xref: /openbmc/linux/scripts/faddr2line (revision ba61bb17) 
1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0
3#
4# Translate stack dump function offsets.
5#
6# addr2line doesn't work with KASLR addresses.  This works similarly to
7# addr2line, but instead takes the 'func+0x123' format as input:
8#
9#   $ ./scripts/faddr2line ~/k/vmlinux meminfo_proc_show+0x5/0x568
10#   meminfo_proc_show+0x5/0x568:
11#   meminfo_proc_show at fs/proc/meminfo.c:27
12#
13# If the address is part of an inlined function, the full inline call chain is
14# printed:
15#
16#   $ ./scripts/faddr2line ~/k/vmlinux native_write_msr+0x6/0x27
17#   native_write_msr+0x6/0x27:
18#   arch_static_branch at arch/x86/include/asm/msr.h:121
19#    (inlined by) static_key_false at include/linux/jump_label.h:125
20#    (inlined by) native_write_msr at arch/x86/include/asm/msr.h:125
21#
22# The function size after the '/' in the input is optional, but recommended.
23# It's used to help disambiguate any duplicate symbol names, which can occur
24# rarely.  If the size is omitted for a duplicate symbol then it's possible for
25# multiple code sites to be printed:
26#
27#   $ ./scripts/faddr2line ~/k/vmlinux raw_ioctl+0x5
28#   raw_ioctl+0x5/0x20:
29#   raw_ioctl at drivers/char/raw.c:122
30#
31#   raw_ioctl+0x5/0xb1:
32#   raw_ioctl at net/ipv4/raw.c:876
33#
34# Multiple addresses can be specified on a single command line:
35#
36#   $ ./scripts/faddr2line ~/k/vmlinux type_show+0x10/45 free_reserved_area+0x90
37#   type_show+0x10/0x2d:
38#   type_show at drivers/video/backlight/backlight.c:213
39#
40#   free_reserved_area+0x90/0x123:
41#   free_reserved_area at mm/page_alloc.c:6429 (discriminator 2)
42
43
44set -o errexit
45set -o nounset
46
47READELF="${CROSS_COMPILE:-}readelf"
48ADDR2LINE="${CROSS_COMPILE:-}addr2line"
49SIZE="${CROSS_COMPILE:-}size"
50NM="${CROSS_COMPILE:-}nm"
51
52command -v awk >/dev/null 2>&1 || die "awk isn't installed"
53command -v ${READELF} >/dev/null 2>&1 || die "readelf isn't installed"
54command -v ${ADDR2LINE} >/dev/null 2>&1 || die "addr2line isn't installed"
55command -v ${SIZE} >/dev/null 2>&1 || die "size isn't installed"
56command -v ${NM} >/dev/null 2>&1 || die "nm isn't installed"
57
58usage() {
59	echo "usage: faddr2line [--list] <object file> <func+offset> <func+offset>..." >&2
60	exit 1
61}
62
63warn() {
64	echo "$1" >&2
65}
66
67die() {
68	echo "ERROR: $1" >&2
69	exit 1
70}
71
72# Try to figure out the source directory prefix so we can remove it from the
73# addr2line output.  HACK ALERT: This assumes that start_kernel() is in
74# kernel/init.c!  This only works for vmlinux.  Otherwise it falls back to
75# printing the absolute path.
76find_dir_prefix() {
77	local objfile=$1
78
79	local start_kernel_addr=$(${READELF} -sW $objfile | awk '$8 == "start_kernel" {printf "0x%s", $2}')
80	[[ -z $start_kernel_addr ]] && return
81
82	local file_line=$(${ADDR2LINE} -e $objfile $start_kernel_addr)
83	[[ -z $file_line ]] && return
84
85	local prefix=${file_line%init/main.c:*}
86	if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then
87		return
88	fi
89
90	DIR_PREFIX=$prefix
91	return 0
92}
93
94__faddr2line() {
95	local objfile=$1
96	local func_addr=$2
97	local dir_prefix=$3
98	local print_warnings=$4
99
100	local func=${func_addr%+*}
101	local offset=${func_addr#*+}
102	offset=${offset%/*}
103	local size=
104	[[ $func_addr =~ "/" ]] && size=${func_addr#*/}
105
106	if [[ -z $func ]] || [[ -z $offset ]] || [[ $func = $func_addr ]]; then
107		warn "bad func+offset $func_addr"
108		DONE=1
109		return
110	fi
111
112	# Go through each of the object's symbols which match the func name.
