From f1222a09a60ae4ef107bb02a0f7fd8de7cd8319e Mon Sep 17 00:00:00 2001
From: Ben Gras <ben@minix3.org>
Date: Thu, 29 Jun 2006 13:35:27 +0000
Subject: [PATCH] Make stack traces on exceptions possible.

---
 kernel/debug.h     |  1 +
 kernel/exception.c | 35 +++++++++++++++++++++++++++++++++++
 kernel/proto.h     |  3 +++
 3 files changed, 39 insertions(+)

diff --git a/kernel/debug.h b/kernel/debug.h
index 534ae06a5..7169559a4 100644
--- a/kernel/debug.h
+++ b/kernel/debug.h
@@ -20,6 +20,7 @@
  * are disabled.
  */
 #define DEBUG_ENABLE_IPC_WARNINGS	0
+#define DEBUG_STACKTRACE		1
 
 /* It's interesting to measure the time spent withing locked regions, because
  * this is the time that the system is deaf to interrupts.
diff --git a/kernel/exception.c b/kernel/exception.c
index d269f4af9..df6343ace 100755
--- a/kernel/exception.c
+++ b/kernel/exception.c
@@ -65,6 +65,10 @@ unsigned vec_nr;
 			saved_proc->p_reg.cs, saved_proc->p_reg.pc,
 			saved_proc->p_reg.ss, saved_proc->p_reg.sp);
 		kprintf("edi = 0x%x\n", saved_proc->p_reg.di);
+
+#if DEBUG_STACKTRACE
+		stacktrace(saved_proc);
+#endif
 	}
 #endif
 
@@ -85,3 +89,34 @@ unsigned vec_nr;
   panic("exception in a kernel task", NO_NUM);
 }
 
+#if DEBUG_STACKTRACE
+/*===========================================================================*
+ *				stacktrace				     *
+ *===========================================================================*/
+PUBLIC void stacktrace(proc)
+struct proc *proc;
+{
+	reg_t bp, v_bp, v_pc, v_hbp;
+
+	v_bp = proc->p_reg.fp;
+
+	kprintf("stacktrace: ");
+	while(v_bp) {
+		phys_bytes p;
+		if(!(p = umap_local(proc, D, v_bp, sizeof(v_bp)))) {
+			kprintf("(bad bp %lx)", v_bp);
+			break;
+		}
+		phys_copy(p+sizeof(v_pc), vir2phys(&v_pc), sizeof(v_pc));
+		phys_copy(p, vir2phys(&v_hbp), sizeof(v_hbp));
+		kprintf("0x%lx ", (unsigned long) v_pc);
+		if(v_hbp != 0 && v_hbp <= v_bp) {
+			kprintf("(bad hbp %lx)", v_hbp);
+			break;
+		}
+		v_bp = v_hbp;
+	}
+	kprintf("\n");
+}
+#endif
+
diff --git a/kernel/proto.h b/kernel/proto.h
index bfaa88e3d..f9a68f226 100755
--- a/kernel/proto.h
+++ b/kernel/proto.h
@@ -74,6 +74,9 @@ _PROTOTYPE( int newmap, (struct proc *rp, struct mem_map *map_ptr)	);
 
 /* exception.c */
 _PROTOTYPE( void exception, (unsigned vec_nr)				);
+#if DEBUG_STACK_TRACE
+_PROTOTYPE( void stacktrace, (struct proc *)				);
+#endif
 
 /* i8259.c */
 _PROTOTYPE( void intr_init, (int mine)					);
-- 
2.44.0