module: refactor load_module part 5

1) Extract out the relocation loop into apply_relocations
2) Extract license and version checks into check_module_license_and_versions
3) Extract icache flushing into flush_module_icache
4) Move __obsparm warning into find_module_sections
5) Move license setting into check_modinfo.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 106 insertions, 76 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 241bc41dd6be..b536db804ca0 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1698,6 +1698,39 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
         return ret;
 }
 
+static int apply_relocations(struct module *mod,
+                             Elf_Ehdr *hdr,
+                             Elf_Shdr *sechdrs,
+                             unsigned int symindex,
+                             unsigned int strindex)
+{
+        unsigned int i;
+        int err = 0;
+
+        /* Now do relocations. */
+        for (i = 1; i < hdr->e_shnum; i++) {
+                const char *strtab = (char *)sechdrs[strindex].sh_addr;
+                unsigned int info = sechdrs[i].sh_info;
+
+                /* Not a valid relocation section? */
+                if (info >= hdr->e_shnum)
+                        continue;
+
+                /* Don't bother with non-allocated sections */
+                if (!(sechdrs[info].sh_flags & SHF_ALLOC))
+                        continue;
+
+                if (sechdrs[i].sh_type == SHT_REL)
+                        err = apply_relocate(sechdrs, strtab, symindex, i, mod);
+                else if (sechdrs[i].sh_type == SHT_RELA)
+                        err = apply_relocate_add(sechdrs, strtab, symindex, i,
+                                                 mod);
+                if (err < 0)
+                        break;
+        }
+        return err;
+}
+
 /* Additional bytes needed by arch in front of individual sections */
 unsigned int __weak arch_mod_section_prepend(struct module *mod,
                                              unsigned int section)
@@ -2179,6 +2212,10 @@ static int check_modinfo(struct module *mod,
                        " the quality is unknown, you have been warned.\n",
                        mod->name);
         }
+
+        /* Set up license info based on the info section */
+        set_license(mod, get_modinfo(sechdrs, infoindex, "license"));
+
         return 0;
 }
 
@@ -2245,6 +2282,10 @@ static void find_module_sections(struct module *mod, Elf_Ehdr *hdr,
                                              sizeof(*mod->ftrace_callsites),
                                              &mod->num_ftrace_callsites);
 #endif
+
+        if (section_addr(hdr, sechdrs, secstrings, "__obsparm"))
+                printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
+                       mod->name);
 }
 
 static struct module *move_module(struct module *mod,
@@ -2311,6 +2352,60 @@ static struct module *move_module(struct module *mod,
         return mod;
 }
 
+static int check_module_license_and_versions(struct module *mod,
+                                             Elf_Shdr *sechdrs)
+{
+        /*
+         * ndiswrapper is under GPL by itself, but loads proprietary modules.
+         * Don't use add_taint_module(), as it would prevent ndiswrapper from
+         * using GPL-only symbols it needs.
+         */
+        if (strcmp(mod->name, "ndiswrapper") == 0)
+                add_taint(TAINT_PROPRIETARY_MODULE);
+
+        /* driverloader was caught wrongly pretending to be under GPL */
+        if (strcmp(mod->name, "driverloader") == 0)
+                add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+
+#ifdef CONFIG_MODVERSIONS
+        if ((mod->num_syms && !mod->crcs)
+            || (mod->num_gpl_syms && !mod->gpl_crcs)
+            || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
+#ifdef CONFIG_UNUSED_SYMBOLS
+            || (mod->num_unused_syms && !mod->unused_crcs)
+            || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
+#endif
+                ) {
+                return try_to_force_load(mod,
+                                         "no versions for exported symbols");
+        }
+#endif
+        return 0;
+}
+
+static void flush_module_icache(const struct module *mod)
+{
+        mm_segment_t old_fs;
+
+        /* flush the icache in correct context */
+        old_fs = get_fs();
+        set_fs(KERNEL_DS);
+
+        /*
+         * Flush the instruction cache, since we've played with text.
+         * Do it before processing of module parameters, so the module
+         * can provide parameter accessor functions of its own.
+         */
+        if (mod->module_init)
+                flush_icache_range((unsigned long)mod->module_init,
+                                   (unsigned long)mod->module_init
+                                   + mod->init_size);
+        flush_icache_range((unsigned long)mod->module_core,
+                           (unsigned long)mod->module_core + mod->core_size);
+
+        set_fs(old_fs);
+}
+
 /* Allocate and load the module: note that size of section 0 is always
    zero, and we rely on this for optional sections. */
 static noinline struct module *load_module(void __user *umod,
@@ -2331,8 +2426,6 @@ static noinline struct module *load_module(void __user *umod,
         struct _ddebug *debug = NULL;
         unsigned int num_debug = 0;
 
