ARM: module: clean up handling of ELF unwind tables

There's no need to keep pointers to the ELF sections available while
the module is loaded - we only need the section pointers while we're
finding and registering the unwind tables, which can all be done during
the finalize stage of loading.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h
index cbb0bc2..12c8e68 100644 (file)
--- a/arch/arm/include/asm/module.h
+++ b/arch/arm/include/asm/module.h
@@ -8,11 +8,6 @@
 struct unwind_table;
 
 #ifdef CONFIG_ARM_UNWIND
-struct arm_unwind_mapping {
-       Elf_Shdr *unw_sec;
-       Elf_Shdr *sec_text;
-       struct unwind_table *unwind;
-};
 enum {
        ARM_SEC_INIT,
        ARM_SEC_DEVINIT,
@@ -21,13 +16,13 @@ enum {
        ARM_SEC_DEVEXIT,
        ARM_SEC_MAX,
 };
+#endif
+
 struct mod_arch_specific {
-       struct arm_unwind_mapping map[ARM_SEC_MAX];
-};
-#else
-struct mod_arch_specific {
-};
+#ifdef CONFIG_ARM_UNWIND
+       struct unwind_table *unwind[ARM_SEC_MAX];
 #endif
+};
 
 /*
  * Include the ARM architecture version.

diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index d9bd786..f9937c4 100644 (file)
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -67,35 +67,6 @@ int module_frob_arch_sections(Elf_Ehdr *hdr,
                              char *secstrings,
                              struct module *mod)
 {
-#ifdef CONFIG_ARM_UNWIND
-       Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
-       struct arm_unwind_mapping *maps = mod->arch.map;
-
-       for (s = sechdrs; s < sechdrs_end; s++) {
-               char const *secname = secstrings + s->sh_name;
-
-               if (strcmp(".ARM.exidx.init.text", secname) == 0)
-                       maps[ARM_SEC_INIT].unw_sec = s;
-               else if (strcmp(".ARM.exidx.devinit.text", secname) == 0)
-                       maps[ARM_SEC_DEVINIT].unw_sec = s;
-               else if (strcmp(".ARM.exidx", secname) == 0)
-                       maps[ARM_SEC_CORE].unw_sec = s;
-               else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
-                       maps[ARM_SEC_EXIT].unw_sec = s;
-               else if (strcmp(".ARM.exidx.devexit.text", secname) == 0)
-                       maps[ARM_SEC_DEVEXIT].unw_sec = s;
-               else if (strcmp(".init.text", secname) == 0)
-                       maps[ARM_SEC_INIT].sec_text = s;
-               else if (strcmp(".devinit.text", secname) == 0)
-                       maps[ARM_SEC_DEVINIT].sec_text = s;
-               else if (strcmp(".text", secname) == 0)
-                       maps[ARM_SEC_CORE].sec_text = s;
-               else if (strcmp(".exit.text", secname) == 0)
-                       maps[ARM_SEC_EXIT].sec_text = s;
-               else if (strcmp(".devexit.text", secname) == 0)
-                       maps[ARM_SEC_DEVEXIT].sec_text = s;
-       }
-#endif
        return 0;
 }
 
@@ -300,41 +271,66 @@ apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
        return -ENOEXEC;
 }
 
-#ifdef CONFIG_ARM_UNWIND
-static void register_unwind_tables(struct module *mod)
+struct mod_unwind_map {
+       const Elf_Shdr *unw_sec;
+       const Elf_Shdr *txt_sec;
+};
+
+int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
+                   struct module *mod)
 {
+#ifdef CONFIG_ARM_UNWIND
+       const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+       const Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
+       struct mod_unwind_map maps[ARM_SEC_MAX];
        int i;
-       for (i = 0; i < ARM_SEC_MAX; ++i) {
-               struct arm_unwind_mapping *map = &mod->arch.map[i];
-               if (map->unw_sec && map->sec_text)
-                       map->unwind = unwind_table_add(map->unw_sec->sh_addr,
-                                                      map->unw_sec->sh_size,
-                                                      map->sec_text->sh_addr,
-                                                      map->sec_text->sh_size);
+
+       memset(maps, 0, sizeof(maps));
+
+       for (s = sechdrs; s < sechdrs_end; s++) {
+               const char *secname = secstrs + s->sh_name;
+
+               if (strcmp(".ARM.exidx.init.text", secname) == 0)
+                       maps[ARM_SEC_INIT].unw_sec = s;
+               else if (strcmp(".ARM.exidx.devinit.text", secname) == 0)
+                       maps[ARM_SEC_DEVINIT].unw_sec = s;
+               else if (strcmp(".ARM.exidx", secname) == 0)
+                       maps[ARM_SEC_CORE].unw_sec = s;
+               else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
+                       maps[ARM_SEC_EXIT].unw_sec = s;
+               else if (strcmp(".ARM.exidx.devexit.text", secname) == 0)
+                       maps[ARM_SEC_DEVEXIT].unw_sec = s;
+               else if (strcmp(".init.text", secname) == 0)
+                       maps[ARM_SEC_INIT].txt_sec = s;
+               else if (strcmp(".devinit.text", secname) == 0)
+                       maps[ARM_SEC_DEVINIT].txt_sec = s;
+               else if (strcmp(".text", secname) == 0)
+                       maps[ARM_SEC_CORE].txt_sec = s;
+               else if (strcmp(".exit.text", secname) == 0)
+                       maps[ARM_SEC_EXIT].txt_sec = s;
+               else if (strcmp(".devexit.text", secname) == 0)
+                       maps[ARM_SEC_DEVEXIT].txt_sec = s;
        }
-}
 
-static void unregister_unwind_tables(struct module *mod)
-{
-       int i = ARM_SEC_MAX;
-       while (--i >= 0)
-               unwind_table_del(mod->arch.map[i].unwind);
-}
-#else
-static inline void register_unwind_tables(struct module *mod) { }
-static inline void unregister_unwind_tables(struct module *mod) { }
+       for (i = 0; i < ARM_SEC_MAX; i++)
+               if (maps[i].unw_sec && maps[i].txt_sec)
+                       mod->arch.unwind[i] =
+                               unwind_table_add(maps[i].unw_sec->sh_addr,
+                                                maps[i].unw_sec->sh_size,
+                                                maps[i].txt_sec->sh_addr,
+                                                maps[i].txt_sec->sh_size);
 #endif
-
-int
-module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
-               struct module *module)
-{
-       register_unwind_tables(module);
        return 0;
 }
 
 void
 module_arch_cleanup(struct module *mod)
 {
-       unregister_unwind_tables(mod);
+#ifdef CONFIG_ARM_UNWIND
+       int i;
+
+       for (i = 0; i < ARM_SEC_MAX; i++)
+               if (mod->arch.unwind[i])
+                       unwind_table_del(mod->arch.unwind[i]);
+#endif
 }