armv8: allow halt on exception
[openocd.git] / src / target / armv8_dpm.c
index a92f92c6cd047e042d189c67ae029a3c1e546fe5..081eed21ba21166ef5babadd78b9537f9a36dde8 100644 (file)
@@ -51,17 +51,11 @@ enum arm_state armv8_dpm_get_core_state(struct arm_dpm *dpm)
 {
        int el = (dpm->dscr >> 8) & 0x3;
        int rw = (dpm->dscr >> 10) & 0xF;
-       int pos;
 
        dpm->last_el = el;
 
-       /* find the first '0' in DSCR.RW */
-       for (pos = 3; pos >= 0; pos--) {
-               if ((rw & (1 << pos)) == 0)
-                       break;
-       }
-
-       if (el > pos)
+       /* In Debug state, each bit gives the current Execution state of each EL */
+       if ((rw >> el) & 0b1)
                return ARM_STATE_AARCH64;
 
        return ARM_STATE_ARM;
@@ -71,7 +65,6 @@ enum arm_state armv8_dpm_get_core_state(struct arm_dpm *dpm)
 
 static int dpmv8_write_dcc(struct armv8_common *armv8, uint32_t data)
 {
-       LOG_DEBUG("write DCC 0x%08" PRIx32, data);
        return mem_ap_write_u32(armv8->debug_ap,
                                armv8->debug_base + CPUV8_DBG_DTRRX, data);
 }
@@ -79,11 +72,10 @@ static int dpmv8_write_dcc(struct armv8_common *armv8, uint32_t data)
 static int dpmv8_write_dcc_64(struct armv8_common *armv8, uint64_t data)
 {
        int ret;
-       LOG_DEBUG("write DCC Low word 0x%08" PRIx32, (unsigned)data);
-       LOG_DEBUG("write DCC High word 0x%08" PRIx32, (unsigned)(data >> 32));
        ret = mem_ap_write_u32(armv8->debug_ap,
                               armv8->debug_base + CPUV8_DBG_DTRRX, data);
-       ret += mem_ap_write_u32(armv8->debug_ap,
+       if (ret == ERROR_OK)
+               ret = mem_ap_write_u32(armv8->debug_ap,
                                armv8->debug_base + CPUV8_DBG_DTRTX, data >> 32);
        return ret;
 }
@@ -116,7 +108,6 @@ static int dpmv8_read_dcc(struct armv8_common *armv8, uint32_t *data,
                                            data);
        if (retval != ERROR_OK)
                return retval;
-       LOG_DEBUG("read DCC 0x%08" PRIx32, *data);
 
        if (dscr_p)
                *dscr_p = dscr;
@@ -143,7 +134,7 @@ static int dpmv8_read_dcc_64(struct armv8_common *armv8, uint64_t *data,
                if (retval != ERROR_OK)
                        return retval;
                if (timeval_ms() > then + 1000) {
-                       LOG_ERROR("Timeout waiting for read dcc");
+                       LOG_ERROR("Timeout waiting for DTR_TX_FULL, dscr = 0x%08" PRIx32, dscr);
                        return ERROR_FAIL;
                }
        }
@@ -161,7 +152,6 @@ static int dpmv8_read_dcc_64(struct armv8_common *armv8, uint64_t *data,
                return retval;
 
        *data = *(uint32_t *)data | (uint64_t)higher << 32;
-       LOG_DEBUG("read DCC 0x%16.16" PRIx64, *data);
 
        if (dscr_p)
                *dscr_p = dscr;
@@ -175,7 +165,7 @@ static int dpmv8_dpm_prepare(struct arm_dpm *dpm)
        uint32_t dscr;
        int retval;
 
