coreboot-kgpe-d16/src/soc/intel/elkhartlake/smmrelocate.c

/* SPDX-License-Identifier: GPL-2.0-only */

#include <console/console.h>
#include <cpu/intel/em64t101_save_state.h>
#include <cpu/intel/smm_reloc.h>
#include <cpu/x86/mp.h>
#include <cpu/x86/msr.h>
#include <cpu/x86/mtrr.h>
#include <cpu/x86/smm.h>
#include <device/device.h>
#include <device/pci.h>
#include <device/pci_ops.h>
#include <smp/node.h>
#include <soc/cpu.h>
#include <soc/msr.h>
#include <soc/pci_devs.h>
#include <soc/soc_chip.h>
#include <string.h>
#include <types.h>

static void update_save_state(int cpu, uintptr_t curr_smbase,
				uintptr_t staggered_smbase,
				struct smm_relocation_params *relo_params)
{
	u32 smbase;
	u32 iedbase;

	/*
	 * The relocated handler runs with all CPUs concurrently. Therefore
	 * stagger the entry points adjusting SMBASE downwards by save state
	 * size * CPU num.
	 */
	smbase = staggered_smbase;
	iedbase = relo_params->ied_base;

	printk(BIOS_DEBUG, "New SMBASE=0x%08x IEDBASE=0x%08x\n",
	       smbase, iedbase);

	/*
	 * All threads need to set IEDBASE and SMBASE to the relocated
	 * handler region. However, the save state location depends on the
	 * smm_save_state_in_msrs field in the relocation parameters. If
	 * smm_save_state_in_msrs is non-zero then the CPUs are relocating
	 * the SMM handler in parallel, and each CPUs save state area is
	 * located in their respective MSR space. If smm_save_state_in_msrs
	 * is zero then the SMM relocation is happening serially so the
	 * save state is at the same default location for all CPUs.
	 */
	if (relo_params->smm_save_state_in_msrs) {
		msr_t smbase_msr;
		msr_t iedbase_msr;

		smbase_msr.lo = smbase;
		smbase_msr.hi = 0;

		/*
		 * According the BWG the IEDBASE MSR is in bits 63:32. It's
		 * not clear why it differs from the SMBASE MSR.
		 */
		iedbase_msr.lo = 0;
		iedbase_msr.hi = iedbase;

		wrmsr(SMBASE_MSR, smbase_msr);
		wrmsr(IEDBASE_MSR, iedbase_msr);
	} else {
		em64t101_smm_state_save_area_t *save_state;

		save_state = (void *)(curr_smbase + SMM_DEFAULT_SIZE -
				      sizeof(*save_state));

		save_state->smbase = smbase;
		save_state->iedbase = iedbase;
	}
}

/* Returns 1 if SMM MSR save state was set. */
static int bsp_setup_msr_save_state(struct smm_relocation_params *relo_params)
{
	msr_t smm_mca_cap;

	smm_mca_cap = rdmsr(SMM_MCA_CAP_MSR);
	if (smm_mca_cap.hi & SMM_CPU_SVRSTR_MASK) {
		msr_t smm_feature_control;

		smm_feature_control = rdmsr(SMM_FEATURE_CONTROL_MSR);
		smm_feature_control.hi = 0;
		smm_feature_control.lo |= SMM_CPU_SAVE_EN;
		wrmsr(SMM_FEATURE_CONTROL_MSR, smm_feature_control);
		relo_params->smm_save_state_in_msrs = 1;
	}
	return relo_params->smm_save_state_in_msrs;
}

/*
 * The relocation work is actually performed in SMM context, but the code
 * resides in the ramstage module. This occurs by trampolining from the default
 * SMRAM entry point to here.
 */
void smm_relocation_handler(int cpu, uintptr_t curr_smbase,
				uintptr_t staggered_smbase)
{
	msr_t mtrr_cap;
	struct smm_relocation_params *relo_params = &smm_reloc_params;

	printk(BIOS_DEBUG, "In relocation handler: CPU %d\n", cpu);

