[PATCH v4] streamline_config.pl: add LMC_KEEP to preserve some kconfigs

From: Changbin Du
Date: Sat May 02 2020 - 20:11:55 EST


Sometimes it is useful to preserve batches of configs when making
localmodconfig. For example, I usually don't want any usb and fs
modules to be disabled. Now we can do it by:

$ make LMC_KEEP="drivers/usb;fs" localmodconfig

Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>

---
v4: fix typo.
v3: rename LOCALMODCONFIG_PRESERVE to shorter LMC_KEEP.
v2: fix typo in documentation. (Randy Dunlap)
---
Documentation/admin-guide/README.rst | 8 +++++++-
scripts/kconfig/Makefile | 1 +
scripts/kconfig/streamline_config.pl | 23 +++++++++++++++++++++++
3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/README.rst b/Documentation/admin-guide/README.rst
index cc6151fc0845..1371deab8bc7 100644
--- a/Documentation/admin-guide/README.rst
+++ b/Documentation/admin-guide/README.rst
@@ -209,10 +209,16 @@ Configuring the kernel
store the lsmod of that machine into a file
and pass it in as a LSMOD parameter.

+ Also, you can preserve modules in certain folders
+ or kconfig files by specifying their paths in
+ parameter LMC_KEEP.
+
target$ lsmod > /tmp/mylsmod
target$ scp /tmp/mylsmod host:/tmp

- host$ make LSMOD=/tmp/mylsmod localmodconfig
+ host$ make LSMOD=/tmp/mylsmod \
+ LMC_KEEP="drivers/usb;drivers/gpu;fs" \
+ localmodconfig

The above also works when cross compiling.

diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index c9d0a4a8efb3..e0abbf5805f5 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -123,6 +123,7 @@ help:
@echo ' gconfig - Update current config utilising a GTK+ based front-end'
@echo ' oldconfig - Update current config utilising a provided .config as base'
@echo ' localmodconfig - Update current config disabling modules not loaded'
+ @echo ' except those preserved by LMC_KEEP environment variable'
@echo ' localyesconfig - Update current config converting local mods to core'
@echo ' defconfig - New config with default from ARCH supplied defconfig'
@echo ' savedefconfig - Save current config as ./defconfig (minimal config)'
diff --git a/scripts/kconfig/streamline_config.pl b/scripts/kconfig/streamline_config.pl
index e2f8504f5a2d..d26543a807c9 100755
--- a/scripts/kconfig/streamline_config.pl
+++ b/scripts/kconfig/streamline_config.pl
@@ -143,6 +143,7 @@ my %depends;
my %selects;
my %prompts;
my %objects;
+my %config2kfile;
my $var;
my $iflevel = 0;
my @ifdeps;
@@ -201,6 +202,7 @@ sub read_kconfig {
if (/^\s*(menu)?config\s+(\S+)\s*$/) {
$state = "NEW";
$config = $2;
+ $config2kfile{"CONFIG_$config"} = $kconfig;

# Add depends for 'if' nesting
for (my $i = 0; $i < $iflevel; $i++) {
@@ -592,6 +594,22 @@ while ($repeat) {

my %setconfigs;

+my @preserved_kconfigs;
+@preserved_kconfigs = split(/;/,$ENV{LMC_KEEP}) if (defined($ENV{LMC_KEEP}));
+
+sub in_preserved_kconfigs {
+ my $kconfig = $config2kfile{$_[0]};
+ if (!defined($kconfig)) {
+ return 0;
+ }
+ foreach my $excl (@preserved_kconfigs) {
+ if($kconfig =~ /^$excl/) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
# Finally, read the .config file and turn off any module enabled that
# we could not find a reason to keep enabled.
foreach my $line (@config_file) {
@@ -644,6 +662,11 @@ foreach my $line (@config_file) {
}

if (/^(CONFIG.*)=(m|y)/) {
+ if (in_preserved_kconfigs($1)) {
+ dprint "Preserve config $1";
+ print;
+ next;
+ }
if (defined($configs{$1})) {
if ($localyesconfig) {
$setconfigs{$1} = 'y';
--
2.25.1