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/* SPDX-License-Identifier: GPL-2.0-only */
/* This file is part of the coreboot project. */
#define __SIMPLE_DEVICE__
#include <assert.h>
#include <stdint.h>
#include <console/console.h>
#include <cpu/x86/smm.h>
#include <cpu/amd/msr.h>
#include <memrange.h>
#include <fsp/util.h>
#include <FspGuids.h>
/*
* For data stored in TSEG, ensure TValid is clear so R/W access can reach
* the DRAM when not in SMM.
*/
static void clear_tvalid(void)
{
msr_t hwcr = rdmsr(HWCR_MSR);
msr_t mask = rdmsr(SMM_MASK_MSR);
int tvalid = !!(mask.lo & SMM_TSEG_VALID);
if (hwcr.lo & SMM_LOCK) {
if (!tvalid) /* not valid but locked means still accessible */
return;
printk(BIOS_ERR, "Error: can't clear TValid, already locked\n");
return;
}
mask.lo &= ~SMM_TSEG_VALID;
wrmsr(SMM_MASK_MSR, mask);
}
void smm_region(uintptr_t *start, size_t *size)
{
static int once;
struct range_entry tseg;
int status;
*start = 0;
*size = 0;
status = fsp_find_range_hob(&tseg, AMD_FSP_TSEG_HOB_GUID.b);
if (status < 0) {
printk(BIOS_ERR, "Error: unable to find TSEG HOB\n");
return;
}
*start = (uintptr_t)range_entry_base(&tseg);
*size = range_entry_size(&tseg);
if (!once) {
clear_tvalid();
once = 1;
}
}
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