arch/blackfin/Kconfig.debug

   1 # SPDX-License-Identifier: GPL-2.0
   2 menu "Kernel hacking"
   3
   4 source "lib/Kconfig.debug"
   5
   6 config DEBUG_VERBOSE
   7         bool "Verbose fault messages"
   8         default y
   9         select PRINTK
  10         help
  11           When a program crashes due to an exception, or the kernel detects
  12           an internal error, the kernel can print a not so brief message
  13           explaining what the problem was. This debugging information is
  14           useful to developers and kernel hackers when tracking down problems,
  15           but mostly meaningless to other people. This is always helpful for
  16           debugging but serves no purpose on a production system.
  17           Most people should say N here.
  18
  19 config DEBUG_MMRS
  20         tristate "Generate Blackfin MMR tree"
  21         depends on !PINCTRL
  22         select DEBUG_FS
  23         help
  24           Create a tree of Blackfin MMRs via the debugfs tree.  If
  25           you enable this, you will find all MMRs laid out in the
  26           /sys/kernel/debug/blackfin/ directory where you can read/write
  27           MMRs directly from userspace.  This is obviously just a debug
  28           feature.
  29
  30 config DEBUG_HWERR
  31         bool "Hardware error interrupt debugging"
  32         depends on DEBUG_KERNEL
  33         help
  34           When enabled, the hardware error interrupt is never disabled, and
  35           will happen immediately when an error condition occurs.  This comes
  36           at a slight cost in code size, but is necessary if you are getting
  37           hardware error interrupts and need to know where they are coming
  38           from.
  39
  40 config EXACT_HWERR
  41         bool "Try to make Hardware errors exact"
  42         depends on DEBUG_HWERR
  43         help
  44           By default, the Blackfin hardware errors are not exact - the error
  45           be reported multiple cycles after the error happens. This delay
  46           can cause the wrong application, or even the kernel to receive a
  47           signal to be killed. If you are getting HW errors in your system,
  48           try turning this on to ensure they are at least coming from the
  49           proper thread.
  50
  51           On production systems, it is safe (and a small optimization) to say N.
  52
  53 config DEBUG_DOUBLEFAULT
  54         bool "Debug Double Faults"
  55         default n
  56         help
  57           If an exception is caused while executing code within the exception
  58           handler, the NMI handler, the reset vector, or in emulator mode,
  59           a double fault occurs. On the Blackfin, this is a unrecoverable
  60           event. You have two options:
  61           - RESET exactly when double fault occurs. The excepting
  62             instruction address is stored in RETX, where the next kernel
  63             boot will print it out.
  64           - Print debug message. This is much more error prone, although
  65             easier to handle. It is error prone since:
  66             - The excepting instruction is not committed.
  67             - All writebacks from the instruction are prevented.
  68             - The generated exception is not taken.
  69             - The EXCAUSE field is updated with an unrecoverable event
  70             The only way to check this is to see if EXCAUSE contains the
  71             unrecoverable event value at every exception return. By selecting
  72             this option, you are skipping over the faulting instruction, and
  73             hoping things stay together enough to print out a debug message.
  74
  75           This does add a little kernel code, but is the only method to debug
  76           double faults - if unsure say "Y"
  77
  78 choice
  79         prompt "Double Fault Failure Method"
  80         default DEBUG_DOUBLEFAULT_PRINT
  81         depends on DEBUG_DOUBLEFAULT
  82
  83 config DEBUG_DOUBLEFAULT_PRINT
  84         bool "Print"
  85
  86 config DEBUG_DOUBLEFAULT_RESET
  87         bool "Reset"
  88
  89 endchoice
  90
  91 config DEBUG_HUNT_FOR_ZERO
  92         bool "Catch NULL pointer reads/writes"
  93         default y
  94         help
  95           Say Y here to catch reads/writes to anywhere in the memory range
  96           from 0x0000 - 0x0FFF (the first 4k) of memory.  This is useful in
  97           catching common programming errors such as NULL pointer dereferences.
  98
  99           Misbehaving applications will be killed (generate a SEGV) while the
 100           kernel will trigger a panic.
 101
 102           Enabling this option will take up an extra entry in CPLB table.
 103           Otherwise, there is no extra overhead.
 104
 105 config DEBUG_BFIN_HWTRACE_ON
 106         bool "Turn on Blackfin's Hardware Trace"
 107         default y
 108         help
 109           All Blackfins include a Trace Unit which stores a history of the last
 110           16 changes in program flow taken by the program sequencer. The history
 111           allows the user to recreate the program sequencer’s recent path. This
 112           can be handy when an application dies - we print out the execution
 113           path of how it got to the offending instruction.
 114
 115           By turning this off, you may save a tiny amount of power.
 116
 117 choice
 118         prompt "Omit loop Tracing"
 119         default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 120         depends on DEBUG_BFIN_HWTRACE_ON
 121         help
 122           The trace buffer can be configured to omit recording of changes in
 123           program flow that match either the last entry or one of the last
 124           two entries. Omitting one of these entries from the record prevents
 125           the trace buffer from overflowing because of any sort of loop (for, do
 126           while, etc) in the program.
