CBMEM console: Fix CAR migration step

With the change it becomes irrelevant if memcpy() car.global_data or
cbmemc_reinit() is done first.

Change-Id: Ie479eef346c959e97dcc55861ccb0db1321fb7b2
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/8032
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@google.com>
Tested-by: build bot (Jenkins)

src/arch/arm/include/arch/early_variables.h

@@ -25,6 +25,7 @@
 #define CAR_MIGRATE(migrate_fn_)
 static inline void *car_get_var_ptr(void *var) { return var; }
 #define car_get_var(var) (var)
+#define car_sync_var(var) (var)
 #define car_set_var(var, val) do { (var) = (val); } while (0)
 static inline void car_migrate_variables(void) { }
 

src/arch/arm64/include/arch/early_variables.h

@@ -25,6 +25,7 @@
 #define CAR_MIGRATE(migrate_fn_)
 static inline void *car_get_var_ptr(void *var) { return var; }
 #define car_get_var(var) (var)
+#define car_sync_var(var) (var)
 #define car_set_var(var, val) do { (var) = (val); } while (0)
 static inline void car_migrate_variables(void) { }
 

src/arch/riscv/include/arch/early_variables.h

@@ -29,6 +29,7 @@
 #define CAR_MIGRATE(migrate_fn_)
 static inline void *car_get_var_ptr(void *var) { return var; }
 #define car_get_var(var) (var)
+#define car_sync_var(var) (var)
 #define car_set_var(var, val) do { (var) = (val); } while (0)
 static inline void car_migrate_variables(void) { }
 

src/arch/x86/include/arch/early_variables.h

@@ -39,9 +39,14 @@ asm(".previous");
 /* Get the correct pointer for the CAR global variable. */
 void *car_get_var_ptr(void *var);
 
+/* Get and update a CAR_GLOBAL pointing elsewhere in car.global_data*/
+void *car_sync_var_ptr(void *var);
+
 /* Get and set a primitive type global variable. */
 #define car_get_var(var) \
 	*(typeof(var) *)car_get_var_ptr(&(var))
+#define car_sync_var(var) \
+	*(typeof (var) *)car_sync_var_ptr(&(var))
 #define car_set_var(var, val) \
 	do { car_get_var(var) = (val); } while(0)
 
@@ -49,6 +54,7 @@ void *car_get_var_ptr(void *var);
 #define CAR_MIGRATE(migrate_fn_)
 static inline void *car_get_var_ptr(void *var) { return var; }
 #define car_get_var(var) (var)
+#define car_sync_var(var) (var)
 #define car_set_var(var, val) do { (var) = (val); } while (0)
 #endif
 

src/cpu/x86/car.c

@@ -73,6 +73,38 @@ void *car_get_var_ptr(void *var)
 	return &migrated_base[offset];
 }
 
+/*
+ * Update a CAR_GLOBAL variable var, originally pointing to CAR region,
+ * with the address in migrated CAR region in DRAM.
+ */
+void *car_sync_var_ptr(void *var)
+{
+	void ** mig_var = car_get_var_ptr(var);
+	void * _car_start = &_car_data_start;
+	void * _car_end = &_car_data_end;
+
+	/* Not moved or migrated yet. */
+	if (mig_var == var)
+		return mig_var;
+
+	/* It's already pointing outside car.global_data. */
+	if (*mig_var < _car_start || *mig_var > _car_end)
+		return mig_var;
+
+#if !IS_ENABLED(CONFIG_PLATFORM_USES_FSP)
+	/* Keep console buffer in CAR until cbmemc_reinit() moves it. */
+	if (*mig_var == _car_end)
+		return mig_var;
+#endif
+
+	/* Move the pointer by the same amount the variable storing it was
+	 * moved by.
+	 */
+	*mig_var += (char *)mig_var - (char *)var;
+
+	return mig_var;
+}
+
 static void do_car_migrate_variables(void)
 {
 	void *migrated_base;

src/lib/cbmem_console.c

@@ -65,7 +65,7 @@ static u8 static_console[STATIC_CONSOLE_SIZE];
 
 static inline struct cbmem_console *current_console(void)
 {
-	return car_get_var(cbmem_console_p);
+	return car_sync_var(cbmem_console_p);
 }
 
 static inline void current_console_set(struct cbmem_console *new_console_p)