target/cortex_a: fix memory leak of register cache

There is no method to free the register cache, allocated in
armv4_5, so we get a memory leak.
Issue identified by valgrind.

Implement the method arm_free_reg_cache() and call it in cortex_a
deinit and to exit for error during arm_dpm_setup().
Tested on dual cortex-A stm32mp15x.
This change is inspired from similar fix in commit b01b5fe13a
("armv7m: Fix memory leak in register caching.").

The same allocation is also used by target types "arm7tdmi",
"arm9tdmi", "arm11" and "xscale" but they all lack the deinit
method and I do not have relevant HW to test the fix. For such
reasons they are not addressed in this patch.

Change-Id: I4da1e1f12e36ec245d1f3b11a4eafcbd9a1d2e25
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5693
Tested-by: jenkins

src/target/arm.h

@@ -272,6 +272,8 @@ struct arm_reg {
 };
 
 struct reg_cache *arm_build_reg_cache(struct target *target, struct arm *arm);
+void arm_free_reg_cache(struct arm *arm);
+
 struct reg_cache *armv8_build_reg_cache(struct target *target);
 
 extern const struct command_registration arm_command_handlers[];

src/target/arm_dpm.c

@@ -1100,6 +1100,7 @@ int arm_dpm_setup(struct arm_dpm *dpm)
 	dpm->dwp = calloc(dpm->nwp, sizeof(*dpm->dwp));
 
 	if (!dpm->dbp || !dpm->dwp) {
+		arm_free_reg_cache(arm);
 		free(dpm->dbp);
 		free(dpm->dwp);
 		return ERROR_FAIL;

src/target/armv4_5.c

@@ -769,6 +769,27 @@ struct reg_cache *arm_build_reg_cache(struct target *target, struct arm *arm)
 	return cache;
 }
 
+void arm_free_reg_cache(struct arm *arm)
+{
+	if (!arm || !arm->core_cache)
+		return;
+
+	struct reg_cache *cache = arm->core_cache;
+
+	for (unsigned int i = 0; i < cache->num_regs; i++) {
+		struct reg *reg = &cache->reg_list[i];
+
+		free(reg->feature);
+		free(reg->reg_data_type);
+	}
+
+	free(cache->reg_list[0].arch_info);
+	free(cache->reg_list);
+	free(cache);
+
+	arm->core_cache = NULL;
+}
+
 int arm_arch_state(struct target *target)
 {
 	struct arm *arm = target_to_arm(target);

src/target/cortex_a.c

@@ -2959,6 +2959,7 @@ static void cortex_a_deinit_target(struct target *target)
 	}
 
 	free(cortex_a->brp_list);
+	arm_free_reg_cache(dpm->arm);
 	free(dpm->dbp);
 	free(dpm->dwp);
 	free(target->private_config);