#
# A set of useful macros that can help debug Pintos.
#
# Include with “source” cmd in gdb.
# Use “help user-defined” for help.
#
# Author: Godmar Back
#
# $Id: gdb-macros,v 1.1 2006-04-07 18:29:34 blp Exp $
#
# for internal use
define offsetof
set $rc = (char*)&((struct $arg0 *)0)->$arg1 – (char*)0
end
define list_entry
offsetof $arg1 $arg2
set $rc = ((struct $arg1 *) ((uint8_t *) ($arg0) – $rc))
end
# dump a Pintos list
define dumplist
set $list = $arg0
set $e = $list->head.next
set $i = 0
while $e != &(($arg0).tail)
list_entry $e $arg1 $arg2
set $l = $rc
printf “pintos-debug: dumplist #%d: %p “, $i++, $l
output *$l
set $e = $e->next
printf “\n”
end
end
document dumplist
Dump the content of a Pintos list,
invoke as dumplist name_of_list name_of_struct name_of_elem_in_list_struct
end
# print a thread’s backtrace, given a pointer to the struct thread *
define btthread
if $arg0 == ($esp – ((unsigned)$esp % 4096))
bt
else
set $saveEIP = $eip
set $saveESP = $esp
set $saveEBP = $ebp
set $esp = ((struct thread *)$arg0)->stack
set $ebp = ((void**)$esp)[2]
set $eip = ((void**)$esp)[4]
bt
set $eip = $saveEIP
set $esp = $saveESP
set $ebp = $saveEBP
end
end
document btthread
Show the backtrace of a thread,
invoke as btthread pointer_to_struct_thread
end
# print backtraces associated with all threads in a list
define btthreadlist
set $list = $arg0
set $e = $list->head.next
while $e != &(($arg0).tail)
list_entry $e thread $arg1
printf “pintos-debug: dumping backtrace of thread ‘%s’ @%p\n”, \
((struct thread*)$rc)->name, $rc
btthread $rc
set $e = $e->next
printf “\n”
end
end
document btthreadlist
Given a list of threads, print each thread’s backtrace
invoke as btthreadlist name_of_list name_of_elem_in_list_struct
end
# print backtraces of all threads (based on ‘all_list’ all threads list)
define btthreadall
btthreadlist all_list allelem
end
document btthreadall
Print backtraces of all threads
end
# print a correct backtrace by adjusting $eip
# this works best right at intr0e_stub
define btpagefault
set $saveeip = $eip
set $eip = ((void**)$esp)[1]
backtrace
set $eip = $saveeip
end
document btpagefault
Print a backtrace of the current thread after a pagefault
end
# invoked whenever the program stops
define hook-stop
# stopped at stub #0E = #14 (page fault exception handler stub)
if ($eip == intr0e_stub)
set $savedeip = ((void**)$esp)[1]
# if this was in user mode, the OS should handle it
# either handle the page fault or terminate the process
if ($savedeip < 0xC0000000)
printf "pintos-debug: a page fault exception occurred in user mode\n"
printf "pintos-debug: hit 'c' to continue, or 's' to step to intr_handler\n"
else
# if this was in kernel mode, a stack trace might be useful
printf "pintos-debug: a page fault occurred in kernel mode\n"
btpagefault
end
end
end
# load symbols for a Pintos user program
define loadusersymbols
shell objdump -h $arg0 | awk '/.text/ { print "add-symbol-file $arg0 0x"$4 }' > .loadsymbols
source .loadsymbols
shell rm -f .loadsymbols
end
document loadusersymbols
Load the symbols contained in a user program’s executable.
Example:
loadusersymbols tests/userprog/exec-multiple
end
define debugpintos
target remote localhost:1234
end
document debugpintos
Attach debugger to pintos process
end