1 files changed, 164 insertions, 16 deletions

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 05509f3aa..7dd2e2d37 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -24,6 +24,9 @@
 #include <linux/of_fdt.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/ucs2_string.h>
 
 #include <asm/early_ioremap.h>
 
@@ -195,6 +198,96 @@ static void generic_ops_unregister(void)
 	efivars_unregister(&generic_efivars);
 }
 
+#if IS_ENABLED(CONFIG_ACPI)
+#define EFIVAR_SSDT_NAME_MAX	16
+static char efivar_ssdt[EFIVAR_SSDT_NAME_MAX] __initdata;
+static int __init efivar_ssdt_setup(char *str)
+{
+	if (strlen(str) < sizeof(efivar_ssdt))
+		memcpy(efivar_ssdt, str, strlen(str));
+	else
+		pr_warn("efivar_ssdt: name too long: %s\n", str);
+	return 0;
+}
+__setup("efivar_ssdt=", efivar_ssdt_setup);
+
+static __init int efivar_ssdt_iter(efi_char16_t *name, efi_guid_t vendor,
+				   unsigned long name_size, void *data)
+{
+	struct efivar_entry *entry;
+	struct list_head *list = data;
+	char utf8_name[EFIVAR_SSDT_NAME_MAX];
+	int limit = min_t(unsigned long, EFIVAR_SSDT_NAME_MAX, name_size);
+
+	ucs2_as_utf8(utf8_name, name, limit - 1);
+	if (strncmp(utf8_name, efivar_ssdt, limit) != 0)
+		return 0;
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return 0;
+
+	memcpy(entry->var.VariableName, name, name_size);
+	memcpy(&entry->var.VendorGuid, &vendor, sizeof(efi_guid_t));
+
+	efivar_entry_add(entry, list);
+
+	return 0;
+}
+
+static __init int efivar_ssdt_load(void)
+{
+	LIST_HEAD(entries);
+	struct efivar_entry *entry, *aux;
+	unsigned long size;
+	void *data;
+	int ret;
+
+	ret = efivar_init(efivar_ssdt_iter, &entries, true, &entries);
+
+	list_for_each_entry_safe(entry, aux, &entries, list) {
+		pr_info("loading SSDT from variable %s-%pUl\n", efivar_ssdt,
+			&entry->var.VendorGuid);
+
+		list_del(&entry->list);
+
+		ret = efivar_entry_size(entry, &size);
+		if (ret) {
+			pr_err("failed to get var size\n");
+			goto free_entry;
+		}
+
+		data = kmalloc(size, GFP_KERNEL);
+		if (!data)
+			goto free_entry;
+
+		ret = efivar_entry_get(entry, NULL, &size, data);
+		if (ret) {
+			pr_err("failed to get var data\n");
+			goto free_data;
+		}
+
+		ret = acpi_load_table(data);
+		if (ret) {
+			pr_err("failed to load table: %d\n", ret);
+			goto free_data;
+		}
+
+		goto free_entry;
+
+free_data:
+		kfree(data);
+
+free_entry:
+		kfree(entry);
+	}
+
+	return ret;
+}
+#else
+static inline int efivar_ssdt_load(void) { return 0; }
+#endif
+
 /*
  * We register the efi subsystem with the firmware subsystem and the
  * efivars subsystem with the efi subsystem, if the system was booted with
@@ -218,6 +311,9 @@ static int __init efisubsys_init(void)
 	if (error)
 		goto err_put;
 
+	if (efi_enabled(EFI_RUNTIME_SERVICES))
+		efivar_ssdt_load();
+
 	error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
 	if (error) {
 		pr_err("efi: Sysfs attribute export failed with error %d.\n",
@@ -472,12 +568,14 @@ device_initcall(efi_load_efivars);
 		FIELD_SIZEOF(struct efi_fdt_params, field) \
 	}
 
