aarch64: fix debug entry from EL0

If we enter debug state from EL0, some registers are not accessible.
Temporarily move to EL1H and back to gain access. Also, fix
armv8_dpm_modeswitch() to not immediately restore the previous state
on elevating the privilege level.

Change-Id: Ic2a92109230ff4eb6834c00ef544397a5b7ad56a
Signed-off-by: Matthias Welwarsky <matthias.welwarsky@sysgo.com>
Reviewed-on: http://openocd.zylin.com/4461
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

diff --git a/src/target/aarch64.c b/src/target/aarch64.c
index 0630ffb9bd00a0abc5f9fc64c629c197476e122a..b586e24eb9aebd5828ce12afa7ba5f23dff939fb 100644 (file)
--- a/src/target/aarch64.c
+++ b/src/target/aarch64.c
@@ -1861,7 +1861,7 @@ static int aarch64_write_cpu_memory(struct target *target,
        if (dscr & (DSCR_ERR | DSCR_SYS_ERROR_PEND)) {
                /* Abort occurred - clear it and exit */
                LOG_ERROR("abort occurred - dscr = 0x%08" PRIx32, dscr);
-               armv8_dpm_handle_exception(dpm);
+               armv8_dpm_handle_exception(dpm, true);
                return ERROR_FAIL;
        }
 
@@ -2080,7 +2080,7 @@ static int aarch64_read_cpu_memory(struct target *target,
        if (dscr & (DSCR_ERR | DSCR_SYS_ERROR_PEND)) {
                /* Abort occurred - clear it and exit */
                LOG_ERROR("abort occurred - dscr = 0x%08" PRIx32, dscr);
-               armv8_dpm_handle_exception(dpm);
+               armv8_dpm_handle_exception(dpm, true);
                return ERROR_FAIL;
        }
 

diff --git a/src/target/armv8.c b/src/target/armv8.c
index 86bb8707e43e3f7d13279bfbe4bced0ab148eb2a..e8c700af35d8da9ca166a34f77f5597ae5fffd02 100644 (file)
--- a/src/target/armv8.c
+++ b/src/target/armv8.c
@@ -620,6 +620,7 @@ void armv8_select_reg_access(struct armv8_common *armv8, bool is_aarch64)
 int armv8_read_mpidr(struct armv8_common *armv8)
 {
        int retval = ERROR_FAIL;
+       struct arm *arm = &armv8->arm;
        struct arm_dpm *dpm = armv8->arm.dpm;
        uint32_t mpidr;
 
@@ -627,6 +628,13 @@ int armv8_read_mpidr(struct armv8_common *armv8)
        if (retval != ERROR_OK)
                goto done;
 
+       /* check if we're in an unprivileged mode */
+       if (armv8_curel_from_core_mode(arm->core_mode) < SYSTEM_CUREL_EL1) {
+               retval = armv8_dpm_modeswitch(dpm, ARMV8_64_EL1H);
+               if (retval != ERROR_OK)
+                       return retval;
+       }
+
        retval = dpm->instr_read_data_r0(dpm, armv8_opcode(armv8, READ_REG_MPIDR), &mpidr);
        if (retval != ERROR_OK)
                goto done;
@@ -642,6 +650,7 @@ int armv8_read_mpidr(struct armv8_common *armv8)
                LOG_ERROR("mpidr not in multiprocessor format");
 
 done:
+       armv8_dpm_modeswitch(dpm, ARM_MODE_ANY);
        dpm->finish(dpm);
        return retval;
 }

diff --git a/src/target/armv8_cache.c b/src/target/armv8_cache.c
index 7f610c953536714f3e36eecbce102929bb4f282c..40965ebd831091f26aa97e1435ccbf99d32aa77b 100644 (file)
--- a/src/target/armv8_cache.c
+++ b/src/target/armv8_cache.c
@@ -310,6 +310,7 @@ int armv8_identify_cache(struct armv8_common *armv8)
 {
        /*  read cache descriptor */
        int retval = ERROR_FAIL;
+       struct arm *arm = &armv8->arm;
        struct arm_dpm *dpm = armv8->arm.dpm;
        uint32_t csselr, clidr, ctr;
        uint32_t cache_reg;
@@ -320,6 +321,13 @@ int armv8_identify_cache(struct armv8_common *armv8)
        if (retval != ERROR_OK)
                goto done;
 
