lint/kconfig: More checks, more errors

This patch changes a few more Kconfig linter warnings to errors that
currently do not show up in the tree and that seem unlikely to become
false positive in the future. One instance of duplicated code that
essentially checks for the same thing was consolidated.

It also adds a new test for references to boolean Kconfig options that
do not use the CONFIG() wrapper macro. It's a little flaky (e.g. hard to
handle multi-line comments), but it should be helpful the majority of
the time as a warning in a Jenkins comment.

Change-Id: I975ee77d392ed426f76f7671d9b6ef9441656e6a
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31777
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

2 files changed, 39 insertions, 38 deletions

diff --git a/util/lint/kconfig_lint b/util/lint/kconfig_lint
index 6cf05a4b63..4d0a755efb 100755
--- a/util/lint/kconfig_lint
+++ b/util/lint/kconfig_lint
@@ -199,35 +199,16 @@ sub check_for_ifdef {
             my $symbol = $3;
 
             if ( ( exists $symbols{$symbol} ) && ( $symbols{$symbol}{type} ne "string" ) ) {
-                show_warning( "#ifdef 'CONFIG_$symbol' used at $file:$lineno."
+                show_error( "#ifdef 'CONFIG_$symbol' used at $file:$lineno."
                       . "  Symbols of type '$symbols{$symbol}{type}' are always defined." );
             }
-        } elsif ( $line =~ /^([^:]+):(\d+):\s*#\s*if\s+!?\s*defined\s*\(?\s*CONFIG(?:_|\()(\w+)/ ) {
+        } elsif ( $line =~ /^([^:]+):(\d+):.+defined\s*\(?\s*CONFIG(?:_|\()(\w+)/ ) {
             my $file   = $1;
             my $lineno = $2;
             my $symbol = $3;
 
             if ( ( exists $symbols{$symbol} ) && ( $symbols{$symbol}{type} ne "string" ) ) {
-                show_warning( "#ifdef 'CONFIG_$symbol' used at $file:$lineno."
-                      . "  Symbols of type '$symbols{$symbol}{type}' are always defined." );
-            }
-        }
-    }
-
-    # look for (#if) defined SYMBOL
-    @ifdef_symbols = @collected_symbols;
-    while ( my $line = shift @ifdef_symbols ) {
-        if ( $line =~ /^([^:]+):(\d+):.+defined\s*\(\s*CONFIG(?:_|\()(\w+)/ ) {
-            my $file   = $1;
-            my $lineno = $2;
-            my $symbol = $3;
-
-            #ignore '#if defined(symbol) && symbol' type statements
-            next
-              if ( $line =~ /^([^:]+):(\d+):.+defined\s*\(\s*CONFIG_$symbol.*(&&|\|\|)\s*!?\s*\(?\s*CONFIG_$symbol/ );
-
-            if ( ( exists $symbols{$symbol} ) && ( $symbols{$symbol}{type} ne "string" ) ) {
-                show_warning( "defined 'CONFIG_$symbol' used at $file:$lineno."
+                show_error( "defined(CONFIG_$symbol) used at $file:$lineno."
                       . "  Symbols of type '$symbols{$symbol}{type}' are always defined." );
             }
         }
@@ -272,10 +253,10 @@ sub check_for_def {
             my $symbol = $3;
 
             if ( ( exists $symbols{$symbol} ) ) {
-                show_warning("#define of symbol 'CONFIG_$symbol' used at $file:$lineno.");
+                show_error("#define of symbol 'CONFIG_$symbol' used at $file:$lineno.");
             }
             else {
-                show_warning( "#define 'CONFIG_$symbol' used at $file:$lineno."
+                show_error( "#define 'CONFIG_$symbol' used at $file:$lineno."
                       . "  Other #defines should not look like Kconfig symbols." );
             }
         }
@@ -383,6 +364,24 @@ sub check_is_enabled {
                           . "  CONFIG($symbol) should be used for type 'bool'" );
                 }
             }
+        } elsif ( $line =~ /^([^:]+):(\d+):(.+\bCONFIG_.+)/ ) {
+            my $file   = $1;
+            my $lineno = $2;
+            $line = $3;
+            if ( $file =~ /.*\.(c|h|asl|ld)/ ) {
+                while ( $line =~ /(.*)\bCONFIG_(\w+)(.*)/ && $1 !~ /\/\/|\/\*/ ) {
+                    my $symbol = $2;
+                    $line = $1 . $3;
+                    if ( exists $symbols{$symbol} ) {
+                        if ( $symbols{$symbol}{type} eq "bool" ) {
+                            show_warning( "Naked reference to CONFIG_$symbol used at $file:$lineno."
+                                . "  A 'bool' Kconfig should always be accessed through CONFIG($symbol)." );
+                        }
+                    } else {
+                        show_warning( "Unknown config option CONFIG_$symbol used at $file:$lineno." );
+                    }
+                }
+            }
         }
     }
 }
@@ -437,7 +436,7 @@ sub check_defaults {
                                 }
                         } elsif  ($symbols{$sym}{type} eq "bool") {
                             if ($symbols{$sym}{$sym_num}{default}{$def_num}{default} =~ /[01YN]/) {
-                                show_warning("default value ($symbols{$sym}{$sym_num}{default}{$def_num}{default}) for bool symbol $sym uses value other than y/n at $filename:$line_no.");
+                                show_error("default value ($symbols{$sym}{$sym_num}{default}{$def_num}{default}) for bool symbol $sym uses value other than y/n at $filename:$line_no.");
                             } else {
                                 show_error("non bool default value ($symbols{$sym}{$sym_num}{default}{$def_num}{default}) used for bool symbol $sym at $filename:$line_no.");
                             }
@@ -447,7 +446,7 @@ sub check_defaults {
 
