1menu "Kernel hacking"
2
3source "lib/Kconfig.debug"
4
5config DEBUG_VERBOSE
6	bool "Verbose fault messages"
7	default y
8	select PRINTK
9	help
10	  When a program crashes due to an exception, or the kernel detects
11	  an internal error, the kernel can print a not so brief message
12	  explaining what the problem was. This debugging information is
13	  useful to developers and kernel hackers when tracking down problems,
14	  but mostly meaningless to other people. This is always helpful for
15	  debugging but serves no purpose on a production system.
16	  Most people should say N here.
17
18config DEBUG_MMRS
19	tristate "Generate Blackfin MMR tree"
20	select DEBUG_FS
21	help
22	  Create a tree of Blackfin MMRs via the debugfs tree.  If
23	  you enable this, you will find all MMRs laid out in the
24	  /sys/kernel/debug/blackfin/ directory where you can read/write
25	  MMRs directly from userspace.  This is obviously just a debug
26	  feature.
27
28config DEBUG_HWERR
29	bool "Hardware error interrupt debugging"
30	depends on DEBUG_KERNEL
31	help
32	  When enabled, the hardware error interrupt is never disabled, and
33	  will happen immediately when an error condition occurs.  This comes
34	  at a slight cost in code size, but is necessary if you are getting
35	  hardware error interrupts and need to know where they are coming
36	  from.
37
38config EXACT_HWERR
39	bool "Try to make Hardware errors exact"
40	depends on DEBUG_HWERR
41	help
42	  By default, the Blackfin hardware errors are not exact - the error
43          be reported multiple cycles after the error happens. This delay
44	  can cause the wrong application, or even the kernel to receive a
45	  signal to be killed. If you are getting HW errors in your system,
46	  try turning this on to ensure they are at least coming from the
47	  proper thread.
48
49	  On production systems, it is safe (and a small optimization) to say N.
50
51config DEBUG_DOUBLEFAULT
52	bool "Debug Double Faults"
53	default n
54	help
55	  If an exception is caused while executing code within the exception
56	  handler, the NMI handler, the reset vector, or in emulator mode,
57	  a double fault occurs. On the Blackfin, this is a unrecoverable
58	  event. You have two options:
59	  - RESET exactly when double fault occurs. The excepting
60	    instruction address is stored in RETX, where the next kernel
61	    boot will print it out.
62	  - Print debug message. This is much more error prone, although
63	    easier to handle. It is error prone since:
64	    - The excepting instruction is not committed.
65	    - All writebacks from the instruction are prevented.
66	    - The generated exception is not taken.
67	    - The EXCAUSE field is updated with an unrecoverable event
68	    The only way to check this is to see if EXCAUSE contains the
69	    unrecoverable event value at every exception return. By selecting
70	    this option, you are skipping over the faulting instruction, and 
71	    hoping things stay together enough to print out a debug message.
72
73	  This does add a little kernel code, but is the only method to debug
74	  double faults - if unsure say "Y"
75
76choice
77	prompt "Double Fault Failure Method"
78	default DEBUG_DOUBLEFAULT_PRINT
79	depends on DEBUG_DOUBLEFAULT
80
81config DEBUG_DOUBLEFAULT_PRINT
82	bool "Print"
83
84config DEBUG_DOUBLEFAULT_RESET
85	bool "Reset"
86
87endchoice
88
89config DEBUG_HUNT_FOR_ZERO
90	bool "Catch NULL pointer reads/writes"
91	default y
92	help
93	  Say Y here to catch reads/writes to anywhere in the memory range
94	  from 0x0000 - 0x0FFF (the first 4k) of memory.  This is useful in
95	  catching common programming errors such as NULL pointer dereferences.
96
97	  Misbehaving applications will be killed (generate a SEGV) while the
98	  kernel will trigger a panic.
99
100	  Enabling this option will take up an extra entry in CPLB table.
101	  Otherwise, there is no extra overhead.
102
103config DEBUG_BFIN_HWTRACE_ON
104	bool "Turn on Blackfin's Hardware Trace"
105	default y
106	help
107	  All Blackfins include a Trace Unit which stores a history of the last
108	  16 changes in program flow taken by the program sequencer. The history
109	  allows the user to recreate the program sequencer’s recent path. This
110	  can be handy when an application dies - we print out the execution
111	  path of how it got to the offending instruction.
112
113	  By turning this off, you may save a tiny amount of power.
114
115choice
116	prompt "Omit loop Tracing"
117	default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
118	depends on DEBUG_BFIN_HWTRACE_ON
119	help
120	  The trace buffer can be configured to omit recording of changes in
121	  program flow that match either the last entry or one of the last
122	  two entries. Omitting one of these entries from the record prevents
123	  the trace buffer from overflowing because of any sort of loop (for, do
124	  while, etc) in the program.
