target-arm: Implement MDCR_EL3.TDA and MDCR_EL2.TDA traps

Implement the debug register traps controlled by MDCR_EL2.TDA
and MDCR_EL3.TDA.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NSergey Fedorov <serge.fdrv@gmail.com>

target-arm/helper.c

@@ -421,6 +421,24 @@ static CPAccessResult access_tdra(CPUARMState *env, const ARMCPRegInfo *ri,
     return CP_ACCESS_OK;
 }
 
+/* Check for traps to general debug registers, which are controlled
+ * by MDCR_EL2.TDA for EL2 and MDCR_EL3.TDA for EL3.
+ */
+static CPAccessResult access_tda(CPUARMState *env, const ARMCPRegInfo *ri,
+                                  bool isread)
+{
+    int el = arm_current_el(env);
+
+    if (el < 2 && (env->cp15.mdcr_el2 & MDCR_TDA)
+        && !arm_is_secure_below_el3(env)) {
+        return CP_ACCESS_TRAP_EL2;
+    }
+    if (el < 3 && (env->cp15.mdcr_el3 & MDCR_TDA)) {
+        return CP_ACCESS_TRAP_EL3;
+    }
+    return CP_ACCESS_OK;
+}
+
 static void dacr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
 {
     ARMCPU *cpu = arm_env_get_cpu(env);
@@ -3384,7 +3402,8 @@ static const ARMCPRegInfo el3_no_el2_cp_reginfo[] = {
       .access = PL2_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
     { .name = "MDCR_EL2", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .opc1 = 4, .crn = 1, .crm = 1, .opc2 = 1,
-      .access = PL2_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
+      .access = PL2_RW, .accessfn = access_tda,
+      .type = ARM_CP_CONST, .resetvalue = 0 },
     { .name = "HPFAR_EL2", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .opc1 = 4, .crn = 6, .crm = 0, .opc2 = 4,
       .access = PL2_RW, .accessfn = access_el3_aa32ns_aa64any,
@@ -3803,7 +3822,7 @@ static const ARMCPRegInfo debug_cp_reginfo[] = {
     /* Monitor debug system control register; the 32-bit alias is DBGDSCRext. */
     { .name = "MDSCR_EL1", .state = ARM_CP_STATE_BOTH,
       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 2,
-      .access = PL1_RW,
+      .access = PL1_RW, .accessfn = access_tda,
       .fieldoffset = offsetof(CPUARMState, cp15.mdscr_el1),
       .resetvalue = 0 },
     /* MDCCSR_EL0, aka DBGDSCRint. This is a read-only mirror of MDSCR_EL1.
@@ -3812,7 +3831,7 @@ static const ARMCPRegInfo debug_cp_reginfo[] = {
     { .name = "MDCCSR_EL0", .state = ARM_CP_STATE_BOTH,
       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 1, .opc2 = 0,
       .type = ARM_CP_ALIAS,
-      .access = PL1_R,
+      .access = PL1_R, .accessfn = access_tda,
       .fieldoffset = offsetof(CPUARMState, cp15.mdscr_el1), },
     { .name = "OSLAR_EL1", .state = ARM_CP_STATE_BOTH,
       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 4,
@@ -3834,7 +3853,8 @@ static const ARMCPRegInfo debug_cp_reginfo[] = {
      */
     { .name = "DBGVCR",
       .cp = 14, .opc1 = 0, .crn = 0, .crm = 7, .opc2 = 0,
-      .access = PL1_RW, .type = ARM_CP_NOP },
+      .access = PL1_RW, .accessfn = access_tda,
+      .type = ARM_CP_NOP },
     REGINFO_SENTINEL
 };
 
@@ -4099,7 +4119,8 @@ static void define_debug_regs(ARMCPU *cpu)
     int wrps, brps, ctx_cmps;
     ARMCPRegInfo dbgdidr = {
         .name = "DBGDIDR", .cp = 14, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 0,
-        .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = cpu->dbgdidr,
+        .access = PL0_R, .accessfn = access_tda,
+        .type = ARM_CP_CONST, .resetvalue = cpu->dbgdidr,
     };
 
     /* Note that all these register fields hold "number of Xs minus 1". */
@@ -4130,13 +4151,13 @@ static void define_debug_regs(ARMCPU *cpu)
         ARMCPRegInfo dbgregs[] = {
             { .name = "DBGBVR", .state = ARM_CP_STATE_BOTH,
               .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 4,
-              .access = PL1_RW,
+              .access = PL1_RW, .accessfn = access_tda,
               .fieldoffset = offsetof(CPUARMState, cp15.dbgbvr[i]),
               .writefn = dbgbvr_write, .raw_writefn = raw_write
             },
             { .name = "DBGBCR", .state = ARM_CP_STATE_BOTH,
               .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 5,
-              .access = PL1_RW,
+              .access = PL1_RW, .accessfn = access_tda,
               .fieldoffset = offsetof(CPUARMState, cp15.dbgbcr[i]),
               .writefn = dbgbcr_write, .raw_writefn = raw_write
             },
@@ -4149,13 +4170,13 @@ static void define_debug_regs(ARMCPU *cpu)
         ARMCPRegInfo dbgregs[] = {
             { .name = "DBGWVR", .state = ARM_CP_STATE_BOTH,
               .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 6,
-              .access = PL1_RW,
+              .access = PL1_RW, .accessfn = access_tda,
               .fieldoffset = offsetof(CPUARMState, cp15.dbgwvr[i]),
               .writefn = dbgwvr_write, .raw_writefn = raw_write
             },
             { .name = "DBGWCR", .state = ARM_CP_STATE_BOTH,
               .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 7,
-              .access = PL1_RW,
+              .access = PL1_RW, .accessfn = access_tda,
               .fieldoffset = offsetof(CPUARMState, cp15.dbgwcr[i]),
               .writefn = dbgwcr_write, .raw_writefn = raw_write
             },