PERFORCE change 152638 for review
Peter Wemm
peter at FreeBSD.org
Fri Nov 7 15:21:36 PST 2008
http://perforce.freebsd.org/chv.cgi?CH=152638
Change 152638 by peter at peter_hammer on 2008/11/07 23:20:41
res2 (%edx) handling across syscalls is "special" on i386. syscalls may
or may not specify it. It is otherwise preserved across a syscall, and
some asm stubs in libc depend on this (eg: brk()). This is not the case
for amd64 where the syscall interface uses the C calling convention and
trashes the scratch registers. %rdx is a scratch register. I always
trash it in valgrind on amd64.
Affected files ...
.. //depot/projects/valgrind/coregrind/m_syswrap/syswrap-main.c#14 edit
Differences ...
==== //depot/projects/valgrind/coregrind/m_syswrap/syswrap-main.c#14 (text+ko) ====
@@ -313,7 +313,8 @@
//VG_(printf)( "eq_SyscallStatus: what %d %d res %ld %ld res2 %ld %ld err %ld %ld isError %d %d\n", s1->what, s2->what, s1->sres.res, s2->sres.res, s1->sres.res2, s2->sres.res2, s1->sres.err, s2->sres.err, s1->sres.isError, s2->sres.isError);
return s1->what == s2->what
&& s1->sres.res == s2->sres.res
-#if defined(VGO_freebsd)
+#if defined(VGP_amd64_freebsd)
+ /* x86 should check this too, but syscall wrappers that call do_syscallN() don't preserve res2 */
&& s1->sres.res2 == s2->sres.res2
#endif
#if !defined(VGO_freebsd) /* getSyscallStatusFromMumble is out of sync */
More information about the p4-projects
mailing list