aboutsummaryrefslogtreecommitdiff
path: root/scripts/faddr2line
blob: 5514c23f45c24fdbe0968c95275103ef2e545f09 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
#
# Translate stack dump function offsets.
#
# addr2line doesn't work with KASLR addresses.  This works similarly to
# addr2line, but instead takes the 'func+0x123' format as input:
#
#   $ ./scripts/faddr2line ~/k/vmlinux meminfo_proc_show+0x5/0x568
#   meminfo_proc_show+0x5/0x568:
#   meminfo_proc_show at fs/proc/meminfo.c:27
#
# If the address is part of an inlined function, the full inline call chain is
# printed:
#
#   $ ./scripts/faddr2line ~/k/vmlinux native_write_msr+0x6/0x27
#   native_write_msr+0x6/0x27:
#   arch_static_branch at arch/x86/include/asm/msr.h:121
#    (inlined by) static_key_false at include/linux/jump_label.h:125
#    (inlined by) native_write_msr at arch/x86/include/asm/msr.h:125
#
# The function size after the '/' in the input is optional, but recommended.
# It's used to help disambiguate any duplicate symbol names, which can occur
# rarely.  If the size is omitted for a duplicate symbol then it's possible for
# multiple code sites to be printed:
#
#   $ ./scripts/faddr2line ~/k/vmlinux raw_ioctl+0x5
#   raw_ioctl+0x5/0x20:
#   raw_ioctl at drivers/char/raw.c:122
#
#   raw_ioctl+0x5/0xb1:
#   raw_ioctl at net/ipv4/raw.c:876
#
# Multiple addresses can be specified on a single command line:
#
#   $ ./scripts/faddr2line ~/k/vmlinux type_show+0x10/45 free_reserved_area+0x90
#   type_show+0x10/0x2d:
#   type_show at drivers/video/backlight/backlight.c:213
#
#   free_reserved_area+0x90/0x123:
#   free_reserved_area at mm/page_alloc.c:6429 (discriminator 2)


set -o errexit
set -o nounset

usage() {
	echo "usage: faddr2line [--list] <object file> <func+offset> <func+offset>..." >&2
	exit 1
}

warn() {
	echo "$1" >&2
}

die() {
	echo "ERROR: $1" >&2
	exit 1
}

READELF="${CROSS_COMPILE:-}readelf"
ADDR2LINE="${CROSS_COMPILE:-}addr2line"
AWK="awk"
GREP="grep"

command -v ${AWK} >/dev/null 2>&1 || die "${AWK} isn't installed"
command -v ${READELF} >/dev/null 2>&1 || die "${READELF} isn't installed"
command -v ${ADDR2LINE} >/dev/null 2>&1 || die "${ADDR2LINE} isn't installed"

# Try to figure out the source directory prefix so we can remove it from the
# addr2line output.  HACK ALERT: This assumes that start_kernel() is in
# init/main.c!  This only works for vmlinux.  Otherwise it falls back to
# printing the absolute path.
find_dir_prefix() {
	local objfile=$1

	local start_kernel_addr=$(${READELF} --symbols --wide $objfile | ${AWK} '$8 == "start_kernel" {printf "0x%s", $2}')
	[[ -z $start_kernel_addr ]] && return

	local file_line=$(${ADDR2LINE} -e $objfile $start_kernel_addr)
	[[ -z $file_line ]] && return

	local prefix=${file_line%init/main.c:*}
	if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then
		return
	fi

	DIR_PREFIX=$prefix
	return 0
}

__faddr2line() {
	local objfile=$1
	local func_addr=$2
	local dir_prefix=$3
	local print_warnings=$4

	local sym_name=${func_addr%+*}
	local func_offset=${func_addr#*+}
	func_offset=${func_offset%/*}
	local user_size=
	local file_type
	local is_vmlinux=0
	[[ $func_addr =~ "/" ]] && user_size=${func_addr#*/}

	if [[ -z $sym_name ]] || [[ -z $func_offset ]] || [[ $sym_name = $func_addr ]]; then
		warn "bad func+offset $func_addr"
		DONE=1
		return
	fi

	# vmlinux uses absolute addresses in the section table rather than
	# section offsets.
	local file_type=$(${READELF} --file-header $objfile |
		${AWK} '$1 == "Type:" { print $2; exit }')
	if [[ $file_type = "EXEC" ]] || [[ $file_type == "DYN" ]]; then
		is_vmlinux=1
	fi

	# Go through each of the object's symbols which match the func name.
	# In rare cases there might be duplicates, in which case we print all
	# matches.
	while read line; do
		local fields=($line)
		local sym_addr=0x${fields[1]}
		local sym_elf_size=${fields[2]}
		local sym_sec=${fields[6]}
		local sec_size
		local sec_name

		# Get the section size:
		sec_size=$(${READELF} --section-headers --wide $objfile |
			sed 's/\[ /\[/' |
			${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print "0x" $6; exit }')

		if [[ -z $sec_size ]]; then
			warn "bad section size: section: $sym_sec"
			DONE=1
			return
		fi

