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
44 set -o errexit
45 set -o nounset
46
47 usage() {
48 echo "usage: faddr2line [--list] <object file> <func+offset> <func+offset>..." >&2
49 exit 1
50 }
51
52 warn() {
53 echo "$1" >&2
54 }
55
56 die() {
57 echo "ERROR: $1" >&2
58 exit 1
59 }
60
61 UTIL_SUFFIX=""
62 if [[ "${LLVM:-}" == "" ]]; then
63 UTIL_PREFIX=${CROSS_COMPILE:-}
64 else
65 UTIL_PREFIX=llvm-
66
67 if [[ "${LLVM}" == *"/" ]]; then
68 UTIL_PREFIX=${LLVM}${UTIL_PREFIX}
69 elif [[ "${LLVM}" == "-"* ]]; then
70 UTIL_SUFFIX=${LLVM}
71 fi
72 fi
73
74 READELF="${UTIL_PREFIX}readelf${UTIL_SUFFIX}"
75 ADDR2LINE="${UTIL_PREFIX}addr2line${UTIL_SUFFIX}"
76 AWK="awk"
77 GREP="grep"
78
79 command -v ${AWK} >/dev/null 2>&1 || die "${AWK} isn't installed"
80 command -v ${READELF} >/dev/null 2>&1 || die "${READELF} isn't installed"
81 command -v ${ADDR2LINE} >/dev/null 2>&1 || die "${ADDR2LINE} isn't installed"
82
83 # Try to figure out the source directory prefix so we can remove it from the
84 # addr2line output. HACK ALERT: This assumes that start_kernel() is in
85 # init/main.c! This only works for vmlinux. Otherwise it falls back to
86 # printing the absolute path.
87 find_dir_prefix() {
88 local start_kernel_addr=$(echo "${ELF_SYMS}" | sed 's/\[.*\]//' |
89 ${AWK} '$8 == "start_kernel" {printf "0x%s", $2}')
90 [[ -z $start_kernel_addr ]] && return
91
92 run_addr2line ${start_kernel_addr} ""
93 [[ -z $ADDR2LINE_OUT ]] && return
94
95 local file_line=${ADDR2LINE_OUT#* at }
96 if [[ -z $file_line ]] || [[ $file_line = $ADDR2LINE_OUT ]]; then
97 return
98 fi
99 local prefix=${file_line%init/main.c:*}
100 if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then
101 return
102 fi
103
104 DIR_PREFIX=$prefix
105 return 0
106 }
107
108 run_readelf() {
109 local objfile=$1
110 local out=$(${READELF} --file-header --section-headers --symbols --wide $objfile)
111
112 # This assumes that readelf first prints the file header, then the section headers, then the symbols.
113 # Note: It seems that GNU readelf does not prefix section headers with the "There are X section headers"
114 # line when multiple options are given, so let's also match with the "Section Headers:" line.
115 ELF_FILEHEADER=$(echo "${out}" | sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/q;p')
116 ELF_SECHEADERS=$(echo "${out}" | sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/,$p' | sed -n '/Symbol table .* contains [0-9]* entries:/q;p')
117 ELF_SYMS=$(echo "${out}" | sed -n '/Symbol table .* contains [0-9]* entries:/,$p')
118 }
119
120 check_vmlinux() {
121 # vmlinux uses absolute addresses in the section table rather than
122 # section offsets.
123 IS_VMLINUX=0
124 local file_type=$(echo "${ELF_FILEHEADER}" |
125 ${AWK} '$1 == "Type:" { print $2; exit }')
126 if [[ $file_type = "EXEC" ]] || [[ $file_type == "DYN" ]]; then
127 IS_VMLINUX=1
128 fi
129 }
130
131 init_addr2line() {
132 local objfile=$1
133
134 check_vmlinux
135
136 ADDR2LINE_ARGS="--functions --pretty-print --inlines --addresses --exe=$objfile"
137 if [[ $IS_VMLINUX = 1 ]]; then
138 # If the executable file is vmlinux, we don't pass section names to
139 # addr2line, so we can launch it now as a single long-running process.
