[src/trunk]: src Add a workaround for older crt0.o that overwrite r2 (tcb poi...

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1cca8d75cd57
branches:  trunk
changeset: 763920:1cca8d75cd57
user:      matt <matt%NetBSD.org@localhost>
date:      Thu Apr 07 02:19:28 2011 +0000

description:
Add a workaround for older crt0.o that overwrite r2 (tcb pointer).
(save tcb pointer using _lwp_setprivate in ld.elf_so and retrieve the tcb
via _lwp_getprivate in libc and use it to restore the value in r2).

diffstat:

 lib/libc/tls/tls.c      |  16 +++++++++++++---
 libexec/ld.elf_so/tls.c |  11 +++++++++--
 2 files changed, 22 insertions(+), 5 deletions(-)

diffs (70 lines):

diff -r 3b4503eaeb29 -r 1cca8d75cd57 lib/libc/tls/tls.c
--- a/lib/libc/tls/tls.c        Thu Apr 07 02:05:02 2011 +0000
+++ b/lib/libc/tls/tls.c        Thu Apr 07 02:19:28 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tls.c,v 1.5 2011/03/18 14:56:01 he Exp $       */
+/*     $NetBSD: tls.c,v 1.6 2011/04/07 02:19:28 matt Exp $     */
 
 /*-
  * Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: tls.c,v 1.5 2011/03/18 14:56:01 he Exp $");
+__RCSID("$NetBSD: tls.c,v 1.6 2011/04/07 02:19:28 matt Exp $");
 
 #include "namespace.h"
 
@@ -154,8 +154,18 @@
 {
        struct tls_tcb *tcb;
 
-       if (&rtld_DYNAMIC != NULL)
+       if (&rtld_DYNAMIC != NULL) {
+#ifdef __powerpc__
+               /*
+                * Old powerpc crt0's are going to overwrite r2 so we need to
+                * restore it but only do so if the saved value isn't NULL (if
+                * it is NULL, ld.elf_so doesn't have the matching change).
+                */
+               if ((tcb = _lwp_getprivate()) != NULL)
+                       __lwp_settcb(tcb);
+#endif
                return;
+       }
 
        dl_iterate_phdr(__libc_static_tls_setup_cb, NULL);
 
diff -r 3b4503eaeb29 -r 1cca8d75cd57 libexec/ld.elf_so/tls.c
--- a/libexec/ld.elf_so/tls.c   Thu Apr 07 02:05:02 2011 +0000
+++ b/libexec/ld.elf_so/tls.c   Thu Apr 07 02:19:28 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tls.c,v 1.5 2011/03/29 20:56:35 joerg Exp $    */
+/*     $NetBSD: tls.c,v 1.6 2011/04/07 02:19:28 matt Exp $     */
 /*-
  * Copyright (c) 2011 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -29,7 +29,7 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: tls.c,v 1.5 2011/03/29 20:56:35 joerg Exp $");
+__RCSID("$NetBSD: tls.c,v 1.6 2011/04/07 02:19:28 matt Exp $");
 
 #include <sys/param.h>
 #include <sys/ucontext.h>
@@ -104,6 +104,13 @@
        tcb = _rtld_tls_allocate_locked();
 #ifdef __HAVE___LWP_SETTCB
        __lwp_settcb(tcb);
+#ifdef __powerpc__
+       /*
+        * Save the tcb pointer so that libc can retrieve it.  Older
+        * crt0 will obliterate r2 so there is code in libc to restore it.
+        */
+       _lwp_setprivate(tcb);
+#endif
 #else
        _lwp_setprivate(tcb);
 #endif