efi_loader: bootmgr: support BootNext and BootCurrent variable behavior

See UEFI v2.7, section 3.1.2 for details of the specification. With efidebug command, you can run any EFI boot option as follows: => efi boot add 1 SHELL ... => efi boot add 2 HELLO ... => efi boot order 1 2 => efi bootmgr (starting SHELL ...) => efi boot next 2 => efi bootmgr (starting HELLO ...) => env print -e <snip ...> BootCurrent: {boot,run}(blob) 00000000: 02 00 .. BootOrder: {boot,run}(blob) 00000000: 01 00 02 00 .... Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

efi_loader: bootmgr: support BootNext and BootCurrent variable behavior
See UEFI v2.7, section 3.1.2 for details of the specification. With efidebug command, you can run any EFI boot option as follows: => efi boot add 1 SHELL ... => efi boot add 2 HELLO ... => efi boot order 1 2 => efi bootmgr (starting SHELL ...) => efi boot next 2 => efi bootmgr (starting HELLO ...) => env print -e <snip ...> BootCurrent: {boot,run}(blob) 00000000: 02 00 .. BootOrder: {boot,run}(blob) 00000000: 01 00 02 00 .... Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
AKASHI Takahiro · Heinrich Schuchardt
1 parent b0c3c346c6
Showing 1 changed file with 47 additions and 4 deletions Side-by-side Diff
lib/efi_loader/efi_bootmgr.c
@@ -141,6 +141,7 @@
 	efi_deserialize_load_option(&lo, load_option);
  
 	if (lo.attributes & LOAD_OPTION_ACTIVE) {
+		u32 attributes;
 		efi_status_t ret;
  
 		debug("%s: trying to load \"%ls\" from %pD\n",
@@ -151,6 +152,16 @@
 		if (ret != EFI_SUCCESS)
 			goto error;
  
+		attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
+			     EFI_VARIABLE_RUNTIME_ACCESS;
+		size = sizeof(n);
+		ret = EFI_CALL(efi_set_variable(
+				L"BootCurrent",
+				(efi_guid_t *)&efi_global_variable_guid,
+				attributes, size, &n));
+		if (ret != EFI_SUCCESS)
+			goto error;
+
 		printf("Booting: %ls\n", lo.label);
 		efi_dp_split_file_path(lo.file_path, device_path, file_path);
 	}
  
  
  
@@ -162,21 +173,53 @@
 }
  
 /*
- * Attempt to load, in the order specified by BootOrder EFI variable, the
- * available load-options, finding and returning the first one that can
- * be loaded successfully.
+ * Attempt to load from BootNext or in the order specified by BootOrder
+ * EFI variable, the available load-options, finding and returning
+ * the first one that can be loaded successfully.
  */
 void *efi_bootmgr_load(struct efi_device_path **device_path,
 		       struct efi_device_path **file_path)
 {
-	uint16_t *bootorder;
+	u16 bootnext, *bootorder;
 	efi_uintn_t size;
 	void *image = NULL;
 	int i, num;
+	efi_status_t ret;
  
 	bs = systab.boottime;
 	rs = systab.runtime;
  
+	/* BootNext */
+	bootnext = 0;
+	size = sizeof(bootnext);
+	ret = EFI_CALL(efi_get_variable(L"BootNext",
+					(efi_guid_t *)&efi_global_variable_guid,
+					NULL, &size, &bootnext));
+	if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
+		/* BootNext does exist here */
+		if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
+			printf("BootNext must be 16-bit integer\n");
+
+		/* delete BootNext */
+		ret = EFI_CALL(efi_set_variable(
+					L"BootNext",
+					(efi_guid_t *)&efi_global_variable_guid,
+					0, 0, &bootnext));
+
+		/* load BootNext */
+		if (ret == EFI_SUCCESS) {
+			if (size == sizeof(u16)) {
+				image = try_load_entry(bootnext, device_path,
+						       file_path);
+				if (image)
+					return image;
+			}
+		} else {
+			printf("Deleting BootNext failed\n");
+		}
+	}
+
+	/* BootOrder */
 	bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
 	if (!bootorder) {
 		printf("BootOrder not defined\n");
...	...	@@ -141,6 +141,7 @@
141	141	efi_deserialize_load_option(&lo, load_option);
142	142
143	143	if (lo.attributes & LOAD_OPTION_ACTIVE) {
	144	+ u32 attributes;
144	145	efi_status_t ret;
145	146
146	147	debug("%s: trying to load \"%ls\" from %pD\n",
...	...	@@ -151,6 +152,16 @@
151	152	if (ret != EFI_SUCCESS)
152	153	goto error;
153	154
	155	+ attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS \|
	156	+ EFI_VARIABLE_RUNTIME_ACCESS;
	157	+ size = sizeof(n);
	158	+ ret = EFI_CALL(efi_set_variable(
	159	+ L"BootCurrent",
	160	+ (efi_guid_t *)&efi_global_variable_guid,
	161	+ attributes, size, &n));
	162	+ if (ret != EFI_SUCCESS)
	163	+ goto error;
	164	+
154	165	printf("Booting: %ls\n", lo.label);
155	166	efi_dp_split_file_path(lo.file_path, device_path, file_path);
156	167	}
157	168
158	169
159	170
...	...	@@ -162,21 +173,53 @@
162	173	}
163	174
164	175	/*
165		- * Attempt to load, in the order specified by BootOrder EFI variable, the
166		- * available load-options, finding and returning the first one that can
167		- * be loaded successfully.
	176	+ * Attempt to load from BootNext or in the order specified by BootOrder
	177	+ * EFI variable, the available load-options, finding and returning
	178	+ * the first one that can be loaded successfully.
168	179	*/
169	180	void efi_bootmgr_load(struct efi_device_path *device_path,
170	181	struct efi_device_path **file_path)
171	182	{
172		- uint16_t *bootorder;
	183	+ u16 bootnext, *bootorder;
173	184	efi_uintn_t size;
174	185	void *image = NULL;
175	186	int i, num;
	187	+ efi_status_t ret;
176	188
177	189	bs = systab.boottime;
178	190	rs = systab.runtime;
179	191
	192	+ /* BootNext */
	193	+ bootnext = 0;
	194	+ size = sizeof(bootnext);
	195	+ ret = EFI_CALL(efi_get_variable(L"BootNext",
	196	+ (efi_guid_t *)&efi_global_variable_guid,
	197	+ NULL, &size, &bootnext));
	198	+ if (ret == EFI_SUCCESS \|\| ret == EFI_BUFFER_TOO_SMALL) {
	199	+ /* BootNext does exist here */
	200	+ if (ret == EFI_BUFFER_TOO_SMALL \|\| size != sizeof(u16))
	201	+ printf("BootNext must be 16-bit integer\n");
	202	+
	203	+ /* delete BootNext */
	204	+ ret = EFI_CALL(efi_set_variable(
	205	+ L"BootNext",
	206	+ (efi_guid_t *)&efi_global_variable_guid,
	207	+ 0, 0, &bootnext));
	208	+
	209	+ /* load BootNext */
	210	+ if (ret == EFI_SUCCESS) {
	211	+ if (size == sizeof(u16)) {
	212	+ image = try_load_entry(bootnext, device_path,
	213	+ file_path);
	214	+ if (image)
	215	+ return image;
	216	+ }
	217	+ } else {
	218	+ printf("Deleting BootNext failed\n");
	219	+ }
	220	+ }
	221	+
	222	+ /* BootOrder */
180	223	bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
181	224	if (!bootorder) {
182	225	printf("BootOrder not defined\n");