwise cause a system to silently reboot. Disabling this
  89           option saves about 4k and might cause you much additional grey
  90           hair.
  91
  92 config IOMMU_DEBUG
  93         bool "Enable IOMMU debugging"
  94         depends on IOMMU && DEBUG_KERNEL
  95         depends on X86_64
  96         help
  97           Force the IOMMU to on even when you have less than 4GB of
  98           memory and add debugging code. On overflow always panic. And
  99           allow to enable IOMMU leak tracing. Can be disabled at boot
 100           time with iommu=noforce. This will also enable scatter gather
 101           list merging.  Currently not recommended for production
 102           code. When you use it make sure you have a big enough
 103           IOMMU/AGP aperture.  Most of the options enabled by this can
 104           be set more finegrained using the iommu= command line
 105           options. See Documentation/x86_64/boot-options.txt for more
 106           details.
 107
 108 config IOMMU_LEAK
 109         bool "IOMMU leak tracing"
 110         depends on DEBUG_KERNEL
 111         depends on IOMMU_DEBUG
 112         help
 113           Add a simple leak tracer to the IOMMU code. This is useful when you
 114           are debugging a buggy device driver that leaks IOMMU mappings.
 115
 116 #config X86_REMOTE_DEBUG
 117 #       bool "kgdb debugging stub"
 118
 119 endmenu