-       /* set up invariant:  INSTR_COMP is set after ever DPM operation */
+       /* set up invariant:  ITE is set after ever DPM operation */
        long long then = timeval_ms();
        for (;; ) {
                retval = mem_ap_read_atomic_u32(armv8->debug_ap,
@@ -202,12 +192,6 @@ static int dpmv8_dpm_prepare(struct arm_dpm *dpm)
                        armv8->debug_base + CPUV8_DBG_DTRRX, &dscr);
                if (retval != ERROR_OK)
                        return retval;
-
-               /* Clear sticky error */
-               retval = mem_ap_write_u32(armv8->debug_ap,
-                       armv8->debug_base + CPUV8_DBG_DRCR, DRCR_CSE);
-               if (retval != ERROR_OK)
-                       return retval;
        }
 
        return retval;
@@ -223,11 +207,9 @@ static int dpmv8_exec_opcode(struct arm_dpm *dpm,
        uint32_t opcode, uint32_t *p_dscr)
 {
        struct armv8_common *armv8 = dpm->arm->arch_info;
-       uint32_t dscr = DSCR_ITE;
+       uint32_t dscr = dpm->dscr;
        int retval;
 
-       LOG_DEBUG("exec opcode 0x%08" PRIx32, opcode);
-
        if (p_dscr)
                dscr = *p_dscr;
 
@@ -276,9 +258,7 @@ static int dpmv8_exec_opcode(struct arm_dpm *dpm,
 
        if (dscr & DSCR_ERR) {
                LOG_ERROR("Opcode 0x%08"PRIx32", DSCR.ERR=1, DSCR.EL=%i", opcode, dpm->last_el);
-               /* clear the sticky error condition */
-               mem_ap_write_atomic_u32(armv8->debug_ap,
-                               armv8->debug_base + CPUV8_DBG_DRCR, DRCR_CSE);
+               armv8_dpm_handle_exception(dpm, true);
                retval = ERROR_FAIL;
        }
 
@@ -342,96 +322,107 @@ static int dpmv8_instr_write_data_r0_64(struct arm_dpm *dpm,
        uint32_t opcode, uint64_t data)
 {
        struct armv8_common *armv8 = dpm->arm->arch_info;
-       uint32_t dscr = DSCR_ITE;
        int retval;
 
-       retval = dpmv8_write_dcc_64(armv8, data);
-       if (retval != ERROR_OK)
-               return retval;
+       if (dpm->arm->core_state != ARM_STATE_AARCH64)
+               return dpmv8_instr_write_data_r0(dpm, opcode, data);
 
-       retval = dpmv8_exec_opcode(dpm, ARMV8_MRS(SYSTEM_DBG_DBGDTR_EL0, 0), &dscr);
-       if (retval != ERROR_OK)
-               return retval;
+       /* transfer data from DCC to R0 */
+       retval = dpmv8_write_dcc_64(armv8, data);
+       if (retval == ERROR_OK)
+               retval = dpmv8_exec_opcode(dpm, ARMV8_MRS(SYSTEM_DBG_DBGDTR_EL0, 0), &dpm->dscr);
 
        /* then the opcode, taking data from R0 */
-       return dpmv8_exec_opcode(dpm, opcode, &dscr);
+       if (retval == ERROR_OK)
+               retval = dpmv8_exec_opcode(dpm, opcode, &dpm->dscr);
+
+       return retval;
 }
 
 static int dpmv8_instr_cpsr_sync(struct arm_dpm *dpm)
 {
+       int retval;
        struct armv8_common *armv8 = dpm->arm->arch_info;
+
        /* "Prefetch flush" after modifying execution status in CPSR */
-       return dpmv8_exec_opcode(dpm, armv8_opcode(armv8, ARMV8_OPC_DSB_SY), NULL);
+       retval = dpmv8_exec_opcode(dpm, armv8_opcode(armv8, ARMV8_OPC_DSB_SY), &dpm->dscr);
+       if (retval == ERROR_OK)
+               dpmv8_exec_opcode(dpm, armv8_opcode(armv8, ARMV8_OPC_ISB_SY), &dpm->dscr);
+       return retval;
 }
 
 static int dpmv8_instr_read_data_dcc(struct arm_dpm *dpm,
        uint32_t opcode, uint32_t *data)
 {
        struct armv8_common *armv8 = dpm->arm->arch_info;
-       uint32_t dscr = DSCR_ITE;
        int retval;
 
        /* the opcode, writing data to DCC */
-       retval = dpmv8_exec_opcode(dpm, opcode, &dscr);
+       retval = dpmv8_exec_opcode(dpm, opcode, &dpm->dscr);
        if (retval != ERROR_OK)
                return retval;
 