140 coproc ADDR2LINE_PROC (${ADDR2LINE} ${ADDR2LINE_ARGS})
141 fi
142 }
143
144 run_addr2line() {
145 local addr=$1
146 local sec_name=$2
147
148 if [[ $IS_VMLINUX = 1 ]]; then
149 # We send to the addr2line process: (1) the address, then (2) a sentinel
150 # value, i.e., something that can't be interpreted as a valid address
151 # (i.e., ","). This causes addr2line to write out: (1) the answer for
152 # our address, then (2) either "?? ??:0" or "0x0...0: ..." (if
153 # using binutils' addr2line), or "," (if using LLVM's addr2line).
154 echo ${addr} >& "${ADDR2LINE_PROC[1]}"
155 echo "," >& "${ADDR2LINE_PROC[1]}"
156 local first_line
157 read -r first_line <& "${ADDR2LINE_PROC[0]}"
158 ADDR2LINE_OUT=$(echo "${first_line}" | sed 's/^0x[0-9a-fA-F]*: //')
159 while read -r line <& "${ADDR2LINE_PROC[0]}"; do
160 if [[ "$line" == "?? ??:0" ]] || [[ "$line" == "," ]] || [[ $(echo "$line" | ${GREP} "^0x00*: ") ]]; then
161 break
162 fi
163 ADDR2LINE_OUT+=$'\n'$(echo "$line" | sed 's/^0x[0-9a-fA-F]*: //')
164 done
165 else
166 # Run addr2line as a single invocation.
167 local sec_arg
168 [[ -z $sec_name ]] && sec_arg="" || sec_arg="--section=${sec_name}"
169 ADDR2LINE_OUT=$(${ADDR2LINE} ${ADDR2LINE_ARGS} ${sec_arg} ${addr} | sed 's/^0x[0-9a-fA-F]*: //')
170 fi
171 }
172
173 __faddr2line() {
174 local objfile=$1
175 local func_addr=$2
176 local dir_prefix=$3
177 local print_warnings=$4
178
179 local sym_name=${func_addr%+*}
180 local func_offset=${func_addr#*+}
181 func_offset=${func_offset%/*}
182 local user_size=
183 [[ $func_addr =~ "/" ]] && user_size=${func_addr#*/}
184
185 if [[ -z $sym_name ]] || [[ -z $func_offset ]] || [[ $sym_name = $func_addr ]]; then
186 warn "bad func+offset $func_addr"
187 DONE=1
188 return
189 fi
190
191 # Go through each of the object's symbols which match the func name.
192 # In rare cases there might be duplicates, in which case we print all
193 # matches.
194 while read line; do
195 local fields=($line)
196 local sym_addr=0x${fields[1]}
197 local sym_elf_size=${fields[2]}
198 local sym_sec=${fields[6]}
199 local sec_size
200 local sec_name
201
202 # Get the section size:
203 sec_size=$(echo "${ELF_SECHEADERS}" | sed 's/\[ /\[/' |
204 ${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print "0x" $6; exit }')
205
206 if [[ -z $sec_size ]]; then
207 warn "bad section size: section: $sym_sec"
208 DONE=1
209 return
210 fi
211
212 # Get the section name:
213 sec_name=$(echo "${ELF_SECHEADERS}" | sed 's/\[ /\[/' |
214 ${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print $2; exit }')
215
216 if [[ -z $sec_name ]]; then
217 warn "bad section name: section: $sym_sec"
218 DONE=1
219 return
220 fi
221
222 # Calculate the symbol size.
223 #
224 # Unfortunately we can't use the ELF size, because kallsyms
225 # also includes the padding bytes in its size calculation. For
226 # kallsyms, the size calculation is the distance between the
227 # symbol and the next symbol in a sorted list.
