The patch titled
kexec jump: __ftrace_enabled_save/restore
has been added to the -mm tree. Its filename is
kexec-jump-__ftrace_enabled_save-restore.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: kexec jump: __ftrace_enabled_save/restore
From: Huang Ying <ying.huang@xxxxxxxxx>
Add __ftrace_enabled_save/restore, used to disable ftrace for a while.
Now, this is used by kexec jump, which need a version without lock, for
general situation, a locked version should be used.
Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/ftrace.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff -puN include/linux/ftrace.h~kexec-jump-__ftrace_enabled_save-restore include/linux/ftrace.h
--- a/include/linux/ftrace.h~kexec-jump-__ftrace_enabled_save-restore
+++ a/include/linux/ftrace.h
@@ -98,6 +98,27 @@ static inline void tracer_disable(void)
#endif
}
+/* Ftrace disable/restore without lock. Some synchronization mechanism
+ * must be used to prevent ftrace_enabled to be changed between
+ * disable/restore. */
+static inline int __ftrace_enabled_save(void)
+{
+#ifdef CONFIG_FTRACE
+ int saved_ftrace_enabled = ftrace_enabled;
+ ftrace_enabled = 0;
+ return saved_ftrace_enabled;
+#else
+ return 0;
+#endif
+}
+
+static inline void __ftrace_enabled_restore(int enabled)
+{
+#ifdef CONFIG_FTRACE
+ ftrace_enabled = enabled;
+#endif
+}
+
#ifdef CONFIG_FRAME_POINTER
/* TODO: need to fix this for ARM */
# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
_
Patches currently in -mm which might be from ying.huang@xxxxxxxxx are
origin.patch
kexec-jump-clean-up-ifdef-and-comments.patch
kexec-jump-rename-kexec_control_code_size-to-kexec_control_page_size.patch
kexec-jump-check-code-size-in-control-page.patch
kexec-jump-remove-duplication-of-kexec_restart_prepare.patch
kexec-jump-in-sync-with-hibernation-implementation.patch
kexec-jump-__ftrace_enabled_save-restore.patch
kexec-jump-fix-for-ftrace.patch
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