1 files changed, 78 insertions, 7 deletions

diff --git a/kernel/extable.c b/kernel/extable.c
index a26cb2e1702..d8a6446adbc 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -15,18 +15,36 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
+#include <linux/ftrace.h>
+#include <linux/memory.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/init.h>
-#include <asm/uaccess.h>
+
 #include <asm/sections.h>
+#include <asm/uaccess.h>
+
+/*
+ * mutex protecting text section modification (dynamic code patching).
+ * some users need to sleep (allocating memory...) while they hold this lock.
+ *
+ * NOT exported to modules - patching kernel text is a really delicate matter.
+ */
+DEFINE_MUTEX(text_mutex);
 
 extern struct exception_table_entry __start___ex_table[];
 extern struct exception_table_entry __stop___ex_table[];
 
+/* Cleared by build time tools if the table is already sorted. */
+u32 __initdata __visible main_extable_sort_needed = 1;
+
 /* Sort the kernel's built-in exception table */
 void __init sort_main_extable(void)
 {
-	sort_extable(__start___ex_table, __stop___ex_table);
+	if (main_extable_sort_needed && __stop___ex_table > __start___ex_table) {
+		pr_notice("Sorting __ex_table...\n");
+		sort_extable(__start___ex_table, __stop___ex_table);
+	}
 }
 
 /* Given an address, look for it in the exception tables. */
@@ -40,15 +58,40 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr)
 	return e;
 }
 
+static inline int init_kernel_text(unsigned long addr)
+{
+	if (addr >= (unsigned long)_sinittext &&
+	    addr < (unsigned long)_einittext)
+		return 1;
+	return 0;
+}
+
 int core_kernel_text(unsigned long addr)
 {
 	if (addr >= (unsigned long)_stext &&
-	    addr <= (unsigned long)_etext)
+	    addr < (unsigned long)_etext)
 		return 1;
 
 	if (system_state == SYSTEM_BOOTING &&
-	    addr >= (unsigned long)_sinittext &&
-	    addr <= (unsigned long)_einittext)
+	    init_kernel_text(addr))
+		return 1;
+	return 0;
+}
+
+/**
+ * core_kernel_data - tell if addr points to kernel data
+ * @addr: address to test
+ *
+ * Returns true if @addr passed in is from the core kernel data
+ * section.
+ *
+ * Note: On some archs it may return true for core RODATA, and false
+ *  for others. But will always be true for core RW data.
+ */
+int core_kernel_data(unsigned long addr)
+{
+	if (addr >= (unsigned long)_sdata &&
+	    addr < (unsigned long)_edata)
 		return 1;
 	return 0;
 }
@@ -57,12 +100,40 @@ int __kernel_text_address(unsigned long addr)
 {
 	if (core_kernel_text(addr))
 		return 1;
-	return __module_text_address(addr) != NULL;
+	if (is_module_text_address(addr))
+		return 1;
+	/*
+	 * There might be init symbols in saved stacktraces.
+	 * Give those symbols a chance to be printed in
+	 * backtraces (such as lockdep traces).
+	 *
+	 * Since we are after the module-symbols check, there's
+	 * no danger of address overlap:
+	 */
+	if (init_kernel_text(addr))
+		return 1;
+	return 0;
 }
 
 int kernel_text_address(unsigned long addr)
 {
 	if (core_kernel_text(addr))
 		return 1;
-	return module_text_address(addr) != NULL;
+	return is_module_text_address(addr);
+}
+
+/*
+ * On some architectures (PPC64, IA64) function pointers
+ * are actually only tokens to some data that then holds the
+ * real function address. As a result, to find if a function
+ * pointer is part of the kernel text, we need to do some
+ * special dereferencing first.
+ */
+int func_ptr_is_kernel_text(void *ptr)
+{
+	unsigned long addr;
+	addr = (unsigned long) dereference_function_descriptor(ptr);
+	if (core_kernel_text(addr))
+		return 1;
+	return is_module_text_address(addr);
 }