[U-Boot] [PATCH v0 19/20] efi_loader: efi variable support

[Rob Clark <robdclark@gmail.com>]

Signed-off-by: Rob Clark <robdclark@gmail.com>
---
 cmd/bootefi.c                 |   4 +
 include/efi.h                 |  19 +++
 include/efi_loader.h          |  10 ++
 lib/efi_loader/Makefile       |   2 +-
 lib/efi_loader/efi_boottime.c |   5 +
 lib/efi_loader/efi_runtime.c  |  17 ++-
 lib/efi_loader/efi_variable.c | 342 ++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 394 insertions(+), 5 deletions(-)
 create mode 100644 lib/efi_loader/efi_variable.c

diff --git a/cmd/bootefi.c b/cmd/bootefi.c
index b9e1e5e131..80f52e9e35 100644
--- a/cmd/bootefi.c
+++ b/cmd/bootefi.c
@@ -181,6 +181,10 @@ static unsigned long do_bootefi_exec(void *efi, void *fdt,
 		goto exit;
 	}
 
+	/* we don't support much: */
+	setenv("efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_OsIndicationsSupported",
+			"{ro,boot}(blob)0000000000000000");
+
 	/* Call our payload! */
 	debug("%s:%d Jumping to 0x%lx\n", __func__, __LINE__, (long)entry);
 
diff --git a/include/efi.h b/include/efi.h
index ddd2b96417..dbd482a5db 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -324,6 +324,25 @@ extern char image_base[];
 /* Start and end of U-Boot image (for payload) */
 extern char _binary_u_boot_bin_start[], _binary_u_boot_bin_end[];
 
+/*
+ * Variable Attributes
+ */
+#define EFI_VARIABLE_NON_VOLATILE       0x0000000000000001
+#define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x0000000000000002
+#define EFI_VARIABLE_RUNTIME_ACCESS     0x0000000000000004
+#define EFI_VARIABLE_HARDWARE_ERROR_RECORD 0x0000000000000008
+#define EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS 0x0000000000000010
+#define EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS 0x0000000000000020
+#define EFI_VARIABLE_APPEND_WRITE	0x0000000000000040
+
+#define EFI_VARIABLE_MASK 	(EFI_VARIABLE_NON_VOLATILE | \
+				EFI_VARIABLE_BOOTSERVICE_ACCESS | \
+				EFI_VARIABLE_RUNTIME_ACCESS | \
+				EFI_VARIABLE_HARDWARE_ERROR_RECORD | \
+				EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS | \
+				EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS | \
+				EFI_VARIABLE_APPEND_WRITE)
+
 /**
  * efi_get_sys_table() - Get access to the main EFI system table
  *
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 4210d5f19a..f14fdfa58e 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -296,6 +296,16 @@ efi_status_t __efi_runtime EFIAPI efi_get_time(
 			struct efi_time_cap *capabilities);
 void efi_get_time_init(void);
 
+efi_status_t EFIAPI efi_get_variable(s16 *variable_name,
+		efi_guid_t *vendor, u32 *attributes,
+		unsigned long *data_size, void *data);
+efi_status_t EFIAPI efi_get_next_variable(
+		unsigned long *variable_name_size,
+		s16 *variable_name, efi_guid_t *vendor);
+efi_status_t EFIAPI efi_set_variable(s16 *variable_name,
+		efi_guid_t *vendor, u32 attributes,
+		unsigned long data_size, void *data);
+
 #else /* defined(EFI_LOADER) && !defined(CONFIG_SPL_BUILD) */
 
 /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index cce92cfeb5..f58cb13337 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -16,7 +16,7 @@ always := $(efiprogs-y)
 obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
 obj-y += efi_image_loader.o efi_boottime.o efi_runtime.o efi_console.o
 obj-y += efi_memory.o efi_device_path_to_text.o efi_device_path.o
-obj-y += efi_file.o
+obj-y += efi_file.o efi_variable.o
 obj-$(CONFIG_LCD) += efi_gop.o
 obj-$(CONFIG_DM_VIDEO) += efi_gop.o
 obj-$(CONFIG_PARTITIONS) += efi_disk.o
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 6187065fdd..19eaea8baf 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -927,6 +927,11 @@ static efi_status_t EFIAPI efi_exit_boot_services(void *image_handle,
 {
 	EFI_ENTRY("%p, %ld", image_handle, map_key);
 
