Merge tag 'kbuild-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:
 "Kbuild core:
   - remove unneeded $(call cc-option,...) switches
   - consolidate Clang compiler flags into CLANG_FLAGS
   - announce the deprecation of SUBDIRS
   - fix single target build for external module
   - simplify the dependencies of 'prepare' stage targets
   - allow fixdep to directly write to .*.cmd files
   - simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS
   - change if_changed_rule to accept multi-line recipe
   - move .SECONDARY special target to scripts/Kbuild.include
   - remove redundant 'set -e'
   - improve parallel execution for CONFIG_HEADERS_CHECK
   - misc cleanups

  Treewide fixes and cleanups
   - set Clang flags correctly for PowerPC boot images
   - fix UML build error with CONFIG_GCC_PLUGINS
   - remove unneeded patterns from .gitignore files
   - refactor firmware/Makefile
   - remove unneeded rules for *offsets.s
   - avoid unneeded regeneration of intermediate .s files
   - clean up ./Kbuild

  Modpost:
   - remove unused -M, -K options
   - fix false positive warnings about section mismatch
   - use simple devtable lookup instead of linker magic
   - misc cleanups

  Coccinelle:
   - relax boolinit.cocci checks for overall consistency
   - fix warning messages of boolinit.cocci

  Other tools:
   - improve -dirty check of scripts/setlocalversion
   - add a tool to generate compile_commands.json from .*.cmd files"

* tag 'kbuild-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (51 commits)
  kbuild: remove unused cmd_gentimeconst
  kbuild: remove $(obj)/ prefixes in ./Kbuild
  treewide: add intermediate .s files to targets
  treewide: remove explicit rules for *offsets.s
  firmware: refactor firmware/Makefile
  firmware: remove unnecessary patterns from .gitignore
  scripts: remove unnecessary ihex2fw and check-lc_ctypes from .gitignore
  um: remove unused filechk_gen_header in Makefile
  scripts: add a tool to produce a compile_commands.json file
  kbuild: add -Werror=implicit-int flag unconditionally
  kbuild: add -Werror=strict-prototypes flag unconditionally
  kbuild: add -fno-PIE flag unconditionally
  scripts: coccinelle: Correct warning message
  scripts: coccinelle: only suggest true/false in files that already use them
  kbuild: handle part-of-module correctly for *.ll and *.symtypes
  kbuild: refactor part-of-module
  kbuild: refactor quiet_modtag
  kbuild: remove redundant quiet_modtag for $(obj-m)
  kbuild: refactor Makefile.asm-generic
  user/Makefile: Fix typo and capitalization in comment section
  ...

1 files changed, 63 insertions, 51 deletions

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 0d998c54564d..0de2fb236640 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1163,6 +1163,14 @@ static const struct sectioncheck *section_mismatch(
  *   fromsec = text section
  *   refsymname = *.constprop.*
  *
+ * Pattern 6:
+ *   Hide section mismatch warnings for ELF local symbols.  The goal
+ *   is to eliminate false positive modpost warnings caused by
+ *   compiler-generated ELF local symbol names such as ".LANCHOR1".
+ *   Autogenerated symbol names bypass modpost's "Pattern 2"
+ *   whitelisting, which relies on pattern-matching against symbol
+ *   names to work.  (One situation where gcc can autogenerate ELF
+ *   local symbols is when "-fsection-anchors" is used.)
  **/
 static int secref_whitelist(const struct sectioncheck *mismatch,
 			    const char *fromsec, const char *fromsym,
@@ -1201,9 +1209,37 @@ static int secref_whitelist(const struct sectioncheck *mismatch,
 	    match(fromsym, optim_symbols))
 		return 0;
 
+	/* Check for pattern 6 */
+	if (strstarts(fromsym, ".L"))
+		return 0;
+
 	return 1;
 }
 
+static inline int is_arm_mapping_symbol(const char *str)
+{
+	return str[0] == '$' && strchr("axtd", str[1])
+	       && (str[2] == '\0' || str[2] == '.');
+}
+
+/*
+ * If there's no name there, ignore it; likewise, ignore it if it's
+ * one of the magic symbols emitted used by current ARM tools.
+ *
+ * Otherwise if find_symbols_between() returns those symbols, they'll
+ * fail the whitelist tests and cause lots of false alarms ... fixable
+ * only by merging __exit and __init sections into __text, bloating
+ * the kernel (which is especially evil on embedded platforms).
+ */
+static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
+{
+	const char *name = elf->strtab + sym->st_name;
+
+	if (!name || !strlen(name))
+		return 0;
+	return !is_arm_mapping_symbol(name);
+}
+
 /**
  * Find symbol based on relocation record info.
  * In some cases the symbol supplied is a valid symbol so
@@ -1229,6 +1265,8 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
 			continue;
 		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
 			continue;
+		if (!is_valid_name(elf, sym))
+			continue;
 		if (sym->st_value == addr)
 			return sym;
 		/* Find a symbol nearby - addr are maybe negative */
@@ -1247,30 +1285,6 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
 		return NULL;
 }
 
