[U-Boot] [PATCH v3 1/7] env: save UEFI non-volatile variables in dedicated storage

AKASHI Takahiro takahiro.akashi at linaro.org
Tue Jun 4 06:52:05 UTC 2019


We need a variant of env_save()/env_load() to handle dedicated storage
for UEFI variables.
It is assumed that env_efi_load() will be called only ince at init
and that env_efi_save() will be called at every SetVariable.

In this patch, new parameters will be expected to be configured:
  CONFIG_ENV_EFI_FAT_DEVICE_AND_PART
  CONFIG_ENV_EFI_FAT_FILE
in case of CONFIG_ENV_IS_IN_FAT.

Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
 env/Kconfig                       |  39 ++++++++
 env/env.c                         | 155 +++++++++++++++++++++++++++++-
 env/fat.c                         | 105 ++++++++++++++++++++
 include/asm-generic/global_data.h |   3 +
 include/environment.h             |  31 ++++++
 5 files changed, 332 insertions(+), 1 deletion(-)

diff --git a/env/Kconfig b/env/Kconfig
index 1e10c7a4c46b..a36b6ee48f10 100644
--- a/env/Kconfig
+++ b/env/Kconfig
@@ -399,6 +399,10 @@ config ENV_IS_IN_UBI
 	  the environment in.  This will enable redundant environments in UBI.
 	  It is assumed that both volumes are in the same MTD partition.
 
+config ENV_EFI
+	bool
+	default n
+
 config ENV_FAT_INTERFACE
 	string "Name of the block device for the environment"
 	depends on ENV_IS_IN_FAT
@@ -438,6 +442,34 @@ config ENV_FAT_FILE
 	  It's a string of the FAT file name. This file use to store the
 	  environment.
 
+config ENV_EFI_FAT_DEVICE_AND_PART
+	string "Device and partition for where to store the UEFI non-volatile variables in FAT"
+	depends on ENV_IS_IN_FAT
+	depends on ENV_EFI
+	help
+	  Define this to a string to specify the partition of the device. It can
+	  be as following:
+
+	    "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
+	       - "D:P": device D partition P. Error occurs if device D has no
+	                partition table.
+	       - "D:0": device D.
+	       - "D" or "D:": device D partition 1 if device D has partition
+	                      table, or the whole device D if has no partition
+	                      table.
+	       - "D:auto": first partition in device D with bootable flag set.
+	                   If none, first valid partition in device D. If no
+	                   partition table then means device D.
+
+config ENV_EFI_FAT_FILE
+	string "Name of the FAT file to use for the UEFI non-volatile variables"
+	depends on ENV_IS_IN_FAT
+	depends on ENV_EFI
+	default "uboot_efi.env"
+	help
+	  It's a string of the FAT file name. This file use to store the
+	  UEFI non-volatile variables.
+
 config ENV_EXT4_INTERFACE
 	string "Name of the block device for the environment"
 	depends on ENV_IS_IN_EXT4
@@ -470,6 +502,13 @@ config ENV_EXT4_FILE
 	  It's a string of the EXT4 file name. This file use to store the
 	  environment (explicit path to the file)
 
+config ENV_EFI_SIZE
+	hex "UEFI Variables Environment Size"
+	depends on ENV_EFI
+	default 0x20000
+	help
+	  Size of the UEFI variables storage area
+
 if ARCH_ROCKCHIP || ARCH_SUNXI || ARCH_ZYNQ || ARCH_ZYNQMP || ARCH_VERSAL || ARC || ARCH_STM32MP
 
 config ENV_OFFSET
diff --git a/env/env.c b/env/env.c
index 4b417b90a291..202079f6d4c0 100644
--- a/env/env.c
+++ b/env/env.c
@@ -24,6 +24,12 @@ void env_fix_drivers(void)
 			entry->load += gd->reloc_off;
 		if (entry->save)
 			entry->save += gd->reloc_off;
+#ifdef CONFIG_ENV_EFI
+		if (entry->efi_load)
+			entry->efi_load += gd->reloc_off;
+		if (entry->efi_save)
+			entry->efi_save += gd->reloc_off;
+#endif
 		if (entry->init)
 			entry->init += gd->reloc_off;
 	}
@@ -125,7 +131,8 @@ __weak enum env_location env_get_location(enum env_operation op, int prio)
 	if (prio >= ARRAY_SIZE(env_locations))
 		return ENVL_UNKNOWN;
 
