====== GDB ======

====== Starting  ======
<code>
gdb <executable>
gdb --args <executable> arg1 arg2 arg3
gdb -x gdbcommands --init-commands=gdb-openocd.cfg
</code>

====== Symbols and paths =====

Add symbols:
<code>
symbol-file /mnt/nfs/binary-with-symbols.elf
dir /mnt/nfs/src
</code>

====== Using ======

==== getting info ====
set print pretty on
  * p[rint] <name> - print value
    * p * <name> - print what is pointed by
    * p/x <name> - print in hex format
    * p <name> @<n> print <n> values starting at <name>
    * p <chars> <TAB> - List all variables starting with <chars>
    * p ((sturct dummy*)variable)[0] - Dump structure members
  * ptype var
  * x /100bx m - eXamine memory located by variable m, print 100 bytes in hex format
  * bt (backtrace)
  * t (threads)

==== call stack ====
  * bt (backtrace)
  * frame 4 - switch to frame #4
  * up
  * down

==== breakpoints ====
  * b[reak] malloc
  * b mall <TAB> - List all starting with mall
  * clear malloc
  * info break
    * i[nfo] b
  * dis[able] 1 - disable brakpoint 1
  * en[able] 1
  * d[elete] 1
  * d 1 2
  * d - delete all breakpoints
  * cond[ition] 1 <expr> - stop at breakpoint 1 only if <expr> is true
  * cond 1 - Remove condition from breakpoint 1

==== stepping ====
  * s [tep] - step to next **source** line
  * c [ontinue] <num_to_ignore>
  * n [ext] - step (do not enter to subroutines)
  * fin [ish] - execute until stack frame returns
  * u [ntil] <line number> - execute to line (to avoid loops)

==== infos ====
  * show debug-file-directory

==== threads ====
  * info threads - show info about threads
  * thread 4 - switch to thread 4
  * print mutex
  * info line - print current code line
  * frame - print current execution position and code

==== OpenOCD ====
Disable Cortex M0 interrupts
  * mon cortex_m maskisr on

<code>
set remote hardware-breakpoint-limit 4
set remote hardware-watchpoint-limit 2
define hook-step
mon cortex_m maskisr on
end
define hookpost-step
mon cortex_m maskisr off
end
</code>

===== gdbcommands file =====
<file | gdbcommands>
set verbose on
set auto-load safe-path /
set debug auto-load on

set sysroot /home/user/prj/buildroot/output/target

source ../../interactive/src

set substitute-path /usr/sbin/app /apps/app/app

add-symbol-file /home/user/prj/stm32/main/bootloader/build/bin/main.elf 0x08005000

dir ../../out/build/app-undefined
dir ../../out/build/app-undefined/apps/app
dir ../../out/build/app-undefined/apps/app/app

set substitute-path /usr/lib ../../out/target/usr/lib

set args -m 0 -c /etc/conf.d/conf.xml

#sharedlibrary

#target extended-remote 192.168.1.62:12345

break myFunction
</file>

<file | gdb-openocd.cfg>
target extended-remote localhost:2331
#monitor reset
monitor halt

# Setup GDB FOR FASTER DOWNLOADS
#set remote memory-write-packet-size 1024
#set remote memory-write-packet-size fixed
</file>

<file>
# Add GDB access to mem range where VTOR is located
mem 0xE0000000 0xE00FFFFF

define bootapp
  monitor reset halt
  # Adjust VTOR (Vector table offset register)
  set {int}0xE000ED08 = &exception_table
  # Set SP/PC to the values from the actual vector table
  set $sp = *(int*)&exception_table
  set $pc = *((int*)(&exception_table)+1)
end
</file>
==== symbols ====
  * set symbol-reloading on
  * add-symbol-file ~/mymodule.o 0xd8be4000
  * add-symbol-file ~/myanother.o 0x12341234

  * set debug-file-directory <directory> - set directory contain symbol file
  * show debug-file-directory

==== file paths and libraries ====
  * set verbose on
  * set auto-load safe-path /
  * info shared
  * set sysroot /home/niziak/n/3/out/host/usr/arm-buildroot-linux-uclibcgnueabi/sysroot

==== source paths ====
Search paths (prefixes):
  * dir /path/to/src1
  * dir /path/to/lib/src2

Translate beginning of paths:
  * set substitute-path /usr/lib ../../out/target/usr/lib


====== Kernel OOPS ======
=== Reading ===
<code>
PC is at RTMPCheckEtherType+0x90/0x4d4 [mt7601Uapsta]
LR is at RTMPCheckEtherType+0x34/0x4d4 [mt7601Uapsta]

Code: e59f3418 e0256593 e2859d43 e289902c (e5d939ba)
</code>

Oops occurs at offset 0x90 from RTMPCheckEtherType. 0x4d4 is length.
"Code" line shows last instruction. Instruction in bracket is problematic instruction (at RTMPCheckEtherType+0x90)

=== Tracing ===
Disassembly kernel binary or module binary:
objdump -dS vmlinux > /tmp/kernel.s
and look into generated code.

====== Python ======

<code bash>apt-get install gdb python2.7-dbg</code>
<code bash>gdb python <pid></code>


====== DRAFTS ======
call raise(kernel-thread-id, signo) or call pthread_kill(pthread-thread-id, signo).