gdb/

	* solib-svr4.c (LM_ADDR_CHECK): New comment on PPC-aware condition.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c26c022..0cd8fd7 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2010-02-11  Jan Kratochvil  <jan.kratochvil@redhat.com>
+           Ulrich Weigand  <uweigand@de.ibm.com>
+
+       * solib-svr4.c (LM_ADDR_CHECK): New comment on PPC-aware condition.
+
 2010-02-11  Pedro Alves  <pedro@codesourcery.com>
 
        * ax-gdb.c (gen_exp_binop_rest) [BINOP_SUBSCRIPT]: Error out if

diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index 2833ed1..9d4e59e 100644 (file)
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -217,7 +217,19 @@ LM_ADDR_CHECK (struct so_list *so, bfd *abfd)
             location, or anything, really.  To avoid regressions,
             don't adjust the base offset in the latter case, although
             odds are that, if things really changed, debugging won't
-            quite work.  */
+            quite work.
+
+            One could expect more the condition
+              ((l_addr & align) == 0 && ((l_dynaddr - dynaddr) & align) == 0)
+            but the one below is relaxed for PPC.  The PPC kernel supports
+            either 4k or 64k page sizes.  To be prepared for 64k pages,
+            PPC ELF files are built using an alignment requirement of 64k.
+            However, when running on a kernel supporting 4k pages, the memory
+            mapping of the library may not actually happen on a 64k boundary!
+
+            (In the usual case where (l_addr & align) == 0, this check is
+            equivalent to the possibly expected check above.)  */
+
          if ((l_addr & align) == ((l_dynaddr - dynaddr) & align))
            {
              l_addr = l_dynaddr - dynaddr;