KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

Manually perform cache maintenance on the source VM during intra-host
migration to ensure no stale data is left in CPU caches after the VM is
destroyed.  Because the source VM is "converted" to a non-SEV VM, KVM's
memory reclaim flows won't trigger cache maintenance, e.g. when all guest
memory is reclaimed in response to detaching from the mmu_notifier.

Note, relying on the destination VM to do cache maintenance isn't an option
as KVM doesn't require identical guest memory configurations, i.e. the
source VM may have access to memory that the destination VM does not.
Enforcing equivalent memory configurations is infeasible, as it would
require a *deep* comparison of memslots, e.g. to verify that not only are
the memslot identical, but what the memslots point at is also identical.

Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration")
Cc: stable@vger.kernel.org
Reported-by: Stefan Teodorescu <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

12 files changed, 2306 insertions, 0 deletions

diff --git a/tools/testing/selftests/gpio/.gitignore b/tools/testing/selftests/gpio/.gitignore
new file mode 100644
index 000000000..16f74de47
--- /dev/null
+++ b/tools/testing/selftests/gpio/.gitignore
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+gpio-mockup-cdev
+gpio-chip-info
+gpio-line-name
+gpio-cdev-uaf
diff --git a/tools/testing/selftests/gpio/Makefile b/tools/testing/selftests/gpio/Makefile
new file mode 100644
index 000000000..741ab21e1
--- /dev/null
+++ b/tools/testing/selftests/gpio/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_PROGS := gpio-mockup.sh gpio-sim.sh gpio-aggregator.sh gpio-cdev-uaf.sh
+TEST_FILES := gpio-mockup-sysfs.sh
+TEST_GEN_PROGS_EXTENDED := gpio-mockup-cdev gpio-chip-info gpio-line-name \
+			   gpio-cdev-uaf
+CFLAGS += -O2 -g -Wall $(KHDR_INCLUDES)
+
+include ../lib.mk
diff --git a/tools/testing/selftests/gpio/config b/tools/testing/selftests/gpio/config
new file mode 100644
index 000000000..1287abeaa
--- /dev/null
+++ b/tools/testing/selftests/gpio/config
@@ -0,0 +1,5 @@
+CONFIG_GPIOLIB=y
+CONFIG_GPIO_CDEV=y
+CONFIG_GPIO_MOCKUP=m
+CONFIG_GPIO_SIM=m
+CONFIG_GPIO_AGGREGATOR=m
diff --git a/tools/testing/selftests/gpio/gpio-aggregator.sh b/tools/testing/selftests/gpio/gpio-aggregator.sh
new file mode 100755
index 000000000..9b6f80ad9
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-aggregator.sh
@@ -0,0 +1,727 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2025 Bartosz Golaszewski <brgl@bgdev.pl>
+# Copyright (C) 2025 Koichiro Den <koichiro.den@canonical.com>
+
+BASE_DIR=$(dirname "$0")
+CONFIGFS_SIM_DIR="/sys/kernel/config/gpio-sim"
+CONFIGFS_AGG_DIR="/sys/kernel/config/gpio-aggregator"
+SYSFS_AGG_DIR="/sys/bus/platform/drivers/gpio-aggregator"
+MODULE="gpio-aggregator"
+
+fail() {
+	echo "$*" >&2
+	echo "GPIO $MODULE test FAIL"
+	exit 1
+}
+
+skip() {
+	echo "$*" >&2
+	echo "GPIO $MODULE test SKIP"
+	exit 4
+}
+
+# gpio-sim
+sim_enable_chip() {
+	local CHIP=$1
+
+	echo 1 > "$CONFIGFS_SIM_DIR/$CHIP/live" || fail "Unable to enable the chip"
+}
+
+sim_disable_chip() {
+	local CHIP=$1
+
+	echo 0 > "$CONFIGFS_SIM_DIR/$CHIP/live" || fail "Unable to disable the chip"
+}
+
+sim_configfs_cleanup() {
+	local NOCHECK=${1:-0}
+
+	for CHIP_DIR in "$CONFIGFS_SIM_DIR"/*; do
+		[ -d "$CHIP_DIR" ] || continue
+		echo 0 > "$CHIP_DIR/live"
+		find "$CHIP_DIR" -depth -type d -exec rmdir {} \;
+	done
+	[ "$NOCHECK" -eq 1 ] && return;
+	remaining=$(find "$CONFIGFS_SIM_DIR" -mindepth 1 -type d 2> /dev/null)
+	if [ -n "$remaining" ]; then
+		fail "Directories remain in $CONFIGFS_SIM_DIR: $remaining"
+	fi
+}
+
+sim_get_chip_label() {
+	local CHIP=$1
+	local BANK=$2
+	local CHIP_NAME=$(cat "$CONFIGFS_SIM_DIR/$CHIP/$BANK/chip_name" 2> /dev/null) || \
+		fail "Unable to read the chip name from configfs"
+
+	$BASE_DIR/gpio-chip-info "/dev/$CHIP_NAME" label || \
+		fail "Unable to read the chip label from the character device"
+}
+
+# gpio-aggregator
+agg_create_chip() {
+	local CHIP=$1
+
+	mkdir "$CONFIGFS_AGG_DIR/$CHIP"
+}
+
+agg_remove_chip() {
+	local CHIP=$1
+
+	find "$CONFIGFS_AGG_DIR/$CHIP/" -depth -type d -exec rmdir {} \; || \
+		fail "Unable to remove $CONFIGFS_AGG_DIR/$CHIP"
+}
+
+agg_create_line() {
+	local CHIP=$1
+	local LINE=$2
+
+	mkdir "$CONFIGFS_AGG_DIR/$CHIP/$LINE"
+}
+
+agg_remove_line() {
+	local CHIP=$1
+	local LINE=$2
+
+	rmdir "$CONFIGFS_AGG_DIR/$CHIP/$LINE"
+}
+
+agg_set_key() {
+	local CHIP=$1
+	local LINE=$2
+	local KEY=$3
+
+	echo "$KEY" > "$CONFIGFS_AGG_DIR/$CHIP/$LINE/key" || fail "Unable to set the lookup key"
+}
+
+agg_set_offset() {
+	local CHIP=$1
+	local LINE=$2
+	local OFFSET=$3
+
+	echo "$OFFSET" > "$CONFIGFS_AGG_DIR/$CHIP/$LINE/offset" || \
+		fail "Unable to set the lookup offset"
+}
+
+agg_set_line_name() {
+	local CHIP=$1
+	local LINE=$2
+	local NAME=$3
+
+	echo "$NAME" > "$CONFIGFS_AGG_DIR/$CHIP/$LINE/name" || fail "Unable to set the line name"
+}
+
+agg_enable_chip() {
+	local CHIP=$1
+
+	echo 1 > "$CONFIGFS_AGG_DIR/$CHIP/live" || fail "Unable to enable the chip"
+}
+
+agg_disable_chip() {
+	local CHIP=$1
+
+	echo 0 > "$CONFIGFS_AGG_DIR/$CHIP/live" || fail "Unable to disable the chip"
+}
+
+agg_configfs_cleanup() {
+	local NOCHECK=${1:-0}
+
+	for CHIP_DIR in "$CONFIGFS_AGG_DIR"/*; do
+		[ -d "$CHIP_DIR" ] || continue
+		echo 0 > "$CHIP_DIR/live" 2> /dev/null
+		find "$CHIP_DIR" -depth -type d -exec rmdir {} \;
+	done
+	[ "$NOCHECK" -eq 1 ] && return;
+	remaining=$(find "$CONFIGFS_AGG_DIR" -mindepth 1 -type d 2> /dev/null)
+	if [ -n "$remaining" ]; then
+		fail "Directories remain in $CONFIGFS_AGG_DIR: $remaining"
+	fi
+}
+
+agg_configfs_dev_name() {
+	local CHIP=$1
+
+	cat "$CONFIGFS_AGG_DIR/$CHIP/dev_name" 2> /dev/null || \
+		fail "Unable to read the device name from configfs"
+}
+
+agg_configfs_chip_name() {
+	local CHIP=$1
+	local DEV_NAME=$(agg_configfs_dev_name "$CHIP")
+	local CHIP_LIST=$(find "/sys/devices/platform/$DEV_NAME" \
+		-maxdepth 1 -type d -name "gpiochip[0-9]*" 2> /dev/null)
+	local CHIP_COUNT=$(echo "$CHIP_LIST" | wc -l)
+
+	if [ -z "$CHIP_LIST" ]; then
+		fail "No gpiochip in /sys/devices/platform/$DEV_NAME/"
+	elif [ "$CHIP_COUNT" -ne 1 ]; then
+		fail "Multiple gpiochips unexpectedly found: $CHIP_LIST"
+	fi
+	basename "$CHIP_LIST"
+}
+
+agg_get_chip_num_lines() {
+	local CHIP=$1
+	local N_DIR=$(ls -d $CONFIGFS_AGG_DIR/$CHIP/line[0-9]* 2> /dev/null | wc -l)
+	local N_LINES
+
+	if [ "$(cat $CONFIGFS_AGG_DIR/$CHIP/live)" = 0 ]; then
+		echo "$N_DIR"
+	else
+		N_LINES=$(
+			$BASE_DIR/gpio-chip-info \
+				"/dev/$(agg_configfs_chip_name "$CHIP")" num-lines
+		) || fail "Unable to read the number of lines from the character device"
+		if [ $N_DIR != $N_LINES ]; then
+			fail "Discrepancy between two sources for the number of lines"
+		fi
+		echo "$N_LINES"
+	fi
+}
+
+agg_get_chip_label() {
+	local CHIP=$1
+
+	$BASE_DIR/gpio-chip-info "/dev/$(agg_configfs_chip_name "$CHIP")" label || \
+		fail "Unable to read the chip label from the character device"
+}
+
+agg_get_line_name() {
+	local CHIP=$1
+	local OFFSET=$2
+	local NAME_CONFIGFS=$(cat "$CONFIGFS_AGG_DIR/$CHIP/line${OFFSET}/name")
+	local NAME_CDEV
+
+	if [ "$(cat "$CONFIGFS_AGG_DIR/$CHIP/live")" = 0 ]; then
+		echo "$NAME_CONFIGFS"
+	else
+		NAME_CDEV=$(
+			$BASE_DIR/gpio-line-name \
+				"/dev/$(agg_configfs_chip_name "$CHIP")" "$OFFSET"
+		) || fail "Unable to read the line name from the character device"
+		if [ "$NAME_CONFIGFS" != "$NAME_CDEV" ]; then
+			fail "Discrepancy between two sources for the name of line"
+		fi
+		echo "$NAME_CDEV"
+	fi
+}
+
+
+# Load the modules. This will pull in configfs if needed too.
