kbuild: code refactoring in modpost

Split a too long function up in smaller bits to make
prgram logic easier to follow.
A few related changes done due to parameter
changes.

No functional changes.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/mod/modpost.c

@@ -937,19 +937,19 @@ static void warn_sec_mismatch(const char *modname, const char *fromsec,
 }
 
 static unsigned int *reloc_location(struct elf_info *elf,
-					   int rsection, Elf_Rela *r)
+				    Elf_Shdr *sechdr, Elf_Rela *r)
 {
 	Elf_Shdr *sechdrs = elf->sechdrs;
-	int section = sechdrs[rsection].sh_info;
+	int section = sechdr->sh_info;
 
 	return (void *)elf->hdr + sechdrs[section].sh_offset +
 		(r->r_offset - sechdrs[section].sh_addr);
 }
 
-static int addend_386_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
+static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
 {
 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
-	unsigned int *location = reloc_location(elf, rsection, r);
+	unsigned int *location = reloc_location(elf, sechdr, r);
 
 	switch (r_typ) {
 	case R_386_32:
@@ -965,7 +965,7 @@ static int addend_386_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
 	return 0;
 }
 
-static int addend_arm_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
+static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
 {
 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
 
@@ -978,8 +978,8 @@ static int addend_arm_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
 	case R_ARM_PC24:
 		/* From ARM ABI: ((S + A) | T) - P */
 		r->r_addend = (int)(long)(elf->hdr +
-		              elf->sechdrs[rsection].sh_offset +
-		              (r->r_offset - elf->sechdrs[rsection].sh_addr));
+		              sechdr->sh_offset +
+		              (r->r_offset - sechdr->sh_addr));
 		break;
 	default:
 		return 1;
@@ -987,10 +987,10 @@ static int addend_arm_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
 	return 0;
 }
 
-static int addend_mips_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
+static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
 {
 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
-	unsigned int *location = reloc_location(elf, rsection, r);
+	unsigned int *location = reloc_location(elf, sechdr, r);
 	unsigned int inst;
 
 	if (r_typ == R_MIPS_HI16)
@@ -1010,44 +1010,29 @@ static int addend_mips_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
 	return 0;
 }
 
-/**
- * A module includes a number of sections that are discarded
- * either when loaded or when used as built-in.
- * For loaded modules all functions marked __init and all data
- * marked __initdata will be discarded when the module has been intialized.
- * Likewise for modules used built-in the sections marked __exit
- * are discarded because __exit marked function are supposed to be called
- * only when a moduel is unloaded which never happes for built-in modules.
- * The check_sec_ref() function traverses all relocation records
- * to find all references to a section that reference a section that will
- * be discarded and warns about it.
- **/
-static void check_sec_ref(struct module *mod, const char *modname,
-			  struct elf_info *elf,
-			  int section(const char *),
+static void section_rela(const char *modname, struct elf_info *elf,
+                         Elf_Shdr *sechdr, int section(const char *),
                          int section_ref_ok(const char *))
 {
-	int i;
 	Elf_Sym  *sym;
+	Elf_Rela *rela;
+	Elf_Rela r;
+	unsigned int r_sym;
+	const char *fromsec;
+	const char * tosec;
+
 	Elf_Ehdr *hdr = elf->hdr;
-	Elf_Shdr *sechdrs = elf->sechdrs;
+	Elf_Rela *start = (void *)hdr + sechdr->sh_offset;
+	Elf_Rela *stop  = (void *)start + sechdr->sh_size;
+
 	const char *secstrings = (void *)hdr +
-				 sechdrs[hdr->e_shstrndx].sh_offset;
+				 elf->sechdrs[hdr->e_shstrndx].sh_offset;
 
-	/* Walk through all sections */
-	for (i = 0; i < hdr->e_shnum; i++) {
-		const char *name = secstrings + sechdrs[i].sh_name;
-		const char *secname;
-		Elf_Rela r;
-		unsigned int r_sym;
-		/* We want to process only relocation sections and not .init */
-		if (sechdrs[i].sh_type == SHT_RELA) {
-			Elf_Rela *rela;
-			Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
-			Elf_Rela *stop  = (void *)start + sechdrs[i].sh_size;
-			name += strlen(".rela");
-			if (section_ref_ok(name))
-				continue;
+	fromsec = secstrings + sechdr->sh_name;
+	fromsec += strlen(".rela");
+	/* if from section (name) is know good then skip it */
+	if (section_ref_ok(fromsec))
+		return;
 
 	for (rela = start; rela < stop; rela++) {
 		r.r_offset = TO_NATIVE(rela->r_offset);
@@ -1072,19 +1057,36 @@ static void check_sec_ref(struct module *mod, const char *modname,
 		if (sym->st_shndx >= SHN_LORESERVE)
 			continue;
 
