linux-kernel - [PATCH v7 2/5] modpost: Track module name for built-in modules

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Message-ID: <20221216221703.294683-3-allenwebb@google.com>
Date:   Fri, 16 Dec 2022 16:17:00 -0600
From:   Allen Webb <allenwebb@...gle.com>
To:     "linux-modules@...r.kernel.org" <linux-modules@...r.kernel.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     Luis Chamberlain <mcgrof@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Allen Webb <allenwebb@...gle.com>
Subject: [PATCH v7 2/5] modpost: Track module name for built-in modules

Keep track of the module name when processing match table symbols.

Signed-off-by: Allen Webb <allenwebb@...gle.com>
---
 scripts/mod/file2alias.c | 37 +++++++++++++++++++++++++++++++++----
 scripts/mod/modpost.h    |  1 +
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 80d973144fded..458e41ae0f5f1 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -28,6 +28,7 @@ typedef Elf64_Addr	kernel_ulong_t;
 #include <stdint.h>
 #endif
 
+#include <assert.h>
 #include <ctype.h>
 #include <stdbool.h>
 
@@ -1540,9 +1541,9 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
 			Elf_Sym *sym, const char *symname)
 {
 	void *symval;
-	char *zeros = NULL;
-	const char *name, *identifier;
-	unsigned int namelen;
+	char *zeros = NULL, *modname_str = NULL;
+	const char *name, *identifier, *modname;
+	unsigned int namelen, modnamelen;
 
 	/* We're looking for a section relative symbol */
 	if (!sym->st_shndx || get_secindex(info, sym) >= info->num_sections)
@@ -1552,7 +1553,11 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
 	if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
 		return;
 
-	/* All our symbols are of form __mod_<name>__<identifier>_device_table. */
+	/* All our symbols are either of form
+	 *   __mod_<name>__<identifier>_device_table
+	 * or
+	 *   __mod_<name>__<identifier>__kmod_<builtin-name>_device_table
+	 */
 	if (strncmp(symname, "__mod_", strlen("__mod_")))
 		return;
 	name = symname + strlen("__mod_");
@@ -1564,8 +1569,29 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
 	identifier = strstr(name, "__");
 	if (!identifier)
 		return;
+	modnamelen = namelen;
 	namelen = identifier - name;
 
+	/* In the vmlinuz.o case we want to handle __kmod_ so aliases from
+	 * builtin modules are attributed correctly.
+	 */
+	modname = strstr(identifier + 2, "__kmod_");
+	if (modname) {
+		modname += strlen("__kmod_");
+		modnamelen -= (modname - name) + strlen("_device_table");
+		modname_str = malloc(modnamelen + 1);
+		/* We don't want to continue if the allocation fails. */
+		assert(modname_str);
+		memcpy(modname_str, modname, modnamelen);
+		modname_str[modnamelen] = '\0';
+	}
+
+	if (modname_str)
+		modname = modname_str;
+	else
+		modname = mod->name;
+	mod->builtin_name = modname;
+
 	/* Handle all-NULL symbols allocated into .bss */
 	if (info->sechdrs[get_secindex(info, sym)].sh_type & SHT_NOBITS) {
 		zeros = calloc(1, sym->st_size);
@@ -1597,6 +1623,9 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
 		}
 	}
 	free(zeros);
+	mod->builtin_name = NULL;
+	if (modname_str)
+		free(modname_str);
 }
 
 /* Now add out buffered information to the generated C source */
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 1178f40a73f3d..34fe5fc0b02cb 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -128,6 +128,7 @@ struct module {
 	struct list_head missing_namespaces;
 	// Actual imported namespaces
 	struct list_head imported_namespaces;
+	const char *builtin_name;
 	char name[];
 };
 
-- 
2.37.3