[MODULES] Centralize undefined symbol checks; handle undef weak.

arch/alpha/kernel/module.c

@@ -190,15 +190,10 @@ apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab,
 		/* This is where to make the change.  */
 		location = base + rela[i].r_offset;
 
-		/* This is the symbol it is referring to.  */
+		/* This is the symbol it is referring to.  Note that all
+		   unresolved symbols have been resolved.  */
 		sym = symtab + r_sym;
-		value = sym->st_value;
-		if (!value) {
-			printk(KERN_ERR "module %s: Unknown symbol %s\n",
-			       me->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
-		value += rela[i].r_addend;
+		value = sym->st_value + rela[i].r_addend;
 
 		switch (r_type) {
 		case R_ALPHA_NONE:

arch/arm/kernel/module.c

@@ -98,11 +98,6 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 		}
 
 		sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
-		if (!sym->st_value) {
-			printk(KERN_WARNING "%s: unknown symbol %s\n",
-				module->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
 
 		if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
 			printk(KERN_ERR "%s: out of bounds relocation, "

arch/i386/kernel/module.c

@@ -70,14 +70,10 @@ int apply_relocate(Elf32_Shdr *sechdrs,
 		/* This is where to make the change */
 		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			+ rel[i].r_offset;
-		/* This is the symbol it is referring to */
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
 		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 			+ ELF32_R_SYM(rel[i].r_info);
-		if (!sym->st_value) {
-			printk(KERN_WARNING "%s: Unknown symbol %s\n",
-			       me->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
 
 		switch (ELF32_R_TYPE(rel[i].r_info)) {
 		case R_386_32:

arch/ppc/kernel/module.c

@@ -197,14 +197,10 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
 		/* This is where to make the change */
 		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			+ rela[i].r_offset;
-		/* This is the symbol it is referring to */
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
 		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 			+ ELF32_R_SYM(rela[i].r_info);
-		if (!sym->st_value) {
-			printk(KERN_WARNING "%s: Unknown symbol %s\n",
-			       module->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
 		/* `Everything is relative'. */
 		value = sym->st_value + rela[i].r_addend;
 

arch/s390/kernel/module.c

 /*
- *  arch/s390x/kernel/module.c - Kernel module help for s390x.
+ *  arch/s390/kernel/module.c - Kernel module help for s390.
  *
  *  S390 version
  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
@@ -77,14 +77,10 @@ int apply_relocate(Elf_Shdr *sechdrs,
 		/* This is where to make the change */
 		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			+ rel[i].r_offset;
-		/* This is the symbol it is referring to */
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
 		sym = (ElfW(Sym) *)sechdrs[symindex].sh_addr
 			+ ELFW(R_SYM)(rel[i].r_info);
-		if (!sym->st_value) {
-			printk(KERN_WARNING "%s: Unknown symbol %s\n",
-			       me->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
 
 		switch (ELF_R_TYPE(rel[i].r_info)) {
 		case R_390_8:		/* Direct 8 bit.   */

arch/s390x/kernel/module.c

@@ -78,14 +78,10 @@ int apply_relocate(Elf_Shdr *sechdrs,
 		/* This is where to make the change */
 		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			+ rel[i].r_offset;
-		/* This is the symbol it is referring to */
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
 		sym = (ElfW(Sym) *)sechdrs[symindex].sh_addr
 			+ ELFW(R_SYM)(rel[i].r_info);
-		if (!sym->st_value) {
-			printk(KERN_WARNING "%s: Unknown symbol %s\n",
-			       me->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
 
 		switch (ELF_R_TYPE(rel[i].r_info)) {
 		case R_390_8:		/* Direct 8 bit.   */

arch/sparc/kernel/module.c

@@ -75,15 +75,11 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
 		location = (u8 *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			+ rel[i].r_offset;
 		loc32 = (u32 *) location;
-		/* This is the symbol it is referring to */
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
 		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 			+ ELF32_R_SYM(rel[i].r_info);
-		if (!(v = sym->st_value)) {
-			printk(KERN_WARNING "%s: Unknown symbol %s\n",
-			       me->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
-		v += rel[i].r_addend;
+		v = sym->st_value + rel[i].r_addend;
 
 		switch (ELF32_R_TYPE(rel[i].r_info)) {
 		case R_SPARC_32:

arch/sparc64/kernel/module.c

@@ -185,15 +185,11 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
 
 		BUG_ON(((u64)location >> (u64)32) != (u64)0);
 
