Add a script for enabling kernel tracepoints
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/amboar/obmc-scripts/tracing/README.md b/amboar/obmc-scripts/tracing/README.md
new file mode 100644
index 0000000..5ee628f
--- /dev/null
+++ b/amboar/obmc-scripts/tracing/README.md
@@ -0,0 +1,83 @@
+Description
+===========
+
+The trace script automates the process of enabling named sets of tracepoints
+and dumping the trace file over the SSH connection, then cleaning up after
+itself.
+
+Usage
+=====
+
+To run:
+
+```
+Usage: ./trace [USER@]HOST EVENTSET [EVENTSET...]
+
+Valid EVENTSETs: fsi, occ, sbefifo, timer, sched
+
+```
+
+To stop the trace output and disable the tracepoints, hit `Return`.
+
+For example, capturing the defined tracepoints for the `sched` event set:
+
+```
+$ ./trace root@my-bmc sched
++ set -eou pipefail
++ set -x
++ EVENT_fsi='fsi fsi_master_gpio'
++ EVENT_occ='occ hwmon_occ'
++ EVENT_sbefifo=sbefifo
++ EVENT_timer='timer/timer_start timer/timer_cancel timer/timer_expire_entry timer/timer_expire_exit'
++ EVENT_sched='sched/sched_switch sched/sched_wakeup sched/sched_wakeup_new sched/sched_waking'
++ trap on_exit EXIT
++ CAT_PID=1867
++ for elem in sched
++ eval 'trace=\${EVENT_${elem}}'
+++ trace='${EVENT_sched}'
+++ eval echo '${EVENT_sched}'
++++ echo sched/sched_switch sched/sched_wakeup sched/sched_wakeup_new sched/sched_waking
++ for event in '$(eval echo ${trace})'
++ echo 1
++ for event in '$(eval echo ${trace})'
++ echo 1
++ for event in '$(eval echo ${trace})'
++ echo 1
++ for event in '$(eval echo ${trace})'
++ echo 1
++ echo 1
++ read
++ cat /sys/kernel/debug/tracing/per_cpu/cpu0/trace_pipe
+ sh-1866 [000] d.h. 201821.030000: sched_waking: comm=rngd pid=987 prio=120 target_cpu=000
+ sh-1866 [000] dnh. 201821.030000: sched_wakeup: comm=rngd pid=987 prio=120 target_cpu=000
+ sh-1866 [000] dn.. 201821.030000: sched_waking: comm=ksoftirqd/0 pid=6 prio=120 target_cpu=000
+ sh-1866 [000] dn.. 201821.030000: sched_wakeup: comm=ksoftirqd/0 pid=6 prio=120 target_cpu=000
+ sh-1866 [000] d... 201821.030000: sched_switch: prev_comm=sh prev_pid=1866 prev_prio=120 prev_state=R ==> next_comm=rngd next_pid=987 next_prio=120
+ rngd-987 [000] d... 201821.030000: sched_switch: prev_comm=rngd prev_pid=987 prev_prio=120 prev_state=S ==> next_comm=ksoftirqd/0 next_pid=6 next_prio=120
+ ksoftirqd/0-6 [000] d... 201821.030000: sched_switch: prev_comm=ksoftirqd/0 prev_pid=6 prev_prio=120 prev_state=S ==> next_comm=sh next_pid=1866 next_prio=120
+ sh-1866 [000] d.h. 201821.030000: sched_waking: comm=phosphor-hwmon- pid=1188 prio=120 target_cpu=000
+ sh-1866 [000] dnh. 201821.030000: sched_wakeup: comm=phosphor-hwmon- pid=1188 prio=120 target_cpu=000
+ sh-1866 [000] d... 201821.030000: sched_switch: prev_comm=sh prev_pid=1866 prev_prio=120 prev_state=R ==> next_comm=phosphor-hwmon- next_pid=1188 next_prio=120
+ phosphor-hwmon--1188 [000] d... 201821.030000: sched_switch: prev_comm=phosphor-hwmon- prev_pid=1188 prev_prio=120 prev_state=D ==> next_comm=sh next_pid=1866 next_prio=120
+...
