[PATCH v2] linux-user/s390x: Use the guest pointer for the sigreturn stub

[Andreas Krebbel <krebbel@linux.ibm.com>]

When setting up the pointer for the sigreturn stub in the return
address register (r14) we have to use the guest frame pointer instead
of the host frame pointer.

Note: This only caused problems if Qemu has been built with
--disable-pie (as it is in distros nowadays). Otherwise guest_base
defaults to 0 hiding the actual problem.

Signed-off-by: Andreas Krebbel <krebbel@linux.ibm.com>
---
 linux-user/s390x/signal.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c
index ecfa2a14a9..e9bf865074 100644
--- a/linux-user/s390x/signal.c
+++ b/linux-user/s390x/signal.c
@@ -213,7 +213,8 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (ka->sa_flags & TARGET_SA_RESTORER) {
         env->regs[14] = (unsigned long) ka->sa_restorer | PSW_ADDR_AMODE;
     } else {
-        env->regs[14] = (unsigned long) frame->retcode | PSW_ADDR_AMODE;
+        env->regs[14] = (target_ulong) (frame_addr + offsetof(rt_sigframe, retcode))
+                        | PSW_ADDR_AMODE;
         __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn,
                    (uint16_t *)(frame->retcode));
     }
-- 
2.30.2