linux-user/s390x: Fix sigframe types

Noticed via gitlab clang-user job:

  TEST    signals on s390x
../linux-user/s390x/signal.c:258:9: runtime error: \
  1.84467e+19 is outside the range of representable values of \
  type 'unsigned long'

Which points to the fact that we were performing a double-to-uint64_t
conversion while storing the fp registers, instead of just copying
the data across.

Turns out there are several errors:

target_ulong is the size of the target register, whereas abi_ulong
is the target 'unsigned long' type.  Not a big deal here, since we
only support 64-bit s390x, but not correct either.

In target_sigcontext and target ucontext, we used a host pointer
instead of a target pointer, aka abi_ulong.

Fixing this allows the removal of a cast to __put_user.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210428193408.233706-2-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/s390x/signal.c

@@ -37,36 +37,37 @@
 
 typedef struct {
     target_psw_t psw;
-    target_ulong gprs[__NUM_GPRS];
-    unsigned int acrs[__NUM_ACRS];
+    abi_ulong gprs[__NUM_GPRS];
+    abi_uint acrs[__NUM_ACRS];
 } target_s390_regs_common;
 
 typedef struct {
-    unsigned int fpc;
-    double   fprs[__NUM_FPRS];
+    uint32_t fpc;
+    uint32_t pad;
+    uint64_t fprs[__NUM_FPRS];
 } target_s390_fp_regs;
 
 typedef struct {
     target_s390_regs_common regs;
     target_s390_fp_regs     fpregs;
 } target_sigregs;
 
-struct target_sigcontext {
-    target_ulong   oldmask[_SIGCONTEXT_NSIG_WORDS];
-    target_sigregs *sregs;
-};
+typedef struct {
+    abi_ulong oldmask[_SIGCONTEXT_NSIG_WORDS];
+    abi_ulong sregs;
+} target_sigcontext;
 
 typedef struct {
     uint8_t callee_used_stack[__SIGNAL_FRAMESIZE];
-    struct target_sigcontext sc;
+    target_sigcontext sc;
     target_sigregs sregs;
     int signo;
     uint8_t retcode[S390_SYSCALL_SIZE];
 } sigframe;
 
 struct target_ucontext {
-    target_ulong tuc_flags;
-    struct target_ucontext *tuc_link;
+    abi_ulong tuc_flags;
+    abi_ulong tuc_link;
     target_stack_t tuc_stack;
     target_sigregs tuc_mcontext;
     target_sigset_t tuc_sigmask;   /* mask last for extensibility */
@@ -143,8 +144,7 @@ void setup_frame(int sig, struct target_sigaction *ka,
 
     save_sigregs(env, &frame->sregs);
 
-    __put_user((abi_ulong)(unsigned long)&frame->sregs,
-               (abi_ulong *)&frame->sc.sregs);
+    __put_user((abi_ulong)(unsigned long)&frame->sregs, &frame->sc.sregs);
 
     /* Set up to return from userspace.  If provided, use a stub
        already in userspace.  */