228 local sym_size
229 local cur_sym_addr
230 local found=0
231 while read line; do
232 local fields=($line)
233 cur_sym_addr=0x${fields[1]}
234 local cur_sym_elf_size=${fields[2]}
235 local cur_sym_name=${fields[7]:-}
236
237 # is_mapping_symbol(cur_sym_name)
238 if [[ ${cur_sym_name} =~ ^(\.L|L0|\$) ]]; then
239 continue
240 fi
241
242 if [[ $cur_sym_addr = $sym_addr ]] &&
243 [[ $cur_sym_elf_size = $sym_elf_size ]] &&
244 [[ $cur_sym_name = $sym_name ]]; then
245 found=1
246 continue
247 fi
248
249 if [[ $found = 1 ]]; then
250 sym_size=$(($cur_sym_addr - $sym_addr))
251 [[ $sym_size -lt $sym_elf_size ]] && continue;
252 found=2
253 break
254 fi
255 done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2 | ${GREP} -A1 --no-group-separator " ${sym_name}$")
256
257 if [[ $found = 0 ]]; then
258 warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"
259 DONE=1
260 return
261 fi
262
263 # If nothing was found after the symbol, assume it's the last
264 # symbol in the section.
265 [[ $found = 1 ]] && sym_size=$(($sec_size - $sym_addr))
266
267 if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then
268 warn "bad symbol size: sym_addr: $sym_addr cur_sym_addr: $cur_sym_addr"
269 DONE=1
270 return
271 fi
272
273 sym_size=0x$(printf %x $sym_size)
274
275 # Calculate the address from user-supplied offset:
276 local addr=$(($sym_addr + $func_offset))
277 if [[ -z $addr ]] || [[ $addr = 0 ]]; then
278 warn "bad address: $sym_addr + $func_offset"
279 DONE=1
280 return
281 fi
282 addr=0x$(printf %x $addr)
283
284 # If the user provided a size, make sure it matches the symbol's size:
285 if [[ -n $user_size ]] && [[ $user_size -ne $sym_size ]]; then
286 [[ $print_warnings = 1 ]] &&
287 echo "skipping $sym_name address at $addr due to size mismatch ($user_size != $sym_size)"
288 continue;
289 fi
290
291 # Make sure the provided offset is within the symbol's range:
292 if [[ $func_offset -gt $sym_size ]]; then
293 [[ $print_warnings = 1 ]] &&
294 echo "skipping $sym_name address at $addr due to size mismatch ($func_offset > $sym_size)"
295 continue
296 fi
297
298 # In case of duplicates or multiple addresses specified on the
299 # cmdline, separate multiple entries with a blank line:
300 [[ $FIRST = 0 ]] && echo
301 FIRST=0
302
303 echo "$sym_name+$func_offset/$sym_size:"
304
305 # Pass section address to addr2line and strip absolute paths
306 # from the output:
307 run_addr2line $addr $sec_name
308 local output=$(echo "${ADDR2LINE_OUT}" | sed "s; $dir_prefix\(\./\)*; ;")
309 [[ -z $output ]] && continue
310
311 # Default output (non --list):
312 if [[ $LIST = 0 ]]; then
313 echo "$output" | while read -r line
314 do
315 echo $line
316 done
317 DONE=1;
318 continue
319 fi
320
321 # For --list, show each line with its corresponding source code:
322 echo "$output" | while read -r line
323 do
324 echo
325 echo $line
326 n=$(echo $line | sed 's/.*:\([0-9]\+\).*/\1/g')
327 n1=$[$n-5]
328 n2=$[$n+5]
329 f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g')
330 ${AWK} 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f
331 done
332
333 DONE=1
334
335 done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$8 == fn')
336 }
337
338 [[ $# -lt 2 ]] && usage
339
340 objfile=$1
341
342 LIST=0
343 [[ "$objfile" == "--list" ]] && LIST=1 && shift && objfile=$1
344
345 [[ ! -f $objfile ]] && die "can't find objfile $objfile"
346 shift
347
348 run_readelf $objfile
349
350 echo "${ELF_SECHEADERS}" | ${GREP} -q '\.debug_info' || die "CONFIG_DEBUG_INFO not enabled"
351
352 init_addr2line $objfile
353
354 DIR_PREFIX=supercalifragilisticexpialidocious
355 find_dir_prefix
356
357 FIRST=1
358 while [[ $# -gt 0 ]]; do
359 func_addr=$1
360 shift
361
362 # print any matches found
363 DONE=0
364 __faddr2line $objfile $func_addr $DIR_PREFIX 0
365
366 # if no match was found, print warnings
367 if [[ $DONE = 0 ]]; then
368 __faddr2line $objfile $func_addr $DIR_PREFIX 1
369 warn "no match for $func_addr"
370 fi
371 done
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