diff --git a/src/cpu/x86/smm/smmrelocate.S b/src/cpu/x86/smm/smmrelocate.S
index 16bccbc..bd12581 100644
--- a/src/cpu/x86/smm/smmrelocate.S
+++ b/src/cpu/x86/smm/smmrelocate.S
@@ -27,9 +27,6 @@
 #include <southbridge/intel/i82801dx/i82801dx.h>
 #elif IS_ENABLED(CONFIG_SOUTHBRIDGE_INTEL_I82801IX)
 #include <southbridge/intel/i82801ix/i82801ix.h>
-#elif IS_ENABLED(CONFIG_SOUTHBRIDGE_INTEL_I82801JX)
-#include <southbridge/intel/i82801jx/i82801jx.h>
-
 #else
 #error "Southbridge needs SMM handler support."
 #endif
diff --git a/src/northbridge/intel/x4x/Kconfig b/src/northbridge/intel/x4x/Kconfig
index 1c65614..117ac03 100644
--- a/src/northbridge/intel/x4x/Kconfig
+++ b/src/northbridge/intel/x4x/Kconfig
@@ -28,6 +28,7 @@
 	select CACHE_MRC_SETTINGS
 	select POSTCAR_STAGE
 	select POSTCAR_CONSOLE
+	select SMM_TSEG
 
 config CBFS_SIZE
 	hex
diff --git a/src/northbridge/intel/x4x/northbridge.c b/src/northbridge/intel/x4x/northbridge.c
index bc7a5b3..d6094ac 100644
--- a/src/northbridge/intel/x4x/northbridge.c
+++ b/src/northbridge/intel/x4x/northbridge.c
@@ -29,14 +29,15 @@
 #include <northbridge/intel/x4x/iomap.h>
 #include <northbridge/intel/x4x/chip.h>
 #include <northbridge/intel/x4x/x4x.h>
+#include <cpu/intel/smm/gen1/smi.h>
 
 static const int legacy_hole_base_k = 0xa0000 / 1024;
 
 static void mch_domain_read_resources(struct device *dev)
 {
-	u8 index, reg8;
+	u8 index;
 	u64 tom, touud;
-	u32 tomk, tseg_sizek = 0, tolud, delta_cbmem;
+	u32 tomk, tolud, delta_cbmem;
 	u32 pcie_config_base, pcie_config_size;
 	u32 uma_sizek = 0;
 
@@ -82,20 +83,8 @@
 	uma_sizek += gsm_sizek;
 
 	printk(BIOS_DEBUG, "TSEG decoded, subtracting ");
-	reg8 = pci_read_config8(mch, D0F0_ESMRAMC);
-	reg8 >>= 1;
-	reg8 &= 3;
-	switch (reg8) {
-	case 0:
-		tseg_sizek = 1024;
-		break;	/* TSEG = 1M */
-	case 1:
-		tseg_sizek = 2048;
-		break;	/* TSEG = 2M */
-	case 2:
-		tseg_sizek = 8192;
-		break;	/* TSEG = 8M */
-	}
+	const u32 tseg_sizek = decode_tseg_size(
+		pci_read_config8(dev, D0F0_ESMRAMC)) >> 10;
 	uma_sizek += tseg_sizek;
 	tomk -= tseg_sizek;
 
@@ -184,6 +173,36 @@
 	return NULL;
 }
 
+void northbridge_write_smram(u8 smram)
+{
+	struct device *dev = dev_find_slot(0, PCI_DEVFN(0, 0));
+
+	if (dev == NULL)
+		die("could not find pci 00:00.0!\n");
+
+	pci_write_config8(dev, D0F0_SMRAM, smram);
+}
+
+/*
+ * Really doesn't belong here but will go away with parallel mp init,
+ * so let it be here for a while...
+ */
+int cpu_get_apic_id_map(int *apic_id_map)
+{
+	unsigned int i;
+
+	/* Logical processors (threads) per core */
+	const struct cpuid_result cpuid1 = cpuid(1);
+	/* Read number of cores. */
+	const char cores = (cpuid1.ebx >> 16) & 0xf;
+
+	/* TODO in parallel MP cpuid(1).ebx */
+	for (i = 0; i < cores; i++)
+		apic_id_map[i] = i;
+
+	return cores;
+}
+
 static struct device_operations pci_domain_ops = {
 	.read_resources   = mch_domain_read_resources,
 	.set_resources    = mch_domain_set_resources,
diff --git a/src/northbridge/intel/x4x/ram_calc.c b/src/northbridge/intel/x4x/ram_calc.c
index 1f1c13f..6484326 100644
--- a/src/northbridge/intel/x4x/ram_calc.c
+++ b/src/northbridge/intel/x4x/ram_calc.c
@@ -28,6 +28,7 @@
 #include <cpu/x86/mtrr.h>
 #include <northbridge/intel/x4x/x4x.h>
 #include <program_loading.h>
+#include <cpu/intel/smm/gen1/smi.h>
 
