diff --git a/src/northbridge/intel/haswell/memmap.c b/src/northbridge/intel/haswell/memmap.c
index 3a63afc..14b66a0 100644
--- a/src/northbridge/intel/haswell/memmap.c
+++ b/src/northbridge/intel/haswell/memmap.c
@@ -16,8 +16,12 @@
 // Use simple device model for this file even in ramstage
 #define __SIMPLE_DEVICE__
 
+#include <arch/cpu.h>
+#include <console/console.h>
+#include <cpu/x86/mtrr.h>
 #include <device/pci_ops.h>
 #include <cbmem.h>
+#include <cpu/intel/romstage.h>
 #include <stage_cache.h>
 #include "haswell.h"
 
@@ -48,3 +52,30 @@
 	*size = CONFIG_SMM_RESERVED_SIZE;
 	*base = (void *)((uint32_t)cbmem_top() + RESERVED_SMM_OFFSET);
 }
+
+/* platform_enter_postcar() determines the stack to use after
+ * cache-as-ram is torn down as well as the MTRR settings to use,
+ * and continues execution in postcar stage. */
+void platform_enter_postcar(void)
+{
+	struct postcar_frame pcf;
+	uintptr_t top_of_ram;
+
+	if (postcar_frame_init(&pcf, 0))
+		die("Unable to initialize postcar frame.\n");
+	/* Cache the ROM as WP just below 4GiB. */
+	postcar_frame_add_romcache(&pcf, MTRR_TYPE_WRPROT);
+
+	/* Cache RAM as WB from 0 -> CACHE_TMP_RAMTOP. */
+	postcar_frame_add_mtrr(&pcf, 0, CACHE_TMP_RAMTOP, MTRR_TYPE_WRBACK);
+
+	/* Cache at least 8 MiB below the top of ram, and at most 8 MiB
+	 * above top of the ram. This satisfies MTRR alignment requirement
+	 * with different TSEG size configurations.
+	 */
+	top_of_ram = ALIGN_DOWN((uintptr_t)cbmem_top(), 8*MiB);
+	postcar_frame_add_mtrr(&pcf, top_of_ram - 8*MiB, 16*MiB,
+			MTRR_TYPE_WRBACK);
+
+	run_postcar_phase(&pcf);
+}