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Message-ID: <20251229114447.45236-1-mikko.rapeli@linaro.org>
Date: Mon, 29 Dec 2025 13:44:45 +0200
From: Mikko Rapeli <mikko.rapeli@...aro.org>
To: Nathan Chancellor <nathan@...nel.org>,
Nicolas Schier <nsc@...nel.org>,
Anders Roxell <anders.roxell@...aro.org>,
linux-kbuild@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Mikko Rapeli <mikko.rapeli@...aro.org>
Subject: [PATCH 1/3] scripts: kconfig: merge_config.sh: refactor from shell/sed/grep to awk
From: Anders Roxell <anders.roxell@...aro.org>
merge_config.sh shell/sed/grep loop scales poorly and is slow.
With Yocto genericarm64 kernel and around 190 config fragments
the script takes more than 20 minutes to run on a fast build machine.
Re-implementation with awk does the same job in 10 seconds.
Using awk since it is likely available in the build environments
and using perl, python etc would introduce more complex runtime
dependencies. awk is good enough and lot better than shell/sed/grep.
Signed-off-by: Anders Roxell <anders.roxell@...aro.org>
Signed-off-by: Mikko Rapeli <mikko.rapeli@...aro.org>
---
scripts/kconfig/merge_config.sh | 161 ++++++++++++++++++++++++--------
1 file changed, 123 insertions(+), 38 deletions(-)
diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh
index 79c09b378be8..46397d7c6957 100755
--- a/scripts/kconfig/merge_config.sh
+++ b/scripts/kconfig/merge_config.sh
@@ -16,8 +16,8 @@
set -e
clean_up() {
- rm -f $TMP_FILE
- rm -f $MERGE_FILE
+ rm -f "${TMP_FILE}"
+ rm -f "${TMP_FILE}.new"
}
usage() {
@@ -121,7 +121,6 @@ SED_CONFIG_EXP1="s/^\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)=.*/\1/p"
SED_CONFIG_EXP2="s/^# \(${CONFIG_PREFIX}[a-zA-Z0-9_]*\) is not set$/\1/p"
TMP_FILE=$(mktemp ./.tmp.config.XXXXXXXXXX)
-MERGE_FILE=$(mktemp ./.merge_tmp.config.XXXXXXXXXX)
echo "Using $INITFILE as base"
@@ -136,42 +135,128 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do
echo "The merge file '$ORIG_MERGE_FILE' does not exist. Exit." >&2
exit 1
fi
- cat $ORIG_MERGE_FILE > $MERGE_FILE
- CFG_LIST=$(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $MERGE_FILE)
-
- for CFG in $CFG_LIST ; do
- grep -q -w $CFG $TMP_FILE || continue
- PREV_VAL=$(grep -w $CFG $TMP_FILE)
- NEW_VAL=$(grep -w $CFG $MERGE_FILE)
- BUILTIN_FLAG=false
- if [ "$BUILTIN" = "true" ] && [ "${NEW_VAL#CONFIG_*=}" = "m" ] && [ "${PREV_VAL#CONFIG_*=}" = "y" ]; then
- ${WARNOVERRIDE} Previous value: $PREV_VAL
- ${WARNOVERRIDE} New value: $NEW_VAL
- ${WARNOVERRIDE} -y passed, will not demote y to m
- ${WARNOVERRIDE}
- BUILTIN_FLAG=true
- elif [ "x$PREV_VAL" != "x$NEW_VAL" ] ; then
- ${WARNOVERRIDE} Value of $CFG is redefined by fragment $ORIG_MERGE_FILE:
- ${WARNOVERRIDE} Previous value: $PREV_VAL
- ${WARNOVERRIDE} New value: $NEW_VAL
- ${WARNOVERRIDE}
- if [ "$STRICT" = "true" ]; then
- STRICT_MODE_VIOLATED=true
- fi
- elif [ "$WARNREDUN" = "true" ]; then
- ${WARNOVERRIDE} Value of $CFG is redundant by fragment $ORIG_MERGE_FILE:
- fi
- if [ "$BUILTIN_FLAG" = "false" ]; then
- sed -i "/$CFG[ =]/d" $TMP_FILE
- else
- sed -i "/$CFG[ =]/d" $MERGE_FILE
- fi
- done
- # In case the previous file lacks a new line at the end
- echo >> $TMP_FILE
- cat $MERGE_FILE >> $TMP_FILE
-done
+ # Use awk for single-pass processing instead of per-symbol grep/sed