-				secname = secstrings +
-					sechdrs[sym->st_shndx].sh_name;
-				if (section(secname))
-					warn_sec_mismatch(modname, name,
-							  elf, sym, r);
+		tosec = secstrings +
+			elf->sechdrs[sym->st_shndx].sh_name;
+		if (section(tosec))
+			warn_sec_mismatch(modname, fromsec, elf, sym, r);
 	}
-		} else if (sechdrs[i].sh_type == SHT_REL) {
+}
+
+static void section_rel(const char *modname, struct elf_info *elf,
+                        Elf_Shdr *sechdr, int section(const char *),
+                        int section_ref_ok(const char *))
+{
+	Elf_Sym *sym;
 	Elf_Rel *rel;
-			Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
-			Elf_Rel *stop  = (void *)start + sechdrs[i].sh_size;
-			name += strlen(".rel");
-			if (section_ref_ok(name))
-				continue;
+	Elf_Rela r;
+	unsigned int r_sym;
+	const char *fromsec;
+	const char * tosec;
+
+	Elf_Ehdr *hdr = elf->hdr;
+	Elf_Rel *start = (void *)hdr + sechdr->sh_offset;
+	Elf_Rel *stop  = (void *)start + sechdr->sh_size;
+
+	const char *secstrings = (void *)hdr +
+				 elf->sechdrs[hdr->e_shstrndx].sh_offset;
+
+	fromsec = secstrings + sechdr->sh_name;
+	fromsec += strlen(".rel");
+	/* if from section (name) is know good then skip it */
+	if (section_ref_ok(fromsec))
+		return;
 
 	for (rel = start; rel < stop; rel++) {
 		r.r_offset = TO_NATIVE(rel->r_offset);
@@ -1106,15 +1108,15 @@ static void check_sec_ref(struct module *mod, const char *modname,
 		r.r_addend = 0;
 		switch (hdr->e_machine) {
 		case EM_386:
-					if (addend_386_rel(elf, i, &r))
+			if (addend_386_rel(elf, sechdr, &r))
 				continue;
 			break;
 		case EM_ARM:
-					if (addend_arm_rel(elf, i, &r))
+			if (addend_arm_rel(elf, sechdr, &r))
 				continue;
 			break;
 		case EM_MIPS:
-					if (addend_mips_rel(elf, i, &r))
+			if (addend_mips_rel(elf, sechdr, &r))
 				continue;
 			break;
 		}
@@ -1123,13 +1125,43 @@ static void check_sec_ref(struct module *mod, const char *modname,
 		if (sym->st_shndx >= SHN_LORESERVE)
 			continue;
 
-				secname = secstrings +
-					sechdrs[sym->st_shndx].sh_name;
-				if (section(secname))
-					warn_sec_mismatch(modname, name,
-							  elf, sym, r);
-			}
+		tosec = secstrings +
+			elf->sechdrs[sym->st_shndx].sh_name;
+		if (section(tosec))
+			warn_sec_mismatch(modname, fromsec, elf, sym, r);
 	}
+}
+
+/**
+ * A module includes a number of sections that are discarded
+ * either when loaded or when used as built-in.
+ * For loaded modules all functions marked __init and all data
+ * marked __initdata will be discarded when the module has been intialized.
+ * Likewise for modules used built-in the sections marked __exit
+ * are discarded because __exit marked function are supposed to be called
+ * only when a moduel is unloaded which never happes for built-in modules.
+ * The check_sec_ref() function traverses all relocation records
+ * to find all references to a section that reference a section that will
+ * be discarded and warns about it.
+ **/
+static void check_sec_ref(struct module *mod, const char *modname,
+			  struct elf_info *elf,
+			  int section(const char *),
+			  int section_ref_ok(const char *))
+{
+	int i;
+	Elf_Ehdr *hdr = elf->hdr;
+	Elf_Shdr *sechdrs = elf->sechdrs;
+
+	/* Walk through all sections */
+	for (i = 0; i < hdr->e_shnum; i++) {
+		/* We want to process only relocation sections and not .init */
+		if (sechdrs[i].sh_type == SHT_RELA)
+			section_rela(modname, elf, &elf->sechdrs[i],
+			             section, section_ref_ok);
+		else if (sechdrs[i].sh_type == SHT_REL)
+			section_rel(modname, elf, &elf->sechdrs[i],
+			            section, section_ref_ok);
 	}
 }