+#if defined(CONFIG_CMD_SAVEENV) && !defined(CONFIG_ENV_IS_NOWHERE)
+	/* save any EFI variables that have been written: */
+	saveenv();
+#endif
+
 	board_quiesce_devices();
 
 	/* Fix up caches for EFI payloads if necessary */
diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index dd52755d1d..7615090ba3 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -184,7 +184,16 @@ static const struct efi_runtime_detach_list_struct efi_runtime_detach_list[] = {
 		/* Clean up system table */
 		.ptr = &systab.boottime,
 		.patchto = NULL,
-	},
+	}, {
+		.ptr = &efi_runtime_services.get_variable,
+		.patchto = &efi_device_error,
+	}, {
+		.ptr = &efi_runtime_services.get_next_variable,
+		.patchto = &efi_device_error,
+	}, {
+		.ptr = &efi_runtime_services.set_variable,
+		.patchto = &efi_device_error,
+	}
 };
 
 static bool efi_runtime_tobedetached(void *p)
@@ -382,9 +391,9 @@ struct efi_runtime_services __efi_runtime_data efi_runtime_services = {
 	.set_wakeup_time = (void *)&efi_unimplemented,
 	.set_virtual_address_map = &efi_set_virtual_address_map,
 	.convert_pointer = (void *)&efi_invalid_parameter,
-	.get_variable = (void *)&efi_device_error,
-	.get_next_variable = (void *)&efi_device_error,
-	.set_variable = (void *)&efi_device_error,
+	.get_variable = efi_get_variable,
+	.get_next_variable = efi_get_next_variable,
+	.set_variable = efi_set_variable,
 	.get_next_high_mono_count = (void *)&efi_device_error,
 	.reset_system = &efi_reset_system_boottime,
 };
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
new file mode 100644
index 0000000000..721b14807f
--- /dev/null
+++ b/lib/efi_loader/efi_variable.c
@@ -0,0 +1,342 @@
+/*
+ *  EFI utils
+ *
+ *  Copyright (c) 2017 Rob Clark
+ *
+ *  SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <malloc.h>
+#include <charset.h>
+#include <efi_loader.h>
+
+#define READ_ONLY BIT(31)
+
+/* Mapping between EFI variables and u-boot variables:
+ *
+ *   efi_$guid_$varname = {attributes}(type)value
+ *
+ * For example:
+ *
+ *   efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_OsIndicationsSupported=
+ *      "{ro,boot,run}(blob)0000000000000000"
+ *   efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder=
+ *      "(blob)00010000"
+ *
+ * The attributes are a comma separated list of these possible attributes:
+
+ *   + ro   - read-only
+ *   + boot - boot-services access
+ *   + run  - runtime access
+ *
+ * NOTE: with current implementation, no variables are available after
+ * ExitBootServices, and all are persisted (if possible).
+ *
+ * If not specified, the attributes default to "{boot}".
+ *
+ * The required type is one of:
+ *
+ *   + utf8 - raw utf8 string
+ *   + blob - arbitrary length hex string
+ *
+ * Maybe a utf16 type would be useful to for a string value to be auto
+ * converted to utf16?
+ */
+
+#define MAX_VAR_NAME 31
+#define MAX_NATIVE_VAR_NAME \
+	(strlen("efi_xxxxxxxx-xxxx-xxxx-xxxxxxxxxxxxxxxx_") + \
+		(MAX_VAR_NAME * MAX_UTF8_PER_UTF16))
+
+static int hex(unsigned char ch)
+{
+	if (ch >= 'a' && ch <= 'f')
+		return ch-'a'+10;
+	if (ch >= '0' && ch <= '9')
+		return ch-'0';
