# .gdbinit for RISC-V kernel debugging with QEMU

set architecture riscv:rv32

# Disable pagination for uninterrupted output

set pagination off

# Enable pretty printing for structures

set print pretty on

# Enable logging to a file for session analysis

set logging file log/debug.log

# Enable manually with `set logging on` during sessions

set logging enabled off

# --- QEMU Connection ---

# Connect to QEMU's GDB server (default port 1234)

target remote :1234

# --- Symbol Loading ---

add-symbol-file kernel.elf 0x80200000

# --- Initial Breakpoints ---

break boot

break kernel_main

break kernel_entry

break handle_trap

break handle_syscall

# --- Display Settings ---

# Automatically display registers and instructions when stopping

display/i $pc

display/x $sp

display/x $a0

# --- Custom Commands ---

# Shortcut to show registers and nearby code

define kregs

info registers

x/10i $pc

end

# Shortcut to dump kernel stack

define kstack

backtrace

info frame

x/20xw $sp

end

# Shortcut to inspect memory at a given address

define kmem10

x/10xw $arg0

end

document kmem10

Usage: kmem10 <address>

Dumps 10 words of memory starting at <address> in hex.

end

# Shortcut to reload symbols (useful after recompiling kernel)

define reload

file kernel.elf

add-symbol-file kernel.elf 0x80200000

end

# # New function to reconnect GDB after recompiling and restarting QEMU

# define reconnect

# # Disconnect from current QEMU session (if connected)

# # Check if connected to a remote target

# python

# if gdb.selected_inferior().connection is not None and gdb.selected_inferior().connection.name.startswith("remote"):

# gdb.execute("disconnect")

# end

# # Reload kernel symbols

# file kernel.elf

# add-symbol-file kernel.elf 0x80200000

# # Reconnect to QEMU's GDB server

# target remote :1234

# # Restore saved breakpoints (from breakpoints.gdb)

# source breakpoints.gdb

# # Optional: Continue execution (uncomment if desired)

# # continue

# end

# document reconnect

# Usage: reconnect

# Reconnects GDB to QEMU after recompiling kernel and restarting QEMU.

# Reloads symbols, reconnects to :1234, and restores breakpoints.

# end

# --- TUI Enhancements ---

# Enable TUI layout for source and assembly (uncomment to enable by default)

# tui enable

# layout src

# layout asm

# --- Exception Debugging ---

# Display mcause and mepc when stopping at traps

define hook-stop

printf "mcause: %d\n", $mcause

printf "mepc: 0x%x\n", $mepc

info registers

end

# --- Save Breakpoints ---

# Save breakpoints to a file for reuse across sessions

save breakpoints breakpoints.gdb

# Later in new session you can load saved breakpoints like this:

#(gdb) source breakpoints.gdb

# --- End of .gdbinit ---