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

6 files changed, 6 insertions, 0 deletions

diff --git a/sys/conf/files.alpha b/sys/conf/files.alpha
index 9854c5d..9733f65 100644
--- a/sys/conf/files.alpha
+++ b/sys/conf/files.alpha
@@ -39,6 +39,7 @@ alpha/alpha/busspace.c		standard
 alpha/alpha/clock.c		standard
 alpha/alpha/clock_if.m		standard
 alpha/alpha/cpuconf.c		standard
+alpha/alpha/critical.c		standard
 alpha/alpha/db_disasm.c		optional	ddb
 alpha/alpha/db_interface.c	optional	ddb
 alpha/alpha/db_trace.c		optional	ddb
diff --git a/sys/conf/files.i386 b/sys/conf/files.i386
index ecae824..5243412 100644
--- a/sys/conf/files.i386
+++ b/sys/conf/files.i386
@@ -199,6 +199,7 @@ i386/i386/autoconf.c		standard
 i386/i386/bios.c		standard
 i386/i386/bioscall.s		standard
 i386/i386/busdma_machdep.c	standard
+i386/i386/critical.c		standard
 i386/i386/db_disasm.c		optional	ddb
 i386/i386/db_interface.c	optional	ddb
 i386/i386/db_trace.c		optional	ddb
diff --git a/sys/conf/files.ia64 b/sys/conf/files.ia64
index 9af5112..9850f3b 100644
--- a/sys/conf/files.ia64
+++ b/sys/conf/files.ia64
@@ -27,6 +27,7 @@ ia64/ia64/autoconf.c		standard
 ia64/ia64/busdma_machdep.c	standard
 ia64/ia64/clock.c		standard
 ia64/ia64/clock_if.m		standard
+ia64/ia64/critical.c		standard
 ia64/ia64/db_disasm.c		optional	ddb
 ia64/ia64/db_interface.c	optional	ddb
 ia64/ia64/db_trace.c		optional	ddb
diff --git a/sys/conf/files.pc98 b/sys/conf/files.pc98
index 7a44e84..c7d9d7f 100644
--- a/sys/conf/files.pc98
+++ b/sys/conf/files.pc98
@@ -183,6 +183,7 @@ i386/i386/autoconf.c		standard
 i386/i386/bios.c		standard
 i386/i386/bioscall.s		standard
 i386/i386/busdma_machdep.c	standard
+i386/i386/critical.c		standard
 i386/i386/db_disasm.c		optional	ddb
 i386/i386/db_interface.c	optional	ddb
 i386/i386/db_trace.c		optional	ddb
diff --git a/sys/conf/files.powerpc b/sys/conf/files.powerpc
index 4d6fa6f..98307c8 100644
--- a/sys/conf/files.powerpc
+++ b/sys/conf/files.powerpc
@@ -16,6 +16,7 @@ powerpc/powerpc/bcopy.c		standard
 powerpc/powerpc/clock.c		standard
 powerpc/powerpc/copyinout.c	standard
 powerpc/powerpc/copystr.c	standard
+powerpc/powerpc/critical.c	standard
 powerpc/powerpc/elf_machdep.c	standard
 powerpc/powerpc/extintr.c	standard
 powerpc/powerpc/fuswintr.c	standard
diff --git a/sys/conf/files.sparc64 b/sys/conf/files.sparc64
index bb2bdee..ba67ba9 100644
--- a/sys/conf/files.sparc64
+++ b/sys/conf/files.sparc64
@@ -28,6 +28,7 @@ sparc64/sparc64/bus_machdep.c	standard
 sparc64/sparc64/cache.c		standard
 sparc64/sparc64/clock.c		standard
 sparc64/sparc64/counter.c	standard
+sparc64/sparc64/critical.c	standard
 sparc64/sparc64/db_disasm.c	optional	ddb
 sparc64/sparc64/db_interface.c	optional	ddb
 sparc64/sparc64/db_trace.c	optional	ddb