 127
 128           Because zero-overhead Hardware loops are not recorded in the trace buffer,
 129           this feature can be used to prevent trace overflow from loops that
 130           are nested four deep.
 131
 132 config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 133         bool "Trace all Loops"
 134         help
 135           The trace buffer records all changes of flow
 136
 137 config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
 138         bool "Compress single-level loops"
 139         help
 140           The trace buffer does not record single loops - helpful if trace
 141           is spinning on a while or do loop.
 142
 143 config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
 144         bool "Compress two-level loops"
 145         help
 146           The trace buffer does not record loops two levels deep. Helpful if
 147           the trace is spinning in a nested loop
 148
 149 endchoice
 150
 151 config DEBUG_BFIN_HWTRACE_COMPRESSION
 152         int
 153         depends on DEBUG_BFIN_HWTRACE_ON
 154         default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
 155         default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
 156         default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
 157
 158
 159 config DEBUG_BFIN_HWTRACE_EXPAND
 160         bool "Expand Trace Buffer greater than 16 entries"
 161         depends on DEBUG_BFIN_HWTRACE_ON
 162         default n
 163         help
 164           By selecting this option, every time the 16 hardware entries in
 165           the Blackfin's HW Trace buffer are full, the kernel will move them
 166           into a software buffer, for dumping when there is an issue. This
 167           has a great impact on performance, (an interrupt every 16 change of
 168           flows) and should normally be turned off, except in those nasty
 169           debugging sessions
 170
 171 config DEBUG_BFIN_HWTRACE_EXPAND_LEN
 172         int "Size of Trace buffer (in power of 2k)"
 173         range 0 4
 174         depends on DEBUG_BFIN_HWTRACE_EXPAND
 175         default 1
 176         help
 177           This sets the size of the software buffer that the trace information
 178           is kept in.
 179           0 for (2^0)  1k, or 256 entries,
 180           1 for (2^1)  2k, or 512 entries,
 181           2 for (2^2)  4k, or 1024 entries,
 182           3 for (2^3)  8k, or 2048 entries,
 183           4 for (2^4) 16k, or 4096 entries
 184
 185 config DEBUG_BFIN_NO_KERN_HWTRACE
 186         bool "Turn off hwtrace in CPLB handlers"
 187         depends on DEBUG_BFIN_HWTRACE_ON
 188         default y
 189         help
 190           The CPLB error handler contains a lot of flow changes which can
 191           quickly fill up the hardware trace buffer.  When debugging crashes,
 192           the hardware trace may indicate that the problem lies in kernel
 193           space when in reality an application is buggy.
 194
 195           Say Y here to disable hardware tracing in some known "jumpy" pieces
 196           of code so that the trace buffer will extend further back.
 197
 198 config EARLY_PRINTK
 199         bool "Early printk"
 200         default n
 201         select SERIAL_CORE_CONSOLE
 202         help
 203           This option enables special console drivers which allow the kernel
 204           to print messages very early in the bootup process.
 205
 206           This is useful for kernel debugging when your machine crashes very
 207           early before the console code is initialized. After enabling this
 208           feature, you must add "earlyprintk=serial,uart0,57600" to the
 209           command line (bootargs). It is safe to say Y here in all cases, as
 210           all of this lives in the init section and is thrown away after the
 211           kernel boots completely.
 212
 213 config NMI_WATCHDOG
 214         bool "Enable NMI watchdog to help debugging lockup on SMP"
 215         default n
 216         depends on SMP
 217         help
 218           If any CPU in the system does not execute the period local timer
 219           interrupt for more than 5 seconds, then the NMI handler dumps debug
 220           information. This information can be used to debug the lockup.
 221
 222 config CPLB_INFO
 223         bool "Display the CPLB information"
 224         help
 225           Display the CPLB information via /proc/cplbinfo.
 226
 227 config ACCESS_CHECK
 228         bool "Check the user pointer address"
 229         default y
 230         help
 231           Usually the pointer transfer from user space is checked to see if its
 232           address is in the kernel space.
 233
 234           Say N here to disable that check to improve the performance.
 235
 236 config BFIN_ISRAM_SELF_TEST
 237         bool "isram boot self tests"
 238         default n
 239         help
 240           Run some self tests of the isram driver code at boot.
 241
 242 config BFIN_PSEUDODBG_INSNS
 243         bool "Support pseudo debug instructions"
 244         default n
 245         help
 246           This option allows the kernel to emulate some pseudo instructions which
 247           allow simulator test cases to be run under Linux with no changes.
 248
 249           Most people should say N here.
 250
 251 config BFIN_PM_WAKEUP_TIME_BENCH
 252         bool "Display the total time for kernel to resume from power saving mode"
 253         default n
 254         help
 255           Display the total time when kernel resumes normal from standby or
 256           suspend to mem mode.
 257
 258 endmenu