[src/trunk]: src/libexec/ld.elf_so/arch/mips It is possible for reloc entries...

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/a5bc431bbac4
branches:  trunk
changeset: 536403:a5bc431bbac4
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat Sep 14 23:53:21 2002 +0000

description:
It is possible for reloc entries to point to unaligned locations; handle
this.

diffstat:

 libexec/ld.elf_so/arch/mips/mips_reloc.c |  72 ++++++++++++++++++++++++++-----
 1 files changed, 59 insertions(+), 13 deletions(-)

diffs (127 lines):

diff -r 805a455ba7b6 -r a5bc431bbac4 libexec/ld.elf_so/arch/mips/mips_reloc.c
--- a/libexec/ld.elf_so/arch/mips/mips_reloc.c  Sat Sep 14 23:34:16 2002 +0000
+++ b/libexec/ld.elf_so/arch/mips/mips_reloc.c  Sat Sep 14 23:53:21 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mips_reloc.c,v 1.32 2002/09/13 20:32:24 mycroft Exp $  */
+/*     $NetBSD: mips_reloc.c,v 1.33 2002/09/14 23:53:21 thorpej Exp $  */
 
 /*
  * Copyright 1997 Michael L. Hitch <mhitch%montana.edu@localhost>
@@ -28,10 +28,9 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-
-#include <stdarg.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <string.h>
 
 #include "debug.h"
 #include "rtld.h"
@@ -145,6 +144,30 @@
        }
 }
 
+/*
+ * It is possible for the compiler to emit relocations for unaligned data.
+ * We handle this situation with these inlines.
+ */
+#define        RELOC_ALIGNED_P(x) \
+       (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
+
+static __inline Elf_Addr
+load_ptr(void *where)
+{
+       Elf_Addr res;
+
+       memcpy(&res, where, sizeof(res));
+
+       return (res);
+}
+
+static __inline void
+store_ptr(void *where, Elf_Addr val)
+{
+
+       memcpy(where, &val, sizeof(val));
+}
+
 int
 _rtld_relocate_nonplt_objects(obj, self)
        const Obj_Entry *obj;
@@ -160,7 +183,7 @@
                return 0;
 
        for (rel = obj->rel; rel < obj->rellim; rel++) {
-               Elf_Addr        *where;
+               Elf_Addr        *where, tmp;
                unsigned long    symnum;
 
                where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
@@ -197,25 +220,48 @@
                                 *
                                 * --rkb, Oct 6, 2001
                                 */
-                               if (def->st_info == STT_SECTION &&
-                                   *where < def->st_value)
-                                       *where += (Elf_Addr)def->st_value;
+                               if (__predict_true(RELOC_ALIGNED_P(where))) {
+                                       tmp = *where;
+
+                                       if (def->st_info == STT_SECTION &&
+                                           tmp < def->st_value)
+                                               tmp += (Elf_Addr)def->st_value;
 
-                               *where += (Elf_Addr)obj->relocbase;
+                                       tmp += (Elf_Addr)obj->relocbase;
+                                       *where = tmp;
+                               } else {
+                                       tmp = load_ptr(where);
+
+                                       if (def->st_info == STT_SECTION &&
+                                           tmp < def->st_value)
+                                               tmp += (Elf_Addr)def->st_value;
+                                       
+                                       tmp += (Elf_Addr)obj->relocbase;
+                                       store_ptr(where, tmp);
+                               }
 
                                rdbg(("REL32 %s in %s --> %p in %s",
                                    obj->strtab + def->st_name, obj->path,
-                                   (void *)*where, obj->path));
+                                   (void *)tmp, obj->path));
                        } else {
                                def = _rtld_find_symdef(symnum, obj, &defobj,
                                    false);
                                if (def == NULL)
                                        return -1;
-                               *where += (Elf_Addr)(defobj->relocbase +
-                                   def->st_value);
+                               if (__predict_true(RELOC_ALIGNED_P(where))) {
+                                       tmp = *where +
+                                           (Elf_Addr)(defobj->relocbase +
+                                                      def->st_value);
+                                       *where = tmp;
+                               } else {
+                                       tmp = load_ptr(where) +
+                                           (Elf_Addr)(defobj->relocbase +
+                                                      def->st_value);
+                                       store_ptr(where, tmp);
+                               }
                                rdbg(("REL32 %s in %s --> %p in %s",
                                    obj->strtab + obj->symtab[symnum].st_name,
-                                   obj->path, (void *)*where, defobj->path));
+                                   obj->path, (void *)tmp, defobj->path));
                        }
                        break;
 
@@ -223,7 +269,7 @@
                        rdbg(("sym = %lu, type = %lu, offset = %p, "
                            "contents = %p, symbol = %s",
                            symnum, (u_long)ELF_R_TYPE(rel->r_info),
-                           (void *)rel->r_offset, (void *)*where,
+                           (void *)rel->r_offset, (void *)load_ptr(where),
                            obj->strtab + obj->symtab[symnum].st_name));
                        _rtld_error("%s: Unsupported relocation type %ld "
                            "in non-PLT relocations\n",