3 files changed, 64 insertions, 5 deletions
diff --git a/development/perf/README b/development/perf/README
index 56771df929c5..1ec21e6c9ef0 100644
--- a/development/perf/README
+++ b/development/perf/README
@@ -4,7 +4,22 @@ such as instructions executed, cache-misses suffered, or branches
 mispredicted. They form a basis for profiling applications to trace
 dynamic control flow and identify hotspots.
 
-Please note that this SBo doesn't have any sources in the DOWNLOAD
-setting, as the sources are already part of a full slackware install.
-
 Optional dependencies: audit, numactl, libunwind
+
+Please note that this build doesn't have any sources in the .info
+file, as the sources are already part of the Slackware kernel-source
+package. Your running kernel's version should match the kernel-source
+version. If it doesn't:
+
+- If your kernel source is located in /usr/src/linux-$VERSION, you
+  can export KERNEL=<version> in the script's environment. Example:
+
+  export KERNEL=4.4.240
+
+- If your kernel source is somewhere else, you can export
+  KERNEL=</path/to/source>. Example:
+
+  export KERNEL=/home/myuser/kernels/linux-4.2.240
+
+Please note that the package's version number will match the version
+of the kernel source, *not* necessarily what's in the perf.info file.
diff --git a/development/perf/perf.SlackBuild b/development/perf/perf.SlackBuild
index 1a81ae0622d1..ac56703e5a7d 100644
--- a/development/perf/perf.SlackBuild
+++ b/development/perf/perf.SlackBuild
@@ -22,8 +22,15 @@
 # OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 # ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+# 20210202 bkw: Modified by SlackBuilds.org, autodetect the kernel
+# version and allow the user to override it. Avoids having this build
+# break every time Pat releases a new kernel in patches/.
+
 PRGNAM=perf
+
+# This VERSION is actually a dummy. Use KERNEL to set the version.
 VERSION=${VERSION:-4.4.227}
+
 BUILD=${BUILD:-1}
 TAG=${TAG:-_SBo}
 
@@ -56,7 +63,44 @@ fi
 
 set -e
 
-SRCDIR="/usr/src/linux-$VERSION/tools/perf"
+die() {
+  echo "$0: fatal: $@" 1>&2
+  cat 1>&2 <<EOF
+
+Please make sure the correct version of the kernel source is
+installed, and/or set the KERNEL environment variable to one of:
+
+- The full path to the kernel source, e.g. KERNEL="/usr/src/linux-4.4.227"
+- Or, the kernel version e.g. KERNEL="4.4.227"
+EOF
+  exit 1
+}
+
+case "$KERNEL" in
+  # if unset, use the running kernel:
+  "") SRCDIR="/usr/src/linux-$( uname -r )" ;;
+  # if it's an absolute path, use it as-is:
+  /*) SRCDIR="$KERNEL" ;;
+  # otherwise assume it's a version number:
+  *)  SRCDIR="/usr/src/linux-$KERNEL" ;;
+esac
+
+[ -f "$SRCDIR/Makefile" ] || die "Can't find kernel source in \"$SRCDIR\""
+
+# get the kernel version number from the top-level Makefile. This
+# allows cases where the kernel source directory isn't named after the
+# version number. It also verifies that the Makefile actually exists
+# (because after upgrading/removing a kernel-source package, the
+# directory might still exist, with the .config and other generated
+# files, but no kernel source!)
+cd $SRCDIR
+VERSION="$( make kernelversion | tail -1 )"
+[ -z "$VERSION" ] && die "Can't get kernel version (source corrupted?)"
+echo "=== VERSION=\"$VERSION\""
+
+SRCDIR="$SRCDIR/tools/perf"
+[ -d "$SRCDIR" ] || die "Kernel source missing tools/perf directory"
+
 BUILDDIR=$TMP/$PRGNAM-$VERSION
 
 rm -rf $PKG $BUILDDIR
diff --git a/development/perf/perf.info b/development/perf/perf.info
index 1dcb42c49514..014af450323a 100644
--- a/development/perf/perf.info
+++ b/development/perf/perf.info
@@ -1,7 +1,7 @@
 PRGNAM="perf"
 VERSION="4.4.227"
 HOMEPAGE="https://perf.wiki.kernel.org/index.php/Main_Page"
-DOWNLOAD="http://www.pastemobile.org/static/perf.dummy"
+DOWNLOAD="https://slackware.uk/~urchlay/src/perf.dummy"
 MD5SUM="9cba6c70fb57a22a155073d54748b614"
 DOWNLOAD_x86_64=""
 MD5SUM_x86_64=""