-       return dpmv8_read_dcc(armv8, data, &dscr);
+       return dpmv8_read_dcc(armv8, data, &dpm->dscr);
 }
 
 static int dpmv8_instr_read_data_dcc_64(struct arm_dpm *dpm,
        uint32_t opcode, uint64_t *data)
 {
        struct armv8_common *armv8 = dpm->arm->arch_info;
-       uint32_t dscr = DSCR_ITE;
        int retval;
 
        /* the opcode, writing data to DCC */
-       retval = dpmv8_exec_opcode(dpm, opcode, &dscr);
+       retval = dpmv8_exec_opcode(dpm, opcode, &dpm->dscr);
        if (retval != ERROR_OK)
                return retval;
 
-       return dpmv8_read_dcc_64(armv8, data, &dscr);
+       return dpmv8_read_dcc_64(armv8, data, &dpm->dscr);
 }
 
 static int dpmv8_instr_read_data_r0(struct arm_dpm *dpm,
        uint32_t opcode, uint32_t *data)
 {
        struct armv8_common *armv8 = dpm->arm->arch_info;
-       uint32_t dscr = DSCR_ITE;
        int retval;
 
        /* the opcode, writing data to R0 */
-       retval = dpmv8_exec_opcode(dpm, opcode, &dscr);
+       retval = dpmv8_exec_opcode(dpm, opcode, &dpm->dscr);
        if (retval != ERROR_OK)
                return retval;
 
        /* write R0 to DCC */
-       retval = dpmv8_exec_opcode(dpm, armv8_opcode(armv8, WRITE_REG_DTRTX), &dscr);
+       retval = dpmv8_exec_opcode(dpm, armv8_opcode(armv8, WRITE_REG_DTRTX), &dpm->dscr);
        if (retval != ERROR_OK)
                return retval;
 
-       return dpmv8_read_dcc(armv8, data, &dscr);
+       return dpmv8_read_dcc(armv8, data, &dpm->dscr);
 }
 
 static int dpmv8_instr_read_data_r0_64(struct arm_dpm *dpm,
        uint32_t opcode, uint64_t *data)
 {
        struct armv8_common *armv8 = dpm->arm->arch_info;
-       uint32_t dscr = DSCR_ITE;
        int retval;
 
+       if (dpm->arm->core_state != ARM_STATE_AARCH64) {
+               uint32_t tmp;
+               retval = dpmv8_instr_read_data_r0(dpm, opcode, &tmp);
+               if (retval == ERROR_OK)
+                       *data = tmp;
+               return retval;
+       }
+
        /* the opcode, writing data to R0 */
-       retval = dpmv8_exec_opcode(dpm, opcode, &dscr);
+       retval = dpmv8_exec_opcode(dpm, opcode, &dpm->dscr);
        if (retval != ERROR_OK)
                return retval;
 
        /* write R0 to DCC */
-       retval = dpmv8_exec_opcode(dpm, ARMV8_MSR_GP(SYSTEM_DBG_DBGDTR_EL0, 0), &dscr);
+       retval = dpmv8_exec_opcode(dpm, ARMV8_MSR_GP(SYSTEM_DBG_DBGDTR_EL0, 0), &dpm->dscr);
        if (retval != ERROR_OK)
                return retval;
 
-       return dpmv8_read_dcc_64(armv8, data, &dscr);
+       return dpmv8_read_dcc_64(armv8, data, &dpm->dscr);
 }
 
 #if 0
@@ -548,115 +539,108 @@ static int dpmv8_mcr(struct target *target, int cpnum,
        return retval;
 }
 
