tracing, Text Edit Lock - kprobes architecture independent support, nommu fix
Impact: build fix on SH !CONFIG_MMU
Stephen Rothwell reported this linux-next build failure on the SH
architecture:
kernel/built-in.o: In function `disable_all_kprobes':
kernel/kprobes.c:1382: undefined reference to `text_mutex'
[...]
And observed:
| Introduced by commit 4460fdad85becd569f11501ad5b91814814335ff ("tracing,
| Text Edit Lock - kprobes architecture independent support") from the
| tracing tree. text_mutex is defined in mm/memory.c which is only built
| if CONFIG_MMU is defined, which is not true for sh allmodconfig.
Move this lock to kernel/extable.c (which is already home to various
kernel text related routines), which file is always built-in.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
LKML-Reference: <20090320110602.86351a91.sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/extable.c b/kernel/extable.c
index 0df6253..25d39b0 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -15,11 +15,21 @@
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/module.h>
-#include <linux/init.h>
#include <linux/ftrace.h>
-#include <asm/uaccess.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/init.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[];