113	# In rare cases there might be duplicates.
114	file_end=$(${SIZE} -Ax $objfile | awk '$1 == ".text" {print $2}')
115	while read symbol; do
116		local fields=($symbol)
117		local sym_base=0x${fields[0]}
118		local sym_type=${fields[1]}
119		local sym_end=${fields[3]}
120
121		# calculate the size
122		local sym_size=$(($sym_end - $sym_base))
123		if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then
124			warn "bad symbol size: base: $sym_base end: $sym_end"
125			DONE=1
126			return
127		fi
128		sym_size=0x$(printf %x $sym_size)
129
130		# calculate the address
131		local addr=$(($sym_base + $offset))
132		if [[ -z $addr ]] || [[ $addr = 0 ]]; then
133			warn "bad address: $sym_base + $offset"
134			DONE=1
135			return
136		fi
137		addr=0x$(printf %x $addr)
138
139		# weed out non-function symbols
140		if [[ $sym_type != t ]] && [[ $sym_type != T ]]; then
141			[[ $print_warnings = 1 ]] &&
142				echo "skipping $func address at $addr due to non-function symbol of type '$sym_type'"
143			continue
144		fi
145
146		# if the user provided a size, make sure it matches the symbol's size
147		if [[ -n $size ]] && [[ $size -ne $sym_size ]]; then
148			[[ $print_warnings = 1 ]] &&
149				echo "skipping $func address at $addr due to size mismatch ($size != $sym_size)"
150			continue;
151		fi
152
153		# make sure the provided offset is within the symbol's range
154		if [[ $offset -gt $sym_size ]]; then
155			[[ $print_warnings = 1 ]] &&
156				echo "skipping $func address at $addr due to size mismatch ($offset > $sym_size)"
157			continue
158		fi
159
160		# separate multiple entries with a blank line
161		[[ $FIRST = 0 ]] && echo
162		FIRST=0
163
164		# pass real address to addr2line
165		echo "$func+$offset/$sym_size:"
166		local file_lines=$(${ADDR2LINE} -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;")
167		[[ -z $file_lines ]] && return
168
169		if [[ $LIST = 0 ]]; then
170			echo "$file_lines" | while read -r line
171			do
172				echo $line
173			done
174			DONE=1;
175			return
176		fi
177
178		# show each line with context
179		echo "$file_lines" | while read -r line
180		do
181			echo
182			echo $line
183			n=$(echo $line | sed 's/.*:\([0-9]\+\).*/\1/g')
184			n1=$[$n-5]
185			n2=$[$n+5]
186			f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g')
187			awk 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f
188		done
189
190		DONE=1
191
192	done < <(${NM} -n $objfile | awk -v fn=$func -v end=$file_end '$3 == fn { found=1; line=$0; start=$1; next } found == 1 { found=0; print line, "0x"$1 } END {if (found == 1) print line, end; }')
193}
194
195[[ $# -lt 2 ]] && usage
196
197objfile=$1
198
199LIST=0
200[[ "$objfile" == "--list" ]] && LIST=1 && shift && objfile=$1
201
202[[ ! -f $objfile ]] && die "can't find objfile $objfile"
203shift
204
205DIR_PREFIX=supercalifragilisticexpialidocious
206find_dir_prefix $objfile
207
208FIRST=1
209while [[ $# -gt 0 ]]; do
210	func_addr=$1
211	shift
212
213	# print any matches found
214	DONE=0
215	__faddr2line $objfile $func_addr $DIR_PREFIX 0
216
217	# if no match was found, print warnings
218	if [[ $DONE = 0 ]]; then
219		__faddr2line $objfile $func_addr $DIR_PREFIX 1
220		warn "no match for $func_addr"
221	fi
222done
223