Root/lib/Kconfig.kmemcheck

Source at commit ec7cab4cbb721bff91ec924ec691efd8daf36579 created 12 years 8 months ago.
By Maarten ter Huurne, MIPS: JZ4740: A320: Updated quickstart documentation.
1config HAVE_ARCH_KMEMCHECK
2    bool
3
4if HAVE_ARCH_KMEMCHECK
5
6menuconfig KMEMCHECK
7    bool "kmemcheck: trap use of uninitialized memory"
8    depends on DEBUG_KERNEL
9    depends on !X86_USE_3DNOW
10    depends on SLUB || SLAB
11    depends on !CC_OPTIMIZE_FOR_SIZE
12    depends on !FUNCTION_TRACER
13    select FRAME_POINTER
14    select STACKTRACE
15    default n
16    help
17      This option enables tracing of dynamically allocated kernel memory
18      to see if memory is used before it has been given an initial value.
19      Be aware that this requires half of your memory for bookkeeping and
20      will insert extra code at *every* read and write to tracked memory
21      thus slow down the kernel code (but user code is unaffected).
22
23      The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
24      or enable kmemcheck at boot-time. If the kernel is started with
25      kmemcheck=0, the large memory and CPU overhead is not incurred.
26
27choice
28    prompt "kmemcheck: default mode at boot"
29    depends on KMEMCHECK
30    default KMEMCHECK_ONESHOT_BY_DEFAULT
31    help
32      This option controls the default behaviour of kmemcheck when the
33      kernel boots and no kmemcheck= parameter is given.
34
35config KMEMCHECK_DISABLED_BY_DEFAULT
36    bool "disabled"
37    depends on KMEMCHECK
38
39config KMEMCHECK_ENABLED_BY_DEFAULT
40    bool "enabled"
41    depends on KMEMCHECK
42
43config KMEMCHECK_ONESHOT_BY_DEFAULT
44    bool "one-shot"
45    depends on KMEMCHECK
46    help
47      In one-shot mode, only the first error detected is reported before
48      kmemcheck is disabled.
49
50endchoice
51
52config KMEMCHECK_QUEUE_SIZE
53    int "kmemcheck: error queue size"
54    depends on KMEMCHECK
55    default 64
56    help
57      Select the maximum number of errors to store in the queue. Since
58      errors can occur virtually anywhere and in any context, we need a
59      temporary storage area which is guarantueed not to generate any
60      other faults. The queue will be emptied as soon as a tasklet may
61      be scheduled. If the queue is full, new error reports will be
62      lost.
63
64config KMEMCHECK_SHADOW_COPY_SHIFT
65    int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
66    depends on KMEMCHECK
67    range 2 8
68    default 5
69    help
70      Select the number of shadow bytes to save along with each entry of
71      the queue. These bytes indicate what parts of an allocation are
72      initialized, uninitialized, etc. and will be displayed when an
73      error is detected to help the debugging of a particular problem.
74
75config KMEMCHECK_PARTIAL_OK
76    bool "kmemcheck: allow partially uninitialized memory"
77    depends on KMEMCHECK
78    default y
79    help
80      This option works around certain GCC optimizations that produce
81      32-bit reads from 16-bit variables where the upper 16 bits are
82      thrown away afterwards. This may of course also hide some real
83      bugs.
84
85config KMEMCHECK_BITOPS_OK
86    bool "kmemcheck: allow bit-field manipulation"
87    depends on KMEMCHECK
88    default n
89    help
90      This option silences warnings that would be generated for bit-field
91      accesses where not all the bits are initialized at the same time.
92      This may also hide some real bugs.
93
94endif
95

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