[PATCH] paravirt: Add startup infrastructure for paravirtualization

1) Each hypervisor writes a probe function to detect whether we are
   running under that hypervisor.  paravirt_probe() registers this
   function.

2) If vmlinux is booted with ring != 0, we call all the probe
   functions (with registers except %esp intact) in link order: the
   winner will not return.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index 0811947..dd707d8 100644
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -120,6 +120,11 @@
 	void (fastcall *iret)(void);
 };
 
+/* Mark a paravirt probe function. */
+#define paravirt_probe(fn)						\
+ static asmlinkage void (*__paravirtprobe_##fn)(void) __attribute_used__ \
+		__attribute__((__section__(".paravirtprobe"))) = fn
+
 extern struct paravirt_ops paravirt_ops;
 
 #define paravirt_enabled() (paravirt_ops.paravirt_enabled)