On Jun 22, 2006, at 5:27 PM, Hollis Blanchard wrote:
On Wed, 2006-06-21 at 13:49 -0500, Hollis Blanchard wrote:
diff -r 6f3d44537b76 include/asm-powerpc/xen/asm/synch_bitops.h
--- a/include/asm-powerpc/xen/asm/synch_bitops.h Fri Jun 16
16:07:38 2006 -0500
+++ b/include/asm-powerpc/xen/asm/synch_bitops.h Wed Jun 21
13:42:56 2006 -0500
@@ -6,6 +6,8 @@
#ifdef CONFIG_SMP
#include <asm/bitops.h>
+
+#define gnttab_cmpxchg_flags(ptr,o,n) synch_cmpxchg((int *)
(ptr),o,n)
#define synch_change_bit(a,b) change_bit(a,b)
#define synch_clear_bit(a,b) clear_bit(a,b)
Of course, this won't work. This should be better:
static inline __u16 gnttab_cmpxchg_flags(__u16 *ptr, __u16 o, __u16 n)
{
unsigned long *laddr;
cmpxchg will actually allow a u32 so there is no need to take it to a
ulong, less bits to mess with and we expect the other short (the
domid) to be relatively static, if fact xen uses cmpxch on both
fields simultaneously.
old = ((unsigned long)o << shift) | (*laddr & ((1UL<<shift)-1));
new = ((unsigned long)n << shift) | (*laddr & ((1UL<<shift)-1));
Good Catch!
It might be prudent to deref laddr only once and make it volatile.
BTW: I'm not sure if you did, but just in case, this endian issue
will need addressing (cscope):
common/grant_table.c gnttab_prepare_for_transfer 567 scombo =
((u32)sdom << 16) | (u32)sflags;
I plan on getting it eventually, I mention it so it does not get
dropped.
-JX
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