+<RETURN>
+...
++ kill 1867
++ on_exit
++ for elem in sched
++ eval 'trace=\${EVENT_${elem}}'
+++ trace='${EVENT_sched}'
+++ eval echo '${EVENT_sched}'
++++ echo sched/sched_switch sched/sched_wakeup sched/sched_wakeup_new sched/sched_waking
++ for event in '$(eval echo ${trace})'
++ echo 0
++ for event in '$(eval echo ${trace})'
++ echo 0
++ for event in '$(eval echo ${trace})'
++ echo 0
++ for event in '$(eval echo ${trace})'
++ echo 0
++ echo 0
++ on_exit
++ rm -f obmc-fsi-trace.Rz15GL
+```
diff --git a/amboar/obmc-scripts/tracing/trace b/amboar/obmc-scripts/tracing/trace
new file mode 100755
index 0000000..89840e1
--- /dev/null
+++ b/amboar/obmc-scripts/tracing/trace
@@ -0,0 +1,77 @@
+#!/bin/bash
+#
+# SPDX-License-Identifier: Apache-2.0
+# Copyright (C) 2018 IBM Corp.
+
+set -eou pipefail
+
+if [ $# -lt 2 ]
+then
+ echo Usage: $0 [USER@]HOST EVENTSET [EVENTSET...]
+ echo
+ echo Valid EVENTSETs: fsi, occ, sbefifo, timer, sched
+ exit 1
+fi
+
+TRACE_TARGET="$1"
+shift 1
+TRACE_EVENT_SET="$@"
+
+TRACESCRIPT_PATH="$(mktemp obmc-fsi-trace.XXXXXX)"
+TRACESCRIPT="$(basename "${TRACESCRIPT_PATH}")"
+
+on_exit() {
+ rm -f "${TRACESCRIPT_PATH}"
+}
+
+trap on_exit EXIT
+
+cat > "${TRACESCRIPT_PATH}" <<-EOF
+set -eou pipefail
+
+set -x
+
+# Look Ma! Associative arrays in ash!
+EVENT_fsi="fsi fsi_master_gpio"
+EVENT_occ="occ hwmon_occ"
+EVENT_sbefifo="sbefifo"
+EVENT_timer="timer/timer_start timer/timer_cancel timer/timer_expire_entry timer/timer_expire_exit"
+EVENT_sched="sched/sched_switch sched/sched_wakeup sched/sched_wakeup_new sched/sched_waking"
+
+on_exit() {
+for elem in ${TRACE_EVENT_SET}
+do
+ # Abuse eval(1) to extract the list of tracepoints to enable from our
+ # fake associative arrays
+ eval 'trace=\\\${EVENT_\${elem}}'
+ for event in \$(eval echo \${trace})
+ do
+ echo 0 > /sys/kernel/debug/tracing/events/\${event}/enable
+ done
+done
+ echo 0 > /sys/kernel/debug/tracing/tracing_on
+}
+
+trap on_exit EXIT
+
+cat /sys/kernel/debug/tracing/per_cpu/cpu0/trace_pipe &
+CAT_PID=\$!
+
+for elem in ${TRACE_EVENT_SET}
+do
+ # See comment in the disable path
+ eval 'trace=\\\${EVENT_\${elem}}'
+ for event in \$(eval echo \${trace})
+ do
+ echo 1 > /sys/kernel/debug/tracing/events/\${event}/enable
+ done
+done
+echo 1 > /sys/kernel/debug/tracing/tracing_on
+
+read
+
+kill \${CAT_PID}
+EOF
+
+scp "${TRACESCRIPT_PATH}" "${TRACE_TARGET}":/tmp/"${TRACESCRIPT}"
+ssh "${TRACE_TARGET}" "/bin/sh -x /tmp/'${TRACESCRIPT}'"