+       /* check if we're in an unprivileged mode */
+       if (armv8_curel_from_core_mode(arm->core_mode) < SYSTEM_CUREL_EL1) {
+               retval = armv8_dpm_modeswitch(dpm, ARMV8_64_EL1H);
+               if (retval != ERROR_OK)
+                       return retval;
+       }
+
        /* retrieve CTR */
        retval = dpm->instr_read_data_r0(dpm,
                        armv8_opcode(armv8, READ_REG_CTR), &ctr);
@@ -417,6 +425,7 @@ int armv8_identify_cache(struct armv8_common *armv8)
        }
 
 done:
+       armv8_dpm_modeswitch(dpm, ARM_MODE_ANY);
        dpm->finish(dpm);
        return retval;
 

diff --git a/src/target/armv8_dpm.c b/src/target/armv8_dpm.c
index 91b2f51718e6c0ac45feeea19764a7baf7eb628b..3c941fa2db17b97f09683dcdaee1c9675d4a164d 100644 (file)
--- a/src/target/armv8_dpm.c
+++ b/src/target/armv8_dpm.c
@@ -258,7 +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);
-               armv8_dpm_handle_exception(dpm);
+               armv8_dpm_handle_exception(dpm, true);
                retval = ERROR_FAIL;
        }
 
@@ -600,7 +600,7 @@ int armv8_dpm_modeswitch(struct arm_dpm *dpm, enum arm_mode mode)
                                armv8_opcode(armv8, ARMV8_OPC_DCPS) | target_el);
 
                /* DCPS clobbers registers just like an exception taken */
-               armv8_dpm_handle_exception(dpm);
+               armv8_dpm_handle_exception(dpm, false);
        } else {
                core_state = armv8_dpm_get_core_state(dpm);
                if (core_state != ARM_STATE_AARCH64) {
@@ -1298,7 +1298,7 @@ void armv8_dpm_report_wfar(struct arm_dpm *dpm, uint64_t addr)
  * 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)
+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;
@@ -1344,7 +1344,8 @@ void armv8_dpm_handle_exception(struct arm_dpm *dpm)
        armv8_select_opcodes(armv8, core_state == ARM_STATE_AARCH64);
        armv8_select_reg_access(armv8, core_state == ARM_STATE_AARCH64);
 
-       armv8_dpm_modeswitch(dpm, ARM_MODE_ANY);
+       if (do_restore)
+               armv8_dpm_modeswitch(dpm, ARM_MODE_ANY);
 }
 
 /*----------------------------------------------------------------------*/

diff --git a/src/target/armv8_dpm.h b/src/target/armv8_dpm.h
index c03935928b95ce6d9e492e8104b63c887e35d087..f40440370f0f4addafe98f60a9a0019c4adea205 100644 (file)
--- a/src/target/armv8_dpm.h
+++ b/src/target/armv8_dpm.h
@@ -116,7 +116,7 @@ void armv8_dpm_report_wfar(struct arm_dpm *, uint64_t wfar);
 #define PRCR_COREPURQ                  (1 << 3)
 
 void armv8_dpm_report_dscr(struct arm_dpm *dpm, uint32_t dcsr);
-void armv8_dpm_handle_exception(struct arm_dpm *dpm);
+void armv8_dpm_handle_exception(struct arm_dpm *dpm, bool do_restore);
 enum arm_state armv8_dpm_get_core_state(struct arm_dpm *dpm);
 
 #endif /* OPENOCD_TARGET_ARM_DPM_H */