linux/arch/blackfin/Kconfig.debug
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   1menu "Kernel hacking"
   2
   3source "lib/Kconfig.debug"
   4
   5config 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
  12config 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
  25config 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
  35config 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
  45config 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
  58config 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
  83choice
  84        prompt "Double Fault Failure Method"
  85        default DEBUG_DOUBLEFAULT_PRINT
  86        depends on DEBUG_DOUBLEFAULT
  87
  88config DEBUG_DOUBLEFAULT_PRINT
  89        bool "Print"
  90
  91config DEBUG_DOUBLEFAULT_RESET
  92        bool "Reset"
  93
  94endchoice
  95
  96config 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
 110config 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
 122choice
 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
 137config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 138        bool "Trace all Loops"
 139        help
 140          The trace buffer records all changes of flow 
 141
 142config 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
 148config 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
 154endchoice
 155
 156config 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
 164config 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
 176config 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
 190config 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
 203config 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
 218config 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
 227config CPLB_INFO
 228        bool "Display the CPLB information"
 229        help
 230          Display the CPLB information via /proc/cplbinfo.
 231
 232config 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
 241config 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
 247config 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
 256config 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
 263endmenu
 264
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