-        mm_segment_t old_fs;
-
         DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
                umod, len, uargs);
 
@@ -2453,20 +2546,13 @@ static noinline struct module *load_module(void __user *umod,
         if (err)
                 goto free_init;
 
-        /* Set up license info based on the info section */
-        set_license(mod, get_modinfo(sechdrs, infoindex, "license"));
-
-        /*
-         * ndiswrapper is under GPL by itself, but loads proprietary modules.
-         * Don't use add_taint_module(), as it would prevent ndiswrapper from
-         * using GPL-only symbols it needs.
-         */
-        if (strcmp(mod->name, "ndiswrapper") == 0)
-                add_taint(TAINT_PROPRIETARY_MODULE);
+        /* Now we've got everything in the final locations, we can
+         * find optional sections. */
+        find_module_sections(mod, hdr, sechdrs, secstrings);
 
-        /* driverloader was caught wrongly pretending to be under GPL */
-        if (strcmp(mod->name, "driverloader") == 0)
-                add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+        err = check_module_license_and_versions(mod, sechdrs);
+        if (err)
+                goto free_unload;
 
         /* Set up MODINFO_ATTR fields */
         setup_modinfo(mod, sechdrs, infoindex);
@@ -2477,47 +2563,9 @@ static noinline struct module *load_module(void __user *umod,
         if (err < 0)
                 goto cleanup;
 
-        /* Now we've got everything in the final locations, we can
-         * find optional sections. */
-        find_module_sections(mod, hdr, sechdrs, secstrings);
-
-#ifdef CONFIG_MODVERSIONS
-        if ((mod->num_syms && !mod->crcs)
-            || (mod->num_gpl_syms && !mod->gpl_crcs)
-            || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
-#ifdef CONFIG_UNUSED_SYMBOLS
-            || (mod->num_unused_syms && !mod->unused_crcs)
-            || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
-#endif
-                ) {
-                err = try_to_force_load(mod,
-                                        "no versions for exported symbols");
-                if (err)
-                        goto cleanup;
-        }
-#endif
-
-        /* Now do relocations. */
-        for (i = 1; i < hdr->e_shnum; i++) {
-                const char *strtab = (char *)sechdrs[strindex].sh_addr;
-                unsigned int info = sechdrs[i].sh_info;
-
-                /* Not a valid relocation section? */
-                if (info >= hdr->e_shnum)
-                        continue;
-
-                /* Don't bother with non-allocated sections */
-                if (!(sechdrs[info].sh_flags & SHF_ALLOC))
-                        continue;
-
-                if (sechdrs[i].sh_type == SHT_REL)
-                        err = apply_relocate(sechdrs, strtab, symindex, i,mod);
-                else if (sechdrs[i].sh_type == SHT_RELA)
-                        err = apply_relocate_add(sechdrs, strtab, symindex, i,
-                                                 mod);
-                if (err < 0)
-                        goto cleanup;
-        }
+        err = apply_relocations(mod, hdr, sechdrs, symindex, strindex);
+        if (err < 0)
+                goto cleanup;
 
         /* Set up and sort exception table */
         mod->extable = section_objs(hdr, sechdrs, secstrings, "__ex_table",
@@ -2541,28 +2589,9 @@ static noinline struct module *load_module(void __user *umod,
         if (err < 0)
                 goto cleanup;
 
-        /* flush the icache in correct context */
-        old_fs = get_fs();
-        set_fs(KERNEL_DS);
-
-        /*
-         * Flush the instruction cache, since we've played with text.
-         * Do it before processing of module parameters, so the module
-         * can provide parameter accessor functions of its own.
-         */
-        if (mod->module_init)
-                flush_icache_range((unsigned long)mod->module_init,
-                                   (unsigned long)mod->module_init
-                                   + mod->init_size);
-        flush_icache_range((unsigned long)mod->module_core,
-                           (unsigned long)mod->module_core + mod->core_size);
-
-        set_fs(old_fs);
+        flush_module_icache(mod);
 
         mod->args = args;
-        if (section_addr(hdr, sechdrs, secstrings, "__obsparm"))
-                printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
-                       mod->name);
 
         /* Now sew it into the lists so we can get lockdep and oops
          * info during argument parsing.  Noone should access us, since
@@ -2619,6 +2648,7 @@ static noinline struct module *load_module(void __user *umod,
         module_arch_cleanup(mod);
  cleanup:
         free_modinfo(mod);
+ free_unload:
         module_unload_free(mod);
  free_init:
         module_free(mod, mod->module_init);