From 8d8d970db15335bb9fb7f39db24d5ed150fa8df3 Mon Sep 17 00:00:00 2001
From: Marcel Moolenaar <marcel@FreeBSD.org>
Date: Fri, 5 Sep 2003 22:50:10 +0000
Subject: [PATCH] Fix a place where I forgot to change the code that checks
 whether we return to kernel or userland. This triggered a panic in a KSE
 application when TDF_USTATCLOCK was set in the case userland was interrupted,
 but we never called ast() on our way out. As such, we called ast() at some
 other time. Unfortunately, TDF_USTATCLOCK handling assumes running in the
 interrupt thread. This was not the case anymore.

To avoid making the same mistake later, interrupt() now returns
to its caller whether we interrupted userland or not. This avoids
that we have to duplicate the check in assembly, where it's bound
to fall off the scope. Now we simply check the return value and
call ast() if appropriate.

Run into this: davidxu
---
 sys/ia64/ia64/exception.S | 22 +++++-----------------
 sys/ia64/ia64/genassym.c  |  2 --
 sys/ia64/ia64/interrupt.c |  4 +++-
 sys/ia64/include/md_var.h |  2 +-
 4 files changed, 9 insertions(+), 21 deletions(-)

diff --git a/sys/ia64/ia64/exception.S b/sys/ia64/ia64/exception.S
index fbbf7b6a214..2105203245a 100644
--- a/sys/ia64/ia64/exception.S
+++ b/sys/ia64/ia64/exception.S
@@ -1151,6 +1151,7 @@ IVT_ENTRY(External_Interrupt, 0x3000)
 	;;
 }
 	alloc		r14=ar.pfs,0,0,2,0
+	cmp4.eq		p14,p0=0,r0
 	;;
 1:
 {	.mii
@@ -1178,29 +1179,16 @@ IVT_ENTRY(External_Interrupt, 0x3000)
 	nop		0
 }
 {	.mfb
-	nop		0
+	cmp4.eq		p14,p0=0,r8	// Return to kernel mode?
 	nop		0
 	br.sptk		1b		// loop for more
 	;;
 }
 2:
-{	.mmi
-	add		r14=16+TF_SPECIAL_IIP,sp
-	;;
-	ld8		r14=[r14]
+{	.mbb
 	add		out0=16,sp
-	;;
-}
-{	.mii
-	nop		0
-	extr.u		r14=r14,61,3
-	;;
-	cmp.gt		p15,p0=5,r14
-}
-{	.mfb
-	nop		0
-	nop		0
-(p15)	br.call.sptk	rp=do_ast
+(p14)	br.sptk		exception_restore
+	br.call.sptk	rp=do_ast
 	;;
 }
 {	.mfb
diff --git a/sys/ia64/ia64/genassym.c b/sys/ia64/ia64/genassym.c
index 0c0ec816062..9679f3ff786 100644
--- a/sys/ia64/ia64/genassym.c
+++ b/sys/ia64/ia64/genassym.c
@@ -112,8 +112,6 @@ ASSYM(TD_PCB,		offsetof(struct thread, td_pcb));
 ASSYM(TDF_ASTPENDING,	TDF_ASTPENDING);
 ASSYM(TDF_NEEDRESCHED,	TDF_NEEDRESCHED);
 
-ASSYM(TF_SPECIAL_IIP, offsetof(struct trapframe, tf_special.iip));
-
 ASSYM(UC_MCONTEXT,	offsetof(ucontext_t, uc_mcontext));
 
 ASSYM(VM_MAX_ADDRESS,	VM_MAX_ADDRESS);
diff --git a/sys/ia64/ia64/interrupt.c b/sys/ia64/ia64/interrupt.c
index e7b5367ab7b..b43306bd8aa 100644
--- a/sys/ia64/ia64/interrupt.c
+++ b/sys/ia64/ia64/interrupt.c
@@ -51,6 +51,7 @@
 #include <sys/sysctl.h>
 
 #include <machine/clock.h>
+#include <machine/cpu.h>
 #include <machine/frame.h>
 #include <machine/intr.h>
 #include <machine/md_var.h>
@@ -122,7 +123,7 @@ static int adjust_ticks = 0;
 SYSCTL_INT(_debug, OID_AUTO, clock_adjust_ticks, CTLFLAG_RW,
     &adjust_ticks, 0, "Total number of ITC interrupts with adjustment");
 
-void
+int
 interrupt(u_int64_t vector, struct trapframe *framep)
 {
 	struct thread *td;
@@ -230,6 +231,7 @@ interrupt(u_int64_t vector, struct trapframe *framep)
 	}
 
 	atomic_subtract_int(&td->td_intr_nesting_level, 1);
+	return (TRAPF_USERMODE(framep));
 }
 
 /*
diff --git a/sys/ia64/include/md_var.h b/sys/ia64/include/md_var.h
index 3301f341621..792742d7b46 100644
--- a/sys/ia64/include/md_var.h
+++ b/sys/ia64/include/md_var.h
@@ -61,7 +61,7 @@ int	ia64_highfp_load(struct thread *);
 int	ia64_highfp_save(struct thread *);
 void	ia64_init(void);
 void	ia64_probe_sapics(void);
-void	interrupt(uint64_t, struct trapframe *);
+int	interrupt(uint64_t, struct trapframe *);
 void	map_gateway_page(void);
 void	map_pal_code(void);
 void	map_port_space(void);