The sync.i instruction in ia64_switch_to() context switch code
looks like an old leftover code. sync.i instruction supposedly
ensures flush cache operation issued by processor become visible
to memory reference. Everywhere I looked where fc instruction is
used (ia64_fc), a sync.i is always accompanied. Everywhere in
the vicinity of context switch (save_switch_stack/load_switch_stack)
don't have any fc instruction in there. I don't see any reason why
we need to issue sync.i in context switch code. Patch to remove it.
Signed-off-by: Ken Chen <[EMAIL PROTECTED]>
--- ./arch/ia64/kernel/entry.S.orig 2005-09-06 22:36:17.114182129 -0700
+++ ./arch/ia64/kernel/entry.S 2005-09-07 00:20:37.216644505 -0700
@@ -213,10 +213,6 @@ GLOBAL_ENTRY(ia64_switch_to)
mov r13=in0 // set "current" pointer
;;
DO_LOAD_SWITCH_STACK
-
-#ifdef CONFIG_SMP
- sync.i // ensure "fc"s done by this CPU are
visible on other CPUs
-#endif
br.ret.sptk.many rp // boogie on out in new context
.map:
-
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