From: Frantisek Hrbata <fhrbata@redhat.com>
Date: Mon, 14 Oct 2013 07:38:46 +0000 (+1030)
Subject: kernel: add support for init_array constructors
X-Git-Tag: firefly_0821_release~3680^2~19^2^2~1
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=eb05fc8193e9632a1910c2a2dedbcaf88a5a361f;p=firefly-linux-kernel-4.4.55.git

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 eb58d2d7d971..4b0f0121d0ab 100644
--- 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 cab4bce49c23..4cdf280c892b 100644
--- 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)