target/sparc: Handle FPRS correctly on big-endian hosts

In CPUSparcState we define the fprs field as uint64_t.  However we
then refer to it in translate.c via a TCGv_i32 which we set up with
tcg_global_mem_new_ptr().  This means that on a big-endian host when
the guest does something to writo te the FPRS register this value
ends up in the wrong half of the uint64_t, and the QEMU C code that
refers to env->fprs sees the wrong value.  The effect of this is that
guest code that enables the FPU crashes with spurious FPU Disabled
exceptions.  In particular, this is why
 tests/avocado/machine_sparc64_sun4u.py:Sun4uMachine.test_sparc64_sun4u
times out on an s390 host.

There are multiple ways we could fix this; since there are actually
only three bits in the FPRS register and the code in translate.c
would be a bit painful to convert to dealing with a TCGv_i64, change
the type of the CPU state struct field to match what translate.c is
expecting.

(None of the other fields referenced by the r32[] array in
sparc_tcg_init() have the wrong type.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20230717103544.637453-1-peter.maydell@linaro.org>

target/sparc/cpu.c

@@ -673,8 +673,8 @@ static void sparc_cpu_dump_state(CPUState *cs, FILE *f, int flags)
                  "cleanwin: %d cwp: %d\n",
                  env->cansave, env->canrestore, env->otherwin, env->wstate,
                  env->cleanwin, env->nwindows - 1 - env->cwp);
-    qemu_fprintf(f, "fsr: " TARGET_FMT_lx " y: " TARGET_FMT_lx " fprs: "
-                 TARGET_FMT_lx "\n", env->fsr, env->y, env->fprs);
+    qemu_fprintf(f, "fsr: " TARGET_FMT_lx " y: " TARGET_FMT_lx " fprs: %016x\n",
+                 env->fsr, env->y, env->fprs);
 
 #else
     qemu_fprintf(f, "psr: %08x (icc: ", cpu_get_psr(env));

target/sparc/cpu.h

@@ -521,7 +521,7 @@ struct CPUArchState {
     uint64_t igregs[8]; /* interrupt general registers */
     uint64_t mgregs[8]; /* mmu general registers */
     uint64_t glregs[8 * MAXTL_MAX];
-    uint64_t fprs;
+    uint32_t fprs;
     uint64_t tick_cmpr, stick_cmpr;
     CPUTimer *tick, *stick;
 #define TICK_NPT_MASK        0x8000000000000000ULL

target/sparc/machine.c

@@ -168,7 +168,8 @@ const VMStateDescription vmstate_sparc_cpu = {
         VMSTATE_UINT64_ARRAY(env.bgregs, SPARCCPU, 8),
         VMSTATE_UINT64_ARRAY(env.igregs, SPARCCPU, 8),
         VMSTATE_UINT64_ARRAY(env.mgregs, SPARCCPU, 8),
-        VMSTATE_UINT64(env.fprs, SPARCCPU),
+        VMSTATE_UNUSED(4), /* was unused high half of uint64_t fprs */
+        VMSTATE_UINT32(env.fprs, SPARCCPU),
         VMSTATE_UINT64(env.tick_cmpr, SPARCCPU),
         VMSTATE_UINT64(env.stick_cmpr, SPARCCPU),
         VMSTATE_CPU_TIMER(env.tick, SPARCCPU),

target/sparc/monitor.c

@@ -154,7 +154,7 @@ const MonitorDef monitor_defs[] = {
     { "otherwin", offsetof(CPUSPARCState, otherwin) },
     { "wstate", offsetof(CPUSPARCState, wstate) },
     { "cleanwin", offsetof(CPUSPARCState, cleanwin) },
-    { "fprs", offsetof(CPUSPARCState, fprs) },
+    { "fprs", offsetof(CPUSPARCState, fprs), NULL, MD_I32 },
 #endif
     { NULL },
 };