-static __initdata struct {
+struct params {
 	const char name[32];
 	const char propname[32];
 	int offset;
 	int size;
-} dt_params[] = {
+};
+
+static __initdata struct params fdt_params[] = {
 	UEFI_PARAM("System Table", "linux,uefi-system-table", system_table),
 	UEFI_PARAM("MemMap Address", "linux,uefi-mmap-start", mmap),
 	UEFI_PARAM("MemMap Size", "linux,uefi-mmap-size", mmap_size),
@@ -485,44 +583,94 @@ static __initdata struct {
 	UEFI_PARAM("MemMap Desc. Version", "linux,uefi-mmap-desc-ver", desc_ver)
 };
 
+static __initdata struct params xen_fdt_params[] = {
+	UEFI_PARAM("System Table", "xen,uefi-system-table", system_table),
+	UEFI_PARAM("MemMap Address", "xen,uefi-mmap-start", mmap),
+	UEFI_PARAM("MemMap Size", "xen,uefi-mmap-size", mmap_size),
+	UEFI_PARAM("MemMap Desc. Size", "xen,uefi-mmap-desc-size", desc_size),
+	UEFI_PARAM("MemMap Desc. Version", "xen,uefi-mmap-desc-ver", desc_ver)
+};
+
+#define EFI_FDT_PARAMS_SIZE	ARRAY_SIZE(fdt_params)
+
+static __initdata struct {
+	const char *uname;
+	const char *subnode;
+	struct params *params;
+} dt_params[] = {
+	{ "hypervisor", "uefi", xen_fdt_params },
+	{ "chosen", NULL, fdt_params },
+};
+
 struct param_info {
 	int found;
 	void *params;
+	const char *missing;
 };
 
-static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
-				       int depth, void *data)
+static int __init __find_uefi_params(unsigned long node,
+				     struct param_info *info,
+				     struct params *params)
 {
-	struct param_info *info = data;
 	const void *prop;
 	void *dest;
 	u64 val;
 	int i, len;
 
-	if (depth != 1 || strcmp(uname, "chosen") != 0)
-		return 0;
-
-	for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
-		prop = of_get_flat_dt_prop(node, dt_params[i].propname, &len);
-		if (!prop)
+	for (i = 0; i < EFI_FDT_PARAMS_SIZE; i++) {
+		prop = of_get_flat_dt_prop(node, params[i].propname, &len);
+		if (!prop) {
+			info->missing = params[i].name;
 			return 0;
-		dest = info->params + dt_params[i].offset;
+		}
+
+		dest = info->params + params[i].offset;
 		info->found++;
 
 		val = of_read_number(prop, len / sizeof(u32));
 
-		if (dt_params[i].size == sizeof(u32))
+		if (params[i].size == sizeof(u32))
 			*(u32 *)dest = val;
 		else
 			*(u64 *)dest = val;
 
 		if (efi_enabled(EFI_DBG))
-			pr_info("  %s: 0x%0*llx\n", dt_params[i].name,
-				dt_params[i].size * 2, val);
+			pr_info("  %s: 0x%0*llx\n", params[i].name,
+				params[i].size * 2, val);
 	}
+
 	return 1;
 }
 
+static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
+				       int depth, void *data)
+{
+	struct param_info *info = data;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
+		const char *subnode = dt_params[i].subnode;
+
+		if (depth != 1 || strcmp(uname, dt_params[i].uname) != 0) {
+			info->missing = dt_params[i].params[0].name;
+			continue;
+		}
+
+		if (subnode) {
+			int err = of_get_flat_dt_subnode_by_name(node, subnode);
+
+			if (err < 0)
+				return 0;
+
+			node = err;
+		}
+
+		return __find_uefi_params(node, info, dt_params[i].params);
+	}
+
+	return 0;
+}
+
 int __init efi_get_fdt_params(struct efi_fdt_params *params)
 {
 	struct param_info info;
@@ -538,7 +686,7 @@ int __init efi_get_fdt_params(struct efi_fdt_params *params)
 		pr_info("UEFI not found.\n");
 	else if (!ret)
 		pr_err("Can't find '%s' in device tree!\n",
-		       dt_params[info.found].name);
+		       info.missing);
 
 	return ret;
 }