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Linux/arch/blackfin/Kconfig.debug

  1 menu "Kernel hacking"
  2 
  3 source "lib/Kconfig.debug"
  4 
  5 config 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 
 18 config 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 
 28 config 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 
 38 config 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 
 51 config 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 
 76 choice
 77         prompt "Double Fault Failure Method"
 78         default DEBUG_DOUBLEFAULT_PRINT
 79         depends on DEBUG_DOUBLEFAULT
 80 
 81 config DEBUG_DOUBLEFAULT_PRINT
 82         bool "Print"
 83 
 84 config DEBUG_DOUBLEFAULT_RESET
 85         bool "Reset"
 86 
 87 endchoice
 88 
 89 config 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 
103 config 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 
115 choice
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 
130 config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
131         bool "Trace all Loops"
132         help
133           The trace buffer records all changes of flow 
134 
135 config 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 
141 config 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 
147 endchoice
148 
149 config 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 
157 config 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 
169 config 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 
183 config 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 
196 config 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 
211 config 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 
220 config CPLB_INFO
221         bool "Display the CPLB information"
222         help
223           Display the CPLB information via /proc/cplbinfo.
224 
225 config 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 
234 config 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 
240 config 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 
249 config 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 
256 endmenu

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