+modprobe gpio-sim || skip "unable to load the gpio-sim module"
+modprobe gpio-aggregator || skip "unable to load the gpio-aggregator module"
+
+# Make sure configfs is mounted at /sys/kernel/config. Wait a bit if needed.
+for IDX in $(seq 5); do
+	if [ "$IDX" -eq "5" ]; then
+		skip "configfs not mounted at /sys/kernel/config"
+	fi
+
+	mountpoint -q /sys/kernel/config && break
+	sleep 0.1
+done
+
+# If the module was already loaded: remove all previous chips
+agg_configfs_cleanup
+sim_configfs_cleanup
+
+trap "exit 1" SIGTERM SIGINT
+trap "agg_configfs_cleanup 1; sim_configfs_cleanup 1" EXIT
+
+# Use gpio-sim chips as the test backend
+for CHIP in $(seq -f "chip%g" 0 1); do
+	mkdir $CONFIGFS_SIM_DIR/$CHIP
+	for BANK in $(seq -f "bank%g" 0 1); do
+		mkdir -p "$CONFIGFS_SIM_DIR/$CHIP/$BANK"
+		echo "${CHIP}_${BANK}" > "$CONFIGFS_SIM_DIR/$CHIP/$BANK/label" || \
+			fail "unable to set the chip label"
+		echo 16 > "$CONFIGFS_SIM_DIR/$CHIP/$BANK/num_lines" || \
+			fail "unable to set the number of lines"
+		for IDX in $(seq 0 15); do
+			LINE_NAME="${CHIP}${BANK}_${IDX}"
+			LINE_DIR="$CONFIGFS_SIM_DIR/$CHIP/$BANK/line$IDX"
+			mkdir -p $LINE_DIR
+			echo "$LINE_NAME" > "$LINE_DIR/name" || fail "unable to set the line name"
+		done
+	done
+	sim_enable_chip "$CHIP"
+done
+
+echo "1. GPIO aggregator creation/deletion"
+
+echo "1.1. Creation/deletion via configfs"
+
+echo "1.1.1. Minimum creation/deletion"
+agg_create_chip   agg0
+agg_create_line   agg0 line0
+agg_set_key       agg0 line0 "$(sim_get_chip_label chip0 bank0)"
+agg_set_offset    agg0 line0 5
+agg_set_line_name agg0 line0 test0
+agg_enable_chip   agg0
+test "$(cat "$CONFIGFS_AGG_DIR/agg0/live")" = 1 || fail "chip unexpectedly dead"
+test "$(agg_get_chip_label agg0)" = "$(agg_configfs_dev_name agg0)" || \
+	fail "label is inconsistent"
+test "$(agg_get_chip_num_lines agg0)" = "1" || fail "number of lines is not 1"
+test "$(agg_get_line_name agg0 0)" = "test0" || fail "line name is unset"
+agg_disable_chip  agg0
+agg_remove_line   agg0 line0
+agg_remove_chip   agg0
+
+echo "1.1.2. Complex creation/deletion"
+agg_create_chip   agg0
+agg_create_line   agg0 line0
+agg_create_line   agg0 line1
+agg_create_line   agg0 line2
+agg_create_line   agg0 line3
+agg_set_key       agg0 line0 "$(sim_get_chip_label chip0 bank0)"
+agg_set_key       agg0 line1 "$(sim_get_chip_label chip0 bank1)"
+agg_set_key       agg0 line2 "$(sim_get_chip_label chip1 bank0)"
+agg_set_key       agg0 line3 "$(sim_get_chip_label chip1 bank1)"
+agg_set_offset    agg0 line0 1
+agg_set_offset    agg0 line1 3
+agg_set_offset    agg0 line2 5
+agg_set_offset    agg0 line3 7
+agg_set_line_name agg0 line0 test0
+agg_set_line_name agg0 line1 test1
+agg_set_line_name agg0 line2 test2
+agg_set_line_name agg0 line3 test3
+agg_enable_chip   agg0
+test "$(cat "$CONFIGFS_AGG_DIR/agg0/live")" = 1 || fail "chip unexpectedly dead"
+test "$(agg_get_chip_label agg0)" = "$(agg_configfs_dev_name agg0)" || \
+	fail "label is inconsistent"
+test "$(agg_get_chip_num_lines agg0)" = "4" || fail "number of lines is not 1"
+test "$(agg_get_line_name agg0 0)" = "test0" || fail "line name is unset"
+test "$(agg_get_line_name agg0 1)" = "test1" || fail "line name is unset"
+test "$(agg_get_line_name agg0 2)" = "test2" || fail "line name is unset"
+test "$(agg_get_line_name agg0 3)" = "test3" || fail "line name is unset"
+agg_disable_chip  agg0
+agg_remove_line   agg0 line0
+agg_remove_line   agg0 line1
+agg_remove_line   agg0 line2
+agg_remove_line   agg0 line3
+agg_remove_chip   agg0
+
+echo "1.1.3. Can't instantiate a chip without any line"
+agg_create_chip   agg0
+echo 1 > "$CONFIGFS_AGG_DIR/agg0/live" 2> /dev/null && fail "chip unexpectedly enabled"
+test "$(cat "$CONFIGFS_AGG_DIR/agg0/live")" = 0 || fail "chip unexpectedly alive"
+agg_remove_chip   agg0
+
+echo "1.1.4. Can't instantiate a chip with invalid configuration"
+agg_create_chip   agg0
+agg_create_line   agg0 line0
+agg_set_key       agg0 line0 "chipX_bankX"
+agg_set_offset    agg0 line0 99
+agg_set_line_name agg0 line0 test0
+echo 1 > "$CONFIGFS_AGG_DIR/agg0/live" 2> /dev/null && fail "chip unexpectedly enabled"
+test "$(cat "$CONFIGFS_AGG_DIR/agg0/live")" = 0 || fail "chip unexpectedly alive"
+agg_remove_line   agg0 line0
+agg_remove_chip   agg0
+
+echo "1.1.5. Can't instantiate a chip asynchronously via deferred probe"
+agg_create_chip   agg0
+agg_create_line   agg0 line0
+agg_set_key       agg0 line0 "chip0_bank0"
+agg_set_offset    agg0 line0 5
+agg_set_line_name agg0 line0 test0
+sim_disable_chip  chip0
+echo 1 > "$CONFIGFS_AGG_DIR/agg0/live" 2> /dev/null && fail "chip unexpectedly enabled"
+test "$(cat "$CONFIGFS_AGG_DIR/agg0/live")" = 0 || fail "chip unexpectedly alive"
+sim_enable_chip   chip0
+sleep 1
+test "$(cat "$CONFIGFS_AGG_DIR/agg0/live")" = 0 || \
+	fail "chip unexpectedly transitioned to 'live' state"
+agg_remove_line   agg0 line0
+agg_remove_chip   agg0
+
+echo "1.1.6. Can't instantiate a chip with _sysfs prefix"
+mkdir "$CONFIGFS_AGG_DIR/_sysfs" 2> /dev/null && fail "chip _sysfs unexpectedly created"
+mkdir "$CONFIGFS_AGG_DIR/_sysfs.foo" 2> /dev/null && fail "chip _sysfs.foo unexpectedly created"
+
+echo "1.2. Creation/deletion via sysfs"
+
+echo "1.2.1. Minimum creation/deletion"
+echo "chip0_bank0 0" > "$SYSFS_AGG_DIR/new_device"
+CHIPNAME=$(agg_configfs_chip_name _sysfs.0)
+test "$(cat "$CONFIGFS_AGG_DIR/_sysfs.0/live")" = 1 || fail "chip unexpectedly dead"
+test "$(agg_get_chip_label _sysfs.0)" = "$(agg_configfs_dev_name _sysfs.0)" || \
+	fail "label is inconsistent"
+test "$(agg_get_chip_num_lines _sysfs.0)" = "1" || fail "number of lines is not 1"
+test "$(agg_get_line_name _sysfs.0 0)" = "" || fail "line name is unset"
+echo "$(agg_configfs_dev_name _sysfs.0)" > "$SYSFS_AGG_DIR/delete_device"
+test -d $CONFIGFS_AGG_DIR/_sysfs.0 && fail "_sysfs.0 unexpectedly remains"
+test -d /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains"
+
+echo "1.2.2. Complex creation/deletion"
+echo "chip0bank0_0 chip1_bank1 10-11" > "$SYSFS_AGG_DIR/new_device"
+CHIPNAME=$(agg_configfs_chip_name _sysfs.0)
+test "$(cat "$CONFIGFS_AGG_DIR/_sysfs.0/live")" = 1 || fail "chip unexpectedly dead"
+test "$(agg_get_chip_label _sysfs.0)" = "$(agg_configfs_dev_name _sysfs.0)" || \
+	fail "label is inconsistent"
+test "$(agg_get_chip_num_lines _sysfs.0)" = "3" || fail "number of lines is not 3"
+test "$(agg_get_line_name _sysfs.0 0)" = "" || fail "line name is unset"
+test "$(agg_get_line_name _sysfs.0 1)" = "" || fail "line name is unset"
+test "$(agg_get_line_name _sysfs.0 2)" = "" || fail "line name is unset"
+echo "$(agg_configfs_dev_name _sysfs.0)" > "$SYSFS_AGG_DIR/delete_device"
+test -d $CONFIGFS_AGG_DIR/_sysfs.0 && fail "_sysfs.0 unexpectedly remains"
+test -d /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains"
+
+echo "1.2.3. Asynchronous creation with deferred probe"
+sim_disable_chip  chip0
+echo 'chip0_bank0 0' > $SYSFS_AGG_DIR/new_device
+sleep 1
+test "$(cat "$CONFIGFS_AGG_DIR/_sysfs.0/live")" = 0 || fail "chip unexpectedly alive"
+sim_enable_chip  chip0
+sleep 1
+CHIPNAME=$(agg_configfs_chip_name _sysfs.0)
+test "$(cat "$CONFIGFS_AGG_DIR/_sysfs.0/live")" = 1 || fail "chip unexpectedly remains dead"
+test "$(agg_get_chip_label _sysfs.0)" = "$(agg_configfs_dev_name _sysfs.0)" || \
+	fail "label is inconsistent"
+test "$(agg_get_chip_num_lines _sysfs.0)" = "1" || fail "number of lines is not 1"
+test "$(agg_get_line_name _sysfs.0 0)" = "" || fail "line name unexpectedly set"
+echo "$(agg_configfs_dev_name _sysfs.0)" > "$SYSFS_AGG_DIR/delete_device"
+test -d $CONFIGFS_AGG_DIR/_sysfs.0 && fail "_sysfs.0 unexpectedly remains"
+test -d /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains"
+
+echo "1.2.4. Can't instantiate a chip with invalid configuration"
+echo "xyz 0" > "$SYSFS_AGG_DIR/new_device"
