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1da177e4 LT |
1 | menu "Kernel hacking" |
2 | ||
55f327fa | 3 | config TRACE_IRQFLAGS_SUPPORT |
d013a27c | 4 | def_bool y |
55f327fa | 5 | |
1da177e4 LT |
6 | source "lib/Kconfig.debug" |
7 | ||
8 | config EARLY_PRINTK | |
076f9776 | 9 | bool "Early printk" if EMBEDDED |
1da177e4 LT |
10 | default y |
11 | help | |
12 | Write kernel log output directly into the VGA buffer or to a serial | |
13 | port. | |
14 | ||
15 | This is useful for kernel debugging when your machine crashes very | |
16 | early before the console code is initialized. For normal operation | |
17 | it is not recommended because it looks ugly and doesn't cooperate | |
18 | with klogd/syslogd or the X server. You should normally N here, | |
19 | unless you want to debug such a crash. | |
20 | ||
21 | config DEBUG_STACKOVERFLOW | |
22 | bool "Check for stack overflows" | |
23 | depends on DEBUG_KERNEL | |
dab175f3 AB |
24 | help |
25 | This option will cause messages to be printed if free stack space | |
26 | drops below a certain limit. | |
1da177e4 | 27 | |
1da177e4 LT |
28 | config DEBUG_STACK_USAGE |
29 | bool "Stack utilization instrumentation" | |
30 | depends on DEBUG_KERNEL | |
31 | help | |
32 | Enables the display of the minimum amount of free stack which each | |
33 | task has ever had available in the sysrq-T and sysrq-P debug output. | |
34 | ||
35 | This option will slow down process creation somewhat. | |
36 | ||
37 | comment "Page alloc debug is incompatible with Software Suspend on i386" | |
b0cb1a19 | 38 | depends on DEBUG_KERNEL && HIBERNATION |
d013a27c | 39 | depends on X86_32 |
1da177e4 LT |
40 | |
41 | config DEBUG_PAGEALLOC | |
4a2f0acf | 42 | bool "Debug page memory allocations" |
b0cb1a19 | 43 | depends on DEBUG_KERNEL && !HIBERNATION && !HUGETLBFS |
d013a27c | 44 | depends on X86_32 |
1da177e4 LT |
45 | help |
46 | Unmap pages from the kernel linear mapping after free_pages(). | |
47 | This results in a large slowdown, but helps to find certain types | |
48 | of memory corruptions. | |
49 | ||
c49a4955 | 50 | config DEBUG_PER_CPU_MAPS |
51 | bool "Debug access to per_cpu maps" | |
52 | depends on DEBUG_KERNEL | |
53 | depends on X86_64_SMP | |
54 | default n | |
55 | help | |
56 | Say Y to verify that the per_cpu map being accessed has | |
57 | been setup. Adds a fair amount of code to kernel memory | |
58 | and decreases performance. | |
59 | ||
60 | Say N if unsure. | |
61 | ||
63aaf308 AV |
62 | config DEBUG_RODATA |
63 | bool "Write protect kernel read-only data structures" | |
64 | depends on DEBUG_KERNEL | |
65 | help | |
66 | Mark the kernel read-only data as write-protected in the pagetables, | |
67 | in order to catch accidental (and incorrect) writes to such const | |
68 | data. This option may have a slight performance impact because a | |
69 | portion of the kernel code won't be covered by a 2MB TLB anymore. | |
70 | If in doubt, say "N". | |
71 | ||
1da177e4 LT |
72 | config 4KSTACKS |
73 | bool "Use 4Kb for kernel stacks instead of 8Kb" | |
74 | depends on DEBUG_KERNEL | |
d013a27c | 75 | depends on X86_32 |
1da177e4 LT |
76 | help |
77 | If you say Y here the kernel will use a 4Kb stacksize for the | |
78 | kernel stack attached to each process/thread. This facilitates | |
79 | running more threads on a system and also reduces the pressure | |
80 | on the VM subsystem for higher order allocations. This option | |
81 | will also use IRQ stacks to compensate for the reduced stackspace. | |
82 | ||
83 | config X86_FIND_SMP_CONFIG | |
d013a27c | 84 | def_bool y |
1da177e4 | 85 | depends on X86_LOCAL_APIC || X86_VOYAGER |
d013a27c | 86 | depends on X86_32 |
1da177e4 LT |
87 | |
88 | config X86_MPPARSE | |
d013a27c | 89 | def_bool y |
6b0c3d44 | 90 | depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) || X86_64 |
1da177e4 | 91 | |
102e41fd AK |
92 | config DOUBLEFAULT |
