Fix kernel module loading on ia64. Cross-module function calls

were improperly relocated due to faulty logic in lookup_fdesc()
in elf_machdep.c. The symbol index (symidx) was bogusly used for
load modules other than the one the relocation applied to. This
resulted in bogus bindings and consequently runtime failures.

The fix is to use the symbol index only for the module being
relocated and to use the symbol name for look-ups in the
modules in the dependent list. As such, we need a function to
return the symbol name given the linker file and symbol index.

sys/ia64/ia64/elf_machdep.c

@@ -95,18 +95,25 @@ extern Elf_Addr fptr_storage[];
 static Elf_Addr
 lookup_fdesc(linker_file_t lf, Elf_Word symidx)
 {
+	linker_file_t top;
 	Elf_Addr addr;
+	const char *symname;
 	int i;
 	static int eot = 0;
 
 	addr = elf_lookup(lf, symidx, 0);
 	if (addr == 0) {
-		for (i = 0; i < lf->ndeps; i++) {
-			addr = lookup_fdesc(lf->deps[i], symidx);
+		top = lf;
+		symname = elf_get_symname(top, symidx);
+		for (i = 0; i < top->ndeps; i++) {
+			lf = top->deps[i];
+			addr = (Elf_Addr)linker_file_lookup_symbol(lf,
+			    symname, 0);
 			if (addr != 0)
-				return (addr);
+				break;
 		}
-		return (0);
+		if (addr == 0)
+			return (0);
 	}
 
 	if (eot)

sys/kern/link_elf.c

@@ -1198,6 +1198,18 @@ elf_get_sym(linker_file_t lf, Elf_Word symidx)
 	return (ef->symtab + symidx);
 }
 
+const char *
+elf_get_symname(linker_file_t lf, Elf_Word symidx)
+{
+	elf_file_t ef = (elf_file_t)lf;
+	const Elf_Sym *sym;
+
+	if (symidx >= ef->nchains)
+		return (NULL);
+	sym = ef->symtab + symidx;
+	return (ef->strtab + sym->st_name);
+}
+
 /*
  * Symbol lookup function that can be used when the symbol index is known (ie
  * in relocations). It uses the symbol index instead of doing a fully fledged

sys/kern/link_elf_obj.c

@@ -1198,6 +1198,18 @@ elf_get_sym(linker_file_t lf, Elf_Word symidx)
 	return (ef->symtab + symidx);
 }
 
+const char *
+elf_get_symname(linker_file_t lf, Elf_Word symidx)
+{
+	elf_file_t ef = (elf_file_t)lf;
+	const Elf_Sym *sym;
+
+	if (symidx >= ef->nchains)
+		return (NULL);
+	sym = ef->symtab + symidx;
+	return (ef->strtab + sym->st_name);
+}
+
 /*
  * Symbol lookup function that can be used when the symbol index is known (ie
  * in relocations). It uses the symbol index instead of doing a fully fledged

sys/sys/linker.h

@@ -231,6 +231,7 @@ extern int kld_debug;
 int	elf_reloc(linker_file_t _lf, const void *_rel, int _type);
 Elf_Addr elf_lookup(linker_file_t, Elf_Word, int);
 const Elf_Sym *elf_get_sym(linker_file_t _lf, Elf_Word _symidx);
+const char *elf_get_symname(linker_file_t _lf, Elf_Word _symidx);
 
 /* values for type */
 #define ELF_RELOC_REL	1