Kconfig updates for v5.8

- allow only 'config', 'comment', 'if' statements inside 'choice' since
    the other statements are not sensible inside 'choice' and should be
    grammatical error
 
  - support LMC_KEEP env variable for 'make local{yes,mod}config' to
    preserve some CONFIG options
 
  - deprecate 'make kvmconfig' and 'make xenconfig' in favor of
    'make kvm_guest.config' and 'make xen.config'
 
  - code cleanups
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Merge tag 'kconfig-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kconfig updates from Masahiro Yamada:

 - allow only 'config', 'comment', 'if' statements inside 'choice' since
   the other statements are not sensible inside 'choice' and should be
   grammatical error

 - support LMC_KEEP env variable for 'make local{yes,mod}config' to
   preserve some CONFIG options

 - deprecate 'make kvmconfig' and 'make xenconfig' in favor of
   'make kvm_guest.config' and 'make xen.config'

 - code cleanups

* tag 'kconfig-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: announce removal of 'kvmconfig' and 'xenconfig' shorthands
  streamline_config.pl: add LMC_KEEP to preserve some kconfigs
  kconfig: allow only 'config', 'comment', and 'if' inside 'choice'
  kconfig: tests: remove randconfig test for choice in choice
  kconfig: do not assign a variable in the return statement
  kconfig: do not use OR-assignment for zero-cleared structure

Documentation/admin-guide/README.rst

@@ -209,15 +209,22 @@ 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.
 
      "make localyesconfig" Similar to localmodconfig, except it will convert
-                           all module options to built in (=y) options.
+                           all module options to built in (=y) options. You can
+                           also preserve modules by LMC_KEEP.
 
      "make kvmconfig"   Enable additional options for kvm guest kernel support.
 

scripts/kconfig/Makefile

@@ -96,11 +96,13 @@ configfiles=$(wildcard $(srctree)/kernel/configs/$@ $(srctree)/arch/$(SRCARCH)/c
 
 PHONY += kvmconfig
 kvmconfig: kvm_guest.config
-	@:
+	@echo >&2 "WARNING: 'make $@' will be removed after Linux 5.10"
+	@echo >&2 "         Please use 'make $<' instead."
 
 PHONY += xenconfig
 xenconfig: xen.config
-	@:
+	@echo >&2 "WARNING: 'make $@' will be removed after Linux 5.10"
+	@echo >&2 "         Please use 'make $<' instead."
 
 PHONY += tinyconfig
 tinyconfig:
@@ -123,7 +125,9 @@ 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  '                    except those preserved by LMC_KEEP environment variable'
 	@echo  '  defconfig	  - New config with default from ARCH supplied defconfig'
 	@echo  '  savedefconfig   - Save current config as ./defconfig (minimal config)'
 	@echo  '  allnoconfig	  - New config where all options are answered with no'
@@ -137,9 +141,6 @@ help:
 	@echo  '  helpnewconfig   - List new options and help text'
 	@echo  '  olddefconfig	  - Same as oldconfig but sets new symbols to their'
 	@echo  '                    default value without prompting'
-	@echo  '  kvmconfig	  - Enable additional options for kvm guest kernel support'
-	@echo  '  xenconfig       - Enable additional options for xen dom0 and guest kernel'
-	@echo  '                    support'
 	@echo  '  tinyconfig	  - Configure the tiniest possible kernel'
 	@echo  '  testconfig	  - Run Kconfig unit tests (requires python3 and pytest)'
 

scripts/kconfig/menu.c

@@ -65,7 +65,8 @@ void menu_add_entry(struct symbol *sym)
 struct menu *menu_add_menu(void)
 {
 	last_entry_ptr = &current_entry->list;
-	return current_menu = current_entry;
+	current_menu = current_entry;
+	return current_menu;
 }
 
 void menu_end_menu(void)

scripts/kconfig/parser.y

@@ -119,20 +119,24 @@ mainmenu_stmt: T_MAINMENU T_WORD_QUOTE T_EOL
 
 stmt_list:
 	  /* empty */
-	| stmt_list common_stmt
+	| stmt_list assignment_stmt
 	| stmt_list choice_stmt
+	| stmt_list comment_stmt
+	| stmt_list config_stmt
+	| stmt_list if_stmt
 	| stmt_list menu_stmt
+	| stmt_list menuconfig_stmt
+	| stmt_list source_stmt
 	| stmt_list T_WORD error T_EOL	{ zconf_error("unknown statement \"%s\"", $2); }
 	| stmt_list error T_EOL		{ zconf_error("invalid statement"); }
 ;
 
