1 # SPDX-License-Identifier: GPL-2.0
4 source "lib/Kconfig.debug"
7 bool "Verbose fault messages"
11 When a program crashes due to an exception, or the kernel detects
12 an internal error, the kernel can print a not so brief message
13 explaining what the problem was. This debugging information is
14 useful to developers and kernel hackers when tracking down problems,
15 but mostly meaningless to other people. This is always helpful for
16 debugging but serves no purpose on a production system.
17 Most people should say N here.
20 tristate "Generate Blackfin MMR tree"
24 Create a tree of Blackfin MMRs via the debugfs tree. If
25 you enable this, you will find all MMRs laid out in the
26 /sys/kernel/debug/blackfin/ directory where you can read/write
27 MMRs directly from userspace. This is obviously just a debug
31 bool "Hardware error interrupt debugging"
32 depends on DEBUG_KERNEL
34 When enabled, the hardware error interrupt is never disabled, and
35 will happen immediately when an error condition occurs. This comes
36 at a slight cost in code size, but is necessary if you are getting
37 hardware error interrupts and need to know where they are coming
41 bool "Try to make Hardware errors exact"
42 depends on DEBUG_HWERR
44 By default, the Blackfin hardware errors are not exact - the error
45 be reported multiple cycles after the error happens. This delay
46 can cause the wrong application, or even the kernel to receive a
47 signal to be killed. If you are getting HW errors in your system,
48 try turning this on to ensure they are at least coming from the
51 On production systems, it is safe (and a small optimization) to say N.
53 config DEBUG_DOUBLEFAULT
54 bool "Debug Double Faults"
57 If an exception is caused while executing code within the exception
58 handler, the NMI handler, the reset vector, or in emulator mode,
59 a double fault occurs. On the Blackfin, this is a unrecoverable
60 event. You have two options:
61 - RESET exactly when double fault occurs. The excepting
62 instruction address is stored in RETX, where the next kernel
63 boot will print it out.
64 - Print debug message. This is much more error prone, although
65 easier to handle. It is error prone since:
66 - The excepting instruction is not committed.
67 - All writebacks from the instruction are prevented.
68 - The generated exception is not taken.
69 - The EXCAUSE field is updated with an unrecoverable event
70 The only way to check this is to see if EXCAUSE contains the
71 unrecoverable event value at every exception return. By selecting
72 this option, you are skipping over the faulting instruction, and
73 hoping things stay together enough to print out a debug message.
75 This does add a little kernel code, but is the only method to debug
76 double faults - if unsure say "Y"
79 prompt "Double Fault Failure Method"
80 default DEBUG_DOUBLEFAULT_PRINT
81 depends on DEBUG_DOUBLEFAULT
83 config DEBUG_DOUBLEFAULT_PRINT
86 config DEBUG_DOUBLEFAULT_RESET
91 config DEBUG_HUNT_FOR_ZERO
92 bool "Catch NULL pointer reads/writes"
95 Say Y here to catch reads/writes to anywhere in the memory range
96 from 0x0000 - 0x0FFF (the first 4k) of memory. This is useful in
97 catching common programming errors such as NULL pointer dereferences.
99 Misbehaving applications will be killed (generate a SEGV) while the
100 kernel will trigger a panic.
102 Enabling this option will take up an extra entry in CPLB table.
103 Otherwise, there is no extra overhead.
105 config DEBUG_BFIN_HWTRACE_ON
106 bool "Turn on Blackfin's Hardware Trace"
109 All Blackfins include a Trace Unit which stores a history of the last
110 16 changes in program flow taken by the program sequencer. The history
111 allows the user to recreate the program sequencer’s recent path. This
112 can be handy when an application dies - we print out the execution
113 path of how it got to the offending instruction.
115 By turning this off, you may save a tiny amount of power.
118 prompt "Omit loop Tracing"
119 default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
120 depends on DEBUG_BFIN_HWTRACE_ON
122 The trace buffer can be configured to omit recording of changes in
123 program flow that match either the last entry or one of the last
124 two entries. Omitting one of these entries from the record prevents
125 the trace buffer from overflowing because of any sort of loop (for, do
126 while, etc) in the program.