-static int dpmv8_mrs(struct target *target, uint32_t op0,
-       uint32_t op1, uint32_t op2, uint32_t CRn, uint32_t CRm,
-       uint32_t *value)
-{
-       struct arm *arm = target_to_arm(target);
-       struct arm_dpm *dpm = arm->dpm;
-       int retval;
-       uint32_t op_code;
-
-       retval = dpm->prepare(dpm);
-       if (retval != ERROR_OK)
-               return retval;
-       op_code = ((op0 & 0x3) << 19 | (op1 & 0x7) << 16 | (CRn & 0xF) << 12 |\
-                               (CRm & 0xF) << 8 | (op2 & 0x7) << 5);
-       op_code >>= 5;
-       LOG_DEBUG("MRS p%d, %d, r0, c%d, c%d, %d", (int)op0,
-               (int) op1, (int) CRn,
-               (int) CRm, (int) op2);
-       /* read coprocessor register into R0; return via DCC */
-       retval = dpm->instr_read_data_r0(dpm,
-                       ARMV8_MRS(op_code, 0),
-                       value);
-
-       /* (void) */ dpm->finish(dpm);
-       return retval;
-}
-
-static int dpmv8_msr(struct target *target, uint32_t op0,
-       uint32_t op1, uint32_t op2, uint32_t CRn, uint32_t CRm,
-       uint32_t value)
-{
-       struct arm *arm = target_to_arm(target);
-       struct arm_dpm *dpm = arm->dpm;
-       int retval;
-       uint32_t op_code;
-
-       retval = dpm->prepare(dpm);
-       if (retval != ERROR_OK)
-               return retval;
-
-       op_code = ((op0 & 0x3) << 19 | (op1 & 0x7) << 16 | (CRn & 0xF) << 12 |\
-                               (CRm & 0xF) << 8 | (op2 & 0x7) << 5);
-       op_code >>= 5;
-       LOG_DEBUG("MSR p%d, %d, r0, c%d, c%d, %d", (int)op0,
-               (int) op1, (int) CRn,
-               (int) CRm, (int) op2);
-
-       /* read DCC into r0; then write coprocessor register from R0 */
-       retval = dpm->instr_write_data_r0(dpm,
-                       ARMV8_MSR_GP(op_code, 0),
-                       value);
-
-       /* (void) */ dpm->finish(dpm);
-       return retval;
-}
-
 /*----------------------------------------------------------------------*/
 
 /*
  * Register access utilities
  */
 
-/* Toggles between recorded core mode (USR, SVC, etc) and a temporary one.
- * Routines *must* restore the original mode before returning!!
- */
-int dpmv8_modeswitch(struct arm_dpm *dpm, enum arm_mode mode)
+int armv8_dpm_modeswitch(struct arm_dpm *dpm, enum arm_mode mode)
 {
        struct armv8_common *armv8 = (struct armv8_common *)dpm->arm->arch_info;
-       int retval;
+       int retval = ERROR_OK;
+       unsigned int target_el;
+       enum arm_state core_state;
        uint32_t cpsr;
 
        /* restore previous mode */
-       if (mode == ARM_MODE_ANY)
+       if (mode == ARM_MODE_ANY) {
                cpsr = buf_get_u32(dpm->arm->cpsr->value, 0, 32);
 
-       /* else force to the specified mode */
-       else
-               cpsr = mode >> 4;
+               LOG_DEBUG("restoring mode, cpsr = 0x%08"PRIx32, cpsr);
 
-       switch ((cpsr & 0xC) >> 2) {
-                       case SYSTEM_CUREL_EL1:
-                               retval = dpm->instr_execute(dpm, ARMV8_DCPS1(11));
-                               if (retval != ERROR_OK)
-                                       return retval;
-                               break;
-                       case SYSTEM_CUREL_EL2:
-                               retval = dpm->instr_execute(dpm, ARMV8_DCPS2(11));
-                               if (retval != ERROR_OK)
-                                       return retval;
-                               break;
-                       break;
-                       case SYSTEM_CUREL_EL3:
-                               retval = dpm->instr_execute(dpm, ARMV8_DCPS3(11));
-                               if (retval != ERROR_OK)
-                                       return retval;
-                               break;
-                       break;
-                       default:
-                               LOG_DEBUG("unknow mode 0x%x", (unsigned) ((cpsr & 0xC) >> 2));
-                               break;
+       } else {
+               LOG_DEBUG("setting mode 0x%"PRIx32, mode);
+               cpsr = mode;
        }
 
