torture: Run kernel build in source directory

For historical reasons, rcutorture places its build products in a
tools/testing/selftests/rcutorture/b1 directory using the O= kbuild
command-line argument.  However, doing this requires that the source
directory be pristine: Not just "make clean" pristine, but instead "make
mrproper" (or, equivalently, "make distclean") pristine.  Therefore,
rcutorture executes a "make mrproper" before each build.  Unfortunately,
"make mrproper" has the side effect of removing pretty much everything,
including tags files and cscope databases, which can be inconvenient
to people whose workflow centers around a single source tree.

This commit therefore makes rcutorture do the build directly in the
source directory, removing the need for "make mrproper".  This works
because all needed build products are moved to their proper place in the
"res" directory immediately after the build completes, so that multiple
rcutorture kernels can still run concurrently.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

tools/testing/selftests/rcutorture/bin/configinit.sh

 #!/bin/bash
 # SPDX-License-Identifier: GPL-2.0+
 #
-# Usage: configinit.sh config-spec-file build-output-dir results-dir
+# Usage: configinit.sh config-spec-file results-dir
 #
 # Create a .config file from the spec file.  Run from the kernel source tree.
 # Exits with 0 if all went well, with 1 if all went well but the config
@@ -11,10 +11,6 @@
 # desired settings, for example, "CONFIG_NO_HZ=y".  For best results,
 # this should be a full pathname.
 #
-# The second argument is a optional path to a build output directory,
-# for example, "O=/tmp/foo".  If this argument is omitted, the .config
-# file will be generated directly in the current directory.
-#
 # Copyright (C) IBM Corporation, 2013
 #
 # Authors: Paul E. McKenney <paulmck@linux.ibm.com>
@@ -26,34 +22,20 @@ mkdir $T
 # Capture config spec file.
 
 c=$1
-buildloc=$2
-resdir=$3
-builddir=
-if echo $buildloc | grep -q '^O='
-then
-	builddir=`echo $buildloc | sed -e 's/^O=//'`
-	if test ! -d $builddir
-	then
-		mkdir $builddir
-	fi
-else
-	echo Bad build directory: \"$buildloc\"
-	exit 2
-fi
+resdir=$2
 
 sed -e 's/^\(CONFIG[0-9A-Z_]*\)=.*$/grep -v "^# \1" |/' < $c > $T/u.sh
 sed -e 's/^\(CONFIG[0-9A-Z_]*=\).*$/grep -v \1 |/' < $c >> $T/u.sh
 grep '^grep' < $T/u.sh > $T/upd.sh
 echo "cat - $c" >> $T/upd.sh
-make mrproper
-make $buildloc distclean > $resdir/Make.distclean 2>&1
-make $buildloc $TORTURE_DEFCONFIG > $resdir/Make.defconfig.out 2>&1
-mv $builddir/.config $builddir/.config.sav
-sh $T/upd.sh < $builddir/.config.sav > $builddir/.config
-cp $builddir/.config $builddir/.config.new
-yes '' | make $buildloc oldconfig > $resdir/Make.oldconfig.out 2> $resdir/Make.oldconfig.err
+make clean > $resdir/Make.clean 2>&1
+make $TORTURE_DEFCONFIG > $resdir/Make.defconfig.out 2>&1
+mv .config .config.sav
+sh $T/upd.sh < .config.sav > .config
+cp .config .config.new
+yes '' | make oldconfig > $resdir/Make.oldconfig.out 2> $resdir/Make.oldconfig.err
 
 # verify new config matches specification.
-configcheck.sh $builddir/.config $c
+configcheck.sh .config $c
 
 exit 0

tools/testing/selftests/rcutorture/bin/kvm-build.sh

@@ -3,7 +3,7 @@
 #
 # Build a kvm-ready Linux kernel from the tree in the current directory.
 #
-# Usage: kvm-build.sh config-template build-dir resdir
+# Usage: kvm-build.sh config-template resdir
 #
 # Copyright (C) IBM Corporation, 2011
 #
@@ -15,8 +15,7 @@ then
 	echo "kvm-build.sh :$config_template: Not a readable file"
 	exit 1
 fi
-builddir=${2}
-resdir=${3}
+resdir=${2}
 