-		/* This is the symbol it is referring to */
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
 		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
 			+ ELF64_R_SYM(rel[i].r_info);
-		if (!(v = sym->st_value)) {
-			printk(KERN_WARNING "%s: Unknown symbol %s\n",
-			       me->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
-		v += rel[i].r_addend;
+		v = sym->st_value + rel[i].r_addend;
 
 		switch (ELF64_R_TYPE(rel[i].r_info) & 0xff) {
 		case R_SPARC_64:

arch/v850/kernel/module.c

@@ -184,19 +184,12 @@ int apply_relocate_add (Elf32_Shdr *sechdrs, const char *strtab,
 		uint32_t *loc
 			= ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			   + rela[i].r_offset);
-		/* This is the symbol it is referring to */
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
 		Elf32_Sym *sym
 			= ((Elf32_Sym *)sechdrs[symindex].sh_addr
 			   + ELF32_R_SYM (rela[i].r_info));
-		uint32_t val = sym->st_value;
-
-		if (! val) {
-			printk (KERN_WARNING "%s: Unknown symbol %s\n",
-				mod->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
-
-		val += rela[i].r_addend;
+		uint32_t val = sym->st_value + rela[i].r_addend;
 
 		switch (ELF32_R_TYPE (rela[i].r_info)) {
 		case R_V850_32:

arch/x86_64/kernel/module.c

@@ -53,14 +53,10 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
 		loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			+ rel[i].r_offset;
 
-		/* This is the symbol it is referring to */
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
 		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
 			+ ELF64_R_SYM(rel[i].r_info);
-		if (!sym->st_value) {
-			printk(KERN_WARNING "%s: Unknown symbol %s\n",
-			       me->name, strtab + sym->st_name);
-			return -ENOENT;
-		}
 
 	        DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
 		       (int)ELF64_R_TYPE(rel[i].r_info), 

include/linux/elf.h

@@ -156,11 +156,12 @@ typedef __s64	Elf64_Sxword;
 #define STT_SECTION 3
 #define STT_FILE    4
 
-#define ELF32_ST_BIND(x) ((x) >> 4)
-#define ELF32_ST_TYPE(x) (((unsigned int) x) & 0xf)
-
-#define ELF64_ST_BIND(x) ((x) >> 4)
-#define ELF64_ST_TYPE(x) (((unsigned int) x) & 0xf)
+#define ELF_ST_BIND(x)		((x) >> 4)
+#define ELF_ST_TYPE(x)		(((unsigned int) x) & 0xf)
+#define ELF32_ST_BIND(x)	ELF_ST_BIND(x)
+#define ELF32_ST_TYPE(x)	ELF_ST_TYPE(x)
+#define ELF64_ST_BIND(x)	ELF_ST_BIND(x)
+#define ELF64_ST_TYPE(x)	ELF_ST_TYPE(x)
 
 /* Symbolic values for the entries in the auxiliary table
    put on the initial stack */

include/linux/moduleloader.h

@@ -5,14 +5,6 @@
 #include <linux/module.h>
 #include <linux/elf.h>
 
-/* Helper function for arch-specific module loaders */
-unsigned long find_symbol_internal(Elf_Shdr *sechdrs,
-				   unsigned int symindex,
-				   const char *strtab,
-				   const char *name,
-				   struct module *mod,
-				   struct kernel_symbol_group **group);
-
 /* These must be implemented by the specific architecture */
 
 /* Adjust arch-specific sections.  Return 0 on success.  */

kernel/module.c

@@ -722,28 +722,22 @@ static int obsolete_params(const char *name,
 }
 #endif /* CONFIG_OBSOLETE_MODPARM */
 
