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74ce8322 MF |
1 | menu "Kernel hacking" |
2 | ||
3 | source "lib/Kconfig.debug" | |
4 | ||
a5ac0129 SZ |
5 | config HAVE_ARCH_KGDB |
6 | def_bool y | |
7 | ||
9f06c38f RG |
8 | config DEBUG_VERBOSE |
9 | bool "Verbose fault messages" | |
10 | default y | |
11 | select PRINTK | |
12 | help | |
13 | When a program crashes due to an exception, or the kernel detects | |
14 | an internal error, the kernel can print a not so brief message | |
15 | explaining what the problem was. This debugging information is | |
16 | useful to developers and kernel hackers when tracking down problems, | |
17 | but mostly meaningless to other people. This is always helpful for | |
18 | debugging but serves no purpose on a production system. | |
19 | Most people should say N here. | |
20 | ||
74ce8322 MF |
21 | config DEBUG_MMRS |
22 | bool "Generate Blackfin MMR tree" | |
23 | select DEBUG_FS | |
24 | help | |
25 | Create a tree of Blackfin MMRs via the debugfs tree. If | |
26 | you enable this, you will find all MMRs laid out in the | |
27 | /sys/kernel/debug/blackfin/ directory where you can read/write | |
28 | MMRs directly from userspace. This is obviously just a debug | |
29 | feature. | |
30 | ||
31 | config DEBUG_HWERR | |
32 | bool "Hardware error interrupt debugging" | |
33 | depends on DEBUG_KERNEL | |
34 | help | |
35 | When enabled, the hardware error interrupt is never disabled, and | |
36 | will happen immediately when an error condition occurs. This comes | |
37 | at a slight cost in code size, but is necessary if you are getting | |
38 | hardware error interrupts and need to know where they are coming | |
39 | from. | |
40 | ||
0c7a6b21 RG |
41 | config DEBUG_DOUBLEFAULT |
42 | bool "Debug Double Faults" | |
43 | default n | |
44 | help | |
45 | If an exception is caused while executing code within the exception | |
46 | handler, the NMI handler, the reset vector, or in emulator mode, | |
47 | a double fault occurs. On the Blackfin, this is a unrecoverable | |
48 | event. You have two options: | |
49 | - RESET exactly when double fault occurs. The excepting | |
50 | instruction address is stored in RETX, where the next kernel | |
51 | boot will print it out. | |
52 | - Print debug message. This is much more error prone, although | |
53 | easier to handle. It is error prone since: | |
54 | - The excepting instruction is not committed. | |
55 | - All writebacks from the instruction are prevented. | |
56 | - The generated exception is not taken. | |
57 | - The EXCAUSE field is updated with an unrecoverable event | |
58 | The only way to check this is to see if EXCAUSE contains the | |
59 | unrecoverable event value at every exception return. By selecting | |
60 | this option, you are skipping over the faulting instruction, and | |
61 | hoping things stay together enough to print out a debug message. | |
62 | ||
63 | This does add a little kernel code, but is the only method to debug | |
64 | double faults - if unsure say "Y" | |
65 | ||
66 | choice | |
67 | prompt "Double Fault Failure Method" | |
68 | default DEBUG_DOUBLEFAULT_PRINT | |
69 | depends on DEBUG_DOUBLEFAULT | |
70 | ||
71 | config DEBUG_DOUBLEFAULT_PRINT | |
72 | bool "Print" | |
73 | ||
74 | config DEBUG_DOUBLEFAULT_RESET | |
75 | bool "Reset" | |
76 | ||
77 | endchoice | |
78 | ||
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79 | config DEBUG_ICACHE_CHECK |
80 | bool "Check Instruction cache coherency" | |
81 | depends on DEBUG_KERNEL | |
82 | depends on DEBUG_HWERR | |
83 | help | |
84 | Say Y here if you are getting weird unexplained errors. This will | |
85 | ensure that icache is what SDRAM says it should be by doing a | |
86 | byte wise comparison between SDRAM and instruction cache. This | |
87 | also relocates the irq_panic() function to L1 memory, (which is | |
88 | un-cached). | |
89 | ||
90 | config DEBUG_HUNT_FOR_ZERO | |
91 | bool "Catch NULL pointer reads/writes" | |
92 | default y | |
93 | help | |
94 | Say Y here to catch reads/writes to anywhere in the memory range | |
95 | from 0x0000 - 0x0FFF (the first 4k) of memory. This is useful in | |
96 | catching common programming errors such as NULL pointer dereferences. | |
97 | ||
98 | Misbehaving applications will be killed (generate a SEGV) while the | |
99 | kernel will trigger a panic. | |
100 | ||
101 | Enabling this option will take up an extra entry in CPLB table. | |
102 | Otherwise, there is no extra overhead. | |
103 | ||
104 | config DEBUG_BFIN_HWTRACE_ON | |
105 | bool "Turn on Blackfin's Hardware Trace" | |
106 | default y | |
107 | help | |
108 | All Blackfins include a Trace Unit which stores a history of the last | |
109 | 16 changes in program flow taken by the program sequencer. The history | |
110 | allows the user to recreate the program sequencer’s recent path. This | |
111 | can be handy when an application dies - we print out the execution | |
112 | path of how it got to the offending instruction. | |