93 | default y | |
94 | bool "Enable doublefault exception handler" if EMBEDDED | |
d013a27c RD |
95 | depends on X86_32 |
96 | help | |
97 | This option allows trapping of rare doublefault exceptions that | |
98 | would otherwise cause a system to silently reboot. Disabling this | |
99 | option saves about 4k and might cause you much additional grey | |
100 | hair. | |
101 | ||
102 | config IOMMU_DEBUG | |
103 | bool "Enable IOMMU debugging" | |
966396d3 | 104 | depends on GART_IOMMU && DEBUG_KERNEL |
d013a27c | 105 | depends on X86_64 |
102e41fd | 106 | help |
d013a27c RD |
107 | Force the IOMMU to on even when you have less than 4GB of |
108 | memory and add debugging code. On overflow always panic. And | |
109 | allow to enable IOMMU leak tracing. Can be disabled at boot | |
110 | time with iommu=noforce. This will also enable scatter gather | |
111 | list merging. Currently not recommended for production | |
112 | code. When you use it make sure you have a big enough | |
113 | IOMMU/AGP aperture. Most of the options enabled by this can | |
114 | be set more finegrained using the iommu= command line | |
115 | options. See Documentation/x86_64/boot-options.txt for more | |
116 | details. | |
117 | ||
118 | config IOMMU_LEAK | |
119 | bool "IOMMU leak tracing" | |
120 | depends on DEBUG_KERNEL | |
121 | depends on IOMMU_DEBUG | |
122 | help | |
123 | Add a simple leak tracer to the IOMMU code. This is useful when you | |
124 | are debugging a buggy device driver that leaks IOMMU mappings. | |
125 | ||
6e7c4025 IM |
126 | # |
127 | # IO delay types: | |
128 | # | |
129 | ||
130 | config IO_DELAY_TYPE_0X80 | |
131 | int | |
132 | default "0" | |
133 | ||
134 | config IO_DELAY_TYPE_0XED | |
135 | int | |
136 | default "1" | |
137 | ||
138 | config IO_DELAY_TYPE_UDELAY | |
139 | int | |
140 | default "2" | |
141 | ||
142 | config IO_DELAY_TYPE_NONE | |
143 | int | |
144 | default "3" | |
145 | ||
146 | choice | |
147 | prompt "IO delay type" | |
d0049e71 | 148 | default IO_DELAY_0XED |
6e7c4025 IM |
149 | |
150 | config IO_DELAY_0X80 | |
151 | bool "port 0x80 based port-IO delay [recommended]" | |
152 | help | |
153 | This is the traditional Linux IO delay used for in/out_p. | |
154 | It is the most tested hence safest selection here. | |
155 | ||
156 | config IO_DELAY_0XED | |
157 | bool "port 0xed based port-IO delay" | |
158 | help | |
159 | Use port 0xed as the IO delay. This frees up port 0x80 which is | |
160 | often used as a hardware-debug port. | |
161 | ||
162 | config IO_DELAY_UDELAY | |
163 | bool "udelay based port-IO delay" | |
164 | help | |
165 | Use udelay(2) as the IO delay method. This provides the delay | |
166 | while not having any side-effect on the IO port space. | |
167 | ||
168 | config IO_DELAY_NONE | |
169 | bool "no port-IO delay" | |
b02aae9c | 170 | help |
6e7c4025 IM |
171 | No port-IO delay. Will break on old boxes that require port-IO |
172 | delay for certain operations. Should work on most new machines. | |
173 | ||
174 | endchoice | |
175 | ||
176 | if IO_DELAY_0X80 | |
177 | config DEFAULT_IO_DELAY_TYPE | |
178 | int | |
179 | default IO_DELAY_TYPE_0X80 | |
180 | endif | |
181 | ||
182 | if IO_DELAY_0XED | |
183 | config DEFAULT_IO_DELAY_TYPE | |
184 | int | |
185 | default IO_DELAY_TYPE_0XED | |
186 | endif | |
187 | ||
188 | if IO_DELAY_UDELAY | |
189 | config DEFAULT_IO_DELAY_TYPE | |
190 | int | |
191 | default IO_DELAY_TYPE_UDELAY | |
192 | endif | |
193 | ||
194 | if IO_DELAY_NONE | |
195 | config DEFAULT_IO_DELAY_TYPE | |
196 | int | |
197 | default IO_DELAY_TYPE_NONE | |
198 | endif | |
b02aae9c | 199 | |
6d7d7433 HY |
200 | config DEBUG_BOOT_PARAMS |
201 | bool "Debug boot parameters" | |
202 | depends on DEBUG_KERNEL | |
203 | depends on DEBUG_FS | |
204 | help | |
205 | This option will cause struct boot_params to be exported via debugfs. | |
206 | ||
1da177e4 | 207 | endmenu |