Andi Kleen wrote:
On Mon, Feb 05, 2007 at 07:53:02PM -0800, Zachary Amsden wrote:
The time initialization changed for i386 when some code moved into time_init.
This made it no longer possible to override the PIT / HPET, which broke
paravirt guests.
Looks still fragile. Can this be done cleaner?
In particularly some comments would be good, but clearer code
logic would be preferred.
-Andi
Well, the logic is still overly complicated, but I axed the ifdef and
commented it. It is difficult to work around the number of different
compile and boot sequences here.
diff -r 31c3528be5d2 arch/i386/kernel/paravirt.c
--- a/arch/i386/kernel/paravirt.c Fri Feb 02 16:29:46 2007 -0800
+++ b/arch/i386/kernel/paravirt.c Tue Feb 06 16:16:54 2007 -0800
@@ -497,7 +497,7 @@ struct paravirt_ops paravirt_ops = {
.memory_setup = machine_specific_memory_setup,
.get_wallclock = native_get_wallclock,
.set_wallclock = native_set_wallclock,
- .time_init = time_init_hook,
+ .time_init = native_time_init,
.init_IRQ = native_init_IRQ,
.cpuid = native_cpuid,
diff -r 31c3528be5d2 arch/i386/kernel/time.c
--- a/arch/i386/kernel/time.c Fri Feb 02 16:29:46 2007 -0800
+++ b/arch/i386/kernel/time.c Tue Feb 06 16:27:06 2007 -0800
@@ -266,10 +266,24 @@ static void __init hpet_time_init(void)
{
if (!hpet_enable())
setup_pit_timer();
+ time_init_hook();
+}
+
+void __init native_time_init(void)
+{
+ late_time_init = hpet_time_init;
+}
+
+/*
+ * This is called directly from init code; we must delay timer setup in the
+ * HPET case as we can't make the decision to turn on HPET this early in the
+ * boot process. So we call do_time_init(), which either calls
+ * native_time_init above or a paravirt-op which implements an alternative
+ * timer. This may seem like overkill, but is necessary for the rather large
+ * number of timer combinations. But remember, this is all dealing with time,
+ * and with time, too much is never enough.
+ */
+void __init time_init(void)
+{
do_time_init();
}
-
-void __init time_init(void)
-{
- late_time_init = hpet_time_init;
-}
diff -r 31c3528be5d2 include/asm-i386/time.h
--- a/include/asm-i386/time.h Fri Feb 02 16:29:46 2007 -0800
+++ b/include/asm-i386/time.h Tue Feb 06 16:21:05 2007 -0800
@@ -28,13 +28,15 @@ static inline int native_set_wallclock(u
return retval;
}
+extern void native_time_init(void);
+
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else /* !CONFIG_PARAVIRT */
#define get_wallclock() native_get_wallclock()
#define set_wallclock(x) native_set_wallclock(x)
-#define do_time_init() time_init_hook()
+#define do_time_init() native_time_init()
#endif /* CONFIG_PARAVIRT */