-	gd->env_load_prio = prio;
+	if (op != ENVOP_EFI)
+		gd->env_load_prio = prio;
 
 	return env_locations[prio];
 }
@@ -280,3 +287,149 @@ int env_init(void)
 
 	return ret;
 }
+
+#ifdef CONFIG_ENV_EFI
+struct hsearch_data efi_var_htab;
+struct hsearch_data efi_nv_var_htab;
+
+int env_efi_import(const char *buf, int check)
+{
+	env_t *ep = (env_t *)buf;
+
+	if (check) {
+		u32 crc;
+
+		memcpy(&crc, &ep->crc, sizeof(crc));
+
+		if (crc32(0, ep->data, CONFIG_ENV_EFI_SIZE - ENV_HEADER_SIZE)
+				!= crc) {
+			pr_err("bad CRC of UEFI variables\n");
+			return -ENOMSG; /* needed for env_load() */
+		}
+	}
+
+	if (himport_r(&efi_nv_var_htab, (char *)ep->data,
+		      CONFIG_ENV_EFI_SIZE - ENV_HEADER_SIZE,
+		      '\0', 0, 0, 0, NULL))
+		return 0;
+
+	pr_err("Cannot import environment: errno = %d\n", errno);
+
+	/* set_default_env("import failed", 0); */
+
+	return -EIO;
+}
+
+int env_efi_export(env_t *env_out)
+{
+	char *res;
+	ssize_t	len;
+
+	res = (char *)env_out->data;
+	len = hexport_r(&efi_nv_var_htab, '\0', 0, &res,
+			CONFIG_ENV_EFI_SIZE - ENV_HEADER_SIZE,
+			0, NULL);
+	if (len < 0) {
+		pr_err("Cannot export environment: errno = %d\n", errno);
+		return 1;
+	}
+
+	env_out->crc = crc32(0, env_out->data,
+			     CONFIG_ENV_EFI_SIZE - ENV_HEADER_SIZE);
+
+	return 0;
+}
+
+int env_efi_save(void)
+{
+#ifdef CONFIG_ENV_IS_NOWHERE
+	return 0;
+#else
+	struct env_driver *drv = NULL;
+	int ret;
+
+	if (!efi_nv_var_htab.table)
+		return 0;
+
+	if (gd->env_efi_prio == -1) {
+		pr_warn("No UEFI non-volatile variable storage\n");
+		return -1;
+	}
+
+	drv = _env_driver_lookup(env_get_location(ENVOP_EFI, gd->env_efi_prio));
+	if (!drv) {
+		pr_warn("No UEFI non-volatile variable storage\n");
+		return -1;
+	}
+
+	ret = drv->efi_save();
+	if (ret)
+		pr_err("Saving UEFI non-volatile variable failed\n");
+
+	return ret;
+#endif
+}
+
+/* This function should be called only once at init */
+int env_efi_load(void)
+{
+#ifndef CONFIG_ENV_IS_NOWHERE
+	struct env_driver *drv;
+	int prio;
+	enum env_location loc;
+#endif
+	int ret;
+
+	/* volatile variables */
+	if (!efi_var_htab.table) {
+		ret = himport_r(&efi_var_htab, NULL, 0, '\0', 0, 0, 0, NULL);
+		if (!ret) {
+			pr_err("Creating UEFI volatile variables failed\n");
+			return -1;
+		}
+	}
+
+#ifndef CONFIG_ENV_IS_NOWHERE
+	gd->env_efi_prio = -1;
+
+	/* non-volatile variables */
+	if (efi_nv_var_htab.table)
+		return 0;
+
+	for (drv = NULL, prio = 0; prio < ARRAY_SIZE(env_locations); prio++) {
+		loc = env_get_location(ENVOP_EFI, prio);
+		drv = _env_driver_lookup(loc);
+		if (!drv)
+			continue;
+
+		if (drv->efi_load && drv->efi_save)
+			break;
+	}
+	if (!drv || prio == ARRAY_SIZE(env_locations)) {
+		pr_warn("No UEFI non-volatile variable storage\n");
+		goto skip_load;
+	}
+
+	gd->env_efi_prio = prio;
+
+	ret = drv->efi_load();
+	if (ret) {
+		pr_err("Loading UEFI non-volatile variables failed\n");
+		return -1;
+	}
+skip_load:
+#endif /* CONFIG_ENV_IS_NOWHERE */
+
+	if (!efi_nv_var_htab.table) {
+		ret = himport_r(&efi_nv_var_htab, NULL, 0, '\0', 0, 0, 0, NULL);
+		if (!ret) {
+			pr_err("Creating UEFI non-volatile variables failed\n");
+			return -1;
+		}
+
+		return 0;
+	}
+
+	return 0;
+}
+#endif /* CONFIG_ENV_EFI */
diff --git a/env/fat.c b/env/fat.c
index 7f74c64dfe7e..7cd6dc51baea 100644
--- a/env/fat.c
+++ b/env/fat.c
@@ -14,6 +14,7 @@
 #include <malloc.h>
 #include <memalign.h>
 #include <search.h>
+#include <efi_loader.h>
 #include <errno.h>
 #include <fat.h>
 #include <mmc.h>
@@ -128,6 +129,106 @@ err_env_relocate:
 }
 #endif /* LOADENV */
 