-static inline int is_arm_mapping_symbol(const char *str)
-{
-	return str[0] == '$' && strchr("axtd", str[1])
-	       && (str[2] == '\0' || str[2] == '.');
-}
-
-/*
- * If there's no name there, ignore it; likewise, ignore it if it's
- * one of the magic symbols emitted used by current ARM tools.
- *
- * Otherwise if find_symbols_between() returns those symbols, they'll
- * fail the whitelist tests and cause lots of false alarms ... fixable
- * only by merging __exit and __init sections into __text, bloating
- * the kernel (which is especially evil on embedded platforms).
- */
-static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
-{
-	const char *name = elf->strtab + sym->st_name;
-
-	if (!name || !strlen(name))
-		return 0;
-	return !is_arm_mapping_symbol(name);
-}
-
 /*
  * Find symbols before or equal addr and after addr - in the section sec.
  * If we find two symbols with equal offset prefer one with a valid name.
@@ -2083,15 +2097,27 @@ static void check_for_unused(enum export exp, const char *m, const char *s)
 	}
 }
 
-static void check_exports(struct module *mod)
+static int check_exports(struct module *mod)
 {
 	struct symbol *s, *exp;
+	int err = 0;
 
 	for (s = mod->unres; s; s = s->next) {
 		const char *basename;
 		exp = find_symbol(s->name);
-		if (!exp || exp->module == mod)
+		if (!exp || exp->module == mod) {
+			if (have_vmlinux && !s->weak) {
+				if (warn_unresolved) {
+					warn("\"%s\" [%s.ko] undefined!\n",
+					     s->name, mod->name);
+				} else {
+					merror("\"%s\" [%s.ko] undefined!\n",
+					       s->name, mod->name);
+					err = 1;
+				}
+			}
 			continue;
+		}
 		basename = strrchr(mod->name, '/');
 		if (basename)
 			basename++;
@@ -2101,6 +2127,8 @@ static void check_exports(struct module *mod)
 			check_for_gpl_usage(exp->export, basename, exp->name);
 		check_for_unused(exp->export, basename, exp->name);
 	}
+
+	return err;
 }
 
 static int check_modname_len(struct module *mod)
@@ -2178,19 +2206,8 @@ static int add_versions(struct buffer *b, struct module *mod)
 
 	for (s = mod->unres; s; s = s->next) {
 		exp = find_symbol(s->name);
-		if (!exp || exp->module == mod) {
-			if (have_vmlinux && !s->weak) {
-				if (warn_unresolved) {
-					warn("\"%s\" [%s.ko] undefined!\n",
-					     s->name, mod->name);
-				} else {
-					merror("\"%s\" [%s.ko] undefined!\n",
-					       s->name, mod->name);
-					err = 1;
-				}
-			}
+		if (!exp || exp->module == mod)
 			continue;
-		}
 		s->module = exp->module;
 		s->crc_valid = exp->crc_valid;
 		s->crc = exp->crc;
@@ -2227,15 +2244,15 @@ static int add_versions(struct buffer *b, struct module *mod)
 	return err;
 }
 
-static void add_depends(struct buffer *b, struct module *mod,
-			struct module *modules)
+static void add_depends(struct buffer *b, struct module *mod)
 {
 	struct symbol *s;
-	struct module *m;
 	int first = 1;
 
-	for (m = modules; m; m = m->next)
-		m->seen = is_vmlinux(m->name);
+	/* Clear ->seen flag of modules that own symbols needed by this. */
+	for (s = mod->unres; s; s = s->next)
+		if (s->module)
+			s->module->seen = is_vmlinux(s->module->name);
 
 	buf_printf(b, "\n");
 	buf_printf(b, "static const char __module_depends[]\n");
@@ -2416,7 +2433,7 @@ int main(int argc, char **argv)
 	struct ext_sym_list *extsym_iter;
 	struct ext_sym_list *extsym_start = NULL;
 
-	while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
+	while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awE")) != -1) {
 		switch (opt) {
 		case 'i':
 			kernel_read = optarg;
@@ -2482,12 +2499,6 @@ int main(int argc, char **argv)
 	if (files_source)
 		read_symbols_from_files(files_source);
 
-	for (mod = modules; mod; mod = mod->next) {
-		if (mod->skip)
-			continue;
-		check_exports(mod);
-	}
-
 	err = 0;
 
 	for (mod = modules; mod; mod = mod->next) {
@@ -2499,12 +2510,13 @@ int main(int argc, char **argv)
 		buf.pos = 0;
 
 		err |= check_modname_len(mod);
+		err |= check_exports(mod);
 		add_header(&buf, mod);
 		add_intree_flag(&buf, !external_module);
 		add_retpoline(&buf);
 		add_staging_flag(&buf, mod->name);
 		err |= add_versions(&buf, mod);
-		add_depends(&buf, mod, modules);
+		add_depends(&buf, mod);
 		add_moddevtable(&buf, mod);
 		add_srcversion(&buf, mod);