[Qemu-devel] Bugs in ppc TCG backend

[Thiemo Seufer]

Hello All,

since Revision 5729 I see failures with my usual set of mips regression
tests. The breakage is limited to the ppc TCG backend, apparently r5729
triggers bugs there.

The problem should be reproducible when attempting to install Debian
mipsel. The symptom is a segfault of qemu-system-mipsel after selecting
the country. For qemu-system-mips64el, the segfault happens much
earlier after only a few instructions.

I think I found one alignment bug, applying the appended patch moves
the crash in qemu-system-mips64el to a later point.


Thiemo


Index: qemu-work/tcg/tcg.c
===================================================================
--- qemu-work.orig/tcg/tcg.c    2008-11-27 19:47:42.000000000 +0100
+++ qemu-work/tcg/tcg.c 2008-11-28 19:24:42.000000000 +0100
@@ -621,7 +621,7 @@
 #endif
 #ifdef TCG_TARGET_CALL_ALIGN_ARGS
             /* some targets want aligned 64 bit args */
-            if (i & 1) {
+            if ((i & 1) && !(sizemask & (2 << (i - 1)))) {
                 *gen_opparam_ptr++ = TCG_CALL_DUMMY_ARG;
             }
 #endif