		# Get the section name:
		sec_name=$(${READELF} --section-headers --wide $objfile |
			sed 's/\[ /\[/' |
			${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print $2; exit }')

		if [[ -z $sec_name ]]; then
			warn "bad section name: section: $sym_sec"
			DONE=1
			return
		fi

		# Calculate the symbol size.
		#
		# Unfortunately we can't use the ELF size, because kallsyms
		# also includes the padding bytes in its size calculation.  For
		# kallsyms, the size calculation is the distance between the
		# symbol and the next symbol in a sorted list.
		local sym_size
		local cur_sym_addr
		local found=0
		while read line; do
			local fields=($line)
			cur_sym_addr=0x${fields[1]}
			local cur_sym_elf_size=${fields[2]}
			local cur_sym_name=${fields[7]:-}

			if [[ $cur_sym_addr = $sym_addr ]] &&
			   [[ $cur_sym_elf_size = $sym_elf_size ]] &&
			   [[ $cur_sym_name = $sym_name ]]; then
				found=1
				continue
			fi

			if [[ $found = 1 ]]; then
				sym_size=$(($cur_sym_addr - $sym_addr))
				[[ $sym_size -lt $sym_elf_size ]] && continue;
				found=2
				break
			fi
		done < <(${READELF} --symbols --wide $objfile | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2)

		if [[ $found = 0 ]]; then
			warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"
			DONE=1
			return
		fi

		# If nothing was found after the symbol, assume it's the last
		# symbol in the section.
		[[ $found = 1 ]] && sym_size=$(($sec_size - $sym_addr))

		if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then
			warn "bad symbol size: sym_addr: $sym_addr cur_sym_addr: $cur_sym_addr"
			DONE=1
			return
		fi

		sym_size=0x$(printf %x $sym_size)

		# Calculate the address from user-supplied offset:
		local addr=$(($sym_addr + $func_offset))
		if [[ -z $addr ]] || [[ $addr = 0 ]]; then
			warn "bad address: $sym_addr + $func_offset"
			DONE=1
			return
		fi
		addr=0x$(printf %x $addr)

		# If the user provided a size, make sure it matches the symbol's size:
		if [[ -n $user_size ]] && [[ $user_size -ne $sym_size ]]; then
			[[ $print_warnings = 1 ]] &&
				echo "skipping $sym_name address at $addr due to size mismatch ($user_size != $sym_size)"
			continue;
		fi

		# Make sure the provided offset is within the symbol's range:
		if [[ $func_offset -gt $sym_size ]]; then
			[[ $print_warnings = 1 ]] &&
				echo "skipping $sym_name address at $addr due to size mismatch ($func_offset > $sym_size)"
			continue
		fi

		# In case of duplicates or multiple addresses specified on the
		# cmdline, separate multiple entries with a blank line:
		[[ $FIRST = 0 ]] && echo
		FIRST=0

		echo "$sym_name+$func_offset/$sym_size:"

		# Pass section address to addr2line and strip absolute paths
		# from the output:
		local args="--functions --pretty-print --inlines --exe=$objfile"
		[[ $is_vmlinux = 0 ]] && args="$args --section=$sec_name"
		local output=$(${ADDR2LINE} $args $addr | sed "s; $dir_prefix\(\./\)*; ;")
		[[ -z $output ]] && continue

		# Default output (non --list):
		if [[ $LIST = 0 ]]; then
			echo "$output" | while read -r line
			do
				echo $line
			done
			DONE=1;
			continue
		fi

		# For --list, show each line with its corresponding source code:
		echo "$output" | while read -r line
		do
			echo
			echo $line
			n=$(echo $line | sed 's/.*:\([0-9]\+\).*/\1/g')
			n1=$[$n-5]
			n2=$[$n+5]
			f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g')
			${AWK} 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f
		done

		DONE=1

	done < <(${READELF} --symbols --wide $objfile | ${AWK} -v fn=$sym_name '$4 == "FUNC" && $8 == fn')
}

[[ $# -lt 2 ]] && usage

objfile=$1

LIST=0
[[ "$objfile" == "--list" ]] && LIST=1 && shift && objfile=$1

[[ ! -f $objfile ]] && die "can't find objfile $objfile"
shift

${READELF} --section-headers --wide $objfile | ${GREP} -q '\.debug_info' || die "CONFIG_DEBUG_INFO not enabled"

DIR_PREFIX=supercalifragilisticexpialidocious
find_dir_prefix $objfile

FIRST=1
while [[ $# -gt 0 ]]; do
	func_addr=$1
	shift

	# print any matches found
	DONE=0
	__faddr2line $objfile $func_addr $DIR_PREFIX 0

	# if no match was found, print warnings
	if [[ $DONE = 0 ]]; then
		__faddr2line $objfile $func_addr $DIR_PREFIX 1
		warn "no match for $func_addr"
	fi
done