kernel: add support for init_array constructors

This adds the .init_array section as yet another section with constructors. This
is needed because gcc could add __gcov_init calls to .init_array or .ctors
section, depending on gcc (and binutils) version .

v2: - reuse mod->ctors for .init_array section for modules, because gcc uses
      .ctors or .init_array, but not both at the same time
v3: - fail to load if that does happen somehow.

Signed-off-by: Frantisek Hrbata <fhrbata@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index eb58d2d7d9718d0c220387b3c60febf30f324e71..4b0f0121d0ab9dbc78c781597dd3b5529c631e6c 100644 (file)
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -495,6 +495,7 @@
 #define KERNEL_CTORS() . = ALIGN(8);                      \
                        VMLINUX_SYMBOL(__ctors_start) = .; \
                        *(.ctors)                          \
+                       *(.init_array)                     \
                        VMLINUX_SYMBOL(__ctors_end) = .;
 #else
 #define KERNEL_CTORS()

diff --git a/kernel/module.c b/kernel/module.c
index cab4bce49c23dbe3779d02db8259dda28b7b4258..4cdf280c892bcecdc5ba00daf33c9cd029cbf7f2 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2723,7 +2723,7 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
        return 0;
 }
 
-static void find_module_sections(struct module *mod, struct load_info *info)
+static int find_module_sections(struct module *mod, struct load_info *info)
 {
        mod->kp = section_objs(info, "__param",
                               sizeof(*mod->kp), &mod->num_kp);
@@ -2753,6 +2753,18 @@ static void find_module_sections(struct module *mod, struct load_info *info)
 #ifdef CONFIG_CONSTRUCTORS
        mod->ctors = section_objs(info, ".ctors",
                                  sizeof(*mod->ctors), &mod->num_ctors);
+       if (!mod->ctors)
+               mod->ctors = section_objs(info, ".init_array",
+                               sizeof(*mod->ctors), &mod->num_ctors);
+       else if (find_sec(info, ".init_array")) {
+               /*
+                * This shouldn't happen with same compiler and binutils
+                * building all parts of the module.
+                */
+               printk(KERN_WARNING "%s: has both .ctors and .init_array.\n",
+                      mod->name);
+               return -EINVAL;
+       }
 #endif
 
 #ifdef CONFIG_TRACEPOINTS
@@ -2791,6 +2803,8 @@ static void find_module_sections(struct module *mod, struct load_info *info)
 
        info->debug = section_objs(info, "__verbose",
                                   sizeof(*info->debug), &info->num_debug);
+
+       return 0;
 }
 
 static int move_module(struct module *mod, struct load_info *info)
@@ -3244,7 +3258,9 @@ static int load_module(struct load_info *info, const char __user *uargs,
 
        /* Now we've got everything in the final locations, we can
         * find optional sections. */
-       find_module_sections(mod, info);
+       err = find_module_sections(mod, info);
+       if (err)
+               goto free_unload;
 
        err = check_module_license_and_versions(mod);
        if (err)