target-arm: Add VBAR support to ARM1176 CPUs

ARM1176 CPUs have TrustZone support and can use the Vector Base
Address Register, but currently, qemu only adds VBAR support to ARMv7
CPUs. Fix this by adding a new feature ARM_FEATURE_VBAR which can used
for ARMv7 and ARM1176 CPUs.

The VBAR feature is always set for ARMv7 because some legacy boards
require it even if this is not architecturally correct.
Signed-off-by: NCédric Le Goater <clg@kaod.org>
Message-id: 1481810970-9692-1-git-send-email-clg@kaod.org
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target/arm/cpu.c

@@ -597,6 +597,11 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
         } else {
             set_feature(env, ARM_FEATURE_V6);
         }
+
+        /* Always define VBAR for V7 CPUs even if it doesn't exist in
+         * non-EL3 configs. This is needed by some legacy boards.
+         */
+        set_feature(env, ARM_FEATURE_VBAR);
     }
     if (arm_feature(env, ARM_FEATURE_V6K)) {
         set_feature(env, ARM_FEATURE_V6);
@@ -721,6 +726,10 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
         }
     }
 
+    if (arm_feature(env, ARM_FEATURE_EL3)) {
+        set_feature(env, ARM_FEATURE_VBAR);
+    }
+
     register_cp_regs_for_features(cpu);
     arm_cpu_register_gdb_regs_for_features(cpu);
 

target/arm/cpu.h

@@ -1125,6 +1125,7 @@ enum arm_features {
     ARM_FEATURE_V8_PMULL, /* implements PMULL part of v8 Crypto Extensions */
     ARM_FEATURE_THUMB_DSP, /* DSP insns supported in the Thumb encodings */
     ARM_FEATURE_PMU, /* has PMU support */
+    ARM_FEATURE_VBAR, /* has cp15 VBAR */
 };
 
 static inline int arm_feature(CPUARMState *env, int feature)

target/arm/helper.c

@@ -1252,12 +1252,6 @@ static const ARMCPRegInfo v7_cp_reginfo[] = {
       .access = PL1_RW, .accessfn = access_tpm, .type = ARM_CP_ALIAS,
       .fieldoffset = offsetof(CPUARMState, cp15.c9_pminten),
       .writefn = pmintenclr_write },
-    { .name = "VBAR", .state = ARM_CP_STATE_BOTH,
-      .opc0 = 3, .crn = 12, .crm = 0, .opc1 = 0, .opc2 = 0,
-      .access = PL1_RW, .writefn = vbar_write,
-      .bank_fieldoffsets = { offsetof(CPUARMState, cp15.vbar_s),
-                             offsetof(CPUARMState, cp15.vbar_ns) },
-      .resetvalue = 0 },
     { .name = "CCSIDR", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 0,
       .access = PL1_R, .readfn = ccsidr_read, .type = ARM_CP_NO_RAW },
@@ -5094,6 +5088,19 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         }
     }
 
+    if (arm_feature(env, ARM_FEATURE_VBAR)) {
+        ARMCPRegInfo vbar_cp_reginfo[] = {
+            { .name = "VBAR", .state = ARM_CP_STATE_BOTH,
+              .opc0 = 3, .crn = 12, .crm = 0, .opc1 = 0, .opc2 = 0,
+              .access = PL1_RW, .writefn = vbar_write,
+              .bank_fieldoffsets = { offsetof(CPUARMState, cp15.vbar_s),
+                                     offsetof(CPUARMState, cp15.vbar_ns) },
+              .resetvalue = 0 },
+            REGINFO_SENTINEL
+        };
+        define_arm_cp_regs(cpu, vbar_cp_reginfo);
+    }
+
     /* Generic registers whose values depend on the implementation */
     {
         ARMCPRegInfo sctlr = {