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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2013 Google, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include <stddef.h>
#include <console/console.h>
#include <cbmem.h>
#include <arch/early_variables.h>
typedef void (* const car_migration_func_t)(void);
extern car_migration_func_t _car_migrate_start;
extern char _car_data_start[];
extern char _car_data_end[];
/*
* The car_migrated global variable determines if the cache-as-ram space has
* been migrated to real RAM. It does this by assuming the following things:
* 1. cache-as-ram space is zero'd out once it is set up.
* 2. Either the cache-as-ram space is memory-backed after getting torn down
* or the space returns 0xff's for each byte read.
* Based on these 2 attributes there is the ability to tell when the
* cache-as-ram region has been migrated.
*/
static int car_migrated CAR_GLOBAL;
void *car_get_var_ptr(void *var)
{
char *migrated_base;
int offset;
void * _car_start = &_car_data_start;
void * _car_end = &_car_data_end;
/* If the cache-as-ram has not been migrated return the pointer
* passed in. */
if (!car_migrated)
return var;
if (var < _car_start || var >= _car_end) {
printk(BIOS_ERR,
"Requesting CAR variable outside of CAR region: %p\n",
var);
return var;
}
migrated_base = cbmem_find(CBMEM_ID_CAR_GLOBALS);
if (migrated_base == NULL) {
printk(BIOS_ERR, "CAR: Could not find migration base!\n");
return var;
}
offset = (char *)var - (char *)_car_start;
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;
car_migration_func_t *migrate_func;
size_t car_data_size = &_car_data_end[0] - &_car_data_start[0];
/* Check if already migrated. */
if (car_migrated)
return;
migrated_base = cbmem_add(CBMEM_ID_CAR_GLOBALS, car_data_size);
if (migrated_base == NULL) {
printk(BIOS_ERR, "Could not migrate CAR data!\n");
return;
}
memcpy(migrated_base, &_car_data_start[0], car_data_size);
/* Mark that the data has been moved. */
car_migrated = ~0;
/* Call all the migration functions. */
migrate_func = &_car_migrate_start;
while (*migrate_func != NULL) {
(*migrate_func)();
migrate_func++;
}
}
void car_migrate_variables(void)
{
if (!IS_ENABLED(CONFIG_BROKEN_CAR_MIGRATE))
do_car_migrate_variables();
}
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