+	if (ch >= 'A' && ch <= 'F')
+		return ch-'A'+10;
+	return -1;
+}
+
+static const char * hex2mem(u8 *mem, const char *hexstr, int count)
+{
+	memset(mem, 0, count/2);
+
+	do {
+		int nibble;
+
+		*mem = 0;
+
+		if (!count || !*hexstr)
+			break;
+
+		nibble = hex(*hexstr);
+		if (nibble < 0)
+			break;
+
+		*mem = nibble;
+		count--;
+		hexstr++;
+
+		if (!count || !*hexstr)
+			break;
+
+		nibble = hex(*hexstr);
+		if (nibble < 0)
+			break;
+
+		*mem = (*mem << 4) | nibble;
+		count--;
+		hexstr++;
+		mem++;
+
+	} while (1);
+
+	if (*hexstr)
+		return hexstr;
+
+	return NULL;
+}
+
+static char * mem2hex(char *hexstr, const u8 *mem, int count)
+{
+	static const char hexchars[] = "0123456789abcdef";
+
+	while (count-- > 0) {
+		u8 ch = *mem++;
+		*hexstr++ = hexchars[ch >> 4];
+		*hexstr++ = hexchars[ch & 0xf];
+	}
+
+	return hexstr;
+}
+
+static efi_status_t efi_to_native(char *native, s16 *variable_name,
+		efi_guid_t *vendor)
+{
+	size_t len;
+
+	len = utf16_strlen((u16 *)variable_name);
+	if (len >= MAX_VAR_NAME)
+		return EFI_DEVICE_ERROR;
+
+	native += sprintf(native, "efi_");
+	native += guidstr(native, vendor);
+	native += sprintf(native, "_");
+	native  = (char *)utf16_to_utf8((u8 *)native, (u16 *)variable_name, len);
+	*native = '\0';
+
+	return EFI_SUCCESS;
+}
+
+static const char * prefix(const char *str, const char *prefix)
+{
+	while (*str && *prefix) {
+		if (*str != *prefix)
+			break;
+		str++;
+		prefix++;
+	}
+
+	if (*prefix)
+		return NULL;
+
+	return str;
+}
+
+/* parse attributes part of variable value, if present: */
+static const char * parse_attr(const char *str, u32 *attrp)
+{
+	u32 attr = 0;
+	char sep = '{';
+
+	if (*str != '{') {
+		*attrp = EFI_VARIABLE_BOOTSERVICE_ACCESS;
+		return str;
+	}
+
+	while (*str == sep) {
+		const char *s;
+
+		str++;
+
+		if ((s = prefix(str, "ro"))) {
+			attr |= READ_ONLY;
+		} else if ((s = prefix(str, "boot"))) {
+			attr |= EFI_VARIABLE_BOOTSERVICE_ACCESS;
+		} else if ((s = prefix(str, "run"))) {
+			attr |= EFI_VARIABLE_RUNTIME_ACCESS;
+		} else {
+			printf("invalid attribute: %s\n", str);
+			break;
+		}
+
+		str = s;
+		sep = ',';
+	}
+
+	str++;
+
+	*attrp = attr;
+
+	return str;
+}
+
+/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetVariable.28.29 */
+efi_status_t EFIAPI efi_get_variable(s16 *variable_name,
+		efi_guid_t *vendor, u32 *attributes,
+		unsigned long *data_size, void *data)
+{
+	char native_name[MAX_NATIVE_VAR_NAME + 1];
+	efi_status_t ret;
+	unsigned long in_size;
+	const char *val, *s;
+	u32 attr;
+
+	EFI_ENTRY("%p %p %p %p %p", variable_name, vendor, attributes,
+			data_size, data);
+
+	if (!variable_name || !vendor || !data_size)
+		return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+	ret = efi_to_native(native_name, variable_name, vendor);
+	if (ret)
+		return EFI_EXIT(ret);
+
+	debug("%s: get '%s'\n", __func__, native_name);
+
+	val = getenv(native_name);
+	if (!val)
+		return EFI_EXIT(EFI_NOT_FOUND);
+
+	val = parse_attr(val, &attr);
+
+	in_size = *data_size;
+
+	if ((s = prefix(val, "(blob)"))) {
+		unsigned len = strlen(s);
+
+		/* two characters per byte: */
+		len = DIV_ROUND_UP(len, 2);
