kbuild: include symbol names in section mismatch warnings

Try to look up the symbol that is referenced. Include the symbol
name in the warning message.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index eeaf574..844f84b 100644 (file)
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -451,6 +451,29 @@ static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
        return NULL;
 }
 
+/**
+ * Find symbol based on relocation record info.
+ * In some cases the symbol supplied is a valid symbol so
+ * return refsym. If st_name != 0 we assume this is a valid symbol.
+ * In other cases the symbol needs to be looked up in the symbol table
+ * based on section and address.
+ *  **/
+static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
+                               Elf_Sym *relsym)
+{
+       Elf_Sym *sym;
+
+       if (relsym->st_name != 0)
+               return relsym;
+       for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
+               if (sym->st_shndx != relsym->st_shndx)
+                       continue;
+               if (sym->st_value == addr)
+                       return sym;
+       }
+       return NULL;
+}
+
 /*
  * Find symbols before or equal addr and after addr - in the section sec
  **/
@@ -499,8 +522,9 @@ static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
 static void warn_sec_mismatch(const char *modname, const char *fromsec,
                              struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
 {
-       Elf_Sym *before;
-       Elf_Sym *after;
+       const char *refsymname = "";
+       Elf_Sym *before, *after;
+       Elf_Sym *refsym;
        Elf_Ehdr *hdr = elf->hdr;
        Elf_Shdr *sechdrs = elf->sechdrs;
        const char *secstrings = (void *)hdr +
@@ -509,29 +533,34 @@ static void warn_sec_mismatch(const char *modname, const char *fromsec,
        
        find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
 
+       refsym = find_elf_symbol(elf, r.r_addend, sym);
+       if (refsym && strlen(elf->strtab + refsym->st_name))
+               refsymname = elf->strtab + refsym->st_name;
+       
        if (before && after) {
-               warn("%s - Section mismatch: reference to %s from %s "
-                    "between '%s' (at offset 0x%lx) and '%s'\n",
-                    modname, secname, fromsec,
+               warn("%s - Section mismatch: reference to %s:%s from %s "
+                    "between '%s' (at offset 0x%llx) and '%s'\n",
+                    modname, secname, refsymname, fromsec,
                     elf->strtab + before->st_name,
-                    (long)(r.r_offset - before->st_value),
+                    (long long)r.r_offset,
                     elf->strtab + after->st_name);
        } else if (before) {
-               warn("%s - Section mismatch: reference to %s from %s "
-                    "after '%s' (at offset 0x%lx)\n",
-                    modname, secname, fromsec, 
+               warn("%s - Section mismatch: reference to %s:%s from %s "
+                    "after '%s' (at offset 0x%llx)\n",
+                    modname, secname, refsymname, fromsec, 
                     elf->strtab + before->st_name,
-                    (long)(r.r_offset - before->st_value));
+                    (long long)r.r_offset);
        } else if (after) {
-               warn("%s - Section mismatch: reference to %s from %s "
-                    "before '%s' (at offset -0x%lx)\n",
-                    modname, secname, fromsec, 
+               warn("%s - Section mismatch: reference to %s:%s from %s "
+                    "before '%s' (at offset -0x%llx)\n",
+                    modname, secname, refsymname, fromsec, 
                     elf->strtab + before->st_name,
-                    (long)(before->st_value - r.r_offset));
+                    (long long)r.r_offset);
        } else {
-               warn("%s - Section mismatch: reference to %s from %s "
-                    "(offset 0x%lx)\n",
-                    modname, secname, fromsec, (long)r.r_offset);
+               warn("%s - Section mismatch: reference to %s:%s from %s "
+                    "(offset 0x%llx)\n",
+                    modname, secname, fromsec, refsymname,
+                    (long long)r.r_offset);
        }
 }
 
@@ -575,6 +604,7 @@ static void check_sec_ref(struct module *mod, const char *modname,
                        const char *secname;
                        r.r_offset = TO_NATIVE(rela->r_offset);
                        r.r_info   = TO_NATIVE(rela->r_info);
+                       r.r_addend = TO_NATIVE(rela->r_addend);
                        sym = elf->symtab_start + ELF_R_SYM(r.r_info);
                        /* Skip special sections */
                        if (sym->st_shndx >= SHN_LORESERVE)