-common_stmt:
-	  if_stmt
-	| comment_stmt
-	| config_stmt
-	| menuconfig_stmt
-	| source_stmt
-	| assignment_stmt
+stmt_list_in_choice:
+	  /* empty */
+	| stmt_list_in_choice comment_stmt
+	| stmt_list_in_choice config_stmt
+	| stmt_list_in_choice if_stmt_in_choice
+	| stmt_list_in_choice error T_EOL	{ zconf_error("invalid statement"); }
 ;
 
 /* config/menuconfig entry */
@@ -254,7 +258,7 @@ choice_end: end
 	}
 };
 
-choice_stmt: choice_entry choice_block choice_end
+choice_stmt: choice_entry stmt_list_in_choice choice_end
 ;
 
 choice_option_list:
@@ -305,11 +309,6 @@ default:
 	| T_DEF_BOOL		{ $$ = S_BOOLEAN; }
 	| T_DEF_TRISTATE	{ $$ = S_TRISTATE; }
 
-choice_block:
-	  /* empty */
-	| choice_block common_stmt
-;
-
 /* if entry */
 
 if_entry: T_IF expr T_EOL
@@ -331,6 +330,9 @@ if_end: end
 if_stmt: if_entry stmt_list if_end
 ;
 
+if_stmt_in_choice: if_entry stmt_list_in_choice if_end
+;
+
 /* menu entry */
 
 menu: T_MENU T_WORD_QUOTE T_EOL

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; $i++) {
@@ -591,6 +593,20 @@ while ($repeat) {
 }
 
 my %setconfigs;
+my @preserved_kconfigs = split(/:/,$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.
@@ -644,6 +660,11 @@ 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';

scripts/kconfig/symbol.c

@@ -831,7 +831,7 @@ struct symbol *sym_lookup(const char *name, int flags)
 	memset(symbol, 0, sizeof(*symbol));
 	symbol->name = new_name;
 	symbol->type = S_UNKNOWN;
-	symbol->flags |= flags;
+	symbol->flags = flags;
 
 	symbol->next = symbol_hash[hash];
 	symbol_hash[hash] = symbol;

scripts/kconfig/tests/rand_nested_choice/Kconfig

@@ -1,35 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-
-choice
-	prompt "choice"
-
-config A
-	bool "A"
-
-config B
-	bool "B"
-
-if B
-choice
-	prompt "sub choice"
-
-config C
-	bool "C"
-
-config D
-	bool "D"
-
-if D
-choice
-	prompt "subsub choice"
-
-config E
-	bool "E"
-
-endchoice
-endif # D
-
-endchoice
-endif # B
-
-endchoice

scripts/kconfig/tests/rand_nested_choice/__init__.py

@@ -1,17 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-"""
-Set random values recursively in nested choices.
-
-Kconfig can create a choice-in-choice structure by using 'if' statement.
-randconfig should correctly set random choice values.
-
-Related Linux commit: 3b9a19e08960e5cdad5253998637653e592a3c29
-"""
-
-
-def test(conf):
-    for i in range(20):
-        assert conf.randconfig() == 0
-        assert (conf.config_contains('expected_stdout0') or
-                conf.config_contains('expected_stdout1') or
-                conf.config_contains('expected_stdout2'))

scripts/kconfig/tests/rand_nested_choice/expected_stdout0

@@ -1,2 +0,0 @@
-CONFIG_A=y
-# CONFIG_B is not set

scripts/kconfig/tests/rand_nested_choice/expected_stdout1

@@ -1,4 +0,0 @@
-# CONFIG_A is not set
-CONFIG_B=y
-CONFIG_C=y
-# CONFIG_D is not set

scripts/kconfig/tests/rand_nested_choice/expected_stdout2

@@ -1,5 +0,0 @@
-# CONFIG_A is not set
-CONFIG_B=y
-# CONFIG_C is not set
-CONFIG_D=y
-CONFIG_E=y