128 Because zero-overhead Hardware loops are not recorded in the trace buffer,
129 this feature can be used to prevent trace overflow from loops that
130 are nested four deep.
132 config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
133 bool "Trace all Loops"
135 The trace buffer records all changes of flow
137 config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
138 bool "Compress single-level loops"
140 The trace buffer does not record single loops - helpful if trace
141 is spinning on a while or do loop.
143 config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
144 bool "Compress two-level loops"
146 The trace buffer does not record loops two levels deep. Helpful if
147 the trace is spinning in a nested loop
151 config DEBUG_BFIN_HWTRACE_COMPRESSION
153 depends on DEBUG_BFIN_HWTRACE_ON
154 default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
155 default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
156 default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
159 config DEBUG_BFIN_HWTRACE_EXPAND
160 bool "Expand Trace Buffer greater than 16 entries"
161 depends on DEBUG_BFIN_HWTRACE_ON
164 By selecting this option, every time the 16 hardware entries in
165 the Blackfin's HW Trace buffer are full, the kernel will move them
166 into a software buffer, for dumping when there is an issue. This
167 has a great impact on performance, (an interrupt every 16 change of
168 flows) and should normally be turned off, except in those nasty
171 config DEBUG_BFIN_HWTRACE_EXPAND_LEN
172 int "Size of Trace buffer (in power of 2k)"
174 depends on DEBUG_BFIN_HWTRACE_EXPAND
177 This sets the size of the software buffer that the trace information
179 0 for (2^0) 1k, or 256 entries,
180 1 for (2^1) 2k, or 512 entries,
181 2 for (2^2) 4k, or 1024 entries,
182 3 for (2^3) 8k, or 2048 entries,
183 4 for (2^4) 16k, or 4096 entries
185 config DEBUG_BFIN_NO_KERN_HWTRACE
186 bool "Turn off hwtrace in CPLB handlers"
187 depends on DEBUG_BFIN_HWTRACE_ON
190 The CPLB error handler contains a lot of flow changes which can
191 quickly fill up the hardware trace buffer. When debugging crashes,
192 the hardware trace may indicate that the problem lies in kernel
193 space when in reality an application is buggy.
195 Say Y here to disable hardware tracing in some known "jumpy" pieces
196 of code so that the trace buffer will extend further back.
201 select SERIAL_CORE_CONSOLE
203 This option enables special console drivers which allow the kernel
204 to print messages very early in the bootup process.
206 This is useful for kernel debugging when your machine crashes very
207 early before the console code is initialized. After enabling this
208 feature, you must add "earlyprintk=serial,uart0,57600" to the
209 command line (bootargs). It is safe to say Y here in all cases, as
210 all of this lives in the init section and is thrown away after the
211 kernel boots completely.
214 bool "Enable NMI watchdog to help debugging lockup on SMP"
218 If any CPU in the system does not execute the period local timer
219 interrupt for more than 5 seconds, then the NMI handler dumps debug
220 information. This information can be used to debug the lockup.
223 bool "Display the CPLB information"
225 Display the CPLB information via /proc/cplbinfo.
228 bool "Check the user pointer address"
231 Usually the pointer transfer from user space is checked to see if its
232 address is in the kernel space.
234 Say N here to disable that check to improve the performance.
236 config BFIN_ISRAM_SELF_TEST
237 bool "isram boot self tests"
240 Run some self tests of the isram driver code at boot.
242 config BFIN_PSEUDODBG_INSNS
243 bool "Support pseudo debug instructions"
246 This option allows the kernel to emulate some pseudo instructions which
247 allow simulator test cases to be run under Linux with no changes.
249 Most people should say N here.
251 config BFIN_PM_WAKEUP_TIME_BENCH
252 bool "Display the total time for kernel to resume from power saving mode"
255 Display the total time when kernel resumes normal from standby or