BACKPORT: x86: provide infrastructure to backup default SMM region

Certain CPUs require the default SMM region to be backed up
on resume after a suspend. The reason is that in order to
relocate the SMM region the default SMM region has to be used.
As coreboot is unaware of how that memory is used it needs to
be backed up. Therefore provide a common method for doing this.

BUG=chrome-os-partner:26563
BRANCH=baytrail
TEST=Confirmed SMM backup region in cbmem. Suspend and Resumed.

Change-Id: I65fe1317dc0b2203cb29118564fdba995770ffea
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/188716
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

src/cpu/x86/Kconfig

@@ -122,3 +122,9 @@ config PARALLEL_MP
 	 This option uses common MP infrastructure for bringing up APs
 	 in parallel. It additionally provides a more flexible mechanism
 	 for sequencing the steps of bringing up the APs.
+
+config BACKUP_DEFAULT_SMM_REGION
+	def_bool n
+	help
+	 The cpu support will select this option if the default SMM region
+	 needs to be backed up for suspend/resume purposes.

src/cpu/x86/smm/Makefile.inc

@@ -17,6 +17,8 @@
 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 ##
 
+ramstage-$(CONFIG_BACKUP_DEFAULT_SMM_REGION) += backup_default_smm.c
+
 ifeq ($(CONFIG_SMM_MODULES),y)
 smmstub-y += smm_stub.S
 smmstub-y += smm_module_header.c

src/cpu/x86/smm/backup_default_smm.c

@@ -0,0 +1,68 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2014 Google Inc
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2 of
+ * the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <string.h>
+#include <arch/acpi.h>
+#include <console/console.h>
+#include <cbmem.h>
+#include <cpu/x86/smm.h>
+
+void *backup_default_smm_area(void)
+{
+	void *save_area;
+	const void *default_smm = (void *)SMM_DEFAULT_BASE;
+
+	if (!IS_ENABLED(CONFIG_HAVE_ACPI_RESUME))
+		return NULL;
+
+	/*
+	 * The buffer needs to be preallocated regardless. In the non-resume
+	 * path it will be allocated for handling resume. Note that cbmem_add()
+	 * does a find before the addition.
+	 */
+	save_area = cbmem_add(CBMEM_ID_SMM_SAVE_SPACE, SMM_DEFAULT_SIZE);
+
+	if (save_area == NULL) {
+		printk(BIOS_DEBUG, "SMM save area not added.\n");
+		return NULL;
+	}
+
+	/* Only back up the area on S3 resume. */
+	if (acpi_slp_type == 3) {
+		memcpy(save_area, default_smm, SMM_DEFAULT_SIZE);
+		return save_area;
+	}
+
+	/*
+	 * Not the S3 resume path. No need to restore memory contents after
+	 * SMM relocation.
+	 */
+	return NULL;
+}
+
+void restore_default_smm_area(void *smm_save_area)
+{
+	void *default_smm = (void *)SMM_DEFAULT_BASE;
+
+	if (smm_save_area == NULL)
+		return;
+
+	memcpy(default_smm, smm_save_area, SMM_DEFAULT_SIZE);
+}

src/include/cbmem.h

@@ -74,6 +74,7 @@
 #define CBMEM_ID_REFCODE_CACHE	0x4efc0de5
 #define CBMEM_ID_POWER_STATE	0x50535454
 #define CBMEM_ID_RAM_OOPS	0x05430095
+#define CBMEM_ID_SMM_SAVE_SPACE	0x07e9acee
 #define CBMEM_ID_NONE		0x00000000
 
 #ifndef __ASSEMBLER__

src/include/cpu/x86/smm.h

@@ -571,4 +571,8 @@ int smm_load_module(void *smram, int size, struct smm_loader_params *params);
 #endif /* __SMM__ */
 #endif /* CONFIG_SMM_MODULES */
 
+/* Backup and restore default SMM region. */
+void *backup_default_smm_area(void);
+void restore_default_smm_area(void *smm_save_area);
+
 #endif

src/lib/cbmem_info.c

@@ -48,6 +48,7 @@ static struct cbmem_id_to_name {
 	{ CBMEM_ID_VBOOT_HANDOFF,	"VBOOT      " },
 	{ CBMEM_ID_CAR_GLOBALS,		"CAR GLOBALS" },
 	{ CBMEM_ID_REFCODE,		"REFCODE    " },
+	{ CBMEM_ID_SMM_SAVE_SPACE,	"SMM BACKUP " },
 	{ CBMEM_ID_REFCODE_CACHE,	"REFCODE $  " },
 	{ CBMEM_ID_POWER_STATE,		"POWER STATE" },
 	{ CBMEM_ID_RAM_OOPS,		"RAMOOPS    " },