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