+test "$(cat $CONFIGFS_AGG_DIR/_sysfs.0/live)" = 0 || fail "chip unexpectedly alive"
+echo "$(agg_configfs_dev_name _sysfs.0)" > "$SYSFS_AGG_DIR/delete_device"
+
+echo "2. GPIO aggregator configuration"
+
+echo "2.1. Configuring aggregators instantiated via configfs"
+setup_2_1() {
+	agg_create_chip   agg0
+	agg_create_line   agg0 line0
+	agg_create_line   agg0 line1
+	agg_set_key       agg0 line0 "$(sim_get_chip_label chip0 bank0)"
+	agg_set_key       agg0 line1 "$(sim_get_chip_label chip1 bank0)"
+	agg_set_offset    agg0 line0 1
+	agg_set_offset    agg0 line1 3
+	agg_set_line_name agg0 line0 test0
+	agg_set_line_name agg0 line1 test1
+	agg_enable_chip   agg0
+}
+teardown_2_1() {
+	agg_configfs_cleanup
+}
+
+echo "2.1.1. While offline"
+
+echo "2.1.1.1. Line can be added/removed"
+setup_2_1
+agg_disable_chip  agg0
+agg_create_line   agg0 line2
+agg_set_key       agg0 line2 "$(sim_get_chip_label chip0 bank1)"
+agg_set_offset    agg0 line2 5
+agg_enable_chip   agg0
+test "$(agg_get_chip_num_lines agg0)" = "3" || fail "number of lines is not 1"
+teardown_2_1
+
+echo "2.1.1.2. Line key can be modified"
+setup_2_1
+agg_disable_chip  agg0
+agg_set_key       agg0 line0 "$(sim_get_chip_label chip0 bank1)"
+agg_set_key       agg0 line1 "$(sim_get_chip_label chip1 bank1)"
+agg_enable_chip   agg0
+teardown_2_1
+
+echo "2.1.1.3. Line name can be modified"
+setup_2_1
+agg_disable_chip  agg0
+agg_set_line_name agg0 line0 new0
+agg_set_line_name agg0 line1 new1
+agg_enable_chip   agg0
+test "$(agg_get_line_name agg0 0)" = "new0" || fail "line name is unset"
+test "$(agg_get_line_name agg0 1)" = "new1" || fail "line name is unset"
+teardown_2_1
+
+echo "2.1.1.4. Line offset can be modified"
+setup_2_1
+agg_disable_chip  agg0
+agg_set_offset    agg0 line0 5
+agg_set_offset    agg0 line1 7
+agg_enable_chip   agg0
+teardown_2_1
+
+echo "2.1.1.5. Can re-enable a chip after valid reconfiguration"
+setup_2_1
+agg_disable_chip  agg0
+agg_set_key       agg0 line0 "$(sim_get_chip_label chip1 bank1)"
+agg_set_offset    agg0 line0 15
+agg_set_key       agg0 line1 "$(sim_get_chip_label chip0 bank1)"
+agg_set_offset    agg0 line0 14
+agg_create_line   agg0 line2
+agg_set_key       agg0 line2 "$(sim_get_chip_label chip0 bank1)"
+agg_set_offset    agg0 line2 13
+agg_enable_chip   agg0
+test "$(agg_get_chip_num_lines agg0)" = "3" || fail "number of lines is not 1"
+teardown_2_1
+
+echo "2.1.1.7. Can't re-enable a chip with invalid reconfiguration"
+setup_2_1
+agg_disable_chip  agg0
+agg_set_key       agg0 line0 invalidkey
+echo 1 > "$CONFIGFS_AGG_DIR/agg0/live" 2> /dev/null && fail "chip unexpectedly enabled"
+teardown_2_1
+setup_2_1
+agg_disable_chip  agg0
+agg_set_offset    agg0 line0 99
+echo 1 > "$CONFIGFS_AGG_DIR/agg0/live" 2> /dev/null && fail "chip unexpectedly enabled"
+teardown_2_1
+
+echo "2.1.2. While online"
+
+echo "2.1.2.1. Can't add/remove line"
+setup_2_1
+mkdir "$CONFIGFS_AGG_DIR/agg0/line2" 2> /dev/null && fail "line unexpectedly added"
+rmdir "$CONFIGFS_AGG_DIR/agg0/line1" 2> /dev/null && fail "line unexpectedly removed"
+teardown_2_1
+
+echo "2.1.2.2. Can't modify line key"
+setup_2_1
+echo "chip1_bank1" > "$CONFIGFS_AGG_DIR/agg0/line0/key" 2> /dev/null && \
+	fail "lookup key unexpectedly updated"
+teardown_2_1
+
+echo "2.1.2.3. Can't modify line name"
+setup_2_1
+echo "new0" > "$CONFIGFS_AGG_DIR/agg0/line0/name" 2> /dev/null && \
+	fail "name unexpectedly updated"
+teardown_2_1
+
+echo "2.1.2.4. Can't modify line offset"
+setup_2_1
+echo "5" > "$CONFIGFS_AGG_DIR/agg0/line0/offset" 2> /dev/null && \
+	fail "offset unexpectedly updated"
+teardown_2_1
+
+echo "2.2. Configuring aggregators instantiated via sysfs"
+setup_2_2() {
+	echo "chip0_bank0 1 chip1_bank0 3" > "$SYSFS_AGG_DIR/new_device"
+}
+teardown_2_2() {
+	echo "$(agg_configfs_dev_name _sysfs.0)" > "$SYSFS_AGG_DIR/delete_device"
+}
+
+echo "2.2.1. While online"
+
+echo "2.2.1.1. Can toggle live"
+setup_2_2
+agg_disable_chip  _sysfs.0
+agg_enable_chip   _sysfs.0
+teardown_2_2
+
+echo "2.2.1.2. Can't add/remove line"
+setup_2_2
+mkdir "$CONFIGFS_AGG_DIR/_sysfs.0/line2" 2> /dev/null && fail "line unexpectedly added"
+rmdir "$CONFIGFS_AGG_DIR/_sysfs.0/line1" 2> /dev/null && fail "line unexpectedly removed"
+teardown_2_2
+
+echo "2.2.1.3. Can't modify line key"
+setup_2_2
+echo "chip1_bank1" > "$CONFIGFS_AGG_DIR/_sysfs.0/line0/key" 2> /dev/null && \
+	fail "lookup key unexpectedly updated"
+teardown_2_2
+
+echo "2.2.1.4. Can't modify line name"
+setup_2_2
+echo "new0" > "$CONFIGFS_AGG_DIR/_sysfs.0/line0/name" 2> /dev/null && \
+	fail "name unexpectedly updated"
+teardown_2_2
+
+echo "2.2.1.5. Can't modify line offset"
+setup_2_2
+echo "5" > "$CONFIGFS_AGG_DIR/_sysfs.0/line0/offset" 2> /dev/null && \
+	fail "offset unexpectedly updated"
+teardown_2_2
+
+echo "2.2.2. While waiting for deferred probe"
+
+echo "2.2.2.1. Can't add/remove line despite live = 0"
+sim_disable_chip chip0
+setup_2_2
+mkdir "$CONFIGFS_AGG_DIR/_sysfs.0/line2" 2> /dev/null && fail "line unexpectedly added"
+rmdir "$CONFIGFS_AGG_DIR/_sysfs.0/line1" 2> /dev/null && fail "line unexpectedly removed"
+teardown_2_2
+sim_enable_chip chip0
+
+echo "2.2.2.2. Can't modify line key"
+sim_disable_chip chip0
+setup_2_2
+echo "chip1_bank1" > "$CONFIGFS_AGG_DIR/_sysfs.0/line0/key" 2> /dev/null && \
+	fail "lookup key unexpectedly updated"
+teardown_2_2
+sim_enable_chip chip0
+
+echo "2.2.2.3. Can't modify line name"
+sim_disable_chip chip0
+setup_2_2
+echo "new0" > "$CONFIGFS_AGG_DIR/_sysfs.0/line0/name" 2> /dev/null && \
+	fail "name unexpectedly updated"
+teardown_2_2
+sim_enable_chip chip0
+
+echo "2.2.2.4. Can't modify line offset"
+sim_disable_chip chip0
+setup_2_2
+echo 5 > "$CONFIGFS_AGG_DIR/_sysfs.0/line0/offset" 2> /dev/null && \
+	fail "offset unexpectedly updated"
+teardown_2_2
+sim_enable_chip chip0
+
+echo "2.2.2.5. Can't toggle live"
+sim_disable_chip chip0
+setup_2_2
+test "$(cat "$CONFIGFS_AGG_DIR/_sysfs.0/live")" = 0 || fail "chip unexpectedly alive"
+echo 1 > "$CONFIGFS_AGG_DIR/_sysfs.0/live" 2> /dev/null && fail "chip unexpectedly enabled"
+teardown_2_2
+sim_enable_chip chip0
+
+echo "2.2.3. While offline"
+
+echo "2.2.3.1. Can't add/remove line despite live = 0"
+setup_2_2
+agg_disable_chip _sysfs.0
+mkdir "$CONFIGFS_AGG_DIR/_sysfs.0/line2" 2> /dev/null && fail "line unexpectedly added"
+rmdir "$CONFIGFS_AGG_DIR/_sysfs.0/line1" 2> /dev/null && fail "line unexpectedly removed"
+teardown_2_2
+
+echo "2.2.3.2. Line key can be modified"
+setup_2_2
+agg_disable_chip  _sysfs.0
+agg_set_key       _sysfs.0 line0 "$(sim_get_chip_label chip0 bank1)"
+agg_set_key       _sysfs.0 line1 "$(sim_get_chip_label chip1 bank1)"
+agg_enable_chip   _sysfs.0
+teardown_2_2
+
+echo "2.2.3.3. Line name can be modified"
+setup_2_2
+agg_disable_chip  _sysfs.0
+agg_set_line_name _sysfs.0 line0 new0
+agg_set_line_name _sysfs.0 line1 new1
+agg_enable_chip   _sysfs.0
+test "$(agg_get_line_name _sysfs.0 0)" = "new0" || fail "line name is unset"
+test "$(agg_get_line_name _sysfs.0 1)" = "new1" || fail "line name is unset"
+teardown_2_2
+
+echo "2.2.3.4. Line offset can be modified"
+setup_2_2
+agg_disable_chip  _sysfs.0
+agg_set_offset    _sysfs.0 line0 5
+agg_set_offset    _sysfs.0 line1 7
+agg_enable_chip   _sysfs.0
+teardown_2_2
+
+echo "2.2.3.5. Can re-enable a chip with valid reconfiguration"
+setup_2_2
+agg_disable_chip  _sysfs.0
+agg_set_key       _sysfs.0 line0 "$(sim_get_chip_label chip1 bank1)"
+agg_set_offset    _sysfs.0 line0 15
+agg_set_key       _sysfs.0 line1 "$(sim_get_chip_label chip0 bank1)"
+agg_set_offset    _sysfs.0 line0 14
+agg_enable_chip   _sysfs.0
+teardown_2_2
+
+echo "2.2.3.6. Can't re-enable a chip with invalid reconfiguration"
+setup_2_2
+agg_disable_chip  _sysfs.0
+agg_set_key       _sysfs.0 line0 invalidkey
+echo 1 > "$CONFIGFS_AGG_DIR/_sysfs.0/live" 2> /dev/null && fail "chip unexpectedly enabled"