+       switch (cpsr & 0x1f) {
+       /* aarch32 modes */
+       case ARM_MODE_USR:
+               target_el = 0;
+               break;
+       case ARM_MODE_SVC:
+       case ARM_MODE_ABT:
+       case ARM_MODE_IRQ:
+       case ARM_MODE_FIQ:
+       case ARM_MODE_SYS:
+               target_el = 1;
+               break;
+       /*
+        * TODO: handle ARM_MODE_HYP
+        * case ARM_MODE_HYP:
+        *      target_el = 2;
+        *      break;
+        */
+       case ARM_MODE_MON:
+               target_el = 3;
+               break;
+       /* aarch64 modes */
+       default:
+               target_el = (cpsr >> 2) & 3;
+       }
 
-       retval = dpm->instr_write_data_r0(dpm, armv8_opcode(armv8, WRITE_REG_DSPSR), cpsr);
-       if (retval != ERROR_OK)
-               return retval;
+       if (target_el > SYSTEM_CUREL_EL3) {
+               LOG_ERROR("%s: Invalid target exception level %i", __func__, target_el);
+               return ERROR_FAIL;
+       }
+
+       LOG_DEBUG("target_el = %i, last_el = %i", target_el, dpm->last_el);
+       if (target_el > dpm->last_el) {
+               retval = dpm->instr_execute(dpm,
+                               armv8_opcode(armv8, ARMV8_OPC_DCPS) | target_el);
 
-       if (dpm->instr_cpsr_sync)
-               retval = dpm->instr_cpsr_sync(dpm);
+               /* DCPS clobbers registers just like an exception taken */
+               armv8_dpm_handle_exception(dpm, false);
+       } else {
+               core_state = armv8_dpm_get_core_state(dpm);
+               if (core_state != ARM_STATE_AARCH64) {
+                       /* cannot do DRPS/ERET when already in EL0 */
+                       if (dpm->last_el != 0) {
+                               /* load SPSR with the desired mode and execute DRPS */
+                               LOG_DEBUG("SPSR = 0x%08"PRIx32, cpsr);
+                               retval = dpm->instr_write_data_r0(dpm,
+                                               ARMV8_MSR_GP_xPSR_T1(1, 0, 15), cpsr);
+                               if (retval == ERROR_OK)
+                                       retval = dpm->instr_execute(dpm, armv8_opcode(armv8, ARMV8_OPC_DRPS));
+                       }
+               } else {
+                       /*
+                        * need to execute multiple DRPS instructions until target_el
+                        * is reached
+                        */
+                       while (retval == ERROR_OK && dpm->last_el != target_el) {
+                               unsigned int cur_el = dpm->last_el;
+                               retval = dpm->instr_execute(dpm, armv8_opcode(armv8, ARMV8_OPC_DRPS));
+                               if (cur_el == dpm->last_el) {
+                                       LOG_INFO("Cannot reach EL %i, SPSR corrupted?", target_el);
+                                       break;
+                               }
+                       }
+               }
+
+               /* On executing DRPS, DSPSR and DLR become UNKNOWN, mark them as dirty */
+               dpm->arm->cpsr->dirty = true;
+               dpm->arm->pc->dirty = true;
+
+               /*
+                * re-evaluate the core state, we might be in Aarch32 state now
+                * we rely on dpm->dscr being up-to-date
+                */
+               core_state = armv8_dpm_get_core_state(dpm);
+               armv8_select_opcodes(armv8, core_state == ARM_STATE_AARCH64);
+               armv8_select_reg_access(armv8, core_state == ARM_STATE_AARCH64);
+       }
 
        return retval;
 }
@@ -667,21 +651,37 @@ int dpmv8_modeswitch(struct arm_dpm *dpm, enum arm_mode mode)
 static int dpmv8_read_reg(struct arm_dpm *dpm, struct reg *r, unsigned regnum)
 {
        struct armv8_common *armv8 = dpm->arm->arch_info;
-       uint64_t value_64;
-       int retval;
+       int retval = ERROR_FAIL;
 
