6 files changed, 87 insertions, 44 deletions

diff --git a/sys/i386/i386/exception.s b/sys/i386/i386/exception.s
index e0e7b3c68631..28f5085ace29 100644
--- a/sys/i386/i386/exception.s
+++ b/sys/i386/i386/exception.s
@@ -30,7 +30,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: exception.s,v 1.9 1995/06/11 19:31:13 rgrimes Exp $
+ *	$Id: exception.s,v 1.9.2.1 1995/08/23 05:22:34 davidg Exp $
  */
 
 #include "npx.h"				/* NNPX */
@@ -111,8 +111,6 @@ IDTVEC(ill)
 	pushl $0; TRAP(T_PRIVINFLT)
 IDTVEC(dna)
 	pushl $0; TRAP(T_DNA)
-IDTVEC(dble)
-	TRAP(T_DOUBLEFLT)
 IDTVEC(fpusegm)
 	pushl $0; TRAP(T_FPOPFLT)
 IDTVEC(tss)
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 57d026f93715..1d62f2bb9d77 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)machdep.c	7.4 (Berkeley) 6/3/91
- *	$Id: machdep.c,v 1.128.4.3 1995/09/08 04:22:49 davidg Exp $
+ *	$Id: machdep.c,v 1.128.4.4 1995/10/25 11:14:38 davidg Exp $
  */
 
 #include "npx.h"
@@ -194,6 +194,8 @@ vm_offset_t pager_sva, pager_eva;
 extern int pager_map_size;
 extern struct linker_set netisr_set;
 
+extern void dblfault_handler __P((void));
+
 #define offsetof(type, member)	((size_t)(&((type *)0)->member))
 
 void
@@ -1051,7 +1053,8 @@ union descriptor gdt[NGDT];		/* global descriptor table */
 struct gate_descriptor idt[NIDT];	/* interrupt descriptor table */
 union descriptor ldt[NLDT];		/* local descriptor table */
 
-struct	i386tss	tss, panic_tss;
+static struct i386tss dblfault_tss;
+static char dblfault_stack[PAGE_SIZE];
 
 extern  struct user *proc0paddr;
 
@@ -1103,8 +1106,8 @@ struct soft_segment_descriptor gdt_segs[] = {
 	0,			/* default 32 vs 16 bit size */
 	0  			/* limit granularity (byte/page units)*/ },
 /* GPANIC_SEL	5 Panic Tss Descriptor */
-{	(int) &panic_tss,	/* segment base address  */
-	sizeof(tss)-1,		/* length - all address space */
+{	(int) &dblfault_tss,	/* segment base address  */
+	sizeof(struct i386tss)-1,/* length - all address space */
 	SDT_SYS386TSS,		/* segment type */
 	0,			/* segment descriptor priority level */
 	1,			/* segment descriptor present */
@@ -1113,7 +1116,7 @@ struct soft_segment_descriptor gdt_segs[] = {
 	0  			/* limit granularity (byte/page units)*/ },
 /* GPROC0_SEL	6 Proc 0 Tss Descriptor */
 {	(int) kstack,		/* segment base address  */
-	sizeof(tss)-1,		/* length - all address space */
+	sizeof(struct i386tss)-1,/* length - all address space */
 	SDT_SYS386TSS,		/* segment type */
 	0,			/* segment descriptor priority level */
 	1,			/* segment descriptor present */
@@ -1207,16 +1210,17 @@ struct soft_segment_descriptor ldt_segs[] = {
 };
 
 void
-setidt(idx, func, typ, dpl)
+setidt(idx, func, typ, dpl, selec)
 	int idx;
 	inthand_t *func;
 	int typ;
 	int dpl;
+	int selec;
 {
 	struct gate_descriptor *ip = idt + idx;
 
 	ip->gd_looffset = (int)func;
-	ip->gd_selector = 8;
+	ip->gd_selector = selec;
 	ip->gd_stkcpy = 0;
 	ip->gd_xx = 0;
 	ip->gd_type = typ;
@@ -1229,7 +1233,7 @@ setidt(idx, func, typ, dpl)
 