+teardown_2_2
+setup_2_2
+agg_disable_chip  _sysfs.0
+agg_set_offset    _sysfs.0 line0 99
+echo 1 > "$CONFIGFS_AGG_DIR/_sysfs.0/live" 2> /dev/null && fail "chip unexpectedly enabled"
+teardown_2_2
+
+echo "3. Module unload"
+
+echo "3.1. Can't unload module if there is at least one device created via configfs"
+agg_create_chip agg0
+modprobe -r gpio-aggregator 2> /dev/null
+test -d /sys/module/gpio_aggregator || fail "module unexpectedly unloaded"
+agg_remove_chip agg0
+
+echo "3.2. Can unload module if there is no device created via configfs"
+echo "chip0_bank0 1 chip1_bank0 3" > "$SYSFS_AGG_DIR/new_device"
+modprobe -r gpio-aggregator 2> /dev/null
+test -d /sys/module/gpio_aggregator && fail "module unexpectedly remains to be loaded"
+modprobe gpio-aggregator 2> /dev/null
+
+echo "4. GPIO forwarder functional"
+SETTINGS="chip0:bank0:2 chip0:bank1:4 chip1:bank0:6 chip1:bank1:8"
+setup_4() {
+	local OFFSET=0
+	agg_create_chip agg0
+	for SETTING in $SETTINGS; do
+		CHIP=$(echo "$SETTING" | cut -d: -f1)
+		BANK=$(echo "$SETTING" | cut -d: -f2)
+		LINE=$(echo "$SETTING" | cut -d: -f3)
+		agg_create_line agg0 "line${OFFSET}"
+		agg_set_key     agg0 "line${OFFSET}" "$(sim_get_chip_label "$CHIP" "$BANK")"
+		agg_set_offset  agg0 "line${OFFSET}" "$LINE"
+		OFFSET=$(expr $OFFSET + 1)
+	done
+	agg_enable_chip agg0
+}
+teardown_4() {
+	agg_configfs_cleanup
+}
+
+echo "4.1. Forwarding set values"
+setup_4
+OFFSET=0
+for SETTING in $SETTINGS; do
+	CHIP=$(echo "$SETTING" | cut -d: -f1)
+	BANK=$(echo "$SETTING" | cut -d: -f2)
+	LINE=$(echo "$SETTING" | cut -d: -f3)
+	DEVNAME=$(cat "$CONFIGFS_SIM_DIR/$CHIP/dev_name")
+	CHIPNAME=$(cat "$CONFIGFS_SIM_DIR/$CHIP/$BANK/chip_name")
+	VAL_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio${LINE}/value"
+	test $(cat $VAL_PATH) = "0" || fail "incorrect value read from sysfs"
+	$BASE_DIR/gpio-mockup-cdev -s 1 "/dev/$(agg_configfs_chip_name agg0)" "$OFFSET" &
+	mock_pid=$!
+	sleep 0.1 # FIXME Any better way?
+	test "$(cat $VAL_PATH)" = "1" || fail "incorrect value read from sysfs"
+	kill "$mock_pid"
+	OFFSET=$(expr $OFFSET + 1)
+done
+teardown_4
+
+echo "4.2. Forwarding set config"
+setup_4
+OFFSET=0
+for SETTING in $SETTINGS; do
+	CHIP=$(echo "$SETTING" | cut -d: -f1)
+	BANK=$(echo "$SETTING" | cut -d: -f2)
+	LINE=$(echo "$SETTING" | cut -d: -f3)
+	DEVNAME=$(cat "$CONFIGFS_SIM_DIR/$CHIP/dev_name")
+	CHIPNAME=$(cat "$CONFIGFS_SIM_DIR/$CHIP/$BANK/chip_name")
+	VAL_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio${LINE}/value"
+	$BASE_DIR/gpio-mockup-cdev -b pull-up "/dev/$(agg_configfs_chip_name agg0)" "$OFFSET"
+	test $(cat "$VAL_PATH") = "1" || fail "incorrect value read from sysfs"
+	OFFSET=$(expr $OFFSET + 1)
+done
+teardown_4
+
+echo "5. Race condition verification"
+
+echo "5.1. Stress test of new_device/delete_device and module load/unload"
+for _ in $(seq 1000); do
+	{
+		echo "dummy 0" > "$SYSFS_AGG_DIR/new_device"
+		cat "$CONFIGFS_AGG_DIR/_sysfs.0/dev_name" > "$SYSFS_AGG_DIR/delete_device"
+	} 2> /dev/null
+done &
+writer_pid=$!
+while kill -0 "$writer_pid" 2> /dev/null; do
+	{
+		modprobe gpio-aggregator
+		modprobe -r gpio-aggregator
+	} 2> /dev/null
+done
+
+echo "GPIO $MODULE test PASS"
diff --git a/tools/testing/selftests/gpio/gpio-cdev-uaf.c b/tools/testing/selftests/gpio/gpio-cdev-uaf.c
new file mode 100644
index 000000000..765d3cc4f
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-cdev-uaf.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * GPIO character device helper for UAF tests.
+ *
+ * Copyright 2026 Google LLC
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/gpio.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define CONFIGFS_DIR "/sys/kernel/config/gpio-sim"
+#define PROCFS_DIR "/proc"
+
+static void print_usage(void)
+{
+	printf("usage:\n");
+	printf("  gpio-cdev-uaf [chip|handle|event|req] [poll|read|ioctl]\n");
+}
+
+static int _create_chip(const char *name, int create)
+{
+	char path[64];
+
+	snprintf(path, sizeof(path), CONFIGFS_DIR "/%s", name);
+
+	if (create)
+		return mkdir(path, 0755);
+	else
+		return rmdir(path);
+}
+
+static int create_chip(const char *name)
+{
+	return _create_chip(name, 1);
+}
+
+static void remove_chip(const char *name)
+{
+	_create_chip(name, 0);
+}
+
+static int _create_bank(const char *chip_name, const char *name, int create)
+{
+	char path[64];
+
+	snprintf(path, sizeof(path), CONFIGFS_DIR "/%s/%s", chip_name, name);
+
+	if (create)
+		return mkdir(path, 0755);
+	else
+		return rmdir(path);
+}
+
+static int create_bank(const char *chip_name, const char *name)
+{
+	return _create_bank(chip_name, name, 1);
+}
+
+static void remove_bank(const char *chip_name, const char *name)
+{
+	_create_bank(chip_name, name, 0);
+}
+
+static int _enable_chip(const char *name, int enable)
+{
+	char path[64];
+	int fd, ret;
+
+	snprintf(path, sizeof(path), CONFIGFS_DIR "/%s/live", name);
+
+	fd = open(path, O_WRONLY);
+	if (fd == -1)
+		return fd;
+
+	if (enable)
+		ret = write(fd, "1", 1);
+	else
+		ret = write(fd, "0", 1);
+
+	close(fd);
+	return ret == 1 ? 0 : -1;
+}
+
+static int enable_chip(const char *name)
+{
+	return _enable_chip(name, 1);
+}
+
+static void disable_chip(const char *name)
+{
+	_enable_chip(name, 0);
+}
+
+static int open_chip(const char *chip_name, const char *bank_name)
+{
+	char path[64], dev_name[32];
+	int ret, fd;
+
+	ret = create_chip(chip_name);
+	if (ret) {
+		fprintf(stderr, "failed to create chip\n");
+		return ret;
+	}
+
+	ret = create_bank(chip_name, bank_name);
+	if (ret) {
+		fprintf(stderr, "failed to create bank\n");
+		goto err_remove_chip;
+	}
+
+	ret = enable_chip(chip_name);
+	if (ret) {
+		fprintf(stderr, "failed to enable chip\n");
+		goto err_remove_bank;
+	}
+
+	snprintf(path, sizeof(path), CONFIGFS_DIR "/%s/%s/chip_name",
+		 chip_name, bank_name);
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1) {
+		ret = fd;
+		fprintf(stderr, "failed to open %s\n", path);
+		goto err_disable_chip;
+	}
+
+	ret = read(fd, dev_name, sizeof(dev_name) - 1);
+	close(fd);
+	if (ret == -1) {
+		fprintf(stderr, "failed to read %s\n", path);
+		goto err_disable_chip;
+	}
+	dev_name[ret] = '\0';
+	if (ret && dev_name[ret - 1] == '\n')
+		dev_name[ret - 1] = '\0';
+
+	snprintf(path, sizeof(path), "/dev/%s", dev_name);
+
+	fd = open(path, O_RDWR);
+	if (fd == -1) {
+		ret = fd;
+		fprintf(stderr, "failed to open %s\n", path);
+		goto err_disable_chip;
+	}
+
+	return fd;
+err_disable_chip:
+	disable_chip(chip_name);
+err_remove_bank:
+	remove_bank(chip_name, bank_name);
+err_remove_chip:
+	remove_chip(chip_name);
+	return ret;
+}
+
+static void close_chip(const char *chip_name, const char *bank_name)
+{
+	disable_chip(chip_name);
+	remove_bank(chip_name, bank_name);
+	remove_chip(chip_name);
+}
+
+static int test_poll(int fd)
+{
+	struct pollfd pfds;
+
+	pfds.fd = fd;
+	pfds.events = POLLIN;
+	pfds.revents = 0;
+
+	if (poll(&pfds, 1, 0) == -1)
+		return -1;
+
+	return (pfds.revents & ~(POLLHUP | POLLERR)) ? -1 : 0;
+}
+
+static int test_read(int fd)
+{
+	char data;
+
+	if (read(fd, &data, 1) == -1 && errno == ENODEV)
+		return 0;
+	return -1;
+}
+
+static int test_ioctl(int fd)
+{
+	if (ioctl(fd, 0, NULL) == -1 && errno == ENODEV)
+		return 0;
+	return -1;
+}
+
+int main(int argc, char **argv)
+{
+	int cfd, fd, ret;
+	int (*test_func)(int);
+
+	if (argc != 3) {
+		print_usage();
+		return EXIT_FAILURE;
+	}
+
+	if (strcmp(argv[1], "chip") == 0 ||
+	    strcmp(argv[1], "event") == 0 ||
+	    strcmp(argv[1], "req") == 0) {
+		if (strcmp(argv[2], "poll") &&
+		    strcmp(argv[2], "read") &&
+		    strcmp(argv[2], "ioctl")) {
+			fprintf(stderr, "unknown command: %s\n", argv[2]);
+			return EXIT_FAILURE;
+		}
+	} else if (strcmp(argv[1], "handle") == 0) {
+		if (strcmp(argv[2], "ioctl")) {
+			fprintf(stderr, "unknown command: %s\n", argv[2]);
+			return EXIT_FAILURE;
+		}
