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_STACK_USAGE
  13         bool "Enable stack utilization instrumentation"
  14         depends on DEBUG_KERNEL
  15         help
  16           Enables the display of the minimum amount of free stack which each
  17           task has ever had available in the sysrq-T output.
  18
  19           This option will slow down process creation somewhat.
  20
  21 config HAVE_ARCH_KGDB
  22         def_bool y
  23
  24 config DEBUG_VERBOSE
  25         bool "Verbose fault messages"
  26         default y
  27         select PRINTK
  28         help
  29           When a program crashes due to an exception, or the kernel detects
  30           an internal error, the kernel can print a not so brief message
  31           explaining what the problem was. This debugging information is
  32           useful to developers and kernel hackers when tracking down problems,
  33           but mostly meaningless to other people. This is always helpful for
  34           debugging but serves no purpose on a production system.
  35           Most people should say N here.
  36
  37 config DEBUG_MMRS
  38         bool "Generate Blackfin MMR tree"
  39         select DEBUG_FS
  40         help
  41           Create a tree of Blackfin MMRs via the debugfs tree.  If
  42           you enable this, you will find all MMRs laid out in the
  43           /sys/kernel/debug/blackfin/ directory where you can read/write
  44           MMRs directly from userspace.  This is obviously just a debug
  45           feature.
  46
  47 config DEBUG_HWERR
  48         bool "Hardware error interrupt debugging"
  49         depends on DEBUG_KERNEL
  50         help
  51           When enabled, the hardware error interrupt is never disabled, and
  52           will happen immediately when an error condition occurs.  This comes
  53           at a slight cost in code size, but is necessary if you are getting
  54           hardware error interrupts and need to know where they are coming
  55           from.
  56
  57 config EXACT_HWERR
  58         bool "Try to make Hardware errors exact"
  59         depends on DEBUG_HWERR
  60         help
  61           By default, the Blackfin hardware errors are not exact - the error
  62           be reported multiple cycles after the error happens. This delay
  63           can cause the wrong application, or even the kernel to receive a
  64           signal to be killed. If you are getting HW errors in your system,
  65           try turning this on to ensure they are at least comming from the
  66           proper thread.
  67
  68           On production systems, it is safe (and a small optimization) to say N.
  69
  70 config DEBUG_DOUBLEFAULT
  71         bool "Debug Double Faults"
  72         default n
  73         help
  74           If an exception is caused while executing code within the exception
  75           handler, the NMI handler, the reset vector, or in emulator mode,
  76           a double fault occurs. On the Blackfin, this is a unrecoverable
  77           event. You have two options:
  78           - RESET exactly when double fault occurs. The excepting
  79             instruction address is stored in RETX, where the next kernel
  80             boot will print it out.
  81           - Print debug message. This is much more error prone, although
  82             easier to handle. It is error prone since:
  83             - The excepting instruction is not committed.
  84             - All writebacks from the instruction are prevented.
  85             - The generated exception is not taken.
  86             - The EXCAUSE field is updated with an unrecoverable event
  87             The only way to check this is to see if EXCAUSE contains the
  88             unrecoverable event value at every exception return. By selecting
  89             this option, you are skipping over the faulting instruction, and
  90             hoping things stay together enough to print out a debug message.
  91
  92           This does add a little kernel code, but is the only method to debug
  93           double faults - if unsure say "Y"
  94
  95 choice
  96         prompt "Double Fault Failure Method"
  97         default DEBUG_DOUBLEFAULT_PRINT
  98         depends on DEBUG_DOUBLEFAULT
  99
 100 config DEBUG_DOUBLEFAULT_PRINT
 101         bool "Print"
 102
 103 config DEBUG_DOUBLEFAULT_RESET
 104         bool "Reset"
 105
 106 endchoice
 107
 108 config DEBUG_ICACHE_CHECK
 109         bool "Check Instruction cache coherency"
 110         depends on DEBUG_KERNEL
 111         depends on DEBUG_HWERR
 112         help
 113           Say Y here if you are getting weird unexplained errors. This will
 114           ensure that icache is what SDRAM says it should be by doing a
 115           byte wise comparison between SDRAM and instruction cache. This
 116           also relocates the irq_panic() function to L1 memory, (which is
 117           un-cached).
 118
 119 config DEBUG_HUNT_FOR_ZERO
 120         bool "Catch NULL pointer reads/writes"
 121         default y
 122         help
 123           Say Y here to catch reads/writes to anywhere in the memory range
 124           from 0x0000 - 0x0FFF (the first 4k) of memory.  This is useful in
 125           catching common programming errors such as NULL pointer dereferences.
 126
 127           Misbehaving applications will be killed (generate a SEGV) while the
 128           kernel will trigger a panic.