-/* Find an symbol for this module (ie. resolve internals first).
-   It we find one, record usage.  Must be holding module_mutex. */
-unsigned long find_symbol_internal(Elf_Shdr *sechdrs,
-				   unsigned int symindex,
-				   const char *strtab,
-				   const char *name,
-				   struct module *mod,
-				   struct kernel_symbol_group **ksg)
+/* Resolve a symbol for this module.  I.e. if we find one, record usage.
+   Must be holding module_mutex. */
+static unsigned long resolve_symbol(Elf_Shdr *sechdrs,
+				    unsigned int symindex,
+				    const char *strtab,
+				    const char *name,
+				    struct module *mod)
 {
+	struct kernel_symbol_group *ksg;
 	unsigned long ret;
 
-	ret = find_local_symbol(sechdrs, symindex, strtab, name);
-	if (ret) {
-		*ksg = NULL;
-		return ret;
-	}
-	/* Look in other modules... */
 	spin_lock_irq(&modlist_lock);
-	ret = __find_symbol(name, ksg, mod->license_gplok);
+	ret = __find_symbol(name, &ksg, mod->license_gplok);
 	if (ret) {
 		/* This can fail due to OOM, or module unloading */
-		if (!use_module(mod, (*ksg)->owner))
+		if (!use_module(mod, ksg->owner))
 			ret = 0;
 	}
 	spin_unlock_irq(&modlist_lock);
@@ -832,21 +826,19 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
 			    unsigned int strindex,
 			    struct module *mod)
 {
-	unsigned int i;
-	Elf_Sym *sym;
-
-	/* First simplify defined symbols, so if they become the
-           "answer" to undefined symbols, copying their st_value us
-           correct. */
-	for (sym = (void *)sechdrs[symindex].sh_addr, i = 0;
-	     i < sechdrs[symindex].sh_size / sizeof(Elf_Sym);
-	     i++) {
+	Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
+	const char *strtab = (char *)sechdrs[strindex].sh_addr;
+	unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
+	int ret = 0;
+
+	for (i = 1; i < n; i++) {
 		switch (sym[i].st_shndx) {
 		case SHN_COMMON:
 			/* We compiled with -fno-common.  These are not
 			   supposed to happen.  */
 			DEBUGP("Common symbol: %s\n", strtab + sym[i].st_name);
-			return -ENOEXEC;
+			ret = -ENOEXEC;
+			break;
 
 		case SHN_ABS:
 			/* Don't need to do anything */
@@ -855,6 +847,20 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
 			break;
 
 		case SHN_UNDEF:
+			sym[i].st_value
+			  = resolve_symbol(sechdrs, symindex, strtab,
+					   strtab + sym[i].st_name, mod);
+
+			/* Ok if resolved.  */
+			if (sym[i].st_value != 0)
+				break;
+			/* Ok if weak.  */
+			if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
+				break;
+
+			printk(KERN_WARNING "%s: Unknown symbol %s\n",
+			       mod->name, strtab + sym[i].st_name);
+			ret = -ENOENT;
 			break;
 
 		default:
@@ -862,30 +868,11 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
 				= (unsigned long)
 				(sechdrs[sym[i].st_shndx].sh_addr
 				 + sym[i].st_value);
+			break;
 		}
 	}
 
-	/* Now try to resolve undefined symbols */
-	for (sym = (void *)sechdrs[symindex].sh_addr, i = 0;
-	     i < sechdrs[symindex].sh_size / sizeof(Elf_Sym);
-	     i++) {
-		if (sym[i].st_shndx == SHN_UNDEF) {
-			/* Look for symbol */
-			struct kernel_symbol_group *ksg = NULL;
-			const char *strtab 
-				= (char *)sechdrs[strindex].sh_addr;
-
-			sym[i].st_value
-				= find_symbol_internal(sechdrs,
-						       symindex,
-						       strtab,
-						       strtab + sym[i].st_name,
-						       mod,
-						       &ksg);
-		}
-	}
-
-	return 0;
+	return ret;
 }
 
 /* Update size with this section: return offset. */