Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 config HAVE_ARCH_KMEMCHECK
  2         bool
  3 
  4 menuconfig KMEMCHECK
  5         bool "kmemcheck: trap use of uninitialized memory"
  6         depends on DEBUG_KERNEL
  7         depends on !X86_USE_3DNOW
  8         depends on SLUB || SLAB
  9         depends on !CC_OPTIMIZE_FOR_SIZE
 10         depends on !FUNCTION_TRACER
 11         select FRAME_POINTER
 12         select STACKTRACE
 13         default n
 14         help
 15           This option enables tracing of dynamically allocated kernel memory
 16           to see if memory is used before it has been given an initial value.
 17           Be aware that this requires half of your memory for bookkeeping and
 18           will insert extra code at *every* read and write to tracked memory
 19           thus slow down the kernel code (but user code is unaffected).
 20 
 21           The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
 22           or enable kmemcheck at boot-time. If the kernel is started with
 23           kmemcheck=0, the large memory and CPU overhead is not incurred.
 24 
 25 choice
 26         prompt "kmemcheck: default mode at boot"
 27         depends on KMEMCHECK
 28         default KMEMCHECK_ONESHOT_BY_DEFAULT
 29         help
 30           This option controls the default behaviour of kmemcheck when the
 31           kernel boots and no kmemcheck= parameter is given.
 32 
 33 config KMEMCHECK_DISABLED_BY_DEFAULT
 34         bool "disabled"
 35         depends on KMEMCHECK
 36 
 37 config KMEMCHECK_ENABLED_BY_DEFAULT
 38         bool "enabled"
 39         depends on KMEMCHECK
 40 
 41 config KMEMCHECK_ONESHOT_BY_DEFAULT
 42         bool "one-shot"
 43         depends on KMEMCHECK
 44         help
 45           In one-shot mode, only the first error detected is reported before
 46           kmemcheck is disabled.
 47 
 48 endchoice
 49 
 50 config KMEMCHECK_QUEUE_SIZE
 51         int "kmemcheck: error queue size"
 52         depends on KMEMCHECK
 53         default 64
 54         help
 55           Select the maximum number of errors to store in the queue. Since
 56           errors can occur virtually anywhere and in any context, we need a
 57           temporary storage area which is guarantueed not to generate any
 58           other faults. The queue will be emptied as soon as a tasklet may
 59           be scheduled. If the queue is full, new error reports will be
 60           lost.
 61 
 62 config KMEMCHECK_SHADOW_COPY_SHIFT
 63         int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
 64         depends on KMEMCHECK
 65         range 2 8
 66         default 5
 67         help
 68           Select the number of shadow bytes to save along with each entry of
 69           the queue. These bytes indicate what parts of an allocation are
 70           initialized, uninitialized, etc. and will be displayed when an
 71           error is detected to help the debugging of a particular problem.
 72 
 73 config KMEMCHECK_PARTIAL_OK
 74         bool "kmemcheck: allow partially uninitialized memory"
 75         depends on KMEMCHECK
 76         default y
 77         help
 78           This option works around certain GCC optimizations that produce
 79           32-bit reads from 16-bit variables where the upper 16 bits are
 80           thrown away afterwards. This may of course also hide some real
 81           bugs.
 82 
 83 config KMEMCHECK_BITOPS_OK
 84         bool "kmemcheck: allow bit-field manipulation"
 85         depends on KMEMCHECK
 86         default n
 87         help
 88           This option silences warnings that would be generated for bit-field
 89           accesses where not all the bits are initialized at the same time.
 90           This may also hide some real bugs.
 91 
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