add patch series

1 files changed, 105 insertions, 0 deletions

diff --git a/debian/patches/try-fence0001-kern-use-proper-memory-fences-when-handling-the-mapp.patch b/debian/patches/try-fence0001-kern-use-proper-memory-fences-when-handling-the-mapp.patch
new file mode 100644
index 0000000..915bc55
--- /dev/null
+++ b/debian/patches/try-fence0001-kern-use-proper-memory-fences-when-handling-the-mapp.patch
@@ -0,0 +1,105 @@
+From 73ea1ec6d0a9cd285d5d5aece0bbc06cea973302 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Mon, 7 Sep 2015 13:04:39 +0200
+Subject: [PATCH gnumach] kern: use proper memory fences when handling the
+ mapped time
+
+* include/mach/time_value.h (struct mapped_time_value): Adjust comment.
+* kern/mach_clock.c (mtime): Likewise.  Also make it volatile.
+(update_mapped_time): Use full hardware barriers.
+(read_mapped_time): New macro with proper fences.
+(record_time_stamp, host_get_time): Use the new macro.
+---
+ include/mach/time_value.h |  2 ++
+ kern/mach_clock.c         | 33 ++++++++++++++++++---------------
+ 2 files changed, 20 insertions(+), 15 deletions(-)
+
+diff --git a/include/mach/time_value.h b/include/mach/time_value.h
+index 61be581..0dfe382 100644
+--- a/include/mach/time_value.h
++++ b/include/mach/time_value.h
+@@ -84,7 +84,9 @@ typedef	struct time_value	time_value_t;
+  *	Read this mapped value with
+  *		do {
+  *			secs = mtime->seconds;
++ *			__sync_synchronize();
+  *			usecs = mtime->microseconds;
++ *			__sync_synchronize();
+  *		} while (secs != mtime->check_seconds);
+  */
+ 
+diff --git a/kern/mach_clock.c b/kern/mach_clock.c
+index 2bcd232..dba2320 100644
+--- a/kern/mach_clock.c
++++ b/kern/mach_clock.c
+@@ -85,26 +85,36 @@ int		bigadj = 1000000;	/* adjust 10*tickadj if adjustment
+  *	This update protocol, with a check value, allows
+  *		do {
+  *			secs = mtime->seconds;
++ *			__sync_synchronize();
+  *			usecs = mtime->microseconds;
++ *			__sync_synchronize();
+  *		} while (secs != mtime->check_seconds);
+- *	to read the time correctly.  (On a multiprocessor this assumes
+- *	that processors see each other's writes in the correct order.
+- *	We have to insert write fence operations.) FIXME
++ *	to read the time correctly.
+  */
+ 
+-mapped_time_value_t *mtime = 0;
++volatile mapped_time_value_t *mtime = 0;
+ 
+ #define update_mapped_time(time)				\
+ MACRO_BEGIN							\
+ 	if (mtime != 0) {					\
+ 		mtime->check_seconds = (time)->seconds;		\
+-		asm volatile("":::"memory");			\
++		__sync_synchronize();				\
+ 		mtime->microseconds = (time)->microseconds;	\
+-		asm volatile("":::"memory");			\
++		__sync_synchronize();				\
+ 		mtime->seconds = (time)->seconds;		\
+ 	}							\
+ MACRO_END
+ 
++#define read_mapped_time(time)					\
++MACRO_BEGIN							\
++	do {							\
++		time->seconds = mtime->seconds;			\
++		__sync_synchronize();				\
++		time->microseconds = mtime->microseconds;	\
++		__sync_synchronize();				\
++	} while (time->seconds != mtime->check_seconds);	\
++MACRO_END
++
+ decl_simple_lock_data(,	timer_lock)	/* lock for ... */
+ timer_elt_data_t	timer_head;	/* ordered list of timeouts */
+ 					/* (doubles as end-of-list) */
+@@ -395,10 +405,7 @@ clock_boottime_update(struct time_value *new_time)
+ void
+ record_time_stamp (time_value_t *stamp)
+ {
+-	do {
+-		stamp->seconds = mtime->seconds;
+-		stamp->microseconds = mtime->microseconds;
+-	} while (stamp->seconds != mtime->check_seconds);
++	read_mapped_time(stamp);
+ 	time_value_add(stamp, &clock_boottime_offset);
+ }
+ 
+@@ -425,11 +432,7 @@ host_get_time(host, current_time)
+ 	if (host == HOST_NULL)
+ 		return(KERN_INVALID_HOST);
+ 
+-	do {
+-		current_time->seconds = access_once(mtime->seconds);
+-		current_time->microseconds = access_once(mtime->microseconds);
+-	} while (current_time->seconds != access_once(mtime->check_seconds));
+-
++	read_mapped_time(current_time);
+ 	return (KERN_SUCCESS);
+ }
+ 
+-- 
+2.1.4
+