PATCH: new "void" memory region attribute

[Greg McGary <gkm@kayak.mcgary.org>]

Add "void" attribute, which disallows both read & write access.  This
useful for guarding holes in a target's address space that cause the
system to hang when read/written.

OK to commit?

gdb:
	
2002-02-13  Greg McGary  <greg@mcgary.org>

	* memattr.h (enum mem_access_mode): s/MEM_RO/MEM_READ/
	s/MEM_WO/MEM_WRITE/. New member MEM_VOID.
	* memattr.c (mem_command, mem_info_command): Handle MEM_VOID.
	* target.c (target_xfer_memory, target_xfer_memory_partial):
	Check read/write validity with bit test.
	* dcache.c (dcache_write_line, dcache_read_line): Likewise.
	
doc:
	
2002-02-13  Greg McGary  <greg@mcgary.org>

	* gdb.texinfo (Memory Region Attributes): Describe `void' attribute.

Index: dcache.c
===================================================================
RCS file: /cvs/src/src/gdb/dcache.c,v
retrieving revision 1.15
diff -u -p -r1.15 dcache.c
--- dcache.c	2001/04/06 22:43:55	1.15
+++ dcache.c	2002/02/14 00:17:25
@@ -1,5 +1,5 @@
 /* Caching code.
-   Copyright 1992, 1993, 1995, 1996, 1998, 1999, 2000, 2001
+   Copyright 1992, 1993, 1995, 1996, 1998, 1999, 2000, 2001, 2002
    Free Software Foundation, Inc.
 
    This file is part of GDB.
@@ -267,7 +267,7 @@ dcache_write_line (DCACHE *dcache, regis
       else
 	reg_len = region->hi - memaddr;
 
-      if (!region->attrib.cache || region->attrib.mode == MEM_RO)
+      if (!region->attrib.cache || !(region->attrib.mode == MEM_WRITE))
 	{
 	  memaddr += reg_len;
 	  myaddr  += reg_len;
@@ -349,7 +349,7 @@ dcache_read_line (DCACHE *dcache, struct
       else
 	reg_len = region->hi - memaddr;
 
-      if (!region->attrib.cache || region->attrib.mode == MEM_WO)
+      if (!region->attrib.cache || !(region->attrib.mode & MEM_READ))
 	{
 	  memaddr += reg_len;
 	  myaddr  += reg_len;
Index: memattr.c
===================================================================
RCS file: /cvs/src/src/gdb/memattr.c,v
retrieving revision 1.9
diff -u -p -r1.9 memattr.c
--- memattr.c	2002/02/13 19:00:47	1.9
+++ memattr.c	2002/02/14 00:17:25
@@ -1,5 +1,5 @@
 /* Memory attributes support, for GDB.
-   Copyright 2001 Free Software Foundation, Inc.
+   Copyright 2001, 2002 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -156,9 +156,11 @@ mem_command (char *args, int from_tty)
       if (strcmp (tok, "rw") == 0)
 	attrib.mode = MEM_RW;
       else if (strcmp (tok, "ro") == 0)
-	attrib.mode = MEM_RO;
+	attrib.mode = MEM_READ;
       else if (strcmp (tok, "wo") == 0)
-	attrib.mode = MEM_WO;
+	attrib.mode = MEM_WRITE;
+      else if (strcmp (tok, "void") == 0)
+	attrib.mode = MEM_VOID;
 
       else if (strcmp (tok, "8") == 0)
 	attrib.width = MEM_WIDTH_8;
@@ -266,13 +268,16 @@ mem_info_command (char *args, int from_t
       attrib = &m->attrib;
       switch (attrib->mode)
 	{
+	case MEM_VOID:
+	  printf_filtered ("void ");
+	  break;
 	case MEM_RW:
 	  printf_filtered ("rw ");
 	  break;
-	case MEM_RO:
+	case MEM_READ:
 	  printf_filtered ("ro ");
 	  break;
-	case MEM_WO:
+	case MEM_WRITE:
 	  printf_filtered ("wo ");
 	  break;
 	}
Index: memattr.h
===================================================================
RCS file: /cvs/src/src/gdb/memattr.h,v
retrieving revision 1.4
diff -u -p -r1.4 memattr.h
--- memattr.h	2001/08/02 11:58:29	1.4
+++ memattr.h	2002/02/14 00:17:25
@@ -1,5 +1,5 @@
 /* Memory attributes support, for GDB.
-   Copyright 2001 Free Software Foundation, Inc.
+   Copyright 2001, 2002 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -23,9 +23,10 @@
 
 enum mem_access_mode
 {
-  MEM_RW,			/* read/write */
-  MEM_RO,			/* read only */
-  MEM_WO			/* write only */
+  MEM_VOID = 0,
+  MEM_READ = 1,
+  MEM_WRITE = 2,
+  MEM_RW = MEM_READ | MEM_WRITE,
 };
 
 enum mem_access_width
Index: target.c
===================================================================
RCS file: /cvs/src/src/gdb/target.c,v
retrieving revision 1.33
diff -u -p -r1.33 target.c
--- target.c	2002/02/01 01:01:21	1.33
+++ target.c	2002/02/14 00:17:25
@@ -933,18 +933,10 @@ target_xfer_memory (CORE_ADDR memaddr, c
       else
 	reg_len = region->hi - memaddr;
 
-      switch (region->attrib.mode)
-	{
-	case MEM_RO:
-	  if (write)
-	    return EIO;
-	  break;
-	  
-	case MEM_WO:
-	  if (!write)
-	    return EIO;
-	  break;
-	}
+      if (write
+	  ? !(region->attrib.mode & MEM_WRITE)
+	  : !(region->attrib.mode & MEM_READ))
+	return EIO;
 
       while (reg_len > 0)
 	{
@@ -1004,23 +996,12 @@ target_xfer_memory_partial (CORE_ADDR me
   else
     reg_len = region->hi - memaddr;
 
-  switch (region->attrib.mode)
+  if (write_p
+      ? !(region->attrib.mode & MEM_WRITE)
+      : !(region->attrib.mode & MEM_READ))
     {
-    case MEM_RO:
-      if (write_p)
-	{
-	  *err = EIO;
-	  return -1;
-	}
-      break;
-
-    case MEM_WO:
-      if (write_p)
-	{
-	  *err = EIO;
-	  return -1;
-	}
-      break;
+      *err = EIO;
+      return -1;
     }
 
   if (region->attrib.cache)
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.89
diff -u -p -r1.89 gdb.texinfo
--- gdb.texinfo	2002/02/08 00:39:45	1.89
+++ gdb.texinfo	2002/02/14 00:17:32
@@ -5642,6 +5642,8 @@ Memory is read only.
 Memory is write only.
 @item rw
 Memory is read/write.  This is the default.
+@item void
+Memory is inaccessible.
 @end table
 
 @subsubsection Memory Access Size