+#ifdef CONFIG_ENV_EFI
+static int env_fat_efi_save(void)
+{
+	env_t __aligned(ARCH_DMA_MINALIGN) env_new;
+	struct blk_desc *dev_desc = NULL;
+	disk_partition_t info;
+	int dev, part;
+	int err;
+	loff_t size;
+
+	err = env_efi_export(&env_new);
+	if (err)
+		return err;
+
+	part = blk_get_device_part_str(CONFIG_ENV_FAT_INTERFACE,
+				       CONFIG_ENV_EFI_FAT_DEVICE_AND_PART,
+				       &dev_desc, &info, 1);
+	if (part < 0)
+		return 1;
+
+	dev = dev_desc->devnum;
+	if (fat_set_blk_dev(dev_desc, &info) != 0) {
+		/*
+		 * This printf is embedded in the messages from env_save that
+		 * will calling it. The missing \n is intentional.
+		 */
+		printf("Unable to use %s %d:%d... ",
+		       CONFIG_ENV_FAT_INTERFACE, dev, part);
+		return 1;
+	}
+
+	err = file_fat_write(CONFIG_ENV_EFI_FAT_FILE,
+			     (void *)&env_new, 0, sizeof(env_t), &size);
+	if (err < 0) {
+		/*
+		 * This printf is embedded in the messages from env_save that
+		 * will calling it. The missing \n is intentional.
+		 */
+		printf("Unable to write \"%s\" from %s%d:%d... ",
+		       CONFIG_ENV_EFI_FAT_FILE, CONFIG_ENV_FAT_INTERFACE,
+		       dev, part);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int env_fat_efi_load(void)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(char, buf, CONFIG_ENV_EFI_SIZE);
+	struct blk_desc *dev_desc = NULL;
+	disk_partition_t info;
+	int dev, part;
+	int err;
+
+#ifdef CONFIG_MMC
+	if (!strcmp(CONFIG_ENV_FAT_INTERFACE, "mmc"))
+		mmc_initialize(NULL);
+#endif
+
+	part = blk_get_device_part_str(CONFIG_ENV_FAT_INTERFACE,
+				       CONFIG_ENV_EFI_FAT_DEVICE_AND_PART,
+				       &dev_desc, &info, 1);
+	if (part < 0)
+		goto err_env_relocate;
+
+	dev = dev_desc->devnum;
+	if (fat_set_blk_dev(dev_desc, &info) != 0) {
+		/*
+		 * This printf is embedded in the messages from env_save that
+		 * will calling it. The missing \n is intentional.
+		 */
+		printf("Unable to use %s %d:%d...\n",
+		       CONFIG_ENV_FAT_INTERFACE, dev, part);
+		goto err_env_relocate;
+	}
+
+	err = file_fat_read(CONFIG_ENV_EFI_FAT_FILE, buf, CONFIG_ENV_EFI_SIZE);
+	if (err <= 0 && (err != -ENOENT)) {
+		/*
+		 * This printf is embedded in the messages from env_save that
+		 * will calling it. The missing \n is intentional.
+		 */
+		printf("Unable to read \"%s\" from %s %d:%d...\n",
+		       CONFIG_ENV_EFI_FAT_FILE, CONFIG_ENV_FAT_INTERFACE,
+		       dev, part);
+		goto err_env_relocate;
+	}
+
+	if (err > 0)
+		return env_efi_import(buf, 1);
+	else
+		return 0;
+
+err_env_relocate:
+
+	return -EIO;
+}
+#endif /* CONFIG_ENV_EFI */
+
 U_BOOT_ENV_LOCATION(fat) = {
 	.location	= ENVL_FAT,
 	ENV_NAME("FAT")
@@ -137,4 +238,8 @@ U_BOOT_ENV_LOCATION(fat) = {
 #ifdef CMD_SAVEENV
 	.save		= env_save_ptr(env_fat_save),
 #endif
+#ifdef CONFIG_ENV_EFI
+	.efi_load	= env_fat_efi_load,
+	.efi_save	= env_fat_efi_save,
+#endif
 };
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 02a3ed683821..5ed390cc31c7 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -52,6 +52,9 @@ typedef struct global_data {
 	unsigned long env_valid;	/* Environment valid? enum env_valid */
 	unsigned long env_has_init;	/* Bitmask of boolean of struct env_location offsets */
 	int env_load_prio;		/* Priority of the loaded environment */
+#ifdef CONFIG_ENV_EFI
+	int env_efi_prio;		/* Priority of the UEFI variables */
+#endif
 
