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 DEBUG_DOUBLEFAULT
  58         bool "Debug Double Faults"
  59         default n
  60         help
  61           If an exception is caused while executing code within the exception
  62           handler, the NMI handler, the reset vector, or in emulator mode,
  63           a double fault occurs. On the Blackfin, this is a unrecoverable
  64           event. You have two options:
  65           - RESET exactly when double fault occurs. The excepting
  66             instruction address is stored in RETX, where the next kernel
  67             boot will print it out.
  68           - Print debug message. This is much more error prone, although
  69             easier to handle. It is error prone since:
  70             - The excepting instruction is not committed.
  71             - All writebacks from the instruction are prevented.
  72             - The generated exception is not taken.
  73             - The EXCAUSE field is updated with an unrecoverable event
  74             The only way to check this is to see if EXCAUSE contains the
  75             unrecoverable event value at every exception return. By selecting
  76             this option, you are skipping over the faulting instruction, and
  77             hoping things stay together enough to print out a debug message.
  78
  79           This does add a little kernel code, but is the only method to debug
  80           double faults - if unsure say "Y"
  81
  82 choice
  83         prompt "Double Fault Failure Method"
  84         default DEBUG_DOUBLEFAULT_PRINT
  85         depends on DEBUG_DOUBLEFAULT
  86
  87 config DEBUG_DOUBLEFAULT_PRINT
  88         bool "Print"
  89
  90 config DEBUG_DOUBLEFAULT_RESET
  91         bool "Reset"
  92
  93 endchoice
  94
  95 config DEBUG_ICACHE_CHECK
  96         bool "Check Instruction cache coherency"
  97         depends on DEBUG_KERNEL
  98         depends on DEBUG_HWERR
  99         help
 100           Say Y here if you are getting weird unexplained errors. This will
 101           ensure that icache is what SDRAM says it should be by doing a
 102           byte wise comparison between SDRAM and instruction cache. This
 103           also relocates the irq_panic() function to L1 memory, (which is
 104           un-cached).
 105
 106 config DEBUG_HUNT_FOR_ZERO
 107         bool "Catch NULL pointer reads/writes"
 108         default y
 109         help
 110           Say Y here to catch reads/writes to anywhere in the memory range
 111           from 0x0000 - 0x0FFF (the first 4k) of memory.  This is useful in
 112           catching common programming errors such as NULL pointer dereferences.
 113
 114           Misbehaving applications will be killed (generate a SEGV) while the
 115           kernel will trigger a panic.
 116
 117           Enabling this option will take up an extra entry in CPLB table.
 118           Otherwise, there is no extra overhead.
 119
 120 config DEBUG_BFIN_HWTRACE_ON
 121         bool "Turn on Blackfin's Hardware Trace"
 122         default y
 123         help
 124           All Blackfins include a Trace Unit which stores a history of the last
 125           16 changes in program flow taken by the program sequencer. The history
 126           allows the user to recreate the program sequencer’s recent path. This
 127           can be handy when an application dies - we print out the execution
 128           path of how it got to the offending instruction.
 129
 130           By turning this off, you may save a tiny amount of power.
 131
 132 choice
 133         prompt "Omit loop Tracing"
 134         default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 135         depends on DEBUG_BFIN_HWTRACE_ON
 136         help
 137           The trace buffer can be configured to omit recording of changes in
 138           program flow that match either the last entry or one of the last
 139           two entries. Omitting one of these entries from the record prevents
 140           the trace buffer from overflowing because of any sort of loop (for, do
 141           while, etc) in the program.
 142
 143           Because zero-overhead Hardware loops are not recorded in the trace buffer,
 144           this feature can be used to prevent trace overflow from loops that
 145           are nested four deep.
 146
 147 config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 148         bool "Trace all Loops"
 149         help
 150           The trace buffer records all changes of flow
 151
 152 config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
 153         bool "Compress single-level loops"
 154         help
 155           The trace buffer does not record single loops - helpful if trace
 156           is spinning on a while or do loop.
 157
 158 config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
 159         bool "Compress two-level loops"
 160         help
 161           The trace buffer does not record loops two levels deep. Helpful if
 162           the trace is spinning in a nested loop
 163
 164 endchoice
 165
 166 config DEBUG_BFIN_HWTRACE_COMPRESSION
 167         int
 168         depends on DEBUG_BFIN_HWTRACE_ON
 169         default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 170         default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
 171         default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
 172
 173
 174 config DEBUG_BFIN_HWTRACE_EXPAND
 175         bool "Expand Trace Buffer greater than 16 entries"
 176         depends on DEBUG_BFIN_HWTRACE_ON
 177         default n
 178         help
 179           By selecting this option, every time the 16 hardware entries in
 180           the Blackfin's HW Trace buffer are full, the kernel will move them
 181           into a software buffer, for dumping when there is an issue. This
 182           has a great impact on performance, (an interrupt every 16 change of
 183           flows) and should normally be turned off, except in those nasty
 184           debugging sessions
 185
 186 config DEBUG_BFIN_HWTRACE_EXPAND_LEN
 187         int "Size of Trace buffer (in power of 2k)"
 188         range 0 4
 189         depends on DEBUG_BFIN_HWTRACE_EXPAND
 190         default 1
 191         help
 192           This sets the size of the software buffer that the trace information
 193           is kept in.
 194           0 for (2^0)  1k, or 256 entries,
 195           1 for (2^1)  2k, or 512 entries,
 196           2 for (2^2)  4k, or 1024 entries,
 197           3 for (2^3)  8k, or 2048 entries,
 198           4 for (2^4) 16k, or 4096 entries
 199
 200 config DEBUG_BFIN_NO_KERN_HWTRACE
 201         bool "Trace user apps (turn off hwtrace in kernel)"
 202         depends on DEBUG_BFIN_HWTRACE_ON
 203         default n
 204         help
 205           Some pieces of the kernel contain a lot of flow changes which can
 206           quickly fill up the hardware trace buffer.  When debugging crashes,
 207           the hardware trace may indicate that the problem lies in kernel
 208           space when in reality an application is buggy.
 209
 210           Say Y here to disable hardware tracing in some known "jumpy" pieces
 211           of code so that the trace buffer will extend further back.
 212
 213 config EARLY_PRINTK
 214         bool "Early printk"
 215         default n
 216         select SERIAL_CORE_CONSOLE
 217         help
 218           This option enables special console drivers which allow the kernel
 219           to print messages very early in the bootup process.
 220
 221           This is useful for kernel debugging when your machine crashes very
 222           early before the console code is initialized. After enabling this
 223           feature, you must add "earlyprintk=serial,uart0,57600" to the
 224           command line (bootargs). It is safe to say Y here in all cases, as
 225           all of this lives in the init section and is thrown away after the
 226           kernel boots completely.
 227
 228 config CPLB_INFO
 229         bool "Display the CPLB information"
 230         help
 231           Display the CPLB information via /proc/cplbinfo.
 232
 233 config ACCESS_CHECK
 234         bool "Check the user pointer address"
 235         default y
 236         help
 237           Usually the pointer transfer from user space is checked to see if its
 238           address is in the kernel space.
 239
 240           Say N here to disable that check to improve the performance.
 241
 242 endmenu