+	} else {
+		fprintf(stderr, "unknown command: %s\n", argv[1]);
+		return EXIT_FAILURE;
+	}
+
+	if (strcmp(argv[2], "poll") == 0)
+		test_func = test_poll;
+	else if (strcmp(argv[2], "read") == 0)
+		test_func = test_read;
+	else	/* strcmp(argv[2], "ioctl") == 0 */
+		test_func = test_ioctl;
+
+	cfd = open_chip("chip", "bank");
+	if (cfd == -1) {
+		fprintf(stderr, "failed to open chip\n");
+		return EXIT_FAILURE;
+	}
+
+	/* Step 1: Hold a FD to the test target. */
+	if (strcmp(argv[1], "chip") == 0) {
+		fd = cfd;
+	} else if (strcmp(argv[1], "handle") == 0) {
+		struct gpiohandle_request req = {0};
+
+		req.lines = 1;
+		if (ioctl(cfd, GPIO_GET_LINEHANDLE_IOCTL, &req) == -1) {
+			fprintf(stderr, "failed to get handle FD\n");
+			goto err_close_chip;
+		}
+
+		close(cfd);
+		fd = req.fd;
+	} else if (strcmp(argv[1], "event") == 0) {
+		struct gpioevent_request req = {0};
+
+		if (ioctl(cfd, GPIO_GET_LINEEVENT_IOCTL, &req) == -1) {
+			fprintf(stderr, "failed to get event FD\n");
+			goto err_close_chip;
+		}
+
+		close(cfd);
+		fd = req.fd;
+	} else {	/* strcmp(argv[1], "req") == 0 */
+		struct gpio_v2_line_request req = {0};
+
+		req.num_lines = 1;
+		if (ioctl(cfd, GPIO_V2_GET_LINE_IOCTL, &req) == -1) {
+			fprintf(stderr, "failed to get req FD\n");
+			goto err_close_chip;
+		}
+
+		close(cfd);
+		fd = req.fd;
+	}
+
+	/* Step 2: Free the chip. */
+	close_chip("chip", "bank");
+
+	/* Step 3: Access the dangling FD to trigger UAF. */
+	ret = test_func(fd);
+	close(fd);
+	return ret ? EXIT_FAILURE : EXIT_SUCCESS;
+err_close_chip:
+	close(cfd);
+	close_chip("chip", "bank");
+	return EXIT_FAILURE;
+}
diff --git a/tools/testing/selftests/gpio/gpio-cdev-uaf.sh b/tools/testing/selftests/gpio/gpio-cdev-uaf.sh
new file mode 100755
index 000000000..6e4753301
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-cdev-uaf.sh
@@ -0,0 +1,63 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright 2026 Google LLC
+
+BASE_DIR=`dirname $0`
+MODULE="gpio-cdev-uaf"
+
+fail() {
+	echo "$*" >&2
+	echo "GPIO $MODULE test FAIL"
+	exit 1
+}
+
+skip() {
+	echo "$*" >&2
+	echo "GPIO $MODULE test SKIP"
+	exit 4
+}
+
+# Load the gpio-sim module. This will pull in configfs if needed too.
+modprobe gpio-sim || skip "unable to load the gpio-sim module"
+# Make sure configfs is mounted at /sys/kernel/config. Wait a bit if needed.
+for _ in `seq 5`; do
+	mountpoint -q /sys/kernel/config && break
+	mount -t configfs none /sys/kernel/config
+	sleep 0.1
+done
+mountpoint -q /sys/kernel/config || \
+	skip "configfs not mounted at /sys/kernel/config"
+
+echo "1. GPIO"
+
+echo "1.1. poll"
+$BASE_DIR/gpio-cdev-uaf chip poll || fail "failed to test chip poll"
+echo "1.2. read"
+$BASE_DIR/gpio-cdev-uaf chip read || fail "failed to test chip read"
+echo "1.3. ioctl"
+$BASE_DIR/gpio-cdev-uaf chip ioctl || fail "failed to test chip ioctl"
+
+echo "2. linehandle"
+
+echo "2.1. ioctl"
+$BASE_DIR/gpio-cdev-uaf handle ioctl || fail "failed to test handle ioctl"
+
+echo "3. lineevent"
+
+echo "3.1. read"
+$BASE_DIR/gpio-cdev-uaf event read || fail "failed to test event read"
+echo "3.2. poll"
+$BASE_DIR/gpio-cdev-uaf event poll || fail "failed to test event poll"
+echo "3.3. ioctl"
+$BASE_DIR/gpio-cdev-uaf event ioctl || fail "failed to test event ioctl"
+
+echo "4. linereq"
+
+echo "4.1. read"
+$BASE_DIR/gpio-cdev-uaf req read || fail "failed to test req read"
+echo "4.2. poll"
+$BASE_DIR/gpio-cdev-uaf req poll || fail "failed to test req poll"
+echo "4.3. ioctl"
+$BASE_DIR/gpio-cdev-uaf req ioctl || fail "failed to test req ioctl"
+
+echo "GPIO $MODULE test PASS"
diff --git a/tools/testing/selftests/gpio/gpio-chip-info.c b/tools/testing/selftests/gpio/gpio-chip-info.c
new file mode 100644
index 000000000..fdc07e742
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-chip-info.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * GPIO character device helper for reading chip information.
+ *
+ * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
+ */
+
+#include <fcntl.h>
+#include <linux/gpio.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+
+static void print_usage(void)
+{
+	printf("usage:\n");
+	printf("  gpio-chip-info <chip path> [name|label|num-lines]\n");
+}
+
+int main(int argc, char **argv)
+{
+	struct gpiochip_info info;
+	int fd, ret;
+
+	if (argc != 3) {
+		print_usage();
+		return EXIT_FAILURE;
+	}
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		perror("unable to open the GPIO chip");
+		return EXIT_FAILURE;
+	}
+
+	memset(&info, 0, sizeof(info));
+	ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &info);
+	if (ret) {
+		perror("chip info ioctl failed");
+		return EXIT_FAILURE;
+	}
+
+	if (strcmp(argv[2], "name") == 0) {
+		printf("%s\n", info.name);
+	} else if (strcmp(argv[2], "label") == 0) {
+		printf("%s\n", info.label);
+	} else if (strcmp(argv[2], "num-lines") == 0) {
+		printf("%u\n", info.lines);
+	} else {
+		fprintf(stderr, "unknown command: %s\n", argv[2]);
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}
diff --git a/tools/testing/selftests/gpio/gpio-line-name.c b/tools/testing/selftests/gpio/gpio-line-name.c
new file mode 100644
index 000000000..e635cfadb
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-line-name.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * GPIO character device helper for reading line names.
+ *
+ * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
+ */
+
+#include <fcntl.h>
+#include <linux/gpio.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+
+static void print_usage(void)
+{
+	printf("usage:\n");
+	printf("  gpio-line-name <chip path> <line offset>\n");
+}
+
+int main(int argc, char **argv)
+{
+	struct gpio_v2_line_info info;
+	int fd, ret;
+	char *endp;
+
+	if (argc != 3) {
+		print_usage();
+		return EXIT_FAILURE;
+	}
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		perror("unable to open the GPIO chip");
+		return EXIT_FAILURE;
+	}
+
+	memset(&info, 0, sizeof(info));
+	info.offset = strtoul(argv[2], &endp, 10);
+	if (*endp != '\0') {
+		print_usage();
+		return EXIT_FAILURE;
+	}
+
+	ret = ioctl(fd, GPIO_V2_GET_LINEINFO_IOCTL, &info);
+	if (ret) {
+		perror("line info ioctl failed");
+		return EXIT_FAILURE;
+	}
+
+	printf("%s\n", info.name);
+
+	return EXIT_SUCCESS;
+}
diff --git a/tools/testing/selftests/gpio/gpio-mockup-cdev.c b/tools/testing/selftests/gpio/gpio-mockup-cdev.c
new file mode 100644
index 000000000..d1640f44f
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-mockup-cdev.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * GPIO mockup cdev test helper
+ *
+ * Copyright (C) 2020 Kent Gibson
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <linux/gpio.h>
+
+#define CONSUMER	"gpio-mockup-cdev"
+
+static int request_line_v2(int cfd, unsigned int offset,
+			   uint64_t flags, unsigned int val)
+{
+	struct gpio_v2_line_request req;
+	int ret;
+
+	memset(&req, 0, sizeof(req));
+	req.num_lines = 1;
+	req.offsets[0] = offset;
+	req.config.flags = flags;
+	strcpy(req.consumer, CONSUMER);
+	if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
+		req.config.num_attrs = 1;
+		req.config.attrs[0].mask = 1;
+		req.config.attrs[0].attr.id = GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES;
+		if (val)
+			req.config.attrs[0].attr.values = 1;
+	}
+	ret = ioctl(cfd, GPIO_V2_GET_LINE_IOCTL, &req);
+	if (ret == -1)
+		return -errno;
+	return req.fd;
+}
+
+
+static int get_value_v2(int lfd)
+{
+	struct gpio_v2_line_values vals;
+	int ret;
+
+	memset(&vals, 0, sizeof(vals));
+	vals.mask = 1;
+	ret = ioctl(lfd, GPIO_V2_LINE_GET_VALUES_IOCTL, &vals);
+	if (ret == -1)
+		return -errno;
+	return vals.bits & 0x1;
+}
+
+static int request_line_v1(int cfd, unsigned int offset,
+			   uint32_t flags, unsigned int val)
+{
+	struct gpiohandle_request req;
+	int ret;
+
+	memset(&req, 0, sizeof(req));
+	req.lines = 1;