+		*data_size = len;
+
+		if (in_size < len)
+			return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
+
+		if (!data)
+			return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+		if (hex2mem(data, s, len * 2))
+			return EFI_EXIT(EFI_DEVICE_ERROR);
+
+		debug("%s: got value: \"%s\"\n", __func__, s);
+	} else if ((s = prefix(val, "(string)"))) {
+		unsigned len = strlen(s) + 1;
+
+		*data_size = len;
+
+		if (in_size < len)
+			return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
+
+		if (!data)
+			return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+		memcpy(data, s, len);
+		((char *)data)[len] = '\0';
+
+		debug("%s: got value: \"%s\"\n", __func__, (char *)data);
+	} else {
+		debug("%s: invalid value: '%s'\n", __func__, val);
+		return EFI_EXIT(EFI_DEVICE_ERROR);
+	}
+
+	if (attributes)
+		*attributes = attr & EFI_VARIABLE_MASK;
+
+	return EFI_EXIT(EFI_SUCCESS);
+}
+
+/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetNextVariableName.28.29 */
+efi_status_t EFIAPI efi_get_next_variable(
+		unsigned long *variable_name_size,
+		s16 *variable_name, efi_guid_t *vendor)
+{
+	EFI_ENTRY("%p %p %p", variable_name_size, variable_name, vendor);
+
+	return EFI_EXIT(EFI_DEVICE_ERROR);
+}
+
+/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#SetVariable.28.29 */
+efi_status_t EFIAPI efi_set_variable(s16 *variable_name,
+		efi_guid_t *vendor, u32 attributes,
+		unsigned long data_size, void *data)
+{
+	char native_name[MAX_NATIVE_VAR_NAME + 1];
+	efi_status_t ret = EFI_SUCCESS;
+	char *val, *s;
+	u32 attr;
+
+	EFI_ENTRY("%p %p %x %lu %p", variable_name, vendor, attributes,
+			data_size, data);
+
+	if (!variable_name || !vendor || !data_size)
+		return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+	ret = efi_to_native(native_name, variable_name, vendor);
+	if (ret)
+		return EFI_EXIT(ret);
+
+#define ACCESS_ATTR (EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS)
+
+	if ((data_size == 0) || !(attributes & ACCESS_ATTR)) {
+		/* delete the variable: */
+		setenv(native_name, NULL);
+		return EFI_EXIT(EFI_SUCCESS);
+	}
+
+	val = getenv(native_name);
+	if (val) {
+		parse_attr(val, &attr);
+
+		if (attr & READ_ONLY)
+			return EFI_EXIT(EFI_WRITE_PROTECTED);
+	}
+
+	val = malloc(2 * data_size + strlen("{ro,run,boot}(blob)") + 1);
+	if (!val)
+		return EFI_EXIT(EFI_OUT_OF_RESOURCES);
+
+	s = val;
+
+	/* store attributes: */
+	attributes &= (EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS);
+	s += sprintf(s, "{");
+	while (attributes) {
+		u32 attr = 1 << (ffs(attributes) - 1);
+
+		if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS)
+			s += sprintf(s, "boot");
+		else if (attr == EFI_VARIABLE_RUNTIME_ACCESS)
+			s += sprintf(s, "run");
+
+		attributes &= ~attr;
+		if (attributes)
+			s += sprintf(s, ",");
+	}
+	s += sprintf(s, "}");
+
+	/* store payload: */
+	s += sprintf(s, "(blob)");
+	s = mem2hex(s, data, data_size);
+	*s = '\0';
+
+	debug("%s: setting: %s=%s\n", __func__, native_name, val);
+
+	if (setenv(native_name, val))
+		ret = EFI_DEVICE_ERROR;
+
+	free(val);
+
+	return EFI_EXIT(ret);
+}
-- 
2.13.0