target/mips: Introduce ase_mt_available() helper

Instead of accessing CP0_Config3 directly and checking
the 'Multi-Threading Present' bit, introduce an helper
to simplify code review.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201204222622.2743175-3-f4bug@amsat.org>

hw/mips/cps.c

@@ -58,8 +58,7 @@ static void main_cpu_reset(void *opaque)
 
 static bool cpu_mips_itu_supported(CPUMIPSState *env)
 {
-    bool is_mt = (env->CP0_Config5 & (1 << CP0C5_VP)) ||
-                 (env->CP0_Config3 & (1 << CP0C3_MT));
+    bool is_mt = (env->CP0_Config5 & (1 << CP0C5_VP)) || ase_mt_available(env);
 
     return is_mt && !kvm_enabled();
 }

target/mips/cp0_helper.c

@@ -1164,7 +1164,7 @@ void helper_mtc0_entryhi(CPUMIPSState *env, target_ulong arg1)
     old = env->CP0_EntryHi;
     val = (arg1 & mask) | (old & ~mask);
     env->CP0_EntryHi = val;
-    if (env->CP0_Config3 & (1 << CP0C3_MT)) {
+    if (ase_mt_available(env)) {
         sync_c0_entryhi(env, env->current_tc);
     }
     /* If the ASID changes, flush qemu's TLB.  */

target/mips/cpu.c

@@ -74,7 +74,7 @@ static bool mips_cpu_has_work(CPUState *cs)
     }
 
     /* MIPS-MT has the ability to halt the CPU.  */
-    if (env->CP0_Config3 & (1 << CP0C3_MT)) {
+    if (ase_mt_available(env)) {
         /*
          * The QEMU model will issue an _WAKE request whenever the CPUs
          * should be woken up.

target/mips/cpu.h

@@ -1289,6 +1289,13 @@ int cpu_mips_signal_handler(int host_signum, void *pinfo, void *puc);
 bool cpu_type_supports_cps_smp(const char *cpu_type);
 bool cpu_supports_isa(const CPUMIPSState *env, uint64_t isa_mask);
 bool cpu_type_supports_isa(const char *cpu_type, uint64_t isa);
+
+/* Check presence of multi-threading ASE implementation */
+static inline bool ase_mt_available(CPUMIPSState *env)
+{
+    return env->CP0_Config3 & (1 << CP0C3_MT);
+}
+
 void cpu_set_exception_base(int vp_index, target_ulong address);
 
 /* addr.c */

target/mips/helper.c

@@ -419,7 +419,7 @@ void cpu_mips_store_status(CPUMIPSState *env, target_ulong val)
         tlb_flush(env_cpu(env));
     }
 #endif
-    if (env->CP0_Config3 & (1 << CP0C3_MT)) {
+    if (ase_mt_available(env)) {
         sync_c0_status(env, env, env->current_tc);
     } else {
         compute_hflags(env);

target/mips/translate.c

@@ -31917,7 +31917,7 @@ void cpu_state_reset(CPUMIPSState *env)
 
     cpu_mips_store_count(env, 1);
 
-    if (env->CP0_Config3 & (1 << CP0C3_MT)) {
+    if (ase_mt_available(env)) {
         int i;
 
         /* Only TC0 on VPE 0 starts as active.  */