Compromise for critical*()/cpu_critical*() recommit. Cleanup the interrupt

disablement assumptions in kern_fork.c by adding another API call,
cpu_critical_fork_exit().  Cleanup the td_savecrit field by moving it
from MI to MD.  Temporarily move cpu_critical*() from <arch>/include/cpufunc.h
to <arch>/<arch>/critical.c (stage-2 will clean this up).

Implement interrupt deferral for i386 that allows interrupts to remain
enabled inside critical sections.  This also fixes an IPI interlock bug,
and requires uses of icu_lock to be enclosed in a true interrupt disablement.

This is the stage-1 commit.  Stage-2 will occur after stage-1 has stabilized,
and will move cpu_critical*() into its own header file(s) + other things.
This commit may break non-i386 architectures in trivial ways.  This should
be temporary.

Reviewed by:	core
Approved by:	core

1 files changed, 7 insertions, 22 deletions

diff --git a/sys/powerpc/include/cpufunc.h b/sys/powerpc/include/cpufunc.h
index 7ea27b0..b788aa6 100644
--- a/sys/powerpc/include/cpufunc.h
+++ b/sys/powerpc/include/cpufunc.h
@@ -35,7 +35,7 @@
 
 #include <machine/psl.h>
 
-#define	CRITICAL_FORK	(mfmsr() | PSL_EE | PSL_RI)
+struct thread;
 
 #ifdef __GNUC__
 
@@ -108,20 +108,6 @@ intr_restore(register_t msr)
 	mtmsr(msr);
 }
 
-static __inline critical_t
-cpu_critical_enter(void)
-{
-	u_int		msr;
-	critical_t	crit;
-
-	msr = mfmsr();
-	crit = (critical_t)msr;
-	msr &= ~(PSL_EE | PSL_RI);
-	mtmsr(msr);
-	
-	return (crit);
-}
-
 static __inline void
 restore_intr(unsigned int msr)
 {
@@ -130,13 +116,6 @@ restore_intr(unsigned int msr)
 }
 
 static __inline void
-cpu_critical_exit(critical_t msr)
-{
-
-	mtmsr(msr);
-}
-
-static __inline void
 powerpc_mb(void)
 {
 
@@ -153,6 +132,12 @@ powerpc_get_pcpup(void)
 	return(ret);
 }
 
+void	cpu_critical_enter(void);
+void	cpu_critical_exit(void);
+void	cpu_critical_fork_exit(void);
+void	cpu_thread_link(struct thread *td);
+
+
 #endif /* _KERNEL */
 
 #endif /* !_MACHINE_CPUFUNC_H_ */