                 #if a default is already set, display an error
                 if ($default_set) {
-                    show_warning( "Default for '$sym' referenced at $filename:$line_no will never be set"
+                    show_error( "Default for '$sym' referenced at $filename:$line_no will never be set"
                           . " - overridden by default set at $default_filename:$default_line_no" );
                 }
                 else {
@@ -1140,7 +1139,7 @@ sub handle_type {
     ( $type, $expression ) = handle_if_line( $type, $inside_config, $filename, $line_no );
 
     if ( $type =~ /tristate/ ) {
-        show_warning("$filename:$line_no - tristate types are not used.");
+        show_error("$filename:$line_no - tristate types are not used.");
     }
 
     if ($inside_config) {
@@ -1265,7 +1264,7 @@ sub load_kconfig_file {
 
         #the directory should exist when using a glob
         else {
-            show_warning("Could not find dir '$dir_prefix'");
+            show_error("Could not find dir '$dir_prefix'");
         }
     }
 
diff --git a/util/lint/kconfig_lint_README b/util/lint/kconfig_lint_README
index d20a933340..832f862422 100644
--- a/util/lint/kconfig_lint_README
+++ b/util/lint/kconfig_lint_README
@@ -43,23 +43,20 @@ Notes:
 - Show when the range set for a hex or int does not match a previous range
 
 Warnings in Kconfig files:
-- Any 'default' expressions that can never be reached.
 - Symbols that are defined but never used.
-- Directories specified in a 'source' keyword do not exist.
 - A 'source' keyword loading a Kconfig file that has already been loaded.
 - A 'source' keyword loading a Kconfig file that doesn't exist. Note that
   globs are excluded from this check.
 
 Warnings in coreboot source files:
-- #define of Kconfig symbol - Symbols should only be defined in Kconfig.
-- #define starting with 'CONFIG_' - these should be reserved for Kconfig
-  symbols.
 - 'IS_ENABLED()' block that could not be interpreted.
 - Kconfig files that are not loaded by a 'source' keyword.
-- '#ifdef' or '#if defined' used on bool, int, or hex - these are always
-  defined in coreboot's version of Kconfig.
+- IS_ENABLED() used on a Kconfig (deprecated in favor of CONFIG())
+- Naked use of boolean CONFIG_XXX Kconfig in C that's not wrapped in CONFIG()
 
 Errors in Kconfig files:
+- Any 'default' expressions that can never be reached.
+- Directories specified in a 'source' keyword do not exist.
 - Selects do not work on symbols created in a choice block.
 - All symbols used in selects or expressions must be defined in a config
   statement.
@@ -94,8 +91,13 @@ Errors in Kconfig that are also caught by Kconfig itself:
 - Symbols with no defined type.
 
 Errors in coreboot source files:
-- The IS_ENABLED macro is only valid for bool symbols.
-- The IS_ENABLED used on unknown CONFIG_ value, like an obsolete symbol.
-- The IS_ENABLED macro is used on a symbol without the CONFIG_ prefix.
+- #define of Kconfig symbol - Symbols should only be defined in Kconfig.
+- #define starting with 'CONFIG_' - these should be reserved for Kconfig
+  symbols.
+- '#ifdef' or '#if defined' used on bool, int, or hex - these are always
+  defined in coreboot's version of Kconfig.
+- The CONFIG() and IS_ENABLED() macros is only valid for bool symbols.
+- CONFIG() or IS_ENABLED() used on unknown Kconfig, like an obsolete symbol.
+- The IS_ENABLED() macro is used on a symbol without the CONFIG_ prefix.
 
 TODO: check for choice entries at the top level