target-alpha: Implement rs/rc properly.

This is a per-cpu flag; there's no need for a spinlock of any kind.

We were also failing to manipulate the flag with $31 as a target reg
and failing to clear the flag on execution of a return-from-interrupt
instruction.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

linux-user/main.c

@@ -2358,6 +2358,11 @@ void cpu_loop (CPUState *env)
     while (1) {
         trapnr = cpu_alpha_exec (env);
 
+        /* All of the traps imply a transition through PALcode, which
+           implies an REI instruction has been executed.  Which means
+           that the intr_flag should be cleared.  */
+        env->intr_flag = 0;
+
         switch (trapnr) {
         case EXCP_RESET:
             fprintf(stderr, "Reset requested. Exit\n");
@@ -2444,7 +2449,7 @@ void cpu_loop (CPUState *env)
                                     env->ir[IR_A0], env->ir[IR_A1],
                                     env->ir[IR_A2], env->ir[IR_A3],
                                     env->ir[IR_A4], env->ir[IR_A5]);
-		if (trapnr != TARGET_NR_sigreturn
+                if (trapnr != TARGET_NR_sigreturn
                     && trapnr != TARGET_NR_rt_sigreturn) {
                     env->ir[IR_V0] = (sysret < 0 ? -sysret : sysret);
                     env->ir[IR_A3] = (sysret < 0);

target-alpha/helper.h

@@ -2,8 +2,6 @@
 
 DEF_HELPER_2(excp, void, int, int)
 DEF_HELPER_FLAGS_0(load_pcc, TCG_CALL_CONST | TCG_CALL_PURE, i64)
-DEF_HELPER_FLAGS_0(rc, TCG_CALL_CONST, i64)
-DEF_HELPER_FLAGS_0(rs, TCG_CALL_CONST, i64)
 
 DEF_HELPER_2(addqv, i64, i64, i64)
 DEF_HELPER_2(addlv, i64, i64, i64)

target-alpha/op_helper.c

@@ -47,32 +47,6 @@ void helper_store_fpcr (uint64_t val)
     cpu_alpha_store_fpcr (env, val);
 }
 
-static spinlock_t intr_cpu_lock = SPIN_LOCK_UNLOCKED;
-
-uint64_t helper_rs(void)
-{
-    uint64_t tmp;
-
-    spin_lock(&intr_cpu_lock);
-    tmp = env->intr_flag;
-    env->intr_flag = 1;
-    spin_unlock(&intr_cpu_lock);
-
-    return tmp;
-}
-
-uint64_t helper_rc(void)
-{
-    uint64_t tmp;
-
-    spin_lock(&intr_cpu_lock);
-    tmp = env->intr_flag;
-    env->intr_flag = 0;
-    spin_unlock(&intr_cpu_lock);
-
-    return tmp;
-}
-
 uint64_t helper_addqv (uint64_t op1, uint64_t op2)
 {
     uint64_t tmp = op1;
@@ -1191,6 +1165,7 @@ void helper_hw_rei (void)
 {
     env->pc = env->ipr[IPR_EXC_ADDR] & ~3;
     env->ipr[IPR_EXC_ADDR] = env->ipr[IPR_EXC_ADDR] & 1;
+    env->intr_flag = 0;
     /* XXX: re-enable interrupts and memory mapping */
 }
 
@@ -1198,6 +1173,7 @@ void helper_hw_ret (uint64_t a)
 {
     env->pc = a & ~3;
     env->ipr[IPR_EXC_ADDR] = a & 1;
+    env->intr_flag = 0;
     /* XXX: re-enable interrupts and memory mapping */
 }
 

target-alpha/translate.c

@@ -1301,6 +1301,19 @@ static void gen_cmp(TCGCond cond, int ra, int rb, int rc,
     }
 }
 
+static void gen_rx(int ra, int set)
+{
+    TCGv_i32 tmp;
+
+    if (ra != 31) {
+        tcg_gen_ld8u_i64(cpu_ir[ra], cpu_env, offsetof(CPUState, intr_flag));
+    }
+
+    tmp = tcg_const_i32(set);
+    tcg_gen_st8_i32(tmp, cpu_env, offsetof(CPUState, intr_flag));
+    tcg_temp_free_i32(tmp);
+}
+
 static inline int translate_one(DisasContext *ctx, uint32_t insn)
 {
     uint32_t palcode;
@@ -2392,16 +2405,14 @@ static inline int translate_one(DisasContext *ctx, uint32_t insn)
             break;
         case 0xE000:
             /* RC */
-            if (ra != 31)
+            gen_rx(ra, 0);
-                gen_helper_rc(cpu_ir[ra]);
             break;
         case 0xE800:
             /* ECB */
             break;
         case 0xF000:
             /* RS */
-            if (ra != 31)
+            gen_rx(ra, 1);
-                gen_helper_rs(cpu_ir[ra]);
             break;
         case 0xF800:
             /* WH64 */