 	unsigned long ram_base;		/* Base address of RAM used by U-Boot */
 	unsigned long ram_top;		/* Top address of RAM used by U-Boot */
diff --git a/include/environment.h b/include/environment.h
index cd966761416e..32a03014690f 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -200,6 +200,7 @@ enum env_operation {
 	ENVOP_INIT,	/* we want to call the init function */
 	ENVOP_LOAD,	/* we want to call the load function */
 	ENVOP_SAVE,	/* we want to call the save function */
+	ENVOP_EFI,	/* we want to call the efi_load/save function */
 };
 
 struct env_driver {
@@ -225,6 +226,26 @@ struct env_driver {
 	 */
 	int (*save)(void);
 
+#ifdef CONFIG_ENV_EFI
+	/**
+	 * efi_load() - Load UEFI non-volatile variables from storage
+	 *
+	 * This method is required for UEFI non-volatile variables
+	 *
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*efi_load)(void);
+
+	/**
+	 * efi_save() - Save UEFI non-volatile variables to storage
+	 *
+	 * This method is required for UEFI non-volatile variables
+	 *
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*efi_save)(void);
+#endif
+
 	/**
 	 * init() - Set up the initial pre-relocation environment
 	 *
@@ -312,6 +333,16 @@ void eth_parse_enetaddr(const char *addr, uint8_t *enetaddr);
 int eth_env_get_enetaddr(const char *name, uint8_t *enetaddr);
 int eth_env_set_enetaddr(const char *name, const uint8_t *enetaddr);
 
+#ifdef CONFIG_ENV_EFI
+extern struct hsearch_data efi_var_htab;
+extern struct hsearch_data efi_nv_var_htab;
+
+int env_efi_import(const char *buf, int check);
+int env_efi_export(env_t *env_out);
+int env_efi_load(void);
+int env_efi_save(void);
+#endif
+
 #endif /* DO_DEPS_ONLY */
 
 #endif /* _ENVIRONMENT_H_ */
-- 
2.21.0



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