gdb/

        * memattr.h (enum mem_access_mode): New value
        MEM_NONE.
        * memattr.c (unknown_mem_attrib): New.
        (inaccessible_by_default): New.
        (show_inaccessible_by_default): New.
        (lookup_mem_region): Check inaccessible_by_default.
        (dummy_cmd): New.
        (mem_set_cmdlist, mem_show_cmdlist): New.
        (_initialize_mem): Register new "set" and "show"
        commands.
        * target.c (memory_xfer_partial): If memory type
        is MEM_NONE, return an error.
        Clip to region size when calling to_xfer_partial.
        If upper limit of memory range is 0, don't clip
        anything.

        gdb/doc/
        * gdb.texinfo (Memory Access Checking): New.

2 files changed, 25 insertions, 0 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index ecf7a8c..71f30c1 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@
+2006-11-21  Vladimir Prus  <vladimir@codesourcery.com>
+
+	* gdb.texinfo (Memory Access Checking): New.
+
 2006-11-16  Daniel Jacobowitz  <dan@codesourcery.com>
 
 	* gdb.texinfo (Remote configuration): Mention
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index f0b5f87..f89cc09 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -6894,6 +6894,27 @@ Enable @value{GDBN} to cache target memory.
 Disable @value{GDBN} from caching target memory.  This is the default.
 @end table
 
+@subsection Memory Access Checking
+@value{GDBN} can be instructed to refuse accesses to memory that is
+not explicitly described.  This can be useful if accessing such
+regions has undesired effects for a specific target, or to provide
+better error checking.  The following commands control this behaviour.
+
+@table @code
+@kindex set mem inaccessible-by-default
+@item set mem inaccessible-by-default [on|off]
+If @code{on} is specified, make  @value{GDBN} treat memory not
+explicitly described by the memory ranges as non-existent and refuse accesses
+to such memory.  The checks are only performed if there's at least one
+memory range defined.  If @code{off} is specified, make @value{GDBN}
+treat the memory not explicitly described by the memory ranges as RAM.
+The default value is @code{off}.
+@kindex show mem inaccessible-by-default
+@item show mem inaccessible-by-default
+Show the current handling of accesses to unknown memory.
+@end table
+
+
 @c @subsubsection Memory Write Verification
 @c The memory write verification attributes set whether @value{GDBN}
 @c will re-reads data after each write to verify the write was successful.