+	req.lineoffsets[0] = offset;
+	req.flags = flags;
+	strcpy(req.consumer_label, CONSUMER);
+	if (flags & GPIOHANDLE_REQUEST_OUTPUT)
+		req.default_values[0] = val;
+
+	ret = ioctl(cfd, GPIO_GET_LINEHANDLE_IOCTL, &req);
+	if (ret == -1)
+		return -errno;
+	return req.fd;
+}
+
+static int get_value_v1(int lfd)
+{
+	struct gpiohandle_data vals;
+	int ret;
+
+	memset(&vals, 0, sizeof(vals));
+	ret = ioctl(lfd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &vals);
+	if (ret == -1)
+		return -errno;
+	return vals.values[0];
+}
+
+static void usage(char *prog)
+{
+	printf("Usage: %s [-l] [-b <bias>] [-s <value>] [-u <uAPI>] <gpiochip> <offset>\n", prog);
+	printf("        -b: set line bias to one of pull-down, pull-up, disabled\n");
+	printf("               (default is to leave bias unchanged):\n");
+	printf("        -l: set line active low (default is active high)\n");
+	printf("        -s: set line value (default is to get line value)\n");
+	printf("        -u: uAPI version to use (default is 2)\n");
+	exit(-1);
+}
+
+static int wait_signal(void)
+{
+	int sig;
+	sigset_t wset;
+
+	sigemptyset(&wset);
+	sigaddset(&wset, SIGHUP);
+	sigaddset(&wset, SIGINT);
+	sigaddset(&wset, SIGTERM);
+	sigwait(&wset, &sig);
+
+	return sig;
+}
+
+int main(int argc, char *argv[])
+{
+	char *chip;
+	int opt, ret, cfd, lfd;
+	unsigned int offset, val = 0, abiv;
+	uint32_t flags_v1;
+	uint64_t flags_v2;
+
+	abiv = 2;
+	ret = 0;
+	flags_v1 = GPIOHANDLE_REQUEST_INPUT;
+	flags_v2 = GPIO_V2_LINE_FLAG_INPUT;
+
+	while ((opt = getopt(argc, argv, "lb:s:u:")) != -1) {
+		switch (opt) {
+		case 'l':
+			flags_v1 |= GPIOHANDLE_REQUEST_ACTIVE_LOW;
+			flags_v2 |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
+			break;
+		case 'b':
+			if (strcmp("pull-up", optarg) == 0) {
+				flags_v1 |= GPIOHANDLE_REQUEST_BIAS_PULL_UP;
+				flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
+			} else if (strcmp("pull-down", optarg) == 0) {
+				flags_v1 |= GPIOHANDLE_REQUEST_BIAS_PULL_DOWN;
+				flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
+			} else if (strcmp("disabled", optarg) == 0) {
+				flags_v1 |= GPIOHANDLE_REQUEST_BIAS_DISABLE;
+				flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
+			}
+			break;
+		case 's':
+			val = atoi(optarg);
+			flags_v1 &= ~GPIOHANDLE_REQUEST_INPUT;
+			flags_v1 |= GPIOHANDLE_REQUEST_OUTPUT;
+			flags_v2 &= ~GPIO_V2_LINE_FLAG_INPUT;
+			flags_v2 |= GPIO_V2_LINE_FLAG_OUTPUT;
+			break;
+		case 'u':
+			abiv = atoi(optarg);
+			break;
+		default:
+			usage(argv[0]);
+		}
+	}
+
+	if (argc < optind + 2)
+		usage(argv[0]);
+
+	chip = argv[optind];
+	offset = atoi(argv[optind + 1]);
+
+	cfd = open(chip, 0);
+	if (cfd == -1) {
+		fprintf(stderr, "Failed to open %s: %s\n", chip, strerror(errno));
+		return -errno;
+	}
+
+	if (abiv == 1)
+		lfd = request_line_v1(cfd, offset, flags_v1, val);
+	else
+		lfd = request_line_v2(cfd, offset, flags_v2, val);
+
+	close(cfd);
+
+	if (lfd < 0) {
+		fprintf(stderr, "Failed to request %s:%d: %s\n", chip, offset, strerror(-lfd));
+		return lfd;
+	}
+
+	if (flags_v2 & GPIO_V2_LINE_FLAG_OUTPUT) {
+		wait_signal();
+	} else {
+		if (abiv == 1)
+			ret = get_value_v1(lfd);
+		else
+			ret = get_value_v2(lfd);
+	}
+
+	close(lfd);
+
+	return ret;
+}
diff --git a/tools/testing/selftests/gpio/gpio-mockup-sysfs.sh b/tools/testing/selftests/gpio/gpio-mockup-sysfs.sh
new file mode 100755
index 000000000..2d2e5d876
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-mockup-sysfs.sh
@@ -0,0 +1,77 @@
+
+# SPDX-License-Identifier: GPL-2.0
+
+# Overrides functions in gpio-mockup.sh to test using the GPIO SYSFS uAPI
+
+SYSFS=`grep -w sysfs /proc/mounts | cut -f2 -d' '`
+[ -d "$SYSFS" ] || skip "sysfs is not mounted"
+
+GPIO_SYSFS="${SYSFS}/class/gpio"
+[ -d "$GPIO_SYSFS" ] || skip "CONFIG_GPIO_SYSFS is not selected"
+
+PLATFORM_SYSFS=$SYSFS/devices/platform
+
+sysfs_nr=
+sysfs_ldir=
+
+# determine the sysfs GPIO number given the $chip and $offset
+# e.g. gpiochip1:32
+find_sysfs_nr()
+{
+	# e.g. /sys/devices/platform/gpio-mockup.1/gpiochip1
+	local platform=$(find $PLATFORM_SYSFS -mindepth 2 -maxdepth 2 -type d -name $chip)
+	[ "$platform" ] || fail "can't find platform of $chip"
+	# e.g. /sys/devices/platform/gpio-mockup.1/gpio/gpiochip508/base
+	local base=$(find ${platform%/*}/gpio/ -mindepth 2 -maxdepth 2 -type f -name base)
+	[ "$base" ] || fail "can't find base of $chip"
+	sysfs_nr=$(($(< "$base") + $offset))
+	sysfs_ldir="$GPIO_SYSFS/gpio$sysfs_nr"
+}
+
+acquire_line()
+{
+	[ "$sysfs_nr" ] && return
+	find_sysfs_nr
+	echo "$sysfs_nr" > "$GPIO_SYSFS/export"
+}
+
+# The helpers being overridden...
+get_line()
+{
+	[ -e "$sysfs_ldir/value" ] && echo $(< "$sysfs_ldir/value")
+}
+
+set_line()
+{
+	acquire_line
+
+	for option in $*; do
+		case $option in
+		active-high)
+			echo 0 > "$sysfs_ldir/active_low"
+			;;
+		active-low)
+			echo 1 > "$sysfs_ldir/active_low"
+			;;
+		input)
+			echo "in" > "$sysfs_ldir/direction"
+			;;
+		0)
+			echo "out" > "$sysfs_ldir/direction"
+			echo 0 > "$sysfs_ldir/value"
+			;;
+		1)
+			echo "out" > "$sysfs_ldir/direction"
+			echo 1 > "$sysfs_ldir/value"
+			;;
+		esac
+	done
+}
+
+release_line()
+{
+	[ "$sysfs_nr" ] || return 0
+	echo "$sysfs_nr" > "$GPIO_SYSFS/unexport"
+	sysfs_nr=
+	sysfs_ldir=
+}
diff --git a/tools/testing/selftests/gpio/gpio-mockup.sh b/tools/testing/selftests/gpio/gpio-mockup.sh
new file mode 100755
index 000000000..fc2dd4c24
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-mockup.sh
@@ -0,0 +1,400 @@
+#!/bin/bash -efu
+# SPDX-License-Identifier: GPL-2.0
+
+#exit status
+#0: success
+#1: fail
+#4: skip test - including run as non-root user
+
+BASE=${0%/*}
+DEBUGFS=
+GPIO_DEBUGFS=
+dev_type="cdev"
+module="gpio-mockup"
+verbose=
+full_test=
+random=
+uapi_opt=
+active_opt=
+bias_opt=
+line_set_pid=
+
+# Kselftest return codes
+ksft_fail=1
+ksft_skip=4
+
+usage()
+{
+	echo "Usage:"
+	echo "$0 [-frv] [-t type]"
+	echo "-f:  full test (minimal set run by default)"
+	echo "-r:  test random lines as well as fence posts"
+	echo "-t:  interface type:"
+	echo "      cdev (character device ABI) - default"
+	echo "      cdev_v1 (deprecated character device ABI)"
+	echo "      sysfs (deprecated SYSFS ABI)"
+	echo "-v:  verbose progress reporting"
+	exit $ksft_fail
+}
+
+skip()
+{
+	echo "$*" >&2
+	echo "GPIO $module test SKIP"
+	exit $ksft_skip
+}
+
+prerequisite()
+{
+	[ $(id -u) -eq 0 ] || skip "must be run as root"
+
+	DEBUGFS=$(grep -w debugfs /proc/mounts | cut -f2 -d' ')
+	[ -d "$DEBUGFS" ] || skip "debugfs is not mounted"
+
+	GPIO_DEBUGFS=$DEBUGFS/$module
+}
+
+remove_module()
+{
+	modprobe -r -q $module
+}
+
+cleanup()
+{
+	set +e
+	release_line
+	remove_module
+	jobs -p | xargs -r kill > /dev/null 2>&1
+}
+
+fail()
+{
+	echo "test failed: $*" >&2
+	echo "GPIO $module test FAIL"
+	exit $ksft_fail
+}
+
+try_insert_module()
+{
+	modprobe -q $module "$1" || fail "insert $module failed with error $?"
+}
+
+log()
+{
+	[ -z "$verbose" ] || echo "$*"
+}
+
+# The following line helpers, release_Line, get_line and set_line, all
+# make use of the global $chip and $offset variables.
+#
+# This implementation drives the GPIO character device (cdev) uAPI.
+# Other implementations may override these to test different uAPIs.
+
+# Release any resources related to the line
+release_line()
+{
+	[ "$line_set_pid" ] && kill $line_set_pid && wait $line_set_pid || true
+	line_set_pid=
+}
+
+# Read the current value of the line
+get_line()
+{
+	release_line
+
+	local cdev_opts=${uapi_opt}${active_opt}
+	$BASE/gpio-mockup-cdev $cdev_opts /dev/$chip $offset
+	echo $?
+}
+
+# Set the state of the line
+#
+# Changes to line configuration are provided as parameters.
+# The line is assumed to be an output if the line value 0 or 1 is
+# specified, else an input.
+set_line()
+{
+	local val=
+
+	release_line
+
+	# parse config options...