 /** Decodes used Graphics Mode Select (GMS) to kilobytes. */
 u32 decode_igd_memory_size(const u32 gms)
@@ -52,6 +53,25 @@
 	return ggc2gtt[gsm] << 10;
 }
 
+/** Decodes used TSEG size to bytes. */
+u32 decode_tseg_size(const u32 esmramc)
+{
+	if (!(esmramc & 1))
+		return 0;
+
+	switch ((esmramc >> 1) & 3) {
+	case 0:
+		return 1 << 20;
+	case 1:
+		return 2 << 20;
+	case 2:
+		return 8 << 20;
+	case 3:
+	default:
+		die("Bad TSEG setting.\n");
+	}
+}
+
 u8 decode_pciebar(u32 *const base, u32 *const len)
 {
 	*base = 0;
@@ -92,14 +112,25 @@
 	return 1;
 }
 
+u32 northbridge_get_tseg_size(void)
+{
+	const u8 esmramc = pci_read_config8(PCI_DEV(0, 0, 0), D0F0_ESMRAMC);
+	return decode_tseg_size(esmramc);
+}
+
+u32 northbridge_get_tseg_base(void)
+{
+	return pci_read_config32(PCI_DEV(0, 0, 0), D0F0_TSEG);
+}
+
+
 /* Depending of UMA and TSEG configuration, TSEG might start at any
  * 1 MiB alignment. As this may cause very greedy MTRR setup, push
  * CBMEM top downwards to 4 MiB boundary.
  */
 void *cbmem_top(void)
 {
-	uintptr_t top_of_ram = pci_read_config32(PCI_DEV(0, 0, 0), D0F0_TSEG);
-	top_of_ram = ALIGN_DOWN(top_of_ram, 4*MiB);
+	uintptr_t top_of_ram = ALIGN_DOWN(northbridge_get_tseg_base(), 4*MiB);
 	return (void *) top_of_ram;
 }
 
@@ -122,14 +153,14 @@
 	/* Cache RAM as WB from 0 -> CACHE_TMP_RAMTOP. */
 	postcar_frame_add_mtrr(&pcf, 0, CACHE_TMP_RAMTOP, MTRR_TYPE_WRBACK);
 
-	/* Cache two separate 4 MiB regions below the top of ram, this
-	 * satisfies MTRR alignment requirements. If you modify this to
-	 * cover TSEG, make sure UMA region is not set with WRBACK as it
-	 * causes hard-to-recover boot failures.
+	/* Cache 8 MiB region below the top of ram and 2 MiB above top of
+	 * ram to cover both cbmem as the TSEG region.
 	 */
 	top_of_ram = (uintptr_t)cbmem_top();
-	postcar_frame_add_mtrr(&pcf, top_of_ram - 4*MiB, 4*MiB, MTRR_TYPE_WRBACK);
-	postcar_frame_add_mtrr(&pcf, top_of_ram - 8*MiB, 4*MiB, MTRR_TYPE_WRBACK);
+	postcar_frame_add_mtrr(&pcf, top_of_ram - 8*MiB, 8*MiB,
+			MTRR_TYPE_WRBACK);
+	postcar_frame_add_mtrr(&pcf, northbridge_get_tseg_base(),
+			       northbridge_get_tseg_size(), MTRR_TYPE_WRBACK);
 
 	run_postcar_phase(&pcf);
 
diff --git a/src/northbridge/intel/x4x/x4x.h b/src/northbridge/intel/x4x/x4x.h
index 9837063..a7efb17 100644
--- a/src/northbridge/intel/x4x/x4x.h
+++ b/src/northbridge/intel/x4x/x4x.h
@@ -373,6 +373,7 @@
 void x4x_late_init(int s3resume);
 u32 decode_igd_memory_size(u32 gms);
 u32 decode_igd_gtt_size(u32 gsm);
+u32 decode_tseg_size(const u32 esmramc);
 u8 decode_pciebar(u32 *const base, u32 *const len);
 void sdram_initialize(int boot_path, const u8 *spd_map);
 void do_raminit(struct sysinfo *, int fast_boot);
diff --git a/src/southbridge/intel/i82801jx/Makefile.inc b/src/southbridge/intel/i82801jx/Makefile.inc
index 1053659..c21a61a 100644
--- a/src/southbridge/intel/i82801jx/Makefile.inc
+++ b/src/southbridge/intel/i82801jx/Makefile.inc
@@ -31,8 +31,6 @@
 
 ramstage-y += ../i82801gx/watchdog.c
 
-ramstage-$(CONFIG_HAVE_SMI_HANDLER) += smi.c
-ramstage-$(CONFIG_HAVE_SMI_HANDLER) += ../../../cpu/x86/smm/smmrelocate.S
 smm-$(CONFIG_HAVE_SMI_HANDLER) += smihandler.c
 
 romstage-y += early_smbus.c