[RFC PATCH 2/9] Ksplice: Add module_data_address (the analogue of module_text_address)

[Jeffrey Brian Arnold <jbarnold@MIT.EDU>]

From: Tim Abbott <tabbott@mit.edu>

Ksplice's run-pre matching process needs to be able to determine the
module that contains a particular data address.

Signed-off-by: Tim Abbott <tabbott@mit.edu>
---
 include/linux/module.h |    2 ++
 kernel/module.c        |   28 ++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 68e0955..b7cdfb4 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -362,6 +362,8 @@ static inline int module_is_live(struct module *mod)
 /* Is this address in a module? (second is with no locks, for oops) */
 struct module *module_text_address(unsigned long addr);
 struct module *__module_text_address(unsigned long addr);
+struct module *module_data_address(unsigned long addr);
+struct module *__module_data_address(unsigned long addr);
 int is_module_address(unsigned long addr);
 
 /* Returns 0 and fills in value, defined and namebuf, or -ERANGE if
diff --git a/kernel/module.c b/kernel/module.c
index 8954556..dda2f80 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2682,6 +2682,34 @@ struct module *module_text_address(unsigned long addr)
 	return mod;
 }
 
+struct module *__module_data_address(unsigned long addr)
+{
+	struct module *mod;
+
+	if (addr < module_addr_min || addr > module_addr_max)
+		return NULL;
+
+	list_for_each_entry(mod, &modules, list) {
+		if (within(addr, mod->module_core + mod->core_text_size,
+			   mod->core_size - mod->core_text_size) ||
+		    within(addr, mod->module_init + mod->init_text_size,
+			   mod->init_size - mod->init_text_size))
+			return mod;
+	}
+	return NULL;
+}
+
+struct module *module_data_address(unsigned long addr)
+{
+	struct module *mod;
+
+	preempt_disable();
+	mod = __module_data_address(addr);
+	preempt_enable();
+
+	return mod;
+}
+
 /* Don't grab lock, we're oopsing. */
 void print_modules(void)
 {
-- 
1.5.4.3