+	for option in $*; do
+		case $option in
+		active-low)
+			active_opt="-l "
+			;;
+		active-high)
+			active_opt=
+			;;
+		bias-none)
+			bias_opt=
+			;;
+		pull-down)
+			bias_opt="-bpull-down "
+			;;
+		pull-up)
+			bias_opt="-bpull-up "
+			;;
+		0)
+			val=0
+			;;
+		1)
+			val=1
+			;;
+		esac
+	done
+
+	local cdev_opts=${uapi_opt}${active_opt}
+	if [ "$val" ]; then
+		$BASE/gpio-mockup-cdev $cdev_opts -s$val /dev/$chip $offset &
+		# failure to set is detected by reading mockup and toggling values
+		line_set_pid=$!
+		# allow for gpio-mockup-cdev to launch and request line
+		# (there is limited value in checking if line has been requested)
+		sleep 0.01
+	elif [ "$bias_opt" ]; then
+		cdev_opts=${cdev_opts}${bias_opt}
+		$BASE/gpio-mockup-cdev $cdev_opts /dev/$chip $offset || true
+	fi
+}
+
+assert_line()
+{
+	local val
+	# don't need any retry here as set_mock allows for propagation
+	val=$(get_line)
+	[ "$val" = "$1" ] || fail "line value is ${val:-empty} when $1 was expected"
+}
+
+# The following mockup helpers all make use of the $mock_line
+assert_mock()
+{
+	local backoff_wait=10
+	local retry=0
+	local val
+	# retry allows for set propagation from uAPI to mockup
+	while true; do
+		val=$(< $mock_line)
+		[ "$val" = "$1" ] && break
+		retry=$((retry + 1))
+		[ $retry -lt 5 ] || fail "mockup $mock_line value ${val:-empty} when $1 expected"
+		sleep $(printf "%0.2f" $((backoff_wait))e-3)
+		backoff_wait=$((backoff_wait * 2))
+	done
+}
+
+set_mock()
+{
+	echo "$1" > $mock_line
+	# allow for set propagation - so we won't be in a race with set_line
+	assert_mock "$1"
+}
+
+# test the functionality of a line
+#
+# The line is set from the mockup side and is read from the userspace side
+# (input), and is set from the userspace side and is read from the mockup side
+# (output).
+#
+# Setting the mockup pull using the userspace interface bias settings is
+# tested where supported by the userspace interface (cdev).
+test_line()
+{
+	chip=$1
+	offset=$2
+	log "test_line $chip $offset"
+	mock_line=$GPIO_DEBUGFS/$chip/$offset
+	[ -e "$mock_line" ] || fail "missing line $chip:$offset"
+
+	# test input active-high
+	set_mock 1
+	set_line input active-high
+	assert_line 1
+	set_mock 0
+	assert_line 0
+	set_mock 1
+	assert_line 1
+
+	if [ "$full_test" ]; then
+		if [ "$dev_type" != "sysfs" ]; then
+			# test pulls
+			set_mock 0
+			set_line input pull-up
+			assert_line 1
+			set_mock 0
+			assert_line 0
+
+			set_mock 1
+			set_line input pull-down
+			assert_line 0
+			set_mock 1
+			assert_line 1
+
+			set_line bias-none
+		fi
+
+		# test input active-low
+		set_mock 0
+		set_line active-low
+		assert_line 1
+		set_mock 1
+		assert_line 0
+		set_mock 0
+		assert_line 1
+
+		# test output active-high
+		set_mock 1
+		set_line active-high 0
+		assert_mock 0
+		set_line 1
+		assert_mock 1
+		set_line 0
+		assert_mock 0
+	fi
+
+	# test output active-low
+	set_mock 0
+	set_line active-low 0
+	assert_mock 1
+	set_line 1
+	assert_mock 0
+	set_line 0
+	assert_mock 1
+
+	release_line
+}
+
+test_no_line()
+{
+	log test_no_line "$*"
+	[ ! -e "$GPIO_DEBUGFS/$1/$2" ] || fail "unexpected line $1:$2"
+}
+
+# Load the module and check that the expected number of gpiochips, with the
+# expected number of lines, are created and are functional.
+#
+# $1 is the gpio_mockup_ranges parameter for the module
+# The remaining parameters are the number of lines, n, expected for each of
+# the gpiochips expected to be created.
+#
+# For each gpiochip the fence post lines, 0 and n-1, are tested, and the
+# line on the far side of the fence post, n, is tested to not exist.
+#
+# If the $random flag is set then a random line in the middle of the
+# gpiochip is tested as well.
+insmod_test()
+{
+	local ranges=
+	local gc=
+	local width=
+
+	[ "${1:-}" ] || fail "missing ranges"
+	ranges=$1 ; shift
+	try_insert_module "gpio_mockup_ranges=$ranges"
+	log "GPIO $module test with ranges: <$ranges>:"
+	# e.g. /sys/kernel/debug/gpio-mockup/gpiochip1
+	gpiochip=$(find "$DEBUGFS/$module/" -name gpiochip* -type d | sort)
+	for chip in $gpiochip; do
+		gc=${chip##*/}
+		[ "${1:-}" ] || fail "unexpected chip - $gc"
+		width=$1 ; shift
+		test_line $gc 0
+		if [ "$random" -a $width -gt 2 ]; then
+			test_line $gc $((RANDOM % ($width - 2) + 1))
+		fi
+		test_line $gc $(($width - 1))
+		test_no_line $gc $width
+	done
+	[ "${1:-}" ] && fail "missing expected chip of width $1"
+	remove_module || fail "failed to remove module with error $?"
+}
+
+while getopts ":frvt:" opt; do
+	case $opt in
+	f)
+		full_test=true
+		;;
+	r)
+		random=true
+		;;
+	t)
+		dev_type=$OPTARG
+		;;
+	v)
+		verbose=true
+		;;
+	*)
+		usage
+		;;
+	esac
+done
+shift $((OPTIND - 1))
+
+[ "${1:-}" ] && fail "unknown argument '$1'"
+
+prerequisite
+
+trap 'exit $ksft_fail' SIGTERM SIGINT
+trap cleanup EXIT
+
+case "$dev_type" in
+sysfs)
+	source $BASE/gpio-mockup-sysfs.sh
+	echo "WARNING: gpio sysfs ABI is deprecated."
+	;;
+cdev_v1)
+	echo "WARNING: gpio cdev ABI v1 is deprecated."
+	uapi_opt="-u1 "
+	;;
+cdev)
+	;;
+*)
+	fail "unknown interface type: $dev_type"
+	;;
+esac
+
+remove_module || fail "can't remove existing $module module"
+
+# manual gpio allocation tests fail if a physical chip already exists
+[ "$full_test" -a -e "/dev/gpiochip0" ] && skip "full tests conflict with gpiochip0"
+
+echo "1.  Module load tests"
+echo "1.1.  dynamic allocation of gpio"
+insmod_test "-1,32" 32
+insmod_test "-1,23,-1,32" 23 32
+insmod_test "-1,23,-1,26,-1,32" 23 26 32
+if [ "$full_test" ]; then
+	echo "1.2.  manual allocation of gpio"
+	insmod_test "0,32" 32
+	insmod_test "0,32,32,60" 32 28
+	insmod_test "0,32,40,64,64,96" 32 24 32
+	echo "1.3.  dynamic and manual allocation of gpio"
+	insmod_test "-1,32,32,62" 32 30
+	insmod_test "-1,22,-1,23,0,24,32,64" 22 23 24 32
+	insmod_test "-1,32,32,60,-1,29" 32 28 29
+	insmod_test "-1,32,40,64,-1,5" 32 24 5
+	insmod_test "0,32,32,44,-1,22,-1,31" 32 12 22 31
+fi
+echo "2.  Module load error tests"
+echo "2.1 no lines defined"
+insmod_test "0,0"
+if [ "$full_test" ]; then
+	echo "2.2 ignore range overlap"
+	insmod_test "0,32,0,1" 32
+	insmod_test "0,32,1,5" 32
+	insmod_test "0,32,30,35" 32
+	insmod_test "0,32,31,32" 32
+	insmod_test "10,32,30,35" 22
+	insmod_test "10,32,9,14" 22
+	insmod_test "0,32,20,21,40,56" 32 16
+	insmod_test "0,32,32,64,32,40" 32 32
+	insmod_test "0,32,32,64,36,37" 32 32
+	insmod_test "0,32,35,64,34,36" 32 29
+	insmod_test "0,30,35,64,35,45" 30 29
+	insmod_test "0,32,40,56,30,33" 32 16
+	insmod_test "0,32,40,56,30,41" 32 16
+	insmod_test "0,32,40,56,39,45" 32 16
+fi
+
+echo "GPIO $module test PASS"
diff --git a/tools/testing/selftests/gpio/gpio-sim.sh b/tools/testing/selftests/gpio/gpio-sim.sh
new file mode 100755
index 000000000..bbc29ed9c
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-sim.sh
@@ -0,0 +1,418 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
+
+BASE_DIR=`dirname $0`
+CONFIGFS_DIR="/sys/kernel/config/gpio-sim"
+MODULE="gpio-sim"
+
+fail() {
+	echo "$*" >&2
+	echo "GPIO $MODULE test FAIL"
+	exit 1
+}
+
+skip() {
+	echo "$*" >&2
+	echo "GPIO $MODULE test SKIP"
+	exit 4
+}
+
+remove_chip() {
+	local CHIP=$1
+
+	for FILE in $CONFIGFS_DIR/$CHIP/*; do
+		BANK=`basename $FILE`
+		if [ "$BANK" = "live" -o "$BANK" = "dev_name" ]; then
+			continue
+		fi
+
+		LINES=`ls $CONFIGFS_DIR/$CHIP/$BANK/ | grep -E ^line`
+		if [ "$?" = 0 ]; then
+			for LINE in $LINES; do
+				if [ -e $CONFIGFS_DIR/$CHIP/$BANK/$LINE/hog ]; then
+					rmdir $CONFIGFS_DIR/$CHIP/$BANK/$LINE/hog || \
+						fail "Unable to remove the hog"
+				fi
+
+				rmdir $CONFIGFS_DIR/$CHIP/$BANK/$LINE || \
+					fail "Unable to remove the line"
+			done
+		fi
+
+		rmdir $CONFIGFS_DIR/$CHIP/$BANK
+	done
+
+	rmdir $CONFIGFS_DIR/$CHIP || fail "Unable to remove the chip"
+}
+
+create_chip() {
+	local CHIP=$1
+
+	mkdir $CONFIGFS_DIR/$CHIP
+}
+
+create_bank() {
+	local CHIP=$1
+	local BANK=$2
+
+	mkdir $CONFIGFS_DIR/$CHIP/$BANK
+}
+
+set_label() {
+	local CHIP=$1
+	local BANK=$2
+	local LABEL=$3
+
+	echo $LABEL > $CONFIGFS_DIR/$CHIP/$BANK/label || fail "Unable to set the chip label"
+}
+
+set_num_lines() {
+	local CHIP=$1
+	local BANK=$2
+	local NUM_LINES=$3
+
+	echo $NUM_LINES > $CONFIGFS_DIR/$CHIP/$BANK/num_lines || \
+		fail "Unable to set the number of lines"
+}
+
+set_line_name() {
+	local CHIP=$1
+	local BANK=$2
+	local OFFSET=$3
+	local NAME=$4
+	local LINE_DIR=$CONFIGFS_DIR/$CHIP/$BANK/line$OFFSET
+
+	test -d $LINE_DIR || mkdir $LINE_DIR
+	echo $NAME > $LINE_DIR/name || fail "Unable to set the line name"
+}
+
+enable_chip() {
+	local CHIP=$1
+
+	echo 1 > $CONFIGFS_DIR/$CHIP/live || fail "Unable to enable the chip"
+}
+
+disable_chip() {
+	local CHIP=$1
+
+	echo 0 > $CONFIGFS_DIR/$CHIP/live || fail "Unable to disable the chip"
+}
+
+configfs_cleanup() {
+	for CHIP in `ls $CONFIGFS_DIR/`; do
+		disable_chip $CHIP
+		remove_chip $CHIP
+	done
+}
+
+configfs_chip_name() {
+	local CHIP=$1
+	local BANK=$2
+
+	cat $CONFIGFS_DIR/$CHIP/$BANK/chip_name 2> /dev/null || \
+		fail "unable to read the chip name from configfs"
+}
+
+configfs_dev_name() {
+	local CHIP=$1
+
+	cat $CONFIGFS_DIR/$CHIP/dev_name 2> /dev/null || \
+		fail "unable to read the device name from configfs"
+}
+
+get_chip_num_lines() {
+	local CHIP=$1
+	local BANK=$2
+
+	$BASE_DIR/gpio-chip-info /dev/`configfs_chip_name $CHIP $BANK` num-lines || \
+		fail "unable to read the number of lines from the character device"
+}
+
+get_chip_label() {
+	local CHIP=$1
+	local BANK=$2
+
+	$BASE_DIR/gpio-chip-info /dev/`configfs_chip_name $CHIP $BANK` label || \
+		fail "unable to read the chip label from the character device"
+}
+
+get_line_name() {
+	local CHIP=$1
+	local BANK=$2
+	local OFFSET=$3
+
+	$BASE_DIR/gpio-line-name /dev/`configfs_chip_name $CHIP $BANK` $OFFSET || \
+		fail "unable to read the line name from the character device"
+}
+
+sysfs_set_pull() {
+	local DEV=$1
+	local BANK=$2
+	local OFFSET=$3
+	local PULL=$4
+	local DEVNAME=`configfs_dev_name $DEV`
+	local CHIPNAME=`configfs_chip_name $DEV $BANK`
+	local SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio$OFFSET/pull"
+
+	echo $PULL > $SYSFS_PATH || fail "Unable to set line pull in sysfs"
+}
+
+# Load the gpio-sim module. This will pull in configfs if needed too.
