diff --git a/src/cpu/intel/haswell/smmrelocate.c b/src/cpu/intel/haswell/smmrelocate.c
index e3b9c38..1eb6f68 100644
--- a/src/cpu/intel/haswell/smmrelocate.c
+++ b/src/cpu/intel/haswell/smmrelocate.c
@@ -48,10 +48,8 @@
 #define PRMRR_SUPPORTED (1 << 12)
 
 struct smm_relocation_params {
-	u32 smram_base;
-	u32 smram_size;
-	u32 ied_base;
-	u32 ied_size;
+	uintptr_t ied_base;
+	size_t ied_size;
 	msr_t smrr_base;
 	msr_t smrr_mask;
 	msr_t prmrr_base;
@@ -212,22 +210,11 @@
 	}
 }
 
-static u32 northbridge_get_base_reg(struct device *dev, int reg)
+static void fill_in_relocation_params(struct smm_relocation_params *params)
 {
-	u32 value;
+	uintptr_t tseg_base;
+	size_t tseg_size;
 
-	value = pci_read_config32(dev, reg);
-	/* Base registers are at 1MiB granularity. */
-	value &= ~((1 << 20) - 1);
-	return value;
-}
-
-static void fill_in_relocation_params(struct device *dev,
-				      struct smm_relocation_params *params)
-{
-	u32 tseg_size;
-	u32 tsegmb;
-	u32 bgsm;
 	u32 prmrr_base;
 	u32 prmrr_size;
 	int phys_bits;
@@ -242,25 +229,16 @@
 	 * SMRAM range as well as the IED range. However, the SMRAM available
 	 * to the handler is 4MiB since the IEDRAM lives TSEGMB + 4MiB.
 	 */
-	tsegmb = northbridge_get_base_reg(dev, TSEG);
-	bgsm = northbridge_get_base_reg(dev, BGSM);
-	tseg_size = bgsm - tsegmb;
-
-	params->smram_base = tsegmb;
-	params->smram_size = 4 << 20;
-	params->ied_base = tsegmb + params->smram_size;
-	params->ied_size = tseg_size - params->smram_size;
-
-	/* Adjust available SMM handler memory size. */
-	params->smram_size -= CONFIG_SMM_RESERVED_SIZE;
+	smm_region(&tseg_base, &tseg_size);
 
 	/* SMRR has 32-bits of valid address aligned to 4KiB. */
-	params->smrr_base.lo = (params->smram_base & rmask) | MTRR_TYPE_WRBACK;
+	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.lo = (~(tseg_size - 1) & rmask) | MTRR_PHYS_MASK_VALID;
 	params->smrr_mask.hi = 0;
 
+	smm_subregion(SMM_SUBREGION_CHIPSET, &params->ied_base, &params->ied_size);
+
 	/* The PRMRR and UNCORE_PRMRR are at IEDBASE + 2MiB */
 	prmrr_base = (params->ied_base + (2 << 20)) & rmask;
 	prmrr_size = params->ied_size - (2 << 20);
@@ -310,16 +288,14 @@
 void smm_info(uintptr_t *perm_smbase, size_t *perm_smsize,
 				size_t *smm_save_state_size)
 {
-	struct device *dev = pcidev_on_root(0, 0);
-
 	printk(BIOS_DEBUG, "Setting up SMI for CPU\n");
 
-	fill_in_relocation_params(dev, &smm_reloc_params);
+	fill_in_relocation_params(&smm_reloc_params);
+
+	smm_subregion(SMM_SUBREGION_HANDLER, perm_smbase, perm_smsize);
 
 	setup_ied_area(&smm_reloc_params);
 
-	*perm_smbase = smm_reloc_params.smram_base;
-	*perm_smsize = smm_reloc_params.smram_size;
 	*smm_save_state_size = sizeof(em64t101_smm_state_save_area_t);
 }
 
diff --git a/src/northbridge/intel/haswell/memmap.c b/src/northbridge/intel/haswell/memmap.c
index 5bc74f8..b1eb770 100644
--- a/src/northbridge/intel/haswell/memmap.c
+++ b/src/northbridge/intel/haswell/memmap.c
@@ -20,9 +20,9 @@
 #include <console/console.h>
 #include <commonlib/helpers.h>
 #include <cpu/x86/mtrr.h>
+#include <cpu/x86/smm.h>
 #include <device/pci_ops.h>
 #include <cbmem.h>
-#include <stage_cache.h>
 #include "haswell.h"
 
 static uintptr_t smm_region_start(void)
@@ -40,17 +40,10 @@
 	return (void *)smm_region_start();
 }
 
-/* Region of SMM space is reserved for multipurpose use. It falls below
- * the IED region and above the SMM handler. */
-#define RESERVED_SMM_OFFSET \
-	(CONFIG_SMM_TSEG_SIZE - CONFIG_IED_REGION_SIZE - CONFIG_SMM_RESERVED_SIZE)
-
-void stage_cache_external_region(void **base, size_t *size)
+void smm_region(uintptr_t *start, size_t *size)
 {
-	/* The ramstage cache lives in the TSEG region at RESERVED_SMM_OFFSET.
-	 * The top of RAM is defined to be the TSEG base address. */
-	*size = CONFIG_SMM_RESERVED_SIZE;
-	*base = (void *)((uint32_t)cbmem_top() + RESERVED_SMM_OFFSET);
+	*start = smm_region_start();
+	*size = CONFIG_SMM_TSEG_SIZE;
 }
 
 void fill_postcar_frame(struct postcar_frame *pcf)