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Linus Torvalds1da177e2005-04-16 15:20:36 -07001menu "Kernel hacking"
2
Ingo Molnar55f327f2006-07-03 00:24:43 -07003config TRACE_IRQFLAGS_SUPPORT
4 bool
5 default y
6
Linus Torvalds1da177e2005-04-16 15:20:36 -07007source "lib/Kconfig.debug"
8
9config EARLY_PRINTK
10 bool "Early printk" if EMBEDDED && DEBUG_KERNEL
11 default y
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
22config DEBUG_STACKOVERFLOW
23 bool "Check for stack overflows"
24 depends on DEBUG_KERNEL
Adrian Bunkdab175f2005-07-27 11:44:23 -070025 help
26 This option will cause messages to be printed if free stack space
27 drops below a certain limit.
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Linus Torvalds1da177e2005-04-16 15:20:36 -070029config 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
38comment "Page alloc debug is incompatible with Software Suspend on i386"
39 depends on DEBUG_KERNEL && SOFTWARE_SUSPEND
40
41config DEBUG_PAGEALLOC
Andrew Morton4a2f0ac2006-03-25 03:07:22 -080042 bool "Debug page memory allocations"
Chen, Kenneth Wa7d06ca2006-03-25 03:06:50 -080043 depends on DEBUG_KERNEL && !SOFTWARE_SUSPEND && !HUGETLBFS
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 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
Arjan van de Ven63aaf302006-01-06 00:12:02 -080049config DEBUG_RODATA
50 bool "Write protect kernel read-only data structures"
51 depends on DEBUG_KERNEL
52 help
53 Mark the kernel read-only data as write-protected in the pagetables,
54 in order to catch accidental (and incorrect) writes to such const
55 data. This option may have a slight performance impact because a
56 portion of the kernel code won't be covered by a 2MB TLB anymore.
57 If in doubt, say "N".
58
Linus Torvalds1da177e2005-04-16 15:20:36 -070059config 4KSTACKS
60 bool "Use 4Kb for kernel stacks instead of 8Kb"
61 depends on DEBUG_KERNEL
62 help
63 If you say Y here the kernel will use a 4Kb stacksize for the
64 kernel stack attached to each process/thread. This facilitates
65 running more threads on a system and also reduces the pressure
66 on the VM subsystem for higher order allocations. This option
67 will also use IRQ stacks to compensate for the reduced stackspace.
68
69config X86_FIND_SMP_CONFIG
70 bool
71 depends on X86_LOCAL_APIC || X86_VOYAGER
72 default y
73
74config X86_MPPARSE
75 bool
76 depends on X86_LOCAL_APIC && !X86_VISWS
77 default y
78
Andi Kleen102e41f2006-04-18 12:35:22 +020079config DOUBLEFAULT
80 default y
81 bool "Enable doublefault exception handler" if EMBEDDED
82 help
83 This option allows trapping of rare doublefault exceptions that
84 would otherwise cause a system to silently reboot. Disabling this
85 option saves about 4k and might cause you much additional grey
86 hair.
87
Rusty Russell139ec7c2006-12-07 02:14:08 +010088config DEBUG_PARAVIRT
89 bool "Enable some paravirtualization debugging"
90 default y
91 depends on PARAVIRT && DEBUG_KERNEL
92 help
93 Currently deliberately clobbers regs which are allowed to be
94 clobbered in inlined paravirt hooks, even in native mode.
95 If turning this off solves a problem, then DISABLE_INTERRUPTS() or
96 ENABLE_INTERRUPTS() is lying about what registers can be clobbered.
97
Linus Torvalds1da177e2005-04-16 15:20:36 -070098endmenu