coreboot/src/cpu/x86/car.c

142 lines
3.7 KiB
C

/*
* This file is part of the coreboot project.
*
* 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.
*/
#include <string.h>
#include <stddef.h>
#include <console/console.h>
#include <cbmem.h>
#include <arch/early_variables.h>
#include <symbols.h>
#if CONFIG(PLATFORM_USES_FSP1_0)
#include <drivers/intel/fsp1_0/fsp_util.h>
#endif
typedef void (* const car_migration_func_t)(void);
extern car_migration_func_t _car_migrate_start;
/*
* 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;
/** @brief returns pointer to a CAR variable, before or after migration.
*
* @param var pointer to the CAR variable
*/
void *car_get_var_ptr(void *var)
{
char *migrated_base = NULL;
int offset;
void *_car_start = _car_relocatable_data_start;
void *_car_end = _car_relocatable_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;
}
#if CONFIG(PLATFORM_USES_FSP1_0)
migrated_base = (char *)find_saved_temp_mem(
*(void **)CBMEM_FSP_HOB_PTR);
/* FSP 1.0 migrates the entire DCACHE RAM */
offset = (char *)var - (char *)CONFIG_DCACHE_RAM_BASE;
#else
migrated_base = cbmem_find(CBMEM_ID_CAR_GLOBALS);
offset = (char *)var - (char *)_car_start;
#endif
if (migrated_base == NULL)
die("CAR: Could not find migration base!\n");
return &migrated_base[offset];
}
#if CONFIG(PLATFORM_USES_FSP1_0)
/*
* When a CAR_GLOBAL points to target object inside CAR, use relative
* addressing. Such CAR_GLOBAL has to be expicitly accessed using
* car_set_reloc_ptr() and car_get_reloc_ptr() as the stored value is now
* an offset instead of the absolute address (pointer) of the target.
*
* This way discovery of objects that are not CAR_GLOBALs themselves,
* remain discoverable after CAR migration has implicitly happened.
*/
void car_set_reloc_ptr(void *var, void *val)
{
uintptr_t *offset = car_get_var_ptr(var);
*offset = 0;
if (val)
*offset = (uintptr_t)offset - (uintptr_t)val;
}
void *car_get_reloc_ptr(void *var)
{
uintptr_t *offset = car_get_var_ptr(var);
void *val = NULL;
if (*offset)
val = (void *)((uintptr_t)offset - *offset);
return val;
}
#endif
int car_active(void)
{
return !car_migrated;
}
static void do_car_migrate_variables(void)
{
void *migrated_base;
size_t car_size = car_data_size();
/* Check if already migrated. */
if (car_migrated)
return;
migrated_base = cbmem_add(CBMEM_ID_CAR_GLOBALS, car_size);
if (migrated_base == NULL) {
printk(BIOS_ERR, "Could not migrate CAR data!\n");
return;
}
memcpy(migrated_base, _car_relocatable_data_start, car_size);
/* Mark that the data has been moved. */
car_migrated = ~0;
}
static void car_migrate_variables(int is_recovery)
{
if (!CONFIG(PLATFORM_USES_FSP1_0))
do_car_migrate_variables();
}
ROMSTAGE_CBMEM_INIT_HOOK(car_migrate_variables)