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Linus Torvalds1da177e2005-04-16 15:20:36 -07001menu "Kernel hacking"
2
3source "lib/Kconfig.debug"
4
5config EARLY_PRINTK
6 bool "Early printk" if EMBEDDED && DEBUG_KERNEL
7 default y
8 help
9 Write kernel log output directly into the VGA buffer or to a serial
10 port.
11
12 This is useful for kernel debugging when your machine crashes very
13 early before the console code is initialized. For normal operation
14 it is not recommended because it looks ugly and doesn't cooperate
15 with klogd/syslogd or the X server. You should normally N here,
16 unless you want to debug such a crash.
17
18config DEBUG_STACKOVERFLOW
19 bool "Check for stack overflows"
20 depends on DEBUG_KERNEL
Adrian Bunkdab175f2005-07-27 11:44:23 -070021 help
22 This option will cause messages to be printed if free stack space
23 drops below a certain limit.
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
Linus Torvalds1da177e2005-04-16 15:20:36 -070025config DEBUG_STACK_USAGE
26 bool "Stack utilization instrumentation"
27 depends on DEBUG_KERNEL
28 help
29 Enables the display of the minimum amount of free stack which each
30 task has ever had available in the sysrq-T and sysrq-P debug output.
31
32 This option will slow down process creation somewhat.
33
Chuck Ebbert4d7d8c82006-03-23 02:59:30 -080034config STACK_BACKTRACE_COLS
35 int "Stack backtraces per line" if DEBUG_KERNEL
36 range 1 3
37 default 2
38 help
39 Selects how many stack backtrace entries per line to display.
40
41 This can save screen space when displaying traces.
42
Linus Torvalds1da177e2005-04-16 15:20:36 -070043comment "Page alloc debug is incompatible with Software Suspend on i386"
44 depends on DEBUG_KERNEL && SOFTWARE_SUSPEND
45
46config DEBUG_PAGEALLOC
Andrew Morton4a2f0ac2006-03-25 03:07:22 -080047 bool "Debug page memory allocations"
Chen, Kenneth Wa7d06ca2006-03-25 03:06:50 -080048 depends on DEBUG_KERNEL && !SOFTWARE_SUSPEND && !HUGETLBFS
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 help
50 Unmap pages from the kernel linear mapping after free_pages().
51 This results in a large slowdown, but helps to find certain types
52 of memory corruptions.
53
Arjan van de Ven63aaf302006-01-06 00:12:02 -080054config DEBUG_RODATA
55 bool "Write protect kernel read-only data structures"
56 depends on DEBUG_KERNEL
57 help
58 Mark the kernel read-only data as write-protected in the pagetables,
59 in order to catch accidental (and incorrect) writes to such const
60 data. This option may have a slight performance impact because a
61 portion of the kernel code won't be covered by a 2MB TLB anymore.
62 If in doubt, say "N".
63
Linus Torvalds1da177e2005-04-16 15:20:36 -070064config 4KSTACKS
65 bool "Use 4Kb for kernel stacks instead of 8Kb"
66 depends on DEBUG_KERNEL
67 help
68 If you say Y here the kernel will use a 4Kb stacksize for the
69 kernel stack attached to each process/thread. This facilitates
70 running more threads on a system and also reduces the pressure
71 on the VM subsystem for higher order allocations. This option
72 will also use IRQ stacks to compensate for the reduced stackspace.
73
74config X86_FIND_SMP_CONFIG
75 bool
76 depends on X86_LOCAL_APIC || X86_VOYAGER
77 default y
78
79config X86_MPPARSE
80 bool
81 depends on X86_LOCAL_APIC && !X86_VISWS
82 default y
83
Andi Kleen102e41f2006-04-18 12:35:22 +020084config DOUBLEFAULT
85 default y
86 bool "Enable doublefault exception handler" if EMBEDDED
87 help
88 This option allows trapping of rare doublefault exceptions that
89 would otherwise cause a system to silently reboot. Disabling this
90 option saves about 4k and might cause you much additional grey
91 hair.
92
Linus Torvalds1da177e2005-04-16 15:20:36 -070093endmenu