Preparation for i386 Meltdown fix:

- provide a cpu_softc for cpu_attach() etc.
- replace per PCB TSS with per CPU TSS

The first change prepares for cpu_info being embedded in a
cpu_full_info.  Therefore during autoconf/cpu_attach we hand down
a softc.

The second change removes the per PCB TSS.  We now have one TSS per
CPU, thus in cpu_switchto() we only have to patch the ring 0 stack
pointer instead of loading a new TSS.  This also allows for cleaning
up the GDT, so we only have a single slot for the TSS.

from hshoexer@;  OK deraadt@

1 files changed, 5 insertions, 4 deletions

diff --git a/sys/arch/i386/include/cpu.h b/sys/arch/i386/include/cpu.h
index e89d43951c0..f3294535bde 100644
--- a/sys/arch/i386/include/cpu.h
+++ b/sys/arch/i386/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.158 2017/10/17 14:25:35 visa Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.159 2018/03/13 13:51:05 bluhm Exp $	*/
 /*	$NetBSD: cpu.h,v 1.35 1996/05/05 19:29:26 christos Exp $	*/
 
 /*-
@@ -46,6 +46,7 @@
 #include <machine/psl.h>
 #include <machine/segments.h>
 #include <machine/intrdefs.h>
+#include <machine/tss.h>
 
 #ifdef MULTIPROCESSOR
 #include <machine/i82489reg.h>
@@ -102,7 +103,7 @@ union vmm_cpu_cap {
 #ifdef _KERNEL
 /* XXX stuff to move to cpuvar.h later */
 struct cpu_info {
-	struct device ci_dev;		/* our device */
+	struct device	*ci_dev;	/* our device */
 	struct cpu_info *ci_self;	/* pointer to this structure */
 	struct schedstate_percpu ci_schedstate; /* scheduler state */
 	struct cpu_info *ci_next;	/* next cpu */
@@ -129,7 +130,6 @@ struct cpu_info {
 
 	struct pcb *ci_curpcb;		/* VA of current HW PCB */
 	struct pcb *ci_idle_pcb;	/* VA of current PCB */
-	int ci_idle_tss_sel;		/* TSS selector of idle PCB */
 	struct pmap *ci_curpmap;
 
 	struct intrsource *ci_isources[MAX_INTR_SOURCES];
@@ -175,6 +175,7 @@ struct cpu_info {
 	int		ci_want_resched;
 
 	union descriptor *ci_gdt;
+	struct i386tss	*ci_tss;
 
 	volatile int ci_ddb_paused;	/* paused due to other proc in ddb */
 #define CI_DDB_RUNNING		0
@@ -230,7 +231,7 @@ extern struct cpu_info *cpu_info_list;
 #define	CPU_INFO_FOREACH(cii, ci)	for (cii = 0, ci = cpu_info_list; \
 					    ci != NULL; ci = ci->ci_next)
 
-#define CPU_INFO_UNIT(ci)	((ci)->ci_dev.dv_unit)
+#define CPU_INFO_UNIT(ci)	((ci)->ci_dev ? (ci)->ci_dev->dv_unit : 0)
 
 #ifdef MULTIPROCESSOR