projects/linux·blob uaccess-cleanups · refs

273 lines · 7.4 KiB

1#!/bin/bash
2# Check branch stack sampling
3
4# SPDX-License-Identifier: GPL-2.0
5# German Gomez <[email protected]>, 2022
6
7shelldir=$(dirname "$0")
8# shellcheck source=lib/perf_has_symbol.sh
9. "${shelldir}"/lib/perf_has_symbol.sh
10
11# skip the test if the hardware doesn't support branch stack sampling
12# and if the architecture doesn't support filter types: any,save_type,u
13if ! perf record -o- --no-buildid --branch-filter any,save_type,u -- true > /dev/null 2>&1 ; then
14 echo "skip: system doesn't support filter types: any,save_type,u"
15 exit 2
16fi
17
18skip_test_missing_symbol brstack_bench
19
20err=0
21TMPDIR=$(mktemp -d /tmp/__perf_test.program.XXXXX)
22TESTPROG="perf test -w brstack"
23
24cleanup() {
25 rm -rf $TMPDIR
26 trap - EXIT TERM INT
27}
28
29trap_cleanup() {
30 set +e
31 echo "Unexpected signal in ${FUNCNAME[1]}"
32 cleanup
33 exit 1
34}
35trap trap_cleanup EXIT TERM INT
36
37is_arm64() {
38 [ "$(uname -m)" = "aarch64" ];
39}
40
41has_kaslr_bug() {
42 [ "$(uname -m)" != "aarch64" ];
43}
44
45check_branches() {
46 if ! tr -s ' ' '\n' < "$TMPDIR/perf.script" | grep -E -m1 -q "$1"; then
47 echo "ERROR: Branches missing $1"
48 err=1
49 fi
50}
51
52test_user_branches() {
53 echo "Testing user branch stack sampling"
54
55 start_err=$err
56 err=0
57 perf record -o "$TMPDIR/perf.data" --branch-filter any,save_type,u -- ${TESTPROG} > "$TMPDIR/record.txt" 2>&1
58 perf script -i "$TMPDIR/perf.data" --fields brstacksym > "$TMPDIR/perf.script"
59
60 # example of branch entries:
61 # brstack_foo+0x14/brstack_bar+0x40/P/-/-/0/CALL
62
63 expected=(
64 "^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/IND_CALL/.*$"
65 "^brstack_foo\+[^ ]*/brstack_bar\+[^ ]*/CALL/.*$"
66 "^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/CALL/.*$"
67 "^brstack_bench\+[^ ]*/brstack_bar\+[^ ]*/CALL/.*$"
68 "^brstack_bar\+[^ ]*/brstack_foo\+[^ ]*/RET/.*$"
69 "^brstack_foo\+[^ ]*/brstack_bench\+[^ ]*/RET/.*$"
70 "^brstack_bench\+[^ ]*/brstack_bench\+[^ ]*/COND/.*$"
71 "^brstack\+[^ ]*/brstack\+[^ ]*/UNCOND/.*$"
72 )
73 for x in "${expected[@]}"
74 do
75 check_branches "$x"
76 done
77
78 # Dump addresses only this time
79 perf script -i "$TMPDIR/perf.data" --fields brstack | \
80 tr ' ' '\n' > "$TMPDIR/perf.script"
81
82 # There should be no kernel addresses in the target with the u option.
83 local regex="0x[89a-f][0-9a-f]{15}"
84 if has_kaslr_bug; then
85 # If the system has a kaslr bug that may leak kernel addresses
86 # in the source of something like an ERET/SYSRET. Make the regex
87 # more specific and just check the target address is in user
88 # code.
89 regex="^0x[0-9a-f]{0,16}/0x[89a-f][0-9a-f]{15}/"
90 fi
91 if grep -q -E -m1 "$regex" $TMPDIR/perf.script; then
92 echo "Testing user branch stack sampling [Failed kernel address found in user mode]"
93 err=1
94 fi
95 # some branch types are still not being tested:
96 # IND COND_CALL COND_RET SYSRET SERROR NO_TX
97 if [ $err -eq 0 ]; then
98 echo "Testing user branch stack sampling [Passed]"
99 err=$start_err
100 else
101 echo "Testing user branch stack sampling [Failed]"
102 fi
103}
104
105test_trap_eret_branches() {
106 echo "Testing trap & eret branches"
107
108 if ! is_arm64; then
109 echo "Testing trap & eret branches [Skipped not arm64]"
110 return
111 fi
112 start_err=$err
113 local ret=1
114 for loops in 1000 10000 100000; do
115 err=0
116 perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u,k -- \
117 perf test -w traploop $loops > "$TMPDIR/record.txt" 2>&1
118 perf script -i $TMPDIR/perf.data --fields brstacksym | \
119 tr ' ' '\n' > $TMPDIR/perf.script
120
121 # BRBINF<n>.TYPE == TRAP are mapped to PERF_BR_IRQ by the BRBE driver
122 check_branches "^trap_bench\+[^ ]+/[^ ]/IRQ/"
123 check_branches "^[^ ]+/trap_bench\+[^ ]+/ERET/"
124 if [ $err -eq 0 ]; then
125 ret=0
126 break
127 fi
128 done
129
130 if [ $ret -eq 0 ]; then
131 echo "Testing trap & eret branches [Passed]"
132 err=$start_err
133 else
134 echo "Testing trap & eret branches [Failed]"
135 err=1
136 fi
137}
138
139test_kernel_branches() {
140 echo "Testing kernel branch sampling"
141
142 if ! perf record --branch-filter any,k -o- -- true > "$TMPDIR/record.txt" 2>&1; then
143 echo "Testing that k option [Skipped not enough privileges]"
144 return
145 fi
146 start_err=$err
147 local ret=1
148 for loops in 1000 10000 100000; do
149 err=0
150 perf record -o $TMPDIR/perf.data --branch-filter any,k -- \
151 perf bench syscall basic --loop $loops > "$TMPDIR/record.txt" 2>&1
152 perf script -i $TMPDIR/perf.data --fields brstack | \
153 tr ' ' '\n' > $TMPDIR/perf.script
154
155 # Example of branch entries:
156 # "0xffffffff93bda241/0xffffffff93bda20f/M/-/-/..."
