* [PATCH] ppc64: Add a sync in context switch on SMP
@ 2004-03-30 5:43 Benjamin Herrenschmidt
0 siblings, 0 replies; only message in thread
From: Benjamin Herrenschmidt @ 2004-03-30 5:43 UTC (permalink / raw)
To: Andrew Morton; +Cc: Linus Torvalds, Linux Kernel list
Hi !
For the same reason as ppc32, we need to ensure that all stores
done on a CPU has reached the coherency domain and are visible
to loads done by another CPU when context switching as the same
thread may be rescheduled almost right away there.
Ben.
diff -urN linux-2.5/arch/ppc64/kernel/entry.S linuxppc-2.5-benh/arch/ppc64/kernel/entry.S
--- linux-2.5/arch/ppc64/kernel/entry.S 2004-03-30 15:15:17.000000000 +1000
+++ linuxppc-2.5-benh/arch/ppc64/kernel/entry.S 2004-03-30 14:55:47.000000000 +1000
@@ -289,6 +289,14 @@
std r23,_CCR(r1)
std r1,KSP(r3) /* Set old stack pointer */
+#ifdef CONFIG_SMP
+ /* We need a sync somewhere here to make sure that if the
+ * previous task gets rescheduled on another CPU, it sees all
+ * stores it has performed on this one.
+ */
+ sync
+#endif /* CONFIG_SMP */
+
addi r6,r4,-THREAD /* Convert THREAD to 'current' */
std r6,PACACURRENT(r13) /* Set new 'current' */
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2004-03-30 5:43 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-03-30 5:43 [PATCH] ppc64: Add a sync in context switch on SMP Benjamin Herrenschmidt
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®