arch/blackfin/Kconfig.debug

   1 menu "Kernel hacking"
   2
   3 source "lib/Kconfig.debug"
   4
   5 config DEBUG_STACKOVERFLOW
   6         bool "Check for stack overflows"
   7         depends on DEBUG_KERNEL
   8         help
   9           This option will cause messages to be printed if free stack space
  10           drops below a certain limit.
  11
  12 config DEBUG_VERBOSE
  13         bool "Verbose fault messages"
  14         default y
  15         select PRINTK
  16         help
  17           When a program crashes due to an exception, or the kernel detects
  18           an internal error, the kernel can print a not so brief message
  19           explaining what the problem was. This debugging information is
  20           useful to developers and kernel hackers when tracking down problems,
  21           but mostly meaningless to other people. This is always helpful for
  22           debugging but serves no purpose on a production system.
  23           Most people should say N here.
  24
  25 config DEBUG_MMRS
  26         tristate "Generate Blackfin MMR tree"
  27         select DEBUG_FS
  28         help
  29           Create a tree of Blackfin MMRs via the debugfs tree.  If
  30           you enable this, you will find all MMRs laid out in the
  31           /sys/kernel/debug/blackfin/ directory where you can read/write
  32           MMRs directly from userspace.  This is obviously just a debug
  33           feature.
  34
  35 config DEBUG_HWERR
  36         bool "Hardware error interrupt debugging"
  37         depends on DEBUG_KERNEL
  38         help
  39           When enabled, the hardware error interrupt is never disabled, and
  40           will happen immediately when an error condition occurs.  This comes
  41           at a slight cost in code size, but is necessary if you are getting
  42           hardware error interrupts and need to know where they are coming
  43           from.
  44
  45 config EXACT_HWERR
  46         bool "Try to make Hardware errors exact"
  47         depends on DEBUG_HWERR
  48         help
  49           By default, the Blackfin hardware errors are not exact - the error
  50           be reported multiple cycles after the error happens. This delay
  51           can cause the wrong application, or even the kernel to receive a
  52           signal to be killed. If you are getting HW errors in your system,
  53           try turning this on to ensure they are at least coming from the
  54           proper thread.
  55
  56           On production systems, it is safe (and a small optimization) to say N.
  57
  58 config DEBUG_DOUBLEFAULT
  59         bool "Debug Double Faults"
  60         default n
  61         help
  62           If an exception is caused while executing code within the exception
  63           handler, the NMI handler, the reset vector, or in emulator mode,
  64           a double fault occurs. On the Blackfin, this is a unrecoverable
  65           event. You have two options:
  66           - RESET exactly when double fault occurs. The excepting
  67             instruction address is stored in RETX, where the next kernel
  68             boot will print it out.
  69           - Print debug message. This is much more error prone, although
  70             easier to handle. It is error prone since:
  71             - The excepting instruction is not committed.
  72             - All writebacks from the instruction are prevented.
  73             - The generated exception is not taken.
  74             - The EXCAUSE field is updated with an unrecoverable event
  75             The only way to check this is to see if EXCAUSE contains the
  76             unrecoverable event value at every exception return. By selecting
  77             this option, you are skipping over the faulting instruction, and
  78             hoping things stay together enough to print out a debug message.
  79
  80           This does add a little kernel code, but is the only method to debug
  81           double faults - if unsure say "Y"
  82
  83 choice
  84         prompt "Double Fault Failure Method"
  85         default DEBUG_DOUBLEFAULT_PRINT
  86         depends on DEBUG_DOUBLEFAULT
  87
  88 config DEBUG_DOUBLEFAULT_PRINT
  89         bool "Print"
  90
  91 config DEBUG_DOUBLEFAULT_RESET
  92         bool "Reset"
  93
  94 endchoice
  95
  96 config DEBUG_HUNT_FOR_ZERO
  97         bool "Catch NULL pointer reads/writes"
  98         default y
  99         help
 100           Say Y here to catch reads/writes to anywhere in the memory range
 101           from 0x0000 - 0x0FFF (the first 4k) of memory.  This is useful in
 102           catching common programming errors such as NULL pointer dereferences.
 103
 104           Misbehaving applications will be killed (generate a SEGV) while the
 105           kernel will trigger a panic.
 106
 107           Enabling this option will take up an extra entry in CPLB table.
 108           Otherwise, there is no extra overhead.
 109
 110 config DEBUG_BFIN_HWTRACE_ON
 111         bool "Turn on Blackfin's Hardware Trace"
 112         default y
 113         help
 114           All Blackfins include a Trace Unit which stores a history of the last
 115           16 changes in program flow taken by the program sequencer. The history
 116           allows the user to recreate the program sequencer’s recent path. This
 117           can be handy when an application dies - we print out the execution
 118           path of how it got to the offending instruction.
 119
 120           By turning this off, you may save a tiny amount of power.
 121
 122 choice
 123         prompt "Omit loop Tracing"
 124         default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 125         depends on DEBUG_BFIN_HWTRACE_ON
 126         help
 127           The trace buffer can be configured to omit recording of changes in
 128           program flow that match either the last entry or one of the last
 129           two entries. Omitting one of these entries from the record prevents
 130           the trace buffer from overflowing because of any sort of loop (for, do
 131           while, etc) in the program.