157 # Source addresses come first in user or kernel code. Next is the target
158 # address that must be in the kernel.
159
160 # Look for source addresses with top bit set
161 if ! grep -q -E -m1 "^0x[89a-f][0-9a-f]{15}" $TMPDIR/perf.script; then
162 err=1
163 fi
164 # Look for no target addresses without top bit set
165 if grep -q -E -m1 "^0x[0-9a-f]{0,16}/0x[0-7][0-9a-f]{1,15}/" \
166 $TMPDIR/perf.script; then
167 err=1
168 fi
169 if [ $err -eq 0 ]; then
170 ret=0
171 break
172 fi
173 done
174
175 if [ $ret -eq 0 ]; then
176 echo "Testing kernel branch sampling [Passed]"
177 err=$start_err
178 else
179 echo "Testing kernel branch sampling [Failed]"
180 err=1
181 fi
182}
183
184# first argument <arg0> is the argument passed to "--branch-stack <arg0>,save_type,u"
185# second argument are the expected branch types for the given filter
186test_filter() {
187 test_filter_filter=$1
188 test_filter_expect=$2
189
190 echo "Testing branch stack filtering permutation ($test_filter_filter,$test_filter_expect)"
191 perf record -o "$TMPDIR/perf.data" --branch-filter "$test_filter_filter,save_type,u" -- \
192 ${TESTPROG} > "$TMPDIR/record.txt" 2>&1
193 perf script -i "$TMPDIR/perf.data" --fields brstack > "$TMPDIR/perf.script"
194
195 # fail if we find any branch type that doesn't match any of the expected ones
196 # also consider UNKNOWN branch types (-)
197 if [ ! -s "$TMPDIR/perf.script" ]
198 then
199 echo "Testing branch stack filtering [Failed empty script output]"
200 err=1
201 return
202 fi
203 # Look for lines not matching test_filter_expect ignoring issues caused
204 # by empty output
205 tr -s ' ' '\n' < "$TMPDIR/perf.script" | grep '.' | \
206 grep -E -vm1 "^[^ ]*/($test_filter_expect|-|( *))/.*$" \
207 > "$TMPDIR/perf.script-filtered" || true
208 if [ -s "$TMPDIR/perf.script-filtered" ]
209 then
210 echo "Testing branch stack filtering [Failed unexpected branch filter]"
211 cat "$TMPDIR/perf.script"
212 err=1
213 return
214 fi
215 echo "Testing branch stack filtering [Passed]"
216}
217
218test_syscall() {
219 echo "Testing syscalls"
220 # skip if perf doesn't have enough privileges
221 if ! perf record --branch-filter any,k -o- -- true > "$TMPDIR/record.txt" 2>&1; then
222 echo "Testing syscalls [Skipped: not enough privileges]"
223 return
224 fi
225 start_err=$err
226 local ret=1
227 for loops in 8000 30000 100000; do
228 err=0
229 perf record -o $TMPDIR/perf.data --branch-filter \
230 any_call,save_type,u,k -c 10007 -- \
231 perf bench syscall basic --loop $loops > "$TMPDIR/record.txt" 2>&1
232 perf script -i $TMPDIR/perf.data --fields brstacksym | \
233 tr ' ' '\n' > $TMPDIR/perf.script
234
235 check_branches "getppid[^ ]*/SYSCALL/"
236 if [ $err -eq 0 ]; then
237 ret=0
238 break
239 fi
240 done
241
242 if [ $ret -eq 0 ]; then
243 echo "Testing syscalls [Passed]"
244 err=$start_err
245 else
246 echo "Testing syscalls [Failed]"
247 err=1
248 fi
249}
250set -e
251
252test_user_branches
253test_syscall
254test_kernel_branches
255test_trap_eret_branches
256
257any_call="CALL|IND_CALL|COND_CALL|SYSCALL|IRQ"
258
259if is_arm64; then
260 any_call="$any_call|FAULT_DATA|FAULT_INST"
261fi
262
263test_filter "any_call" "$any_call"
264test_filter "call" "CALL|SYSCALL"
265test_filter "cond" "COND"
266test_filter "any_ret" "RET|COND_RET|SYSRET|ERET"
267
268test_filter "call,cond" "CALL|SYSCALL|COND"
269test_filter "any_call,cond" "$any_call|COND"
270test_filter "any_call,cond,any_ret" "$any_call|COND|RET|COND_RET"
271
272cleanup
273exit $err