From 7031746224c2c274548596b5ee1e856360d860c5 Mon Sep 17 00:00:00 2001
From: "kfraser@localhost.localdomain" <kfraser@localhost.localdomain>
Date: Wed, 27 Sep 2006 14:28:26 +0100
Subject: [PATCH] [XEN] gdbstub return value is used to determine whether or
 not to continue execution. Signed-off-by: Keir Fraser <keir@xensource.com>

---
 xen/common/gdbstub.c           | 26 ++++++++------------
 xen/include/asm-x86/debugger.h | 43 ++++++----------------------------
 2 files changed, 17 insertions(+), 52 deletions(-)

diff --git a/xen/common/gdbstub.c b/xen/common/gdbstub.c
index 708357c56a..54a81680a7 100644
--- a/xen/common/gdbstub.c
+++ b/xen/common/gdbstub.c
@@ -506,14 +506,13 @@ gdbstub_console_puts(const char *str)
 int 
 __trap_to_gdb(struct cpu_user_regs *regs, unsigned long cookie)
 {
-    int resume = 0;
-    int r;
+    int rc = 0;
     unsigned long flags;
 
     if ( gdb_ctx->serhnd < 0 )
     {
         dbg_printk("Debugger not ready yet.\n");
-        return 0;
+        return -EBUSY;
     }
 
     /* We rely on our caller to ensure we're only on one processor
@@ -532,7 +531,7 @@ __trap_to_gdb(struct cpu_user_regs *regs, unsigned long cookie)
     {
         printk("WARNING WARNING WARNING: Avoiding recursive gdb.\n");
         atomic_inc(&gdb_ctx->running);
-        return 0;
+        return -EBUSY;
     }
 
     if ( !gdb_ctx->connected )
@@ -565,19 +564,14 @@ __trap_to_gdb(struct cpu_user_regs *regs, unsigned long cookie)
         gdb_cmd_signum(gdb_ctx);
     }
 
-    while ( resume == 0 )
-    {
-        r = receive_command(gdb_ctx);
-        if ( r < 0 )
-        {
-            dbg_printk("GDB disappeared, trying to resume Xen...\n");
-            resume = 1;
-        }
-        else
+    do {
+        if ( receive_command(gdb_ctx) < 0 )
         {
-            resume = process_command(regs, gdb_ctx);
+            dbg_printk("Error in GDB session...\n");
+            rc = -EIO;
+            break;
         }
-    }
+    } while ( process_command(regs, gdb_ctx) == 0 );
 
     gdb_arch_exit(regs);
     console_end_sync();
@@ -586,7 +580,7 @@ __trap_to_gdb(struct cpu_user_regs *regs, unsigned long cookie)
 
     local_irq_restore(flags);
 
-    return 0;
+    return rc;
 }
 
 void
diff --git a/xen/include/asm-x86/debugger.h b/xen/include/asm-x86/debugger.h
index 3e5debebd8..743dc2d8e5 100644
--- a/xen/include/asm-x86/debugger.h
+++ b/xen/include/asm-x86/debugger.h
@@ -15,14 +15,13 @@
  * 2. debugger_trap_fatal():
  *  Called when Xen is about to give up and crash. Typically you will use this
  *  hook to drop into a debug session. It can also be used to hook off
- *  deliberately caused traps (which you then handle and return non-zero)
- *  but really these should be hooked off 'debugger_trap_entry'.
+ *  deliberately caused traps (which you then handle and return non-zero).
  *
  * 3. debugger_trap_immediate():
  *  Called if we want to drop into a debugger now.  This is essentially the
  *  same as debugger_trap_fatal, except that we use the current register state
  *  rather than the state which was in effect when we took the trap.
- *  Essentially, if we're dying because of an unhandled exception, we call
+ *  For example: if we're dying because of an unhandled exception, we call
  *  debugger_trap_fatal; if we're dying because of a panic() we call
  *  debugger_trap_immediate().
  */
@@ -44,42 +43,19 @@
 
 #include <xen/gdbstub.h>
 
-#define __debugger_trap_entry(_v, _r) (0)
-
-static inline int __debugger_trap_fatal(
+static inline int debugger_trap_fatal(
     unsigned int vector, struct cpu_user_regs *regs)
 {
-    (void)__trap_to_gdb(regs, vector);
-    return (vector == TRAP_int3); /* int3 is harmless */
+    return (__trap_to_gdb(regs, vector) == 0);
 }
 
 /* Int3 is a trivial way to gather cpu_user_regs context. */
 #define debugger_trap_immediate() __asm__ __volatile__ ( "int3" );
 
-#elif 0
-
-extern int kdb_trap(int, int, struct cpu_user_regs *);
-
-static inline int __debugger_trap_entry(
-    unsigned int vector, struct cpu_user_regs *regs)
-{
-    return 0;
-}
-
-static inline int __debugger_trap_fatal(
-    unsigned int vector, struct cpu_user_regs *regs)
-{
-    return kdb_trap(vector, 0, regs);
-}
-
-/* Int3 is a trivial way to gather cpu_user_regs context. */
-#define debugger_trap_immediate() __asm__ __volatile__ ( "int3" )
-
 #else
 
-#define __debugger_trap_entry(_v, _r) (0)
-#define __debugger_trap_fatal(_v, _r) (0)
-#define __debugger_trap_immediate()   ((void)0)
+#define debugger_trap_fatal(v, r) (0)
+#define debugger_trap_immediate() ((void)0)
 
 #endif
 
@@ -96,12 +72,7 @@ static inline int debugger_trap_entry(
         return 1;
     }
 
-    return __debugger_trap_entry(vector, regs);
+    return 0;
 }
 
-#define debugger_trap_fatal(v, r) (__debugger_trap_fatal(v, r))
-#ifndef debugger_trap_immediate
-#define debugger_trap_immediate() (__debugger_trap_immediate())
-#endif
-
 #endif /* __X86_DEBUGGER_H__ */
-- 
2.30.2