 129
 130           Enabling this option will take up an extra entry in CPLB table.
 131           Otherwise, there is no extra overhead.
 132
 133 config DEBUG_BFIN_HWTRACE_ON
 134         bool "Turn on Blackfin's Hardware Trace"
 135         default y
 136         help
 137           All Blackfins include a Trace Unit which stores a history of the last
 138           16 changes in program flow taken by the program sequencer. The history
 139           allows the user to recreate the program sequencer’s recent path. This
 140           can be handy when an application dies - we print out the execution
 141           path of how it got to the offending instruction.
 142
 143           By turning this off, you may save a tiny amount of power.
 144
 145 choice
 146         prompt "Omit loop Tracing"
 147         default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 148         depends on DEBUG_BFIN_HWTRACE_ON
 149         help
 150           The trace buffer can be configured to omit recording of changes in
 151           program flow that match either the last entry or one of the last
 152           two entries. Omitting one of these entries from the record prevents
 153           the trace buffer from overflowing because of any sort of loop (for, do
 154           while, etc) in the program.
 155
 156           Because zero-overhead Hardware loops are not recorded in the trace buffer,
 157           this feature can be used to prevent trace overflow from loops that
 158           are nested four deep.
 159
 160 config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 161         bool "Trace all Loops"
 162         help
 163           The trace buffer records all changes of flow
 164
 165 config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
 166         bool "Compress single-level loops"
 167         help
 168           The trace buffer does not record single loops - helpful if trace
 169           is spinning on a while or do loop.
 170
 171 config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
 172         bool "Compress two-level loops"
 173         help
 174           The trace buffer does not record loops two levels deep. Helpful if
 175           the trace is spinning in a nested loop
 176
 177 endchoice
 178
 179 config DEBUG_BFIN_HWTRACE_COMPRESSION
 180         int
 181         depends on DEBUG_BFIN_HWTRACE_ON
 182         default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 183         default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
 184         default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
 185
 186
 187 config DEBUG_BFIN_HWTRACE_EXPAND
 188         bool "Expand Trace Buffer greater than 16 entries"
 189         depends on DEBUG_BFIN_HWTRACE_ON
 190         default n
 191         help
 192           By selecting this option, every time the 16 hardware entries in
 193           the Blackfin's HW Trace buffer are full, the kernel will move them
 194           into a software buffer, for dumping when there is an issue. This
 195           has a great impact on performance, (an interrupt every 16 change of
 196           flows) and should normally be turned off, except in those nasty
 197           debugging sessions
 198
 199 config DEBUG_BFIN_HWTRACE_EXPAND_LEN
 200         int "Size of Trace buffer (in power of 2k)"
 201         range 0 4
 202         depends on DEBUG_BFIN_HWTRACE_EXPAND
 203         default 1
 204         help
 205           This sets the size of the software buffer that the trace information
 206           is kept in.
 207           0 for (2^0)  1k, or 256 entries,
 208           1 for (2^1)  2k, or 512 entries,
 209           2 for (2^2)  4k, or 1024 entries,
 210           3 for (2^3)  8k, or 2048 entries,
 211           4 for (2^4) 16k, or 4096 entries
 212
 213 config DEBUG_BFIN_NO_KERN_HWTRACE
 214         bool "Turn off hwtrace in CPLB handlers"
 215         depends on DEBUG_BFIN_HWTRACE_ON
 216         default y
 217         help
 218           The CPLB error handler contains a lot of flow changes which can
 219           quickly fill up the hardware trace buffer.  When debugging crashes,
 220           the hardware trace may indicate that the problem lies in kernel
 221           space when in reality an application is buggy.
 222
 223           Say Y here to disable hardware tracing in some known "jumpy" pieces
 224           of code so that the trace buffer will extend further back.
 225
 226 config EARLY_PRINTK
 227         bool "Early printk"
 228         default n
 229         select SERIAL_CORE_CONSOLE
 230         help
 231           This option enables special console drivers which allow the kernel
 232           to print messages very early in the bootup process.
 233
 234           This is useful for kernel debugging when your machine crashes very
 235           early before the console code is initialized. After enabling this
 236           feature, you must add "earlyprintk=serial,uart0,57600" to the
 237           command line (bootargs). It is safe to say Y here in all cases, as
 238           all of this lives in the init section and is thrown away after the
 239           kernel boots completely.
 240
 241 config CPLB_INFO
 242         bool "Display the CPLB information"
 243         help
 244           Display the CPLB information via /proc/cplbinfo.
 245
 246 config ACCESS_CHECK
 247         bool "Check the user pointer address"
 248         default y
 249         help
 250           Usually the pointer transfer from user space is checked to see if its
 251           address is in the kernel space.
 252
 253           Say N here to disable that check to improve the performance.
 254
 255 config BFIN_ISRAM_SELF_TEST
 256         bool "isram boot self tests"
 257         default n
 258         help
 259           Run some self tests of the isram driver code at boot.
 260
 261 endmenu