1 files changed, 399 insertions, 0 deletions
diff --git a/lib/efi_loader/efi_var_mem.c b/lib/efi_loader/efi_var_mem.c
new file mode 100644
index 00000000000..139e16aad7c
--- /dev/null
+++ b/lib/efi_loader/efi_var_mem.c
@@ -0,0 +1,399 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * File interface for UEFI variables
+ *
+ * Copyright (c) 2020, Heinrich Schuchardt
+ */
+
+#include <efi_loader.h>
+#include <efi_variable.h>
+#include <u-boot/crc.h>
+
+/*
+ * The variables efi_var_file and efi_var_entry must be static to avoid
+ * referencing them via the global offset table (section .got). The GOT
+ * is neither mapped as EfiRuntimeServicesData nor do we support its
+ * relocation during SetVirtualAddressMap().
+ */
+static struct efi_var_file __efi_runtime_data *efi_var_buf;
+static struct efi_var_entry __efi_runtime_data *efi_current_var;
+
+/**
+ * efi_var_mem_compare() - compare GUID and name with a variable
+ *
+ * @var:	variable to compare
+ * @guid:	GUID to compare
+ * @name:	variable name to compare
+ * @next:	pointer to next variable
+ * Return:	true if match
+ */
+static bool __efi_runtime
+efi_var_mem_compare(struct efi_var_entry *var, const efi_guid_t *guid,
+		    const u16 *name, struct efi_var_entry **next)
+{
+	int i;
+	u8 *guid1, *guid2;
+	const u16 *data, *var_name;
+	bool match = true;
+
+	for (guid1 = (u8 *)&var->guid, guid2 = (u8 *)guid, i = 0;
+	     i < sizeof(efi_guid_t) && match; ++i)
+		match = (guid1[i] == guid2[i]);
+
+	for (data = var->name, var_name = name;; ++data) {
+		if (match)
+			match = (*data == *var_name);
+		if (!*data)
+			break;
+		if (*var_name)
+			++var_name;
+	}
+
+	++data;
+
+	if (next)
+		*next = (struct efi_var_entry *)
+			ALIGN((uintptr_t)data + var->length, 8);
+
+	if (match)
+		efi_current_var = var;
+
+	return match;
+}
+
+/**
+ * efi_var_entry_len() - Get the entry len including headers & name
+ *
+ * @var:	pointer to variable start
+ *
+ * Return:	8-byte aligned variable entry length
+ */
+
+u32 __efi_runtime efi_var_entry_len(struct efi_var_entry *var)
+{
+	if (!var)
+		return 0;
+
+	return ALIGN((sizeof(u16) * (u16_strlen(var->name) + 1)) +
+		     var->length + sizeof(*var), 8);
+}
+
+struct efi_var_entry __efi_runtime
+*efi_var_mem_find(const efi_guid_t *guid, const u16 *name,
+		  struct efi_var_entry **next)
+{
+	struct efi_var_entry *var, *last;
+
+	last = (struct efi_var_entry *)
+	       ((uintptr_t)efi_var_buf + efi_var_buf->length);
+
+	if (!*name) {
+		if (next) {
+			*next = efi_var_buf->var;
+			if (*next >= last)
+				*next = NULL;
+		}
+		return NULL;
+	}
+	if (efi_current_var &&
+	    efi_var_mem_compare(efi_current_var, guid, name, next)) {
+		if (next && *next >= last)
+			*next = NULL;
+		return efi_current_var;
+	}
+
+	var = efi_var_buf->var;
+	if (var < last) {
+		for (; var;) {
+			struct efi_var_entry *pos;
+			bool match;
+
+			match = efi_var_mem_compare(var, guid, name, &pos);
+			if (pos >= last)
+				pos = NULL;
+			if (match) {
+				if (next)
+					*next = pos;
+				return var;
+			}
+			var = pos;
+		}
+	}
+	if (next)
+		*next = NULL;
+	return NULL;
+}
+
+void __efi_runtime efi_var_mem_del(struct efi_var_entry *var)
+{
+	u16 *data;
+	struct efi_var_entry *next, *last;
+
+	if (!var)
+		return;
+
+	last = (struct efi_var_entry *)
+	       ((uintptr_t)efi_var_buf + efi_var_buf->length);
+	if (var <= efi_current_var)
+		efi_current_var = NULL;
+
+	for (data = var->name; *data; ++data)