 extern inthand_t
 	IDTVEC(div), IDTVEC(dbg), IDTVEC(nmi), IDTVEC(bpt), IDTVEC(ofl),
-	IDTVEC(bnd), IDTVEC(ill), IDTVEC(dna), IDTVEC(dble), IDTVEC(fpusegm),
+	IDTVEC(bnd), IDTVEC(ill), IDTVEC(dna), IDTVEC(fpusegm),
 	IDTVEC(tss), IDTVEC(missing), IDTVEC(stk), IDTVEC(prot),
 	IDTVEC(page), IDTVEC(rsvd), IDTVEC(fpu), IDTVEC(align),
 	IDTVEC(syscall);
@@ -1315,27 +1319,27 @@ init386(first)
 
 	/* exceptions */
 	for (x = 0; x < NIDT; x++)
-		setidt(x, &IDTVEC(rsvd), SDT_SYS386TGT, SEL_KPL);
-	setidt(0, &IDTVEC(div),  SDT_SYS386TGT, SEL_KPL);
-	setidt(1, &IDTVEC(dbg),  SDT_SYS386TGT, SEL_KPL);
-	setidt(2, &IDTVEC(nmi),  SDT_SYS386TGT, SEL_KPL);
- 	setidt(3, &IDTVEC(bpt),  SDT_SYS386TGT, SEL_UPL);
-	setidt(4, &IDTVEC(ofl),  SDT_SYS386TGT, SEL_UPL);
-	setidt(5, &IDTVEC(bnd),  SDT_SYS386TGT, SEL_KPL);
-	setidt(6, &IDTVEC(ill),  SDT_SYS386TGT, SEL_KPL);
-	setidt(7, &IDTVEC(dna),  SDT_SYS386TGT, SEL_KPL);
-	setidt(8, &IDTVEC(dble),  SDT_SYS386TGT, SEL_KPL);
-	setidt(9, &IDTVEC(fpusegm),  SDT_SYS386TGT, SEL_KPL);
-	setidt(10, &IDTVEC(tss),  SDT_SYS386TGT, SEL_KPL);
-	setidt(11, &IDTVEC(missing),  SDT_SYS386TGT, SEL_KPL);
-	setidt(12, &IDTVEC(stk),  SDT_SYS386TGT, SEL_KPL);
-	setidt(13, &IDTVEC(prot),  SDT_SYS386TGT, SEL_KPL);
-	setidt(14, &IDTVEC(page),  SDT_SYS386TGT, SEL_KPL);
-	setidt(15, &IDTVEC(rsvd),  SDT_SYS386TGT, SEL_KPL);
-	setidt(16, &IDTVEC(fpu),  SDT_SYS386TGT, SEL_KPL);
-	setidt(17, &IDTVEC(align), SDT_SYS386TGT, SEL_KPL);
-#ifdef COMPAT_LINUX
- 	setidt(0x80, &IDTVEC(linux_syscall),  SDT_SYS386TGT, SEL_UPL);
+		setidt(x, &IDTVEC(rsvd), SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(0, &IDTVEC(div),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(1, &IDTVEC(dbg),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(2, &IDTVEC(nmi),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+ 	setidt(3, &IDTVEC(bpt),  SDT_SYS386TGT, SEL_UPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(4, &IDTVEC(ofl),  SDT_SYS386TGT, SEL_UPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(5, &IDTVEC(bnd),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(6, &IDTVEC(ill),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(7, &IDTVEC(dna),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(8, 0,  SDT_SYSTASKGT, SEL_KPL, GSEL(GPANIC_SEL, SEL_KPL));
+	setidt(9, &IDTVEC(fpusegm),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(10, &IDTVEC(tss),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(11, &IDTVEC(missing),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(12, &IDTVEC(stk),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(13, &IDTVEC(prot),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(14, &IDTVEC(page),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(15, &IDTVEC(rsvd),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(16, &IDTVEC(fpu),  SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(17, &IDTVEC(align), SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+#if defined(COMPAT_LINUX) || defined(LINUX)
+ 	setidt(0x80, &IDTVEC(linux_syscall),  SDT_SYS386TGT, SEL_UPL, GSEL(GCODE_SEL, SEL_KPL));
 #endif
 