-       retval = armv8->read_reg_u64(armv8, regnum, &value_64);
+       if (r->size <= 64) {
+               uint64_t value_64;
+               retval = armv8->read_reg_u64(armv8, regnum, &value_64);
+
+               if (retval == ERROR_OK) {
+                       r->valid = true;
+                       r->dirty = false;
+                       buf_set_u64(r->value, 0, r->size, value_64);
+                       if (r->size == 64)
+                               LOG_DEBUG("READ: %s, %16.8llx", r->name, (unsigned long long) value_64);
+                       else
+                               LOG_DEBUG("READ: %s, %8.8x", r->name, (unsigned int) value_64);
+               }
+       } else if (r->size <= 128) {
+               uint64_t lvalue = 0, hvalue = 0;
+               retval = armv8->read_reg_u128(armv8, regnum, &lvalue, &hvalue);
 
-       if (retval == ERROR_OK) {
-               r->valid = true;
-               r->dirty = false;
-               buf_set_u64(r->value, 0, r->size, value_64);
-               if (r->size == 64)
-                       LOG_DEBUG("READ: %s, %16.8llx", r->name, (unsigned long long) value_64);
-               else
-                       LOG_DEBUG("READ: %s, %8.8x", r->name, (unsigned int) value_64);
+               if (retval == ERROR_OK) {
+                       r->valid = true;
+                       r->dirty = false;
+
+                       buf_set_u64(r->value, 0, 64, lvalue);
+                       buf_set_u64(r->value + 8, 0, r->size - 64, hvalue);
+
+                       LOG_DEBUG("READ: %s, lvalue=%16.8llx", r->name, (unsigned long long) lvalue);
+                       LOG_DEBUG("READ: %s, hvalue=%16.8llx", r->name, (unsigned long long) hvalue);
+               }
        }
-       return ERROR_OK;
+       return retval;
 }
 
 /*
@@ -691,20 +691,36 @@ static int dpmv8_write_reg(struct arm_dpm *dpm, struct reg *r, unsigned regnum)
 {
        struct armv8_common *armv8 = dpm->arm->arch_info;
        int retval = ERROR_FAIL;
-       uint64_t value_64;
 
-       value_64 = buf_get_u64(r->value, 0, r->size);
+       if (r->size <= 64) {
+               uint64_t value_64;
+
+               value_64 = buf_get_u64(r->value, 0, r->size);
+               retval = armv8->write_reg_u64(armv8, regnum, value_64);
+
+               if (retval == ERROR_OK) {
+                       r->dirty = false;
+                       if (r->size == 64)
+                               LOG_DEBUG("WRITE: %s, %16.8llx", r->name, (unsigned long long)value_64);
+                       else
+                               LOG_DEBUG("WRITE: %s, %8.8x", r->name, (unsigned int)value_64);
+               }
+       } else if (r->size <= 128) {
+               uint64_t lvalue, hvalue;
+
+               lvalue = buf_get_u64(r->value, 0, 64);
+               hvalue = buf_get_u64(r->value + 8, 0, r->size - 64);
+               retval = armv8->write_reg_u128(armv8, regnum, lvalue, hvalue);
 
-       retval = armv8->write_reg_u64(armv8, regnum, value_64);
-       if (retval == ERROR_OK) {
-               r->dirty = false;
-               if (r->size == 64)
-                       LOG_DEBUG("WRITE: %s, %16.8llx", r->name, (unsigned long long)value_64);
-               else
-                       LOG_DEBUG("WRITE: %s, %8.8x", r->name, (unsigned int)value_64);
+               if (retval == ERROR_OK) {
+                       r->dirty = false;
+
+                       LOG_DEBUG("WRITE: %s, lvalue=%16.8llx", r->name, (unsigned long long) lvalue);
+                       LOG_DEBUG("WRITE: %s, hvalue=%16.8llx", r->name, (unsigned long long) hvalue);
+               }
        }
 
-       return ERROR_OK;
+       return retval;
 }
 
 /**
@@ -730,14 +746,22 @@ int armv8_dpm_read_current_registers(struct arm_dpm *dpm)
        cache = arm->core_cache;
 
        /* read R0 first (it's used for scratch), then CPSR */
-       r = cache->reg_list + 0;
+       r = cache->reg_list + ARMV8_R0;
        if (!r->valid) {
-               retval = dpmv8_read_reg(dpm, r, 0);
+               retval = dpmv8_read_reg(dpm, r, ARMV8_R0);
                if (retval != ERROR_OK)
                        goto fail;
        }
        r->dirty = true;
 
