target-arm: Implement CBAR for Cortex-A57

The Cortex-A57, like most of the other ARM cores, has a CBAR
register which defines the base address of the per-CPU
peripherals. However it has a 64-bit view as well as a
32-bit view; expand the QOM reset-cbar property from UINT32
to UINT64 so this can be specified, and implement the
32-bit and 64-bit views of a 64-bit CBAR.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>

target-arm/cpu-qom.h

@@ -148,7 +148,7 @@ typedef struct ARMCPU {
      * in the order L1DCache, L1ICache, L2DCache, L2ICache, etc.
      */
     uint32_t ccsidr[16];
-    uint32_t reset_cbar;
+    uint64_t reset_cbar;
     uint32_t reset_auxcr;
     bool reset_hivecs;
     /* DCZ blocksize, in log_2(words), ie low 4 bits of DCZID_EL0 */

target-arm/cpu.c

@@ -262,7 +262,7 @@ static void arm_cpu_initfn(Object *obj)
 }
 
 static Property arm_cpu_reset_cbar_property =
-            DEFINE_PROP_UINT32("reset-cbar", ARMCPU, reset_cbar, 0);
+            DEFINE_PROP_UINT64("reset-cbar", ARMCPU, reset_cbar, 0);
 
 static Property arm_cpu_reset_hivecs_property =
             DEFINE_PROP_BOOL("reset-hivecs", ARMCPU, reset_hivecs, false);
@@ -274,7 +274,8 @@ static void arm_cpu_post_init(Object *obj)
 {
     ARMCPU *cpu = ARM_CPU(obj);
 
-    if (arm_feature(&cpu->env, ARM_FEATURE_CBAR)) {
+    if (arm_feature(&cpu->env, ARM_FEATURE_CBAR) ||
+        arm_feature(&cpu->env, ARM_FEATURE_CBAR_RO)) {
         qdev_property_add_static(DEVICE(obj), &arm_cpu_reset_cbar_property,
                                  &error_abort);
     }
@@ -349,6 +350,9 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
         set_feature(env, ARM_FEATURE_V7MP);
         set_feature(env, ARM_FEATURE_PXN);
     }
+    if (arm_feature(env, ARM_FEATURE_CBAR_RO)) {
+        set_feature(env, ARM_FEATURE_CBAR);
+    }
 
     if (cpu->reset_hivecs) {
             cpu->reset_sctlr |= (1 << 13);

target-arm/cpu.h

@@ -630,6 +630,7 @@ enum arm_features {
     ARM_FEATURE_V8_AES, /* implements AES part of v8 Crypto Extensions */
     ARM_FEATURE_CBAR, /* has cp15 CBAR */
     ARM_FEATURE_CRC, /* ARMv8 CRC instructions */
+    ARM_FEATURE_CBAR_RO, /* has cp15 CBAR and it is read-only */
 };
 
 static inline int arm_feature(CPUARMState *env, int feature)

target-arm/cpu64.c

@@ -97,6 +97,7 @@ static void aarch64_a57_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_NEON);
     set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER);
     set_feature(&cpu->env, ARM_FEATURE_AARCH64);
+    set_feature(&cpu->env, ARM_FEATURE_CBAR_RO);
     cpu->kvm_target = QEMU_KVM_ARM_TARGET_CORTEX_A57;
     cpu->midr = 0x411fd070;
     cpu->reset_fpsid = 0x41034070;

target-arm/helper.c

@@ -2464,12 +2464,39 @@ void register_cp_regs_for_features(ARMCPU *cpu)
     }
 
     if (arm_feature(env, ARM_FEATURE_CBAR)) {
-        ARMCPRegInfo cbar = {
-            .name = "CBAR", .cp = 15, .crn = 15, .crm = 0, .opc1 = 4, .opc2 = 0,
-            .access = PL1_R|PL3_W, .resetvalue = cpu->reset_cbar,
-            .fieldoffset = offsetof(CPUARMState, cp15.c15_config_base_address)
-        };
-        define_one_arm_cp_reg(cpu, &cbar);
+        if (arm_feature(env, ARM_FEATURE_AARCH64)) {
+            /* 32 bit view is [31:18] 0...0 [43:32]. */
+            uint32_t cbar32 = (extract64(cpu->reset_cbar, 18, 14) << 18)
+                | extract64(cpu->reset_cbar, 32, 12);
+            ARMCPRegInfo cbar_reginfo[] = {
+                { .name = "CBAR",
+                  .type = ARM_CP_CONST,
+                  .cp = 15, .crn = 15, .crm = 0, .opc1 = 4, .opc2 = 0,
+                  .access = PL1_R, .resetvalue = cpu->reset_cbar },
+                { .name = "CBAR_EL1", .state = ARM_CP_STATE_AA64,
+                  .type = ARM_CP_CONST,
+                  .opc0 = 3, .opc1 = 1, .crn = 15, .crm = 3, .opc2 = 0,
+                  .access = PL1_R, .resetvalue = cbar32 },
+                REGINFO_SENTINEL
+            };
+            /* We don't implement a r/w 64 bit CBAR currently */
+            assert(arm_feature(env, ARM_FEATURE_CBAR_RO));
+            define_arm_cp_regs(cpu, cbar_reginfo);
+        } else {
+            ARMCPRegInfo cbar = {
+                .name = "CBAR",
+                .cp = 15, .crn = 15, .crm = 0, .opc1 = 4, .opc2 = 0,
+                .access = PL1_R|PL3_W, .resetvalue = cpu->reset_cbar,
+                .fieldoffset = offsetof(CPUARMState,
+                                        cp15.c15_config_base_address)
+            };
+            if (arm_feature(env, ARM_FEATURE_CBAR_RO)) {
+                cbar.access = PL1_R;
+                cbar.fieldoffset = 0;
+                cbar.type = ARM_CP_CONST;
+            }
+            define_one_arm_cp_reg(cpu, &cbar);
+        }
     }
 
     /* Generic registers whose values depend on the implementation */