	/*
	 * Determine if the processor supports saving state in MSRs. If so,
	 * enable it before the non-BSPs run so that SMM relocation can occur
	 * in parallel in the non-BSP CPUs.
	 */
	if (cpu == 0) {
		/*
		 * If smm_save_state_in_msrs is 1 then that means this is the
		 * 2nd time through the relocation handler for the BSP.
		 * Parallel SMM handler relocation is taking place. However,
		 * it is desired to access other CPUs save state in the real
		 * SMM handler. Therefore, disable the SMM save state in MSRs
		 * feature.
		 */
		if (relo_params->smm_save_state_in_msrs) {
			msr_t smm_feature_control;

			smm_feature_control = rdmsr(SMM_FEATURE_CONTROL_MSR);
			smm_feature_control.lo &= ~SMM_CPU_SAVE_EN;
			wrmsr(SMM_FEATURE_CONTROL_MSR, smm_feature_control);
		} else if (bsp_setup_msr_save_state(relo_params))
			/*
			 * Just return from relocation handler if MSR save
			 * state is enabled. In that case the BSP will come
			 * back into the relocation handler to setup the new
			 * SMBASE as well disabling SMM save state in MSRs.
			 */
			return;
	}

	/* Make appropriate changes to the save state map. */
	update_save_state(cpu, curr_smbase, staggered_smbase, relo_params);

	/* Write SMRR MSRs based on indicated support. */
	mtrr_cap = rdmsr(MTRR_CAP_MSR);
	if (mtrr_cap.lo & SMRR_SUPPORTED)
		write_smrr(relo_params);
}

static void fill_in_relocation_params(struct smm_relocation_params *params)
{
	uintptr_t tseg_base;
	size_t tseg_size;
	/* All range registers are aligned to 4KiB */
	const u32 rmask = ~(4 * KiB - 1);

	smm_region(&tseg_base, &tseg_size);

	if (!IS_ALIGNED(tseg_base, tseg_size)) {
		printk(BIOS_WARNING,
		     "TSEG base not aligned with TSEG SIZE! Not setting SMRR\n");
		return;
	}

	smm_subregion(SMM_SUBREGION_CHIPSET, &params->ied_base, &params->ied_size);

	/* SMRR has 32-bits of valid address aligned to 4KiB. */
	params->smrr_base.lo = (tseg_base & rmask) | MTRR_TYPE_WRBACK;
	params->smrr_base.hi = 0;
	params->smrr_mask.lo = (~(tseg_size - 1) & rmask) | MTRR_PHYS_MASK_VALID;
	params->smrr_mask.hi = 0;
}

static void setup_ied_area(struct smm_relocation_params *params)
{
	char *ied_base;

	struct ied_header ied = {
		.signature = "INTEL RSVD",
		.size = params->ied_size,
		.reserved = {0},
	};

	ied_base = (void *)params->ied_base;

	printk(BIOS_DEBUG, "IED base = 0x%08x\n", (u32)params->ied_base);
	printk(BIOS_DEBUG, "IED size = 0x%08x\n", (u32)params->ied_size);

	/* Place IED header at IEDBASE. */
	memcpy(ied_base, &ied, sizeof(ied));

	/* Zero out 32KiB at IEDBASE + 1MiB */
	memset(ied_base + 1 * MiB, 0, 32 * KiB);
}

void smm_info(uintptr_t *perm_smbase, size_t *perm_smsize,
				size_t *smm_save_state_size)
{
	printk(BIOS_DEBUG, "Setting up SMI for CPU\n");

	fill_in_relocation_params(&smm_reloc_params);

	smm_subregion(SMM_SUBREGION_HANDLER, perm_smbase, perm_smsize);

	if (smm_reloc_params.ied_size)
		setup_ied_area(&smm_reloc_params);

	*smm_save_state_size = sizeof(em64t101_smm_state_save_area_t);
}

void smm_initialize(void)
{
	/* Clear the SMM state in the southbridge. */
	smm_southbridge_clear_state();

	/*
	 * Run the relocation handler for on the BSP to check and set up
	 * parallel SMM relocation.
	 */
	smm_initiate_relocation();

	if (smm_reloc_params.smm_save_state_in_msrs)
		printk(BIOS_DEBUG, "Doing parallel SMM relocation.\n");
}

void smm_relocate(void)
{
	/*
	 * If smm_save_state_in_msrs is non-zero then parallel SMM relocation
	 * shall take place. Run the relocation handler a second time on the
	 * BSP to do * the final move. For APs, a relocation handler always
	 * needs to be run.
	 */
	if (smm_reloc_params.smm_save_state_in_msrs)
		smm_initiate_relocation_parallel();
	else if (!boot_cpu())
		smm_initiate_relocation();
}