+		;
+	++data;
+	next = (struct efi_var_entry *)
+	       ALIGN((uintptr_t)data + var->length, 8);
+	efi_var_buf->length -= (uintptr_t)next - (uintptr_t)var;
+
+	/* efi_memcpy_runtime() can be used because next >= var. */
+	efi_memcpy_runtime(var, next, (uintptr_t)last - (uintptr_t)next);
+	efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
+				   efi_var_buf->length -
+				   sizeof(struct efi_var_file));
+}
+
+efi_status_t __efi_runtime efi_var_mem_ins(
+				const u16 *variable_name,
+				const efi_guid_t *vendor, u32 attributes,
+				const efi_uintn_t size1, const void *data1,
+				const efi_uintn_t size2, const void *data2,
+				const u64 time)
+{
+	u16 *data;
+	struct efi_var_entry *var;
+	u32 var_name_len;
+
+	var = (struct efi_var_entry *)
+	      ((uintptr_t)efi_var_buf + efi_var_buf->length);
+	var_name_len = u16_strlen(variable_name) + 1;
+	data = var->name + var_name_len;
+
+	if ((uintptr_t)data - (uintptr_t)efi_var_buf + size1 + size2 >
+	    EFI_VAR_BUF_SIZE)
+		return EFI_OUT_OF_RESOURCES;
+
+	var->attr = attributes;
+	var->length = size1 + size2;
+	var->time = time;
+
+	efi_memcpy_runtime(&var->guid, vendor, sizeof(efi_guid_t));
+	efi_memcpy_runtime(var->name, variable_name,
+			   sizeof(u16) * var_name_len);
+	efi_memcpy_runtime(data, data1, size1);
+	efi_memcpy_runtime((u8 *)data + size1, data2, size2);
+
+	var = (struct efi_var_entry *)
+	      ALIGN((uintptr_t)data + var->length, 8);
+	efi_var_buf->length = (uintptr_t)var - (uintptr_t)efi_var_buf;
+	efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
+				   efi_var_buf->length -
+				   sizeof(struct efi_var_file));
+
+	return EFI_SUCCESS;
+}
+
+u64 __efi_runtime efi_var_mem_free(void)
+{
+	if (efi_var_buf->length + sizeof(struct efi_var_entry) >=
+	    EFI_VAR_BUF_SIZE)
+		return 0;
+
+	return EFI_VAR_BUF_SIZE - efi_var_buf->length -
+	       sizeof(struct efi_var_entry);
+}
+
+/**
+ * efi_var_mem_notify_exit_boot_services() - SetVirtualMemoryMap callback
+ *
+ * @event:	callback event
+ * @context:	callback context
+ */
+static void EFIAPI __efi_runtime
+efi_var_mem_notify_virtual_address_map(struct efi_event *event, void *context)
+{
+	efi_convert_pointer(0, (void **)&efi_var_buf);
+	efi_current_var = NULL;
+}
+
+efi_status_t efi_var_mem_init(void)
+{
+	u64 memory;
+	efi_status_t ret;
+	struct efi_event *event;
+
+	ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
+				 EFI_RUNTIME_SERVICES_DATA,
+				 efi_size_in_pages(EFI_VAR_BUF_SIZE),
+				 &memory);
+	if (ret != EFI_SUCCESS)
+		return ret;
+	efi_var_buf = (struct efi_var_file *)(uintptr_t)memory;
+	memset(efi_var_buf, 0, EFI_VAR_BUF_SIZE);
+	efi_var_buf->magic = EFI_VAR_FILE_MAGIC;
+	efi_var_buf->length = (uintptr_t)efi_var_buf->var -
+			      (uintptr_t)efi_var_buf;
+
+	ret = efi_create_event(EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE, TPL_CALLBACK,
+			       efi_var_mem_notify_virtual_address_map, NULL,
+			       NULL, &event);
+	if (ret != EFI_SUCCESS)
+		return ret;
+	return ret;
+}
+
+/**
+ * efi_var_collect_mem() - Copy EFI variables matching attributes mask from
+ *                         efi_var_buf
+ *
+ * @buf:	buffer containing variable collection
+ * @lenp:	buffer length
+ * @mask:	mask of matched attributes
+ *
+ * Return:	Status code
+ */
+efi_status_t __efi_runtime
+efi_var_collect_mem(struct efi_var_file *buf, efi_uintn_t *lenp, u32 mask)
+{
+	static struct efi_var_file __efi_runtime_data hdr = {
