Index: arch/ia64/include/interrupt.h
===================================================================
--- arch/ia64/include/interrupt.h	(revision b994a60c2699d4cf29d9c28497e8256a75eb2a1c)
+++ arch/ia64/include/interrupt.h	(revision a2a46ba180ede6fa62fc39caa28877a06ce899a4)
@@ -58,8 +58,16 @@
 	cr_isr_t cr_isr;
 	__address cr_iipa;
-	__u64 cr_ips;
+	psr_t cr_ipsr;
 	__address cr_iip;
 	__u64 pr;
 	__address sp;
+	
+	/*
+	 * The following variables are defined only for break_instruction handler. 
+	 */
+	__u64 in0;
+	__u64 in1;
+	__u64 in2;
+	__u64 in3;
 } __attribute__ ((packed));
 
@@ -67,5 +75,5 @@
 
 extern void general_exception(__u64 vector, struct exception_regdump *pstate);
-extern void break_instruction(__u64 vector, struct exception_regdump *pstate);
+extern int break_instruction(__u64 vector, struct exception_regdump *pstate);
 extern void universal_handler(__u64 vector, struct exception_regdump *pstate);
 extern void external_interrupt(__u64 vector, struct exception_regdump *pstate);
Index: arch/ia64/src/interrupt.c
===================================================================
--- arch/ia64/src/interrupt.c	(revision b994a60c2699d4cf29d9c28497e8256a75eb2a1c)
+++ arch/ia64/src/interrupt.c	(revision a2a46ba180ede6fa62fc39caa28877a06ce899a4)
@@ -41,4 +41,6 @@
 #include <symtab.h>
 #include <debug.h>
+#include <syscall/syscall.h>
+#include <print.h>
 
 #define VECTORS_64_BUNDLE	20
@@ -132,5 +134,5 @@
 	printf("ar.rnat=%Q\tar.rsc=%Q\n", pstate->ar_rnat, pstate->ar_rsc);
 	printf("ar.ifs=%Q\tar.pfs=%Q\n", pstate->ar_ifs, pstate->ar_pfs);
-	printf("cr.isr=%Q\tcr.ips=%Q\t\n", pstate->cr_isr.value, pstate->cr_ips);
+	printf("cr.isr=%Q\tcr.ipsr=%Q\t\n", pstate->cr_isr.value, pstate->cr_ipsr);
 	
 	printf("cr.iip=%Q, #%d\t(%s)\n", pstate->cr_iip, pstate->cr_isr.ei ,iip ? iip : "?");
@@ -172,8 +174,23 @@
 }
 
-void break_instruction(__u64 vector, struct exception_regdump *pstate)
-{
-	dump_interrupted_context(pstate);
-	panic("Break Instruction\n");
+/** Handle syscall. */
+int break_instruction(__u64 vector, struct exception_regdump *pstate)
+{
+	/*
+	 * Move to next instruction after BREAK.
+	 */
+	if (pstate->cr_ipsr.ri == 2) {
+		pstate->cr_ipsr.ri = 0;
+		pstate->cr_iip += 16;
+	} else {
+		pstate->cr_ipsr.ri++;
+	}
+
+	if (pstate->in0 < SYSCALL_END)
+		return syscall_table[pstate->in0](pstate->in1, pstate->in2, pstate->in3);
+	else
+		panic("Undefined syscall %d", pstate->in0);
+		
+	return -1;
 }
 
Index: arch/ia64/src/ivt.S
===================================================================
--- arch/ia64/src/ivt.S	(revision b994a60c2699d4cf29d9c28497e8256a75eb2a1c)
+++ arch/ia64/src/ivt.S	(revision a2a46ba180ede6fa62fc39caa28877a06ce899a4)
@@ -33,5 +33,5 @@
 #include <align.h>
 
-#define STACK_ITEMS		14
+#define STACK_ITEMS		18
 #define STACK_FRAME_SIZE	ALIGN_UP((STACK_ITEMS*STACK_ITEM_SIZE) + STACK_SCRATCH_AREA_SIZE, STACK_ALIGNMENT)
 
@@ -46,4 +46,5 @@
 #define R_HANDLER	r17
 #define R_RET		r18
+#define R_TMP		r19
 #define R_KSTACK_BSP	r22	/* keep in sync with before_thread_runs_arch() */
 #define R_KSTACK	r23	/* keep in sync with before_thread_runs_arch() */
@@ -105,5 +106,5 @@
 	 * Set p4 to false if the stack register doesn't reference kernel address space.
 	 */
-	(p3) cmp.eq p3, p4 = VRN_KERNEL, r31 ;;
+(p3)	cmp.eq p3, p4 = VRN_KERNEL, r31 ;;
 	
 	/*
@@ -111,10 +112,30 @@
 	 */
 	mov r30 = r12
-	(p4) mov r12 = R_KSTACK ;;
+(p4)	mov r12 = R_KSTACK ;;
 	
 	add r31 = -STACK_FRAME_BIAS, r12 ;;
 	add r12 = -STACK_FRAME_SIZE, r12
 
-    /* 4. save registers in bank 0 into memory stack */	
+    /* 4. save registers in bank 0 into memory stack */
+
+	/*
+	 * If this is break_instruction handler,
+	 * copy input parameters to stack.
+	 */
+    	mov R_TMP = 0x2c00 ;;
+	cmp.eq p6,p5 = R_OFFS, R_TMP ;;
+	
+	/*
+	 * From now on, if this is break_instruction handler, p6 is true and p5 is false.
+	 * Otherwise p6 is false and p5 is true.
+	 * Note that p5 is a preserved predicate register and we make use of it.
+	 */
+	
+(p6)	st8 [r31] = r35, -8 ;;		/* save in3 */
+(p6) 	st8 [r31] = r34, -8 ;;		/* save in2 */
+(p6)	st8 [r31] = r33, -8 ;;		/* save in1 */
+(p6)	st8 [r31] = r32, -8 ;;		/* save in0 */
+(p5)	add r31 = -32, r31 ;;
+    
 	st8 [r31] = r30, -8 ;;		/* save old stack pointer */ 
 	
@@ -147,13 +168,13 @@
 	 * Inspect BSPSTORE to figure out whether it is necessary to switch to kernel BSPSTORE.
 	 */
-	(p1) shr.u r30 = r28, VRN_SHIFT ;;
-	(p1) cmp.eq p1, p2 = VRN_KERNEL, r30 ;;
+(p1)	shr.u r30 = r28, VRN_SHIFT ;;
+(p1)	cmp.eq p1, p2 = VRN_KERNEL, r30 ;;
 	
 	/*
 	 * If BSPSTORE needs to be switched, p1 is false and p2 is true.
 	 */
-	(p1) mov r30 = r28
-	(p2) mov r30 = R_KSTACK_BSP ;;
-	(p2) mov ar.bspstore = r30 ;;
+(p1)	mov r30 = r28
+(p2)	mov r30 = R_KSTACK_BSP ;;
+(p2)	mov ar.bspstore = r30 ;;
 	
 	mov r29 = ar.bsp
@@ -269,5 +290,5 @@
 	mov loc22 = r6
 	mov loc23 = r7
-	mov loc24 = r8
+(p5)	mov loc24 = r8		/* only if not in break_instruction handler */
 	mov loc25 = r9
 	mov loc26 = r10
@@ -326,5 +347,5 @@
 	mov r6 = loc22
 	mov r7 = loc23
-	mov r8 = loc24
+(p5)	mov r8 = loc24		/* only if not in break_instruction handler */
 	mov r9 = loc25
 	mov r10 = loc26