 #include	"isa.h"
@@ -1554,8 +1558,20 @@ init386(first)
 	proc0.p_addr->u_pcb.pcb_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL) ;
 	gsel_tss = GSEL(GPROC0_SEL, SEL_KPL);
 
+	dblfault_tss.tss_esp = dblfault_tss.tss_esp0 = dblfault_tss.tss_esp1 =
+	    dblfault_tss.tss_esp2 = (int) &dblfault_stack[sizeof(dblfault_stack)];
+	dblfault_tss.tss_ss = dblfault_tss.tss_ss0 = dblfault_tss.tss_ss1 =
+	    dblfault_tss.tss_ss2 = GSEL(GDATA_SEL, SEL_KPL);
+	dblfault_tss.tss_cr3 = IdlePTD;
+	dblfault_tss.tss_eip = (int) dblfault_handler;
+	dblfault_tss.tss_eflags = PSL_KERNEL;
+	dblfault_tss.tss_ds = dblfault_tss.tss_es = dblfault_tss.tss_fs = dblfault_tss.tss_gs =
+		GSEL(GDATA_SEL, SEL_KPL);
+	dblfault_tss.tss_cs = GSEL(GCODE_SEL, SEL_KPL);
+	dblfault_tss.tss_ldt = GSEL(GLDT_SEL, SEL_KPL);
+
 	((struct i386tss *)gdt_segs[GPROC0_SEL].ssd_base)->tss_ioopt =
-		(sizeof(tss))<<16;
+		(sizeof(struct i386tss))<<16;
 
 	ltr(gsel_tss);
 
diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c
index 3883c3d16f72..c156ca42fbe7 100644
--- a/sys/i386/i386/trap.c
+++ b/sys/i386/i386/trap.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)trap.c	7.4 (Berkeley) 5/13/91
- *	$Id: trap.c,v 1.53.2.2 1995/08/23 07:31:17 davidg Exp $
+ *	$Id: trap.c,v 1.53.2.3 1995/10/10 00:45:46 davidg Exp $
  */
 
 /*
@@ -80,8 +80,9 @@ extern int trapwrite __P((unsigned addr));
 extern void syscall __P((struct trapframe frame));
 extern void linux_syscall __P((struct trapframe frame));
 
-int	trap_pfault	__P((struct trapframe *, int));
-void	trap_fatal	__P((struct trapframe *));
+static int trap_pfault __P((struct trapframe *, int));
+static void trap_fatal __P((struct trapframe *));
+void dblfault_handler __P((void));
 
 extern inthand_t IDTVEC(syscall);
 
@@ -748,6 +749,33 @@ trap_fatal(frame)
 }
 
 /*
+ * Double fault handler. Called when a fault occurs while writing
+ * a frame for a trap/exception onto the stack. This usually occurs
+ * when the stack overflows (such is the case with infinite recursion,
+ * for example).
+ *
+ * XXX Note that the current PTD gets replaced by IdlePTD when the
+ * task switch occurs. This means that the stack that was active at
+ * the time of the double fault is not available at <kstack> unless
+ * the machine was idle when the double fault occurred. The downside
+ * of this is that "trace <ebp>" in ddb won't work.
+ */
+void
+dblfault_handler()
+{
+	struct pcb *pcb = curpcb;
+
+	if (pcb != NULL) {
+		printf("\nFatal double fault:\n");
+		printf("eip = 0x%x\n", pcb->pcb_tss.tss_eip);
+		printf("esp = 0x%x\n", pcb->pcb_tss.tss_esp);
+		printf("ebp = 0x%x\n", pcb->pcb_tss.tss_ebp);
+	}
+
+	panic("double fault");
+}
+
+/*
  * Compensate for 386 brain damage (missing URKR).
  * This is a little simpler than the pagefault handler in trap() because
  * it the page tables have already been faulted in and high addresses
diff --git a/sys/i386/include/cpufunc.h b/sys/i386/include/cpufunc.h
index a05ef1223e50..4880e4c8ebf1 100644
--- a/sys/i386/include/cpufunc.h
+++ b/sys/i386/include/cpufunc.h
@@ -30,7 +30,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: cpufunc.h,v 1.37.4.2 1995/09/12 05:48:43 davidg Exp $
+ *	$Id: cpufunc.h,v 1.37.4.3 1995/12/20 17:06:35 nate Exp $
  */
 
