target/arm: Convert Clear-Exclusive, Barriers

Backports commit 519b84711ea36bb8a339096e207b6b9b65cd2051 from qemu

qemu/target/arm/a32-uncond.decode

@@ -22,6 +22,7 @@
 # All of those that have a COND field in insn[31:28] are in a32.decode
 #
 
+&empty           !extern
 &i               !extern imm
 
 # Branch with Link and Exchange
@@ -37,3 +38,12 @@ BLX_i            1111 101 . ........................          &i imm=%imm24h
 
 RFE              1111 100 pu:2 0 w:1 1 rn:4 0000 1010 0000 0000   &rfe
 SRS              1111 100 pu:2 1 w:1 0 1101 0000 0101 000 mode:5  &srs
+
+# Clear-Exclusive, Barriers
+
+# QEMU does not require the option field for the barriers.
+CLREX            1111 0101 0111 1111 1111 0000 0001 1111
+DSB              1111 0101 0111 1111 1111 0000 0100 ----
+DMB              1111 0101 0111 1111 1111 0000 0101 ----
+ISB              1111 0101 0111 1111 1111 0000 0110 ----
+SB               1111 0101 0111 1111 1111 0000 0111 0000

qemu/target/arm/t32.decode

@@ -305,6 +305,16 @@ CLZ              1111 1010 1011 ---- 1111 .... 1000 ....      @rdm
       # of the space is "reserved hint, behaves as nop".
       NOP        1111 0011 1010 1111 1000 0000 ---- ----
     }
+
+    # Miscellaneous control
+    {
+      CLREX      1111 0011 1011 1111 1000 1111 0010 1111
+      DSB        1111 0011 1011 1111 1000 1111 0100 ----
+      DMB        1111 0011 1011 1111 1000 1111 0101 ----
+      ISB        1111 0011 1011 1111 1000 1111 0110 ----
+      SB         1111 0011 1011 1111 1000 1111 0111 0000
+    }
+
     # Note that the v7m insn overlaps both the normal and banked insn.
     {
       MRS_bank   1111 0011 111 r:1 .... 1000 rd:4   001. 0000  \

qemu/target/arm/translate.c

@@ -10482,6 +10482,65 @@ static bool trans_SRS(DisasContext *s, arg_SRS *a)
     return true;
 }
 
+/*
+ * Clear-Exclusive, Barriers
+ */
+
+static bool trans_CLREX(DisasContext *s, arg_CLREX *a)
+{
+    if (s->thumb
+        ? !ENABLE_ARCH_7 && !arm_dc_feature(s, ARM_FEATURE_M)
+        : !ENABLE_ARCH_6K) {
+        return false;
+    }
+    gen_clrex(s);
+    return true;
+}
+
+static bool trans_DSB(DisasContext *s, arg_DSB *a)
+{
+    TCGContext *tcg_ctx = s->uc->tcg_ctx;
+    if (!ENABLE_ARCH_7 && !arm_dc_feature(s, ARM_FEATURE_M)) {
+        return false;
+    }
+    tcg_gen_mb(tcg_ctx, TCG_MO_ALL | TCG_BAR_SC);
+    return true;
+}
+
+static bool trans_DMB(DisasContext *s, arg_DMB *a)
+{
+    return trans_DSB(s, NULL);
+}
+
+static bool trans_ISB(DisasContext *s, arg_ISB *a)
+{
+    if (!ENABLE_ARCH_7 && !arm_dc_feature(s, ARM_FEATURE_M)) {
+        return false;
+    }
+    /*
+     * We need to break the TB after this insn to execute
+     * self-modifying code correctly and also to take
+     * any pending interrupts immediately.
+     */
+    gen_goto_tb(s, 0, s->base.pc_next);
+    return true;
+}
+
+static bool trans_SB(DisasContext *s, arg_SB *a)
+{
+    TCGContext *tcg_ctx = s->uc->tcg_ctx;
+    if (!dc_isar_feature(aa32_sb, s)) {
+        return false;
+    }
+    /*
+     * TODO: There is no speculation barrier opcode
+     * for TCG; MB and end the TB instead.
+     */
+    tcg_gen_mb(tcg_ctx, TCG_MO_ALL | TCG_BAR_SC);
+    gen_goto_tb(s, 0, s->base.pc_next);
+    return true;
+}
+
 /*
  * Legacy decoder.
  */
@@ -10584,38 +10643,6 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn)
                 s->base.is_jmp = DISAS_UPDATE;
             }
             return;
-        } else if ((insn & 0x0fffff00) == 0x057ff000) {
-            switch ((insn >> 4) & 0xf) {
-            case 1: /* clrex */
-                ARCH(6K);
-                gen_clrex(s);
-                return;
-            case 4: /* dsb */
-            case 5: /* dmb */
-                ARCH(7);
-                tcg_gen_mb(tcg_ctx, TCG_MO_ALL | TCG_BAR_SC);
-                return;
-            case 6: /* isb */
-                /* We need to break the TB after this insn to execute
-                 * self-modifying code correctly and also to take
-                 * any pending interrupts immediately.
-                 */
-                gen_goto_tb(s, 0, s->base.pc_next);
-                return;
-            case 7: /* sb */
-                if ((insn & 0xf) || !dc_isar_feature(aa32_sb, s)) {
-                    goto illegal_op;
-                }
-                /*
-                 * TODO: There is no speculation barrier opcode
-                 * for TCG; MB and end the TB instead.
-                 */
-                tcg_gen_mb(tcg_ctx, TCG_MO_ALL | TCG_BAR_SC);
-                gen_goto_tb(s, 0, s->base.pc_next);
-                return;
-            default:
-                goto illegal_op;
-            }
         } else if ((insn & 0x0e000f00) == 0x0c000100) {
             if (arm_dc_feature(s, ARM_FEATURE_IWMMXT)) {
                 /* iWMMXt register transfer.  */
@@ -11080,43 +11107,7 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
                             gen_set_psr_im(s, offset, 0, imm);
                         }
                         break;
-                    case 3: /* Special control operations.  */
+                    case 3: /* Special control operations, in decodetree */
-                        if (!arm_dc_feature(s, ARM_FEATURE_V7) &&
-                            !arm_dc_feature(s, ARM_FEATURE_M)) {
-                            goto illegal_op;
-                        }
-                        op = (insn >> 4) & 0xf;
-                        switch (op) {
-                        case 2: /* clrex */
-                            gen_clrex(s);
-                            break;
-                        case 4: /* dsb */
-                        case 5: /* dmb */
-                            tcg_gen_mb(tcg_ctx, TCG_MO_ALL | TCG_BAR_SC);
-                            break;
-                        case 6: /* isb */
-                            /* We need to break the TB after this insn
-                             * to execute self-modifying code correctly
-                             * and also to take any pending interrupts
-                             * immediately.
-                             */
-                            gen_goto_tb(s, 0, s->base.pc_next);
-                            break;
-                        case 7: /* sb */
-                            if ((insn & 0xf) || !dc_isar_feature(aa32_sb, s)) {
-                                goto illegal_op;
-                            }
-                            /*
-                             * TODO: There is no speculation barrier opcode
-                             * for TCG; MB and end the TB instead.
-                             */
-                            tcg_gen_mb(tcg_ctx, TCG_MO_ALL | TCG_BAR_SC);
-                            gen_goto_tb(s, 0, s->base.pc_next);
-                            break;
-                        default:
-                            goto illegal_op;
-                        }
-                        break;
                     case 4: /* bxj, in decodetree */
                         goto illegal_op;
                     case 5: /* Exception return.  */