125
126	  Because zero-overhead Hardware loops are not recorded in the trace buffer,
127	  this feature can be used to prevent trace overflow from loops that
128	  are nested four deep.
129
130config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
131	bool "Trace all Loops"
132	help
133	  The trace buffer records all changes of flow 
134
135config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
136	bool "Compress single-level loops"
137	help
138	  The trace buffer does not record single loops - helpful if trace 
139	  is spinning on a while or do loop.
140
141config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
142	bool "Compress two-level loops"
143	help
144	  The trace buffer does not record loops two levels deep. Helpful if
145	  the trace is spinning in a nested loop
146
147endchoice
148
149config DEBUG_BFIN_HWTRACE_COMPRESSION
150	int
151	depends on DEBUG_BFIN_HWTRACE_ON
152	default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
153	default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
154	default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
155
156
157config DEBUG_BFIN_HWTRACE_EXPAND
158	bool "Expand Trace Buffer greater than 16 entries"
159	depends on DEBUG_BFIN_HWTRACE_ON
160	default n
161	help
162	  By selecting this option, every time the 16 hardware entries in
163	  the Blackfin's HW Trace buffer are full, the kernel will move them
164	  into a software buffer, for dumping when there is an issue. This 
165	  has a great impact on performance, (an interrupt every 16 change of 
166	  flows) and should normally be turned off, except in those nasty
167	  debugging sessions
168
169config DEBUG_BFIN_HWTRACE_EXPAND_LEN
170	int "Size of Trace buffer (in power of 2k)"
171	range 0 4
172	depends on DEBUG_BFIN_HWTRACE_EXPAND
173	default 1
174	help
175	  This sets the size of the software buffer that the trace information
176	  is kept in.
177	  0 for (2^0)  1k, or 256 entries,
178	  1 for (2^1)  2k, or 512 entries,
179	  2 for (2^2)  4k, or 1024 entries,
180	  3 for (2^3)  8k, or 2048 entries,
181	  4 for (2^4) 16k, or 4096 entries
182
183config DEBUG_BFIN_NO_KERN_HWTRACE
184	bool "Turn off hwtrace in CPLB handlers"
185	depends on DEBUG_BFIN_HWTRACE_ON
186	default y
187	help
188	  The CPLB error handler contains a lot of flow changes which can
189	  quickly fill up the hardware trace buffer.  When debugging crashes,
190	  the hardware trace may indicate that the problem lies in kernel
191	  space when in reality an application is buggy.
192
193	  Say Y here to disable hardware tracing in some known "jumpy" pieces
194	  of code so that the trace buffer will extend further back.
195
196config EARLY_PRINTK
197	bool "Early printk" 
198	default n
199	select SERIAL_CORE_CONSOLE
200	help
201	  This option enables special console drivers which allow the kernel
202	  to print messages very early in the bootup process.
203
204	  This is useful for kernel debugging when your machine crashes very
205	  early before the console code is initialized. After enabling this
206	  feature, you must add "earlyprintk=serial,uart0,57600" to the
207	  command line (bootargs). It is safe to say Y here in all cases, as
208	  all of this lives in the init section and is thrown away after the
209	  kernel boots completely.
210
211config NMI_WATCHDOG
212	bool "Enable NMI watchdog to help debugging lockup on SMP"
213	default n
214	depends on SMP
215	help
216	  If any CPU in the system does not execute the period local timer
217	  interrupt for more than 5 seconds, then the NMI handler dumps debug
218	  information. This information can be used to debug the lockup.
219
220config CPLB_INFO
221	bool "Display the CPLB information"
222	help
223	  Display the CPLB information via /proc/cplbinfo.
224
225config ACCESS_CHECK
226	bool "Check the user pointer address"
227	default y
228	help
229	  Usually the pointer transfer from user space is checked to see if its
230	  address is in the kernel space.
231
232	  Say N here to disable that check to improve the performance.
233
234config BFIN_ISRAM_SELF_TEST
235	bool "isram boot self tests"
236	default n
237	help
238	  Run some self tests of the isram driver code at boot.
239
240config BFIN_PSEUDODBG_INSNS
241	bool "Support pseudo debug instructions"
242	default n
243	help
244	  This option allows the kernel to emulate some pseudo instructions which
245	  allow simulator test cases to be run under Linux with no changes.
246
247	  Most people should say N here.
248
249config BFIN_PM_WAKEUP_TIME_BENCH
250	bool "Display the total time for kernel to resume from power saving mode"
251	default n
252	help
253	  Display the total time when kernel resumes normal from standby or
254	  suspend to mem mode.
255
256endmenu
257