 /*
@@ -448,6 +448,6 @@ u_long	kvtop		__P((void *addr));
 typedef void alias_for_inthand_t __P((u_int cs, u_int ef, u_int esp,
 				      u_int ss));
 void	setidt		__P((int idx, alias_for_inthand_t *func, int typ,
-			     int dpl));
+			     int dpl, int selec));
 
 #endif /* !_MACHINE_CPUFUNC_H_ */
diff --git a/sys/i386/isa/isa.c b/sys/i386/isa/isa.c
index eae0629c0902..3f52c84050cc 100644
--- a/sys/i386/isa/isa.c
+++ b/sys/i386/isa/isa.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)isa.c	7.2 (Berkeley) 5/13/91
- *	$Id: isa.c,v 1.50 1995/05/30 08:02:35 rgrimes Exp $
+ *	$Id: isa.c,v 1.50.4.1 1996/01/04 08:54:12 gibbs Exp $
  */
 
 /*
@@ -962,7 +962,7 @@ register_intr(intr, device_id, flags, handler, maskptr, unit)
 	intr_unit[intr] = unit;
 	setidt(ICU_OFFSET + intr,
 	       flags & RI_FAST ? fastintr[intr] : slowintr[intr],
-	       SDT_SYS386IGT, SEL_KPL);
+	       SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
 	write_eflags(ef);
 	for (cp = intrnames, id = 0; id <= device_id; id++)
 		while (*cp++ != '\0')
@@ -1009,7 +1009,8 @@ unregister_intr(intr, handler)
 	intr_mptr[intr] = NULL;
 	intr_mask[intr] = HWI_MASK | SWI_MASK;
 	intr_unit[intr] = intr;
-	setidt(ICU_OFFSET + intr, slowintr[intr], SDT_SYS386IGT, SEL_KPL);
+	setidt(ICU_OFFSET + intr, slowintr[intr], SDT_SYS386IGT, SEL_KPL,
+	    GSEL(GCODE_SEL, SEL_KPL));
 	write_eflags(ef);
 	return (0);
 }
diff --git a/sys/i386/isa/npx.c b/sys/i386/isa/npx.c
index 0a5327941724..e83a7aa301d4 100644
--- a/sys/i386/isa/npx.c
+++ b/sys/i386/isa/npx.c
@@ -32,7 +32,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)npx.c	7.2 (Berkeley) 5/12/91
- *	$Id: npx.c,v 1.22 1995/04/12 20:48:01 wollman Exp $
+ *	$Id: npx.c,v 1.23 1995/05/30 08:02:51 rgrimes Exp $
  */
 
 #include "npx.h"
@@ -205,8 +205,8 @@ npxprobe(dvp)
 	save_idt_npxtrap = idt[16];
 	outb(IO_ICU1 + 1, ~(IRQ_SLAVE | dvp->id_irq));
 	outb(IO_ICU2 + 1, ~(dvp->id_irq >> 8));
-	setidt(16, probetrap, SDT_SYS386TGT, SEL_KPL);
-	setidt(npx_intrno, probeintr, SDT_SYS386IGT, SEL_KPL);
+	setidt(16, probetrap, SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
+	setidt(npx_intrno, probeintr, SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
 	npx_idt_probeintr = idt[npx_intrno];
 	enable_intr();
 	result = npxprobe1(dvp);