+       /* read R1, too, it will be clobbered during memory access */
+       r = cache->reg_list + ARMV8_R1;
+       if (!r->valid) {
+               retval = dpmv8_read_reg(dpm, r, ARMV8_R1);
+               if (retval != ERROR_OK)
+                       goto fail;
+       }
+
        /* read cpsr to r0 and get it back */
        retval = dpm->instr_read_data_r0(dpm,
                        armv8_opcode(armv8, READ_REG_DSPSR), &cpsr);
@@ -747,13 +771,17 @@ int armv8_dpm_read_current_registers(struct arm_dpm *dpm)
        /* update core mode and state */
        armv8_set_cpsr(arm, cpsr);
 
-       for (unsigned int i = 1; i < cache->num_regs ; i++) {
+       for (unsigned int i = ARMV8_PC; i < cache->num_regs ; i++) {
                struct arm_reg *arm_reg;
 
                r = armv8_reg_current(arm, i);
                if (r->valid)
                        continue;
 
+               /* Skip reading FP-SIMD registers */
+               if (r->number >= ARMV8_V0 && r->number <= ARMV8_FPCR)
+                       continue;
+
                /*
                 * Only read registers that are available from the
                 * current EL (or core mode).
@@ -763,6 +791,10 @@ int armv8_dpm_read_current_registers(struct arm_dpm *dpm)
                                dpm->last_el != armv8_curel_from_core_mode(arm_reg->mode))
                        continue;
 
+               /* Special case: ARM_MODE_SYS has no SPSR at EL1 */
+               if (r->number == ARMV8_SPSR_EL1 && arm->core_mode == ARM_MODE_SYS)
+                       continue;
+
                retval = dpmv8_read_reg(dpm, r, i);
                if (retval != ERROR_OK)
                        goto fail;
@@ -875,7 +907,7 @@ int armv8_dpm_write_dirty_registers(struct arm_dpm *dpm, bool bpwp)
         */
 
        /* Restore original core mode and state */
-       retval = dpmv8_modeswitch(dpm, ARM_MODE_ANY);
+       retval = armv8_dpm_modeswitch(dpm, ARM_MODE_ANY);
        if (retval != ERROR_OK)
                goto done;
 
@@ -1022,9 +1054,9 @@ static int armv8_dpm_full_context(struct target *target)
                                 * in FIQ mode we need to patch mode.
                                 */
                                if (mode != ARM_MODE_ANY)
-                                       retval = dpmv8_modeswitch(dpm, mode);
+                                       retval = armv8_dpm_modeswitch(dpm, mode);
                                else
-                                       retval = dpmv8_modeswitch(dpm, ARM_MODE_USR);
+                                       retval = armv8_dpm_modeswitch(dpm, ARM_MODE_USR);
 
                                if (retval != ERROR_OK)
                                        goto done;
@@ -1042,7 +1074,7 @@ static int armv8_dpm_full_context(struct target *target)
 
        } while (did_read);
 
-       retval = dpmv8_modeswitch(dpm, ARM_MODE_ANY);
+       retval = armv8_dpm_modeswitch(dpm, ARM_MODE_ANY);
        /* (void) */ dpm->finish(dpm);
 done:
        return retval;
@@ -1255,12 +1287,72 @@ void armv8_dpm_report_wfar(struct arm_dpm *dpm, uint64_t addr)
                        /* ?? */
                        break;
                default:
-                       LOG_DEBUG("Unknow core_state");
+                       LOG_DEBUG("Unknown core_state");
                        break;
        }
        dpm->wp_pc = addr;
 }
 