 132
 133           Because zero-overhead Hardware loops are not recorded in the trace buffer,
 134           this feature can be used to prevent trace overflow from loops that
 135           are nested four deep.
 136
 137 config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 138         bool "Trace all Loops"
 139         help
 140           The trace buffer records all changes of flow
 141
 142 config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
 143         bool "Compress single-level loops"
 144         help
 145           The trace buffer does not record single loops - helpful if trace
 146           is spinning on a while or do loop.
 147
 148 config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
 149         bool "Compress two-level loops"
 150         help
 151           The trace buffer does not record loops two levels deep. Helpful if
 152           the trace is spinning in a nested loop
 153
 154 endchoice
 155
 156 config DEBUG_BFIN_HWTRACE_COMPRESSION
 157         int
 158         depends on DEBUG_BFIN_HWTRACE_ON
 159         default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 160         default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
 161         default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
 162
 163
 164 config DEBUG_BFIN_HWTRACE_EXPAND
 165         bool "Expand Trace Buffer greater than 16 entries"
 166         depends on DEBUG_BFIN_HWTRACE_ON
 167         default n
 168         help
 169           By selecting this option, every time the 16 hardware entries in
 170           the Blackfin's HW Trace buffer are full, the kernel will move them
 171           into a software buffer, for dumping when there is an issue. This
 172           has a great impact on performance, (an interrupt every 16 change of
 173           flows) and should normally be turned off, except in those nasty
 174           debugging sessions
 175
 176 config DEBUG_BFIN_HWTRACE_EXPAND_LEN
 177         int "Size of Trace buffer (in power of 2k)"
 178         range 0 4
 179         depends on DEBUG_BFIN_HWTRACE_EXPAND
 180         default 1
 181         help
 182           This sets the size of the software buffer that the trace information
 183           is kept in.
 184           0 for (2^0)  1k, or 256 entries,
 185           1 for (2^1)  2k, or 512 entries,
 186           2 for (2^2)  4k, or 1024 entries,
 187           3 for (2^3)  8k, or 2048 entries,
 188           4 for (2^4) 16k, or 4096 entries
 189
 190 config DEBUG_BFIN_NO_KERN_HWTRACE
 191         bool "Turn off hwtrace in CPLB handlers"
 192         depends on DEBUG_BFIN_HWTRACE_ON
 193         default y
 194         help
 195           The CPLB error handler contains a lot of flow changes which can
 196           quickly fill up the hardware trace buffer.  When debugging crashes,
 197           the hardware trace may indicate that the problem lies in kernel
 198           space when in reality an application is buggy.
 199
 200           Say Y here to disable hardware tracing in some known "jumpy" pieces
 201           of code so that the trace buffer will extend further back.
 202
 203 config EARLY_PRINTK
 204         bool "Early printk"
 205         default n
 206         select SERIAL_CORE_CONSOLE
 207         help
 208           This option enables special console drivers which allow the kernel
 209           to print messages very early in the bootup process.
 210
 211           This is useful for kernel debugging when your machine crashes very
 212           early before the console code is initialized. After enabling this
 213           feature, you must add "earlyprintk=serial,uart0,57600" to the
 214           command line (bootargs). It is safe to say Y here in all cases, as
 215           all of this lives in the init section and is thrown away after the
 216           kernel boots completely.
 217
 218 config NMI_WATCHDOG
 219         bool "Enable NMI watchdog to help debugging lockup on SMP"
 220         default n
 221         depends on SMP
 222         help
 223           If any CPU in the system does not execute the period local timer
 224           interrupt for more than 5 seconds, then the NMI handler dumps debug
 225           information. This information can be used to debug the lockup.
 226
 227 config CPLB_INFO
 228         bool "Display the CPLB information"
 229         help
 230           Display the CPLB information via /proc/cplbinfo.
 231
 232 config ACCESS_CHECK
 233         bool "Check the user pointer address"
 234         default y
 235         help
 236           Usually the pointer transfer from user space is checked to see if its
 237           address is in the kernel space.
 238
 239           Say N here to disable that check to improve the performance.
 240
 241 config BFIN_ISRAM_SELF_TEST
 242         bool "isram boot self tests"
 243         default n
 244         help
 245           Run some self tests of the isram driver code at boot.
 246
 247 config BFIN_PSEUDODBG_INSNS
 248         bool "Support pseudo debug instructions"
 249         default n
 250         help
 251           This option allows the kernel to emulate some pseudo instructions which
 252           allow simulator test cases to be run under Linux with no changes.
 253
 254           Most people should say N here.
 255
 256 config BFIN_PM_WAKEUP_TIME_BENCH
 257         bool "Display the total time for kernel to resume from power saving mode"
 258         default n
 259         help
 260           Display the total time when kernel resumes normal from standby or
 261           suspend to mem mode.
 262
 263 endmenu