1 #!/usr/bin/env bash
2
3 set -euo pipefail
4
5 TIMEOUT=10
6
7 function do_one
8 {
9 local mitigation="$1"
10 local orig
11 local start
12 local now
13
14 orig=$(cat "$mitigation")
15
16 start=$(date +%s)
17 now=$start
18
19 while [[ $((now-start)) -lt "$TIMEOUT" ]]
20 do
21 echo 0 > "$mitigation"
22 echo 1 > "$mitigation"
23
24 now=$(date +%s)
25 done
26
27 echo "$orig" > "$mitigation"
28 }
29
30 rc=0
31 cd /sys/kernel/debug/powerpc || rc=1
32 if [[ "$rc" -ne 0 ]]; then
33 echo "Error: couldn't cd to /sys/kernel/debug/powerpc" >&2
34 exit 1
35 fi
36
37 tainted=$(cat /proc/sys/kernel/tainted)
38 if [[ "$tainted" -ne 0 ]]; then
39 echo "Error: kernel already tainted!" >&2
40 exit 1
41 fi
42
43 mitigations="barrier_nospec stf_barrier count_cache_flush rfi_flush entry_flush uaccess_flush"
44
45 for m in $mitigations
46 do
47 if [[ -f /sys/kernel/debug/powerpc/$m ]]
48 then
49 do_one "$m" &
50 fi
51 done
52
53 echo "Spawned threads enabling/disabling mitigations ..."
54
55 if stress-ng > /dev/null 2>&1; then
56 stress="stress-ng"
57 elif stress > /dev/null 2>&1; then
58 stress="stress"
59 else
60 stress=""
61 fi
62
63 if [[ -n "$stress" ]]; then
64 "$stress" -m "$(nproc)" -t "$TIMEOUT" &
65 echo "Spawned VM stressors ..."
66 fi
67
68 echo "Waiting for timeout ..."
69 wait
70
71 tainted=$(cat /proc/sys/kernel/tainted)
72 if [[ "$tainted" -ne 0 ]]; then
73 echo "Error: kernel became tainted!" >&2
74 exit 1
75 fi
76
77 echo "OK"
78 exit 0
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