+		.magic = EFI_VAR_FILE_MAGIC,
+	};
+	struct efi_var_entry *last, *var, *var_to;
+
+	hdr.length = sizeof(struct efi_var_file);
+
+	var = efi_var_buf->var;
+	last = (struct efi_var_entry *)
+	       ((uintptr_t)efi_var_buf + efi_var_buf->length);
+	if (buf)
+		var_to = buf->var;
+
+	while (var < last) {
+		u32 len = efi_var_entry_len(var);
+
+		if ((var->attr & mask) != mask) {
+			var = (void *)((uintptr_t)var + len);
+			continue;
+		}
+
+		hdr.length += len;
+
+		if (buf && hdr.length <= *lenp) {
+			efi_memcpy_runtime(var_to, var, len);
+			var_to = (void *)var_to + len;
+		}
+		var = (void *)var + len;
+	}
+
+	if (!buf && hdr.length <= *lenp) {
+		*lenp = hdr.length;
+		return EFI_INVALID_PARAMETER;
+	}
+
+	if (!buf || hdr.length > *lenp) {
+		*lenp = hdr.length;
+		return EFI_BUFFER_TOO_SMALL;
+	}
+	hdr.crc32 = crc32(0, (u8 *)buf->var,
+			  hdr.length - sizeof(struct efi_var_file));
+
+	efi_memcpy_runtime(buf, &hdr, sizeof(hdr));
+	*lenp = hdr.length;
+
+	return EFI_SUCCESS;
+}
+
+efi_status_t __efi_runtime
+efi_get_variable_mem(const u16 *variable_name, const efi_guid_t *vendor,
+		     u32 *attributes, efi_uintn_t *data_size, void *data,
+		     u64 *timep, u32 mask)
+{
+	efi_uintn_t old_size;
+	struct efi_var_entry *var;
+	u16 *pdata;
+
+	if (!variable_name || !vendor || !data_size)
+		return EFI_INVALID_PARAMETER;
+	var = efi_var_mem_find(vendor, variable_name, NULL);
+	if (!var)
+		return EFI_NOT_FOUND;
+
+	/*
+	 * This function is used at runtime to dump EFI variables.
+	 * The memory backend we keep around has BS-only variables as
+	 * well. At runtime we filter them here
+	 */
+	if (mask && !((var->attr & mask) == mask))
+		return EFI_NOT_FOUND;
+
+	if (attributes)
+		*attributes = var->attr;
+	if (timep)
+		*timep = var->time;
+
+	if (!u16_strcmp(variable_name, u"VarToFile"))
+		return efi_var_collect_mem(data, data_size, EFI_VARIABLE_NON_VOLATILE);
+
+	old_size = *data_size;
+	*data_size = var->length;
+	if (old_size < var->length)
+		return EFI_BUFFER_TOO_SMALL;
+
+	if (!data)
+		return EFI_INVALID_PARAMETER;
+
+	for (pdata = var->name; *pdata; ++pdata)
+		;
+	++pdata;
+
+	efi_memcpy_runtime(data, pdata, var->length);
+
+	return EFI_SUCCESS;
+}
+
+efi_status_t __efi_runtime
+efi_get_next_variable_name_mem(efi_uintn_t *variable_name_size,
+			       u16 *variable_name, efi_guid_t *vendor,
+			       u32 mask)
+{
+	struct efi_var_entry *var;
+	efi_uintn_t len, old_size;
+	u16 *pdata;
+
+	if (!variable_name_size || !variable_name || !vendor)
+		return EFI_INVALID_PARAMETER;
+
+skip:
+	len = *variable_name_size >> 1;
+	if (u16_strnlen(variable_name, len) == len)
+		return EFI_INVALID_PARAMETER;
+
+	if (!efi_var_mem_find(vendor, variable_name, &var) && *variable_name)
+		return EFI_INVALID_PARAMETER;
+
+	if (!var)
+		return EFI_NOT_FOUND;
+
+	for (pdata = var->name; *pdata; ++pdata)
+		;
+	++pdata;
+
+	old_size = *variable_name_size;
+	*variable_name_size = (uintptr_t)pdata - (uintptr_t)var->name;
+
+	if (old_size < *variable_name_size)
+		return EFI_BUFFER_TOO_SMALL;
+
+	efi_memcpy_runtime(variable_name, var->name, *variable_name_size);
+	efi_memcpy_runtime(vendor, &var->guid, sizeof(efi_guid_t));
+
+	if (mask && !((var->attr & mask) == mask)) {
+		*variable_name_size = old_size;
+		goto skip;
+	}
+
+	return EFI_SUCCESS;
+}
+
+void efi_var_buf_update(struct efi_var_file *var_buf)
+{
+	memcpy(efi_var_buf, var_buf, EFI_VAR_BUF_SIZE);
+}