[commit] Fix OpenBSD/i386 and OpenBSD/amd64 kernel trapframe unwinders

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

Teach OpenBSD/i386 how to unwind from interrupt frames too.  Plus a
small fix for OpenBSD/amd64 for interrupts from user space.

Mark

Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>

	* amd64obsd-tdep.c (amd64obsd_trapframe_cache): Fix detection of
	interrupts from user space.
	* i386obsd-tdep.c (i386obsd_trapframe_cache): Handle interrupt
	frames too.
	(i386obsd_trapframe_sniffer): Turn into a proper unwinder sniffer.
	(i386obsd_trapframe_unwind): Add sniffer.
	(i386obsd_init_abi): Prepend i386obsd_trapframe_unwind instead of
	appending i386obsd_trapframe_sniffer.

Index: amd64obsd-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/amd64obsd-tdep.c,v
retrieving revision 1.19
diff -u -p -r1.19 amd64obsd-tdep.c
--- amd64obsd-tdep.c 22 Dec 2005 13:17:49 -0000 1.19
+++ amd64obsd-tdep.c 22 Dec 2005 14:06:28 -0000
@@ -370,7 +370,7 @@ amd64obsd_trapframe_cache(struct frame_i
       trad_frame_set_reg_addr (cache, i, addr + amd64obsd_tf_reg_offset[i]);
 
   /* Read %cs from trap frame.  */
-  addr = sp + amd64obsd_tf_reg_offset[AMD64_CS_REGNUM];
+  addr += amd64obsd_tf_reg_offset[AMD64_CS_REGNUM];
   cs = read_memory_unsigned_integer (addr, 8); 
   if ((cs & I386_SEL_RPL) == I386_SEL_UPL)
     {
Index: i386obsd-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/i386obsd-tdep.c,v
retrieving revision 1.26
diff -u -p -r1.26 i386obsd-tdep.c
--- i386obsd-tdep.c 19 Dec 2005 22:19:49 -0000 1.26
+++ i386obsd-tdep.c 22 Dec 2005 14:06:28 -0000
@@ -345,6 +345,7 @@ i386obsd_trapframe_cache(struct frame_in
   struct trad_frame_cache *cache;
   CORE_ADDR func, sp, addr;
   ULONGEST cs;
+  char *name;
   int i;
 
   if (*this_cache)
@@ -355,12 +356,19 @@ i386obsd_trapframe_cache(struct frame_in
 
   func = frame_func_unwind (next_frame);
   sp = frame_unwind_register_unsigned (next_frame, I386_ESP_REGNUM);
+
+  find_pc_partial_function (func, &name, NULL, NULL);
+  if (name && strncmp(name, "Xintr", 5) == 0)
+    addr = sp + 8;		/* It's an interrupt frame.  */
+  else
+    addr = sp;
+
   for (i = 0; i < ARRAY_SIZE (i386obsd_tf_reg_offset); i++)
     if (i386obsd_tf_reg_offset[i] != -1)
-      trad_frame_set_reg_addr (cache, i, sp + i386obsd_tf_reg_offset[i]);
+      trad_frame_set_reg_addr (cache, i, addr + i386obsd_tf_reg_offset[i]);
 
   /* Read %cs from trap frame.  */
-  addr = sp + i386obsd_tf_reg_offset[I386_CS_REGNUM];
+  addr += i386obsd_tf_reg_offset[I386_CS_REGNUM];
   cs = read_memory_unsigned_integer (addr, 4); 
   if ((cs & I386_SEL_RPL) == I386_SEL_UPL)
     {
@@ -400,17 +408,10 @@ i386obsd_trapframe_prev_register (struct
 			   optimizedp, lvalp, addrp, realnump, valuep);
 }
 
-static const struct frame_unwind i386obsd_trapframe_unwind = {
-  /* FIXME: kettenis/20051219: This really is more like an interrupt
-     frame, but SIGTRAMP_FRAME would print <signal handler called>,
-     which really is not what we want here.  */
-  NORMAL_FRAME,
-  i386obsd_trapframe_this_id,
-  i386obsd_trapframe_prev_register
-};
-
-static const struct frame_unwind *
-i386obsd_trapframe_sniffer (struct frame_info *next_frame)
+static int
+i386obsd_trapframe_sniffer (const struct frame_unwind *self,
+			    struct frame_info *next_frame,
+			    void **this_prologue_cache)
 {
   ULONGEST cs;
   char *name;
@@ -420,12 +421,21 @@ i386obsd_trapframe_sniffer (struct frame
     return NULL;
 
   find_pc_partial_function (frame_pc_unwind (next_frame), &name, NULL, NULL);
-  if (name && ((strcmp ("calltrap", name) == 0)
-	       || (strcmp ("syscall1", name) == 0)))
-    return &i386obsd_trapframe_unwind;
-
-  return NULL;
+  return (name && ((strcmp (name, "calltrap") == 0)
+		   || (strcmp (name, "syscall1") == 0)
+		   || (strncmp (name, "Xintr", 5) == 0)));
 }
+
+static const struct frame_unwind i386obsd_trapframe_unwind = {
+  /* FIXME: kettenis/20051219: This really is more like an interrupt
+     frame, but SIGTRAMP_FRAME would print <signal handler called>,
+     which really is not what we want here.  */
+  NORMAL_FRAME,
+  i386obsd_trapframe_this_id,
+  i386obsd_trapframe_prev_register,
+  NULL,
+  i386obsd_trapframe_sniffer
+};
 
 
 static void 
@@ -459,7 +469,7 @@ i386obsd_init_abi (struct gdbarch_info i
   bsd_uthread_set_collect_uthread (gdbarch, i386obsd_collect_uthread);
 
   /* Unwind kernel trap frames correctly.  */
-  frame_unwind_append_sniffer (gdbarch, i386obsd_trapframe_sniffer);
+  frame_unwind_prepend_unwinder (gdbarch, &i386obsd_trapframe_unwind);
 }
 
 /* OpenBSD a.out.  */