linux-stable/tools/memory-model/scripts/runlitmus.sh
Paul E. McKenney 719bef0cbe tools/memory-model: Use "-unroll 0" to keep --hw runs finite
Litmus tests involving atomic operations produce LL/SC loops on a number
of architectures, and unrolling these loops can result in excessive
verification times or even stack overflows.  This commit therefore uses
the "-unroll 0" herd7 argument to avoid unrolling, on the grounds that
additional passes through an LL/SC loop should not change the verification.

Note however, that certain bugs in the mapping of the LL/SC loop to
machine instructions may go undetected.  On the other hand, herd7 might
not be the best vehicle for finding such bugs in any case.  (You do
stress-test your architecture-specific code, don't you?)

Suggested-by: Luc Maranget <luc.maranget@inria.fr>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2023-03-24 10:24:15 -07:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0+
#
# Without the -hw argument, runs a herd7 test and outputs verification
# results to a file whose name is that of the specified litmus test,
# but with ".out" appended.
#
# If the --hw argument is specified, this script translates the .litmus
# C-language file to the specified type of assembly and verifies that.
# But in this case, litmus tests using complex synchronization (such as
# locking, RCU, and SRCU) are cheerfully ignored.
#
# Either way, return the status of the herd7 command.
#
# Usage:
# runlitmus.sh file.litmus
#
# Run this in the directory containing the memory model, specifying the
# pathname of the litmus test to check. The caller is expected to have
# properly set up the LKMM environment variables.
#
# Copyright IBM Corporation, 2019
#
# Author: Paul E. McKenney <paulmck@linux.ibm.com>
litmus=$1
if test -f "$litmus" -a -r "$litmus"
then
:
else
echo ' !!! ' error: \"$litmus\" is not a readable file
exit 255
fi
if test -z "$LKMM_HW_MAP_FILE" -o ! -e $LKMM_DESTDIR/$litmus.out
then
# LKMM run
herdoptions=${LKMM_HERD_OPTIONS--conf linux-kernel.cfg}
echo Herd options: $herdoptions > $LKMM_DESTDIR/$litmus.out
/usr/bin/time $LKMM_TIMEOUT_CMD herd7 $herdoptions $litmus >> $LKMM_DESTDIR/$litmus.out 2>&1
ret=$?
if test -z "$LKMM_HW_MAP_FILE"
then
exit $ret
fi
echo " --- " Automatically generated LKMM output for '"'--hw $LKMM_HW_MAP_FILE'"' run
fi
# Hardware run
T=/tmp/checklitmushw.sh.$$
trap 'rm -rf $T' 0 2
mkdir $T
# Generate filenames
mapfile="Linux2${LKMM_HW_MAP_FILE}.map"
themefile="$T/${LKMM_HW_MAP_FILE}.theme"
herdoptions="-model $LKMM_HW_CAT_FILE"
hwlitmus=`echo $litmus | sed -e 's/\.litmus$/.litmus.'${LKMM_HW_MAP_FILE}'/'`
hwlitmusfile=`echo $hwlitmus | sed -e 's,^.*/,,'`
# Don't run on litmus tests with complex synchronization
if ! scripts/simpletest.sh $litmus
then
echo ' --- ' error: \"$litmus\" contains locking, RCU, or SRCU
exit 254
fi
# Generate the assembly code and run herd7 on it.
gen_theme7 -n 10 -map $mapfile -call Linux.call > $themefile
jingle7 -v -theme $themefile $litmus > $LKMM_DESTDIR/$hwlitmus 2> $T/$hwlitmusfile.jingle7.out
if grep -q "Generated 0 tests" $T/$hwlitmusfile.jingle7.out
then
echo ' !!! ' jingle7 failed, errors in $hwlitmus.err
cp $T/$hwlitmusfile.jingle7.out $LKMM_DESTDIR/$hwlitmus.err
exit 253
fi
/usr/bin/time $LKMM_TIMEOUT_CMD herd7 -unroll 0 $LKMM_DESTDIR/$hwlitmus > $LKMM_DESTDIR/$hwlitmus.out 2>&1
exit $?