[PATCH v3 16/31] target-arm: Implement AArch64 dummy breakpoint and watchpoint registers

[Peter Maydell <peter.maydell@xxxxxxxxxx>]

In AArch64 the breakpoint and watchpoint registers are mandatory, so the
kernel always accesses them on bootup. Implement dummy versions, which
read as written but have no actual effect.

Signed-off-by: Peter Maydell <peter.maydell@xxxxxxxxxx>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xxxxxxxxxx>
---
 target-arm/cpu.h    |  4 ++++
 target-arm/helper.c | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 48419ae..db74ab7 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -216,6 +216,10 @@ typedef struct CPUARMState {
         uint32_t c15_diagnostic; /* diagnostic register */
         uint32_t c15_power_diagnostic;
         uint32_t c15_power_control; /* power control */
+        uint64_t dbgbvr[16]; /* breakpoint value registers */
+        uint64_t dbgbcr[16]; /* breakpoint control registers */
+        uint64_t dbgwvr[16]; /* watchpoint value registers */
+        uint64_t dbgwcr[16]; /* watchpoint control registers */
     } cp15;
 
     struct {
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 0b2be71..0eb56ae 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -1761,6 +1761,37 @@ static CPAccessResult ctr_el0_access(CPUARMState *env, const ARMCPRegInfo *ri)
     return CP_ACCESS_OK;
 }
 
+static void define_aarch64_debug_regs(ARMCPU *cpu)
+{
+    /* Define breakpoint and watchpoint registers. These do nothing
+     * but read as written, for now.
+     */
+    int i;
+
+    for (i = 0; i < 16; i++) {
+        ARMCPRegInfo dbgregs[] = {
+            { .name = "DBGBVR", .state = ARM_CP_STATE_AA64,
+              .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 4,
+              .access = PL1_RW,
+              .fieldoffset = offsetof(CPUARMState, cp15.dbgbvr[i]) },
+            { .name = "DBGBCR", .state = ARM_CP_STATE_AA64,
+              .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 5,
+              .access = PL1_RW,
+              .fieldoffset = offsetof(CPUARMState, cp15.dbgbcr[i]) },
+            { .name = "DBGWVR", .state = ARM_CP_STATE_AA64,
+              .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 6,
+              .access = PL1_RW,
+              .fieldoffset = offsetof(CPUARMState, cp15.dbgwvr[i]) },
+            { .name = "DBGWCR", .state = ARM_CP_STATE_AA64,
+              .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 7,
+              .access = PL1_RW,
+              .fieldoffset = offsetof(CPUARMState, cp15.dbgwcr[i]) },
+               REGINFO_SENTINEL
+        };
+        define_arm_cp_regs(cpu, dbgregs);
+    }
+}
+
 void register_cp_regs_for_features(ARMCPU *cpu)
 {
     /* Register all the coprocessor registers based on feature bits */
@@ -1902,6 +1933,7 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         };
         define_arm_cp_regs(cpu, v8_idregs);
         define_arm_cp_regs(cpu, v8_cp_reginfo);
+        define_aarch64_debug_regs(cpu);
     }
     if (arm_feature(env, ARM_FEATURE_MPU)) {
         /* These are the MPU registers prior to PMSAv6. Any new
-- 
1.8.5

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