ec: Prevent #undef or #define of zephyr Kconfigs

Block all #undef or #define of Kconfigs in include/config.h. This will
allow removing the #include <autoconf.h> from
zephyr/shim/include/config_chip.h, which will in turn allow removing
all of the #line directives we've sprinkled throughout the headers.

BRANCH=None
BUG=b:272518464
TEST=make buildall_only -j$(nproc), fails before crrev/c/4396143
TEST=CQ, fails before crrev/c/4396143, passes after

Change-Id: I09649cf778e339fb45dc05c6ebdffc9aaa5778d2
Signed-off-by: Jeremy Bettis <jbettis@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4396142
Auto-Submit: Jeremy Bettis <jbettis@chromium.org>
Reviewed-by: Keith Short <keithshort@chromium.org>
Commit-Queue: Keith Short <keithshort@chromium.org>
Tested-by: Jeremy Bettis <jbettis@chromium.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/util/kconfig_check.py b/util/kconfig_check.py
index aebaa24cbd..48060f6782 100755
--- a/util/kconfig_check.py
+++ b/util/kconfig_check.py
@@ -22,6 +22,7 @@ Use the -d flag to select the second format.
 """
 
 import argparse
+import glob
 import os
 import pathlib
 import re
@@ -119,6 +120,9 @@ a corresponding Kconfig option for Zephyr"""
 
     subparsers.add_parser("build", help="Build new list of ad-hoc CONFIGs")
     subparsers.add_parser("check", help="Check for new ad-hoc CONFIGs")
+    subparsers.add_parser(
+        "check_undef", help="Verify #undef directives in ec headers"
+    )
 
     return parser.parse_args(argv)
 
@@ -496,6 +500,68 @@ update in your CL:
                 print(f"CONFIG_{config}", file=out)
         print(f"New list is in {NEW_ALLOWED_FNAME}")
 
+    def check_undef(
+        self,
+        srcdir,
+        search_paths,
+    ):
+        """Parse the ec header files and find zephyr Kconfigs that are
+        incorrectly undefined or defined to a default value.
+
+        Args:
+            srcdir: Source directory to scan for Kconfig files
+            search_paths: List of project paths to search for Kconfig files, in
+                addition to the current directory
+
+        Returns:
+            Exit code: 0 if OK, 1 if a problem was found
+        """
+        kconfigs = set(self.scan_kconfigs(srcdir, "", search_paths))
+
+        if_re = re.compile(r"^\s*#\s*if(ndef CONFIG_ZEPHYR)?")
+        endif_re = re.compile(r"^\s*#\s*endif")
+        modify_config_re = re.compile(r"^\s*#\s*(define|undef)\s+CONFIG_(\S*)")
+        exit_code = 0
+        files_to_check = glob.glob(
+            os.path.join(srcdir, "include/**/*.h"), recursive=True
+        )
+        files_to_check += glob.glob(
+            os.path.join(srcdir, "common/**/public/*.h"), recursive=True
+        )
+        files_to_check += glob.glob(
+            os.path.join(srcdir, "driver/**/*.h"), recursive=True
+        )
+        for filename in files_to_check:
+            with open(filename, "r") as config_h:
+                depth = 0
+                ignore_depth = 0
+                line_count = 0
+                for line in config_h.readlines():
+                    line_count += 1
+                    line = line.strip("\n")
+                    match = if_re.match(line)
+                    if match:
+                        depth += 1
+                        if match[1] or ignore_depth > 0:
+                            ignore_depth += 1
+                    if endif_re.match(line):
+                        if depth > 0:
+                            depth -= 1
+                        if ignore_depth > 0:
+                            ignore_depth -= 1
+                    if ignore_depth == 0:
+                        match = modify_config_re.match(line)
+                        if match:
+                            if match[2] in kconfigs:
+                                print(
+                                    f"ERROR: Modifying CONFIG_{match[2]} "
+                                    "outside of #ifndef CONFIG_ZEPHYR not "
+                                    f"allowed at {filename}:{line_count}",
+                                    file=sys.stderr,
+                                )
+                                exit_code = 1
+        return exit_code
+
 
 def main(argv):
     """Main function"""
@@ -522,6 +588,11 @@ def main(argv):
             use_defines=args.use_defines,
             search_paths=args.search_path,
         )
+    if args.cmd == "check_undef":
+        return checker.check_undef(
+            srcdir=args.srctree,
+            search_paths=args.search_path,
+        )
     return 2