+modprobe gpio-sim || skip "unable to load the gpio-sim module"
+# Make sure configfs is mounted at /sys/kernel/config. Wait a bit if needed.
+for IDX in `seq 5`; do
+	if [ "$IDX" -eq "5" ]; then
+		skip "configfs not mounted at /sys/kernel/config"
+	fi
+
+	mountpoint -q /sys/kernel/config && break
+	sleep 0.1
+done
+# If the module was already loaded: remove all previous chips
+configfs_cleanup
+
+trap "exit 1" SIGTERM SIGINT
+trap configfs_cleanup EXIT
+
+echo "1. chip_name and dev_name attributes"
+
+echo "1.1. Chip name is communicated to user"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+test -n `cat $CONFIGFS_DIR/chip/bank/chip_name` || fail "chip_name doesn't work"
+disable_chip chip
+remove_chip chip
+
+echo "1.2. chip_name returns 'none' if the chip is still pending"
+create_chip chip
+create_bank chip bank
+test "`cat $CONFIGFS_DIR/chip/bank/chip_name`" = "none" || \
+	fail "chip_name doesn't return 'none' for a pending chip"
+remove_chip chip
+
+echo "1.3. Device name is communicated to user"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+test -n `cat $CONFIGFS_DIR/chip/dev_name` || fail "dev_name doesn't work"
+disable_chip chip
+remove_chip chip
+
+echo "2. Creating and configuring simulated chips"
+
+echo "2.1. Default number of lines is 1"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+test "`get_chip_num_lines chip bank`" = "1" || fail "default number of lines is not 1"
+disable_chip chip
+remove_chip chip
+
+echo "2.2. Number of lines can be specified"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 16
+enable_chip chip
+test "`get_chip_num_lines chip bank`" = "16" || fail "number of lines is not 16"
+disable_chip chip
+remove_chip chip
+
+echo "2.3. Label can be set"
+create_chip chip
+create_bank chip bank
+set_label chip bank foobar
+enable_chip chip
+test "`get_chip_label chip bank`" = "foobar" || fail "label is incorrect"
+disable_chip chip
+remove_chip chip
+
+echo "2.4. Label can be left empty"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+test -z "`cat $CONFIGFS_DIR/chip/bank/label`" || fail "label is not empty"
+disable_chip chip
+remove_chip chip
+
+echo "2.5. Line names can be configured"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 16
+set_line_name chip bank 0 foo
+set_line_name chip bank 2 bar
+enable_chip chip
+test "`get_line_name chip bank 0`" = "foo" || fail "line name is incorrect"
+test "`get_line_name chip bank 2`" = "bar" || fail "line name is incorrect"
+disable_chip chip
+remove_chip chip
+
+echo "2.6. Line config can remain unused if offset is greater than number of lines"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 2
+set_line_name chip bank 5 foobar
+enable_chip chip
+test "`get_line_name chip bank 0`" = "" || fail "line name is incorrect"
+test "`get_line_name chip bank 1`" = "" || fail "line name is incorrect"
+disable_chip chip
+remove_chip chip
+
+echo "2.7. Line configfs directory names are sanitized"
+create_chip chip
+create_bank chip bank
+mkdir $CONFIGFS_DIR/chip/bank/line12foobar 2> /dev/null && \
+	fail "invalid configfs line name accepted"
+mkdir $CONFIGFS_DIR/chip/bank/line_no_offset 2> /dev/null && \
+	fail "invalid configfs line name accepted"
+remove_chip chip
+
+echo "2.8. Multiple chips can be created"
+CHIPS="chip0 chip1 chip2"
+for CHIP in $CHIPS; do
+	create_chip $CHIP
+	create_bank $CHIP bank
+	enable_chip $CHIP
+done
+for CHIP in $CHIPS; do
+  disable_chip $CHIP
+	remove_chip $CHIP
+done
+
+echo "2.9. Can't modify settings when chip is live"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+echo foobar > $CONFIGFS_DIR/chip/bank/label 2> /dev/null && \
+	fail "Setting label of a live chip should fail"
+echo 8 > $CONFIGFS_DIR/chip/bank/num_lines 2> /dev/null && \
+	fail "Setting number of lines of a live chip should fail"
+disable_chip chip
+remove_chip chip
+
+echo "2.10. Can't create line items when chip is live"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+mkdir $CONFIGFS_DIR/chip/bank/line0 2> /dev/null && fail "Creating line item should fail"
+disable_chip chip
+remove_chip chip
+
+echo "2.11. Probe errors are propagated to user-space"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 99999
+echo 1 > $CONFIGFS_DIR/chip/live 2> /dev/null && fail "Probe error was not propagated"
+remove_chip chip
+
+echo "2.12. Cannot enable a chip without any GPIO banks"
+create_chip chip
+echo 1 > $CONFIGFS_DIR/chip/live 2> /dev/null && fail "Chip enabled without any GPIO banks"
+remove_chip chip
+
+echo "2.13. Duplicate chip labels are not allowed"
+create_chip chip
+create_bank chip bank0
+set_label chip bank0 foobar
+create_bank chip bank1
+set_label chip bank1 foobar
+echo 1 > $CONFIGFS_DIR/chip/live 2> /dev/null && fail "Duplicate chip labels were not rejected"
+remove_chip chip
+
+echo "2.14. Lines can be hogged"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+mkdir -p $CONFIGFS_DIR/chip/bank/line4/hog
+enable_chip chip
+$BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip bank` 4 2> /dev/null && \
+	fail "Setting the value of a hogged line shouldn't succeed"
+disable_chip chip
+remove_chip chip
+
+echo "3. Controlling simulated chips"
+
+echo "3.1. Pull can be set over sysfs"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+sysfs_set_pull chip bank 0 pull-up
+$BASE_DIR/gpio-mockup-cdev /dev/`configfs_chip_name chip bank` 0
+test "$?" = "1" || fail "pull set incorrectly"
+sysfs_set_pull chip bank 0 pull-down
+$BASE_DIR/gpio-mockup-cdev /dev/`configfs_chip_name chip bank` 1
+test "$?" = "0" || fail "pull set incorrectly"
+disable_chip chip
+remove_chip chip
+
+echo "3.2. Pull can be read from sysfs"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH=/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/pull
+test `cat $SYSFS_PATH` = "pull-down" || fail "reading the pull failed"
+sysfs_set_pull chip bank 0 pull-up
+test `cat $SYSFS_PATH` = "pull-up" || fail "reading the pull failed"
+disable_chip chip
+remove_chip chip
+
+echo "3.3. Incorrect input in sysfs is rejected"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/pull"
+echo foobar > $SYSFS_PATH 2> /dev/null && fail "invalid input not detected"
+disable_chip chip
+remove_chip chip
+
+echo "3.4. Can't write to value"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value"
+echo 1 > $SYSFS_PATH 2> /dev/null && fail "writing to 'value' succeeded unexpectedly"
+disable_chip chip
+remove_chip chip
+
+echo "4. Simulated GPIO chips are functional"
+
+echo "4.1. Values can be read from sysfs"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value"
+test `cat $SYSFS_PATH` = "0" || fail "incorrect value read from sysfs"
+$BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip bank` 0 &
+sleep 0.1 # FIXME Any better way?
+test `cat $SYSFS_PATH` = "1" || fail "incorrect value read from sysfs"
+kill $!
+disable_chip chip
+remove_chip chip
+
+echo "4.2. Bias settings work correctly"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value"
+$BASE_DIR/gpio-mockup-cdev -b pull-up /dev/`configfs_chip_name chip bank` 0
+test `cat $SYSFS_PATH` = "1" || fail "bias setting does not work"
+disable_chip chip
+remove_chip chip
+
+echo "GPIO $MODULE test PASS"