+ if ! awk -v prefix="$CONFIG_PREFIX" \
+ -v warnoverride="$WARNOVERRIDE" \
+ -v strict="$STRICT" \
+ -v builtin="$BUILTIN" \
+ -v warnredun="$WARNREDUN" '
+ BEGIN {
+ strict_violated = 0
+ cfg_regex = "^" prefix "[a-zA-Z0-9_]+"
+ notset_regex = "^# " prefix "[a-zA-Z0-9_]+ is not set$"
+ }
+
+ # Extract config name from a line, returns "" if not a config line
+ function get_cfg(line) {
+ if (match(line, cfg_regex)) {
+ return substr(line, RSTART, RLENGTH)
+ } else if (match(line, notset_regex)) {
+ # Extract CONFIG_FOO from "# CONFIG_FOO is not set"
+ sub(/^# /, "", line)
+ sub(/ is not set$/, "", line)
+ return line
+ }
+ return ""
+ }
+
+ # Normalize: strip trailing comments, convert "is not set" to "=n"
+ function normalize(line) {
+ if (line == "") return ""
+ sub(/[[:space:]]+#.*/, "", line)
+ if (line ~ / is not set$/) {
+ sub(/^# /, "", line)
+ sub(/ is not set$/, "=n", line)
+ }
+ return line
+ }
+
+ function warn_builtin(cfg, prev, new) {
+ if (warnoverride == "true") return
+ print cfg ": -y passed, will not demote y to m" > "/dev/stderr"
+ print " Previous value: " prev > "/dev/stderr"
+ print " New value: " new > "/dev/stderr"
+ print "" > "/dev/stderr"
+ }
+
+ function warn_redefined(cfg, prev, new) {
+ if (warnoverride == "true") return
+ print "Value of " cfg " is redefined by fragment " mergefile ":" > "/dev/stderr"
+ print " Previous value: " prev > "/dev/stderr"
+ print " New value: " new > "/dev/stderr"
+ print "" > "/dev/stderr"
+ }
+
+ function warn_redundant(cfg) {
+ if (warnredun != "true" || warnoverride == "true") return
+ print "Value of " cfg " is redundant by fragment " mergefile ":" > "/dev/stderr"
+ }
+
+ # First pass: read merge file, store all lines and index
+ FILENAME == ARGV[1] {
+ mergefile = FILENAME
+ merge_lines[FNR] = $0
+ merge_total = FNR
+ cfg = get_cfg($0)
+ if (cfg != "") {
+ merge_cfg[cfg] = $0
+ merge_cfg_line[cfg] = FNR
+ }
+ next
+ }
+ # Second pass: process base file (TMP_FILE)
+ cfg = get_cfg($0)
+
+ # Not a config or not in merge file - keep it
+ if (cfg == "" || !(cfg in merge_cfg)) {
+ print $0
+ next
+ }
+
+ prev_val = normalize($0)
+ new_val = normalize(merge_cfg[cfg])
+
+ # BUILTIN: do not demote y to m
+ if (builtin == "true" && new_val ~ /=m$/ && prev_val ~ /=y$/) {
+ warn_builtin(cfg, prev_val, new_val)
+ print $0
+ skip_merge[merge_cfg_line[cfg]] = 1
+ next
+ }
+
+ # Values equal - redundant
+ if (prev_val == new_val) {
+ warn_redundant(cfg)
+ next
+ }
+
+ # Values differ - redefined
+ warn_redefined(cfg, prev_val, new_val)
+ if (strict == "true") {
+ strict_violated = 1
+ }
+ }
+
+ END {
+ # Newline in case base file lacks trailing newline
+ print ""
+ # Append merge file, skipping lines marked for builtin preservation
+ for (i = 1; i <= merge_total; i++) {
+ if (!(i in skip_merge)) {
+ print merge_lines[i]
+ }
+ }
+ if (strict_violated) {
+ exit 1
+ }
+ }' \
+ "$ORIG_MERGE_FILE" "$TMP_FILE" > "${TMP_FILE}.new"; then
+ # awk exited non-zero, strict mode was violated
+ STRICT_MODE_VIOLATED=true
+ fi
+ mv "${TMP_FILE}.new" "$TMP_FILE"
+done
if [ "$STRICT_MODE_VIOLATED" = "true" ]; then
echo "The fragment redefined a value and strict mode had been passed."
exit 1
--
2.34.1
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