+/*
+ * Handle exceptions taken in debug state. This happens mostly for memory
+ * accesses that violated a MMU policy. Taking an exception while in debug
+ * state clobbers certain state registers on the target exception level.
+ * Just mark those registers dirty so that they get restored on resume.
+ * This works both for Aarch32 and Aarch64 states.
+ *
+ * This function must not perform any actions that trigger another exception
+ * or a recursion will happen.
+ */
+void armv8_dpm_handle_exception(struct arm_dpm *dpm, bool do_restore)
+{
+       struct armv8_common *armv8 = dpm->arm->arch_info;
+       struct reg_cache *cache = dpm->arm->core_cache;
+       enum arm_state core_state;
+       uint64_t dlr;
+       uint32_t dspsr;
+       unsigned int el;
+
+       static const int clobbered_regs_by_el[3][5] = {
+               { ARMV8_PC, ARMV8_xPSR, ARMV8_ELR_EL1, ARMV8_ESR_EL1, ARMV8_SPSR_EL1 },
+               { ARMV8_PC, ARMV8_xPSR, ARMV8_ELR_EL2, ARMV8_ESR_EL2, ARMV8_SPSR_EL2 },
+               { ARMV8_PC, ARMV8_xPSR, ARMV8_ELR_EL3, ARMV8_ESR_EL3, ARMV8_SPSR_EL3 },
+       };
+
+       el = (dpm->dscr >> 8) & 3;
+
+       /* safety check, must not happen since EL0 cannot be a target for an exception */
+       if (el < SYSTEM_CUREL_EL1 || el > SYSTEM_CUREL_EL3) {
+               LOG_ERROR("%s: EL %i is invalid, DSCR corrupted?", __func__, el);
+               return;
+       }
+
+       /* Clear sticky error */
+       mem_ap_write_u32(armv8->debug_ap,
+               armv8->debug_base + CPUV8_DBG_DRCR, DRCR_CSE);
+
+       armv8->read_reg_u64(armv8, ARMV8_xPSR, &dlr);
+       dspsr = dlr;
+       armv8->read_reg_u64(armv8, ARMV8_PC, &dlr);
+
+       LOG_DEBUG("Exception taken to EL %i, DLR=0x%016"PRIx64" DSPSR=0x%08"PRIx32,
+                       el, dlr, dspsr);
+
+       /* mark all clobbered registers as dirty */
+       for (int i = 0; i < 5; i++)
+               cache->reg_list[clobbered_regs_by_el[el-1][i]].dirty = true;
+
+       /*
+        * re-evaluate the core state, we might be in Aarch64 state now
+        * we rely on dpm->dscr being up-to-date
+        */
+       core_state = armv8_dpm_get_core_state(dpm);
+       armv8_select_opcodes(armv8, core_state == ARM_STATE_AARCH64);
+       armv8_select_reg_access(armv8, core_state == ARM_STATE_AARCH64);
+
+       if (do_restore)
+               armv8_dpm_modeswitch(dpm, ARM_MODE_ANY);
+}
+
 /*----------------------------------------------------------------------*/
 
 /*
@@ -1289,13 +1381,15 @@ void armv8_dpm_report_dscr(struct arm_dpm *dpm, uint32_t dscr)
                case DSCRV8_ENTRY_BKPT: /* SW BKPT (?) */
                case DSCRV8_ENTRY_RESET_CATCH:  /* Reset catch */
                case DSCRV8_ENTRY_OS_UNLOCK:  /*OS unlock catch*/
-               case DSCRV8_ENTRY_EXCEPTION_CATCH:  /*exception catch*/
                case DSCRV8_ENTRY_SW_ACCESS_DBG: /*SW access dbg register*/
                        target->debug_reason = DBG_REASON_BREAKPOINT;
                        break;
                case DSCRV8_ENTRY_WATCHPOINT:   /* asynch watchpoint */
                        target->debug_reason = DBG_REASON_WATCHPOINT;
                        break;
+               case DSCRV8_ENTRY_EXCEPTION_CATCH:  /*exception catch*/
+                       target->debug_reason = DBG_REASON_EXC_CATCH;
+                       break;
                default:
                        target->debug_reason = DBG_REASON_UNDEFINED;
                        break;
@@ -1336,8 +1430,6 @@ int armv8_dpm_setup(struct arm_dpm *dpm)
        /* coprocessor access setup */
        arm->mrc = dpmv8_mrc;
        arm->mcr = dpmv8_mcr;
-       arm->mrs = dpmv8_mrs;
-       arm->msr = dpmv8_msr;
 
        dpm->prepare = dpmv8_dpm_prepare;
        dpm->finish = dpmv8_dpm_finish;

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