1#!/bin/sh
2# SPDX-License-Identifier: GPL-2.0-only
3
4export KSELFTESTS_SKIP=4
5
6log() {
7	echo >/dev/stderr $*
8}
9
10pe_ok() {
11	local dev="$1"
12	local path="/sys/bus/pci/devices/$dev/eeh_pe_state"
13
14	# if a driver doesn't support the error handling callbacks then the
15	# device is recovered by removing and re-probing it. This causes the
16	# sysfs directory to disappear so read the PE state once and squash
17	# any potential error messages
18	local eeh_state="$(cat $path 2>/dev/null)"
19	if [ -z "$eeh_state" ]; then
20		return 1;
21	fi
22
23	local fw_state="$(echo $eeh_state | cut -d' ' -f1)"
24	local sw_state="$(echo $eeh_state | cut -d' ' -f2)"
25
26	# If EEH_PE_ISOLATED or EEH_PE_RECOVERING are set then the PE is in an
27	# error state or being recovered. Either way, not ok.
28	if [ "$((sw_state & 0x3))" -ne 0 ] ; then
29		return 1
30	fi
31
32	# A functioning PE should have the EEH_STATE_MMIO_ACTIVE and
33	# EEH_STATE_DMA_ACTIVE flags set. For some goddamn stupid reason
34	# the platform backends set these when the PE is in reset. The
35	# RECOVERING check above should stop any false positives though.
36	if [ "$((fw_state & 0x18))" -ne "$((0x18))" ] ; then
37		return 1
38	fi
39
40	return 0;
41}
42
43eeh_supported() {
44	test -e /proc/powerpc/eeh && \
45	grep -q 'EEH Subsystem is enabled' /proc/powerpc/eeh
46}
47
48eeh_test_prep() {
49	if ! eeh_supported ; then
50		echo "EEH not supported on this system, skipping"
51		exit $KSELFTESTS_SKIP;
52	fi
53
54	if [ ! -e "/sys/kernel/debug/powerpc/eeh_dev_check" ] && \
55	   [ ! -e "/sys/kernel/debug/powerpc/eeh_dev_break" ] ; then
56		log "debugfs EEH testing files are missing. Is debugfs mounted?"
57		exit $KSELFTESTS_SKIP;
58	fi
59
60	# Bump the max freeze count to something absurd so we don't
61	# trip over it while breaking things.
62	echo 5000 > /sys/kernel/debug/powerpc/eeh_max_freezes
63}
64
65eeh_can_break() {
66	# skip bridges since we can't recover them (yet...)
67	if [ -e "/sys/bus/pci/devices/$dev/pci_bus" ] ; then
68		log "$dev, Skipped: bridge"
69		return 1;
70	fi
71
72	# The ahci driver doesn't support error recovery. If the ahci device
73	# happens to be hosting the root filesystem, and then we go and break
74	# it the system will generally go down. We should probably fix that
75	# at some point
76	if [ "ahci" = "$(basename $(realpath /sys/bus/pci/devices/$dev/driver))" ] ; then
77		log "$dev, Skipped: ahci doesn't support recovery"
78		return 1;
79	fi
80
81	# Don't inject errosr into an already-frozen PE. This happens with
82	# PEs that contain multiple PCI devices (e.g. multi-function cards)
83	# and injecting new errors during the recovery process will probably
84	# result in the recovery failing and the device being marked as
85	# failed.
86	if ! pe_ok $dev ; then
87		log "$dev, Skipped: Bad initial PE state"
88		return 1;
89	fi
90
91	return 0
92}
93
94eeh_one_dev() {
95	local dev="$1"
96
97	# Using this function from the command line is sometimes useful for
98	# testing so check that the argument is a well-formed sysfs device
99	# name.
100	if ! test -e /sys/bus/pci/devices/$dev/ ; then
101		log "Error: '$dev' must be a sysfs device name (DDDD:BB:DD.F)"
102		return 1;
103	fi
104
105	# Break it
106	echo $dev >/sys/kernel/debug/powerpc/eeh_dev_break
107
108	# Force an EEH device check. If the kernel has already
109	# noticed the EEH (due to a driver poll or whatever), this
110	# is a no-op.
111	echo $dev >/sys/kernel/debug/powerpc/eeh_dev_check
112
113	# Default to a 60s timeout when waiting for a device to recover. This
114	# is an arbitrary default which can be overridden by setting the
115	# EEH_MAX_WAIT environmental variable when required.
116
117	# The current record holder for longest recovery time is:
118	#  "Adaptec Series 8 12G SAS/PCIe 3" at 39 seconds
119	max_wait=${EEH_MAX_WAIT:=60}
120
121	for i in `seq 0 ${max_wait}` ; do
122		if pe_ok $dev ; then
123			break;
124		fi
125		log "$dev, waited $i/${max_wait}"
126		sleep 1
127	done
128
129	if ! pe_ok $dev ; then
130		log "$dev, Failed to recover!"
131		return 1;
132	fi
133
134	log "$dev, Recovered after $i seconds"
135	return 0;
136}
137
138