 T=${TMPDIR-/tmp}/test-linux.sh.$$
 trap 'rm -rf $T' 0
@@ -29,14 +28,14 @@ CONFIG_VIRTIO_PCI=y
 CONFIG_VIRTIO_CONSOLE=y
 ___EOF___
 
-configinit.sh $T/config O=$builddir $resdir
+configinit.sh $T/config $resdir
 retval=$?
 if test $retval -gt 1
 then
 	exit 2
 fi
 ncpus=`cpus2use.sh`
-make O=$builddir -j$ncpus $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
+make -j$ncpus $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
 retval=$?
 if test $retval -ne 0 || grep "rcu[^/]*": < $resdir/Make.out | egrep -q "Stop|Error|error:|warning:" || egrep -q "Stop|Error|error:" < $resdir/Make.out
 then

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh

@@ -36,11 +36,6 @@ config_template=${1}
 config_dir=`echo $config_template | sed -e 's,/[^/]*$,,'`
 title=`echo $config_template | sed -e 's/^.*\///'`
 builddir=${2}
-if test -z "$builddir" -o ! -d "$builddir" -o ! -w "$builddir"
-then
-	echo "kvm-test-1-run.sh :$builddir: Not a writable directory, cannot build into it"
-	exit 1
-fi
 resdir=${3}
 if test -z "$resdir" -o ! -d "$resdir" -o ! -w "$resdir"
 then
@@ -85,18 +80,18 @@ then
 	ln -s $base_resdir/.config $resdir  # for kvm-recheck.sh
 	# Arch-independent indicator
 	touch $resdir/builtkernel
-elif kvm-build.sh $T/Kc2 $builddir $resdir
+elif kvm-build.sh $T/Kc2 $resdir
 then
 	# Had to build a kernel for this test.
-	QEMU="`identify_qemu $builddir/vmlinux`"
+	QEMU="`identify_qemu vmlinux`"
 	BOOT_IMAGE="`identify_boot_image $QEMU`"
-	cp $builddir/vmlinux $resdir
-	cp $builddir/.config $resdir
-	cp $builddir/Module.symvers $resdir > /dev/null || :
-	cp $builddir/System.map $resdir > /dev/null || :
+	cp vmlinux $resdir
+	cp .config $resdir
+	cp Module.symvers $resdir > /dev/null || :
+	cp System.map $resdir > /dev/null || :
 	if test -n "$BOOT_IMAGE"
 	then
-		cp $builddir/$BOOT_IMAGE $resdir
+		cp $BOOT_IMAGE $resdir
 		KERNEL=$resdir/${BOOT_IMAGE##*/}
 		# Arch-independent indicator
 		touch $resdir/builtkernel
@@ -107,7 +102,7 @@ then
 	parse-build.sh $resdir/Make.out $title
 else
 	# Build failed.
-	cp $builddir/.config $resdir || :
+	cp .config $resdir || :
 	echo Build failed, not running KVM, see $resdir.
 	if test -f $builddir.wait
 	then

tools/testing/selftests/rcutorture/bin/kvm.sh

@@ -342,7 +342,7 @@ function dump(first, pastlast, batchnum)
 	print "needqemurun="
 	jn=1
 	for (j = first; j < pastlast; j++) {
-		builddir=KVM "/b1"
+		builddir=KVM "/b" j - first + 1
 		cpusr[jn] = cpus[j];
 		if (cfrep[cf[j]] == "") {
 			cfr[jn] = cf[j];
@@ -358,7 +358,6 @@ function dump(first, pastlast, batchnum)
 		print "echo ", cfr[jn], cpusr[jn] ovf ": Starting build. `date` | tee -a " rd "log";
 		print "rm -f " builddir ".*";
 		print "touch " builddir ".wait";
-		print "mkdir " builddir " > /dev/null 2>&1 || :";
 		print "mkdir " rd cfr[jn] " || :";
 		print "kvm-test-1-run.sh " CONFIGDIR cf[j], builddir, rd cfr[jn], dur " \"" TORTURE_QEMU_ARG "\" \"" TORTURE_BOOTARGS "\" > " rd cfr[jn]  "/kvm-test-1-run.sh.out 2>&1 &"
 		print "echo ", cfr[jn], cpusr[jn] ovf ": Waiting for build to complete. `date` | tee -a " rd "log";