113 | ||
114 | By turning this off, you may save a tiny amount of power. | |
115 | ||
116 | choice | |
117 | prompt "Omit loop Tracing" | |
118 | default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF | |
119 | depends on DEBUG_BFIN_HWTRACE_ON | |
120 | help | |
121 | The trace buffer can be configured to omit recording of changes in | |
122 | program flow that match either the last entry or one of the last | |
123 | two entries. Omitting one of these entries from the record prevents | |
124 | the trace buffer from overflowing because of any sort of loop (for, do | |
125 | while, etc) in the program. | |
126 | ||
127 | Because zero-overhead Hardware loops are not recorded in the trace buffer, | |
128 | this feature can be used to prevent trace overflow from loops that | |
129 | are nested four deep. | |
130 | ||
131 | config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF | |
132 | bool "Trace all Loops" | |
133 | help | |
134 | The trace buffer records all changes of flow | |
135 | ||
136 | config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE | |
137 | bool "Compress single-level loops" | |
138 | help | |
139 | The trace buffer does not record single loops - helpful if trace | |
140 | is spinning on a while or do loop. | |
141 | ||
142 | config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO | |
143 | bool "Compress two-level loops" | |
144 | help | |
145 | The trace buffer does not record loops two levels deep. Helpful if | |
146 | the trace is spinning in a nested loop | |
147 | ||
148 | endchoice | |
149 | ||
150 | config DEBUG_BFIN_HWTRACE_COMPRESSION | |
151 | int | |
152 | depends on DEBUG_BFIN_HWTRACE_ON | |
153 | default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF | |
154 | default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE | |
155 | default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO | |
156 | ||
157 | ||
158 | config DEBUG_BFIN_HWTRACE_EXPAND | |
159 | bool "Expand Trace Buffer greater than 16 entries" | |
160 | depends on DEBUG_BFIN_HWTRACE_ON | |
161 | default n | |
162 | help | |
163 | By selecting this option, every time the 16 hardware entries in | |
164 | the Blackfin's HW Trace buffer are full, the kernel will move them | |
165 | into a software buffer, for dumping when there is an issue. This | |
166 | has a great impact on performance, (an interrupt every 16 change of | |
167 | flows) and should normally be turned off, except in those nasty | |
168 | debugging sessions | |
169 | ||
170 | config DEBUG_BFIN_HWTRACE_EXPAND_LEN | |
171 | int "Size of Trace buffer (in power of 2k)" | |
172 | range 0 4 | |
173 | depends on DEBUG_BFIN_HWTRACE_EXPAND | |
174 | default 1 | |
175 | help | |
176 | This sets the size of the software buffer that the trace information | |
177 | is kept in. | |
178 | 0 for (2^0) 1k, or 256 entries, | |
179 | 1 for (2^1) 2k, or 512 entries, | |
180 | 2 for (2^2) 4k, or 1024 entries, | |
181 | 3 for (2^3) 8k, or 2048 entries, | |
182 | 4 for (2^4) 16k, or 4096 entries | |
183 | ||
184 | config DEBUG_BFIN_NO_KERN_HWTRACE | |
185 | bool "Trace user apps (turn off hwtrace in kernel)" | |
186 | depends on DEBUG_BFIN_HWTRACE_ON | |
187 | default n | |
188 | help | |
189 | Some pieces of the kernel contain a lot of flow changes which can | |
190 | quickly fill up the hardware trace buffer. When debugging crashes, | |
191 | the hardware trace may indicate that the problem lies in kernel | |
192 | space when in reality an application is buggy. | |
193 | ||
194 | Say Y here to disable hardware tracing in some known "jumpy" pieces | |
195 | of code so that the trace buffer will extend further back. | |
196 | ||
197 | config EARLY_PRINTK | |
198 | bool "Early printk" | |
199 | default n | |
0cfbb323 | 200 | select SERIAL_CORE_CONSOLE |
74ce8322 MF |
201 | help |
202 | This option enables special console drivers which allow the kernel | |
203 | to print messages very early in the bootup process. | |
204 | ||
205 | This is useful for kernel debugging when your machine crashes very | |
206 | early before the console code is initialized. After enabling this | |
207 | feature, you must add "earlyprintk=serial,uart0,57600" to the | |
208 | command line (bootargs). It is safe to say Y here in all cases, as | |
209 | all of this lives in the init section and is thrown away after the | |
210 | kernel boots completely. | |
211 | ||
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212 | config CPLB_INFO |
213 | bool "Display the CPLB information" | |
214 | help | |
cf93425d | 215 | Display the CPLB information via /proc/cplbinfo. |
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216 | |
217 | config ACCESS_CHECK | |
218 | bool "Check the user pointer address" | |
219 | default y | |
220 | help | |
221 | Usually the pointer transfer from user space is checked to see if its | |
222 | address is in the kernel space. | |
223 | ||
224 | Say N here to disable that check to improve the performance. | |
225 | ||
226 | endmenu |