[PATCH v5 1/3] efi_var_file: refactor to move buffer functions
Michal Simek
michal.simek at amd.com
Fri Jan 23 15:17:21 CET 2026
From: Shantur Rathore <i at shantur.com>
Currently efi_var_file.c has functions to store/read
EFI variables to/from memory buffer. These functions
can be used with other EFI variable stores so move
them out to efi_var_common.c
Signed-off-by: Shantur Rathore <i at shantur.com>
Signed-off-by: Michal Simek <michal.simek at amd.com>
---
Changes in v5:
- Invert logic in efi_variable.c and avoid #if
include/efi_variable.h | 5 +++
lib/efi_loader/Makefile | 2 +-
lib/efi_loader/efi_var_common.c | 42 ++++++++++++++++++++++++
lib/efi_loader/efi_var_file.c | 57 ---------------------------------
lib/efi_loader/efi_variable.c | 17 +++++++---
5 files changed, 60 insertions(+), 63 deletions(-)
diff --git a/include/efi_variable.h b/include/efi_variable.h
index 4065cf45ecaf..ee68fa4a885f 100644
--- a/include/efi_variable.h
+++ b/include/efi_variable.h
@@ -161,6 +161,11 @@ efi_status_t efi_var_to_file(void);
efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
u32 check_attr_mask);
+/* GUID used by Shim to store the MOK database */
+#define SHIM_LOCK_GUID \
+ EFI_GUID(0x605dab50, 0xe046, 0x4300, \
+ 0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23)
+
/**
* efi_var_restore() - restore EFI variables from buffer
*
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index f490081f6542..ca1775eb03be 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -53,7 +53,7 @@ ifeq ($(CONFIG_EFI_MM_COMM_TEE),y)
obj-y += efi_variable_tee.o
else
obj-y += efi_variable.o
-obj-y += efi_var_file.o
+obj-$(CONFIG_EFI_VARIABLE_FILE_STORE) += efi_var_file.o
obj-$(CONFIG_EFI_VARIABLES_PRESEED) += efi_var_seed.o
endif
obj-y += efi_watchdog.o
diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c
index 4b34a58b4cf7..5ea1688dca3d 100644
--- a/lib/efi_loader/efi_var_common.c
+++ b/lib/efi_loader/efi_var_common.c
@@ -41,6 +41,7 @@ static const struct efi_auth_var_name_type name_type[] = {
static bool efi_secure_boot;
static enum efi_secure_mode efi_secure_mode;
+static const efi_guid_t shim_lock_guid = SHIM_LOCK_GUID;
/**
* efi_efi_get_variable() - retrieve value of a UEFI variable
@@ -488,3 +489,44 @@ efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *
return EFI_SUCCESS;
}
+
+efi_status_t efi_var_restore(struct efi_var_file *buf, bool safe)
+{
+ struct efi_var_entry *var, *last_var;
+ u16 *data;
+ efi_status_t ret;
+
+ if (buf->reserved || buf->magic != EFI_VAR_FILE_MAGIC ||
+ buf->crc32 != crc32(0, (u8 *)buf->var,
+ buf->length - sizeof(struct efi_var_file))) {
+ log_err("Invalid EFI variables file\n");
+ return EFI_INVALID_PARAMETER;
+ }
+
+ last_var = (struct efi_var_entry *)((u8 *)buf + buf->length);
+ for (var = buf->var; var < last_var;
+ var = (struct efi_var_entry *)ALIGN((uintptr_t)data + var->length, 8)) {
+ data = var->name + u16_strlen(var->name) + 1;
+
+ /*
+ * Secure boot related and volatile variables shall only be
+ * restored from U-Boot's preseed.
+ */
+ if (!safe &&
+ (efi_auth_var_get_type(var->name, &var->guid) !=
+ EFI_AUTH_VAR_NONE ||
+ !guidcmp(&var->guid, &shim_lock_guid) ||
+ !(var->attr & EFI_VARIABLE_NON_VOLATILE)))
+ continue;
+ if (!var->length)
+ continue;
+ if (efi_var_mem_find(&var->guid, var->name, NULL))
+ continue;
+ ret = efi_var_mem_ins(var->name, &var->guid, var->attr,
+ var->length, data, 0, NULL,
+ var->time);
+ if (ret != EFI_SUCCESS)
+ log_err("Failed to set EFI variable %ls\n", var->name);
+ }
+ return EFI_SUCCESS;
+}
diff --git a/lib/efi_loader/efi_var_file.c b/lib/efi_loader/efi_var_file.c
index ba0bf33ffbd1..d32edaac277d 100644
--- a/lib/efi_loader/efi_var_file.c
+++ b/lib/efi_loader/efi_var_file.c
@@ -14,17 +14,9 @@
#include <mapmem.h>
#include <efi_loader.h>
#include <efi_variable.h>
-#include <u-boot/crc.h>
#define PART_STR_LEN 10
-/* GUID used by Shim to store the MOK database */
-#define SHIM_LOCK_GUID \
- EFI_GUID(0x605dab50, 0xe046, 0x4300, \
- 0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23)
-
-static const efi_guid_t shim_lock_guid = SHIM_LOCK_GUID;
-
/**
* efi_set_blk_dev_to_system_partition() - select EFI system partition
*
@@ -59,7 +51,6 @@ static efi_status_t __maybe_unused efi_set_blk_dev_to_system_partition(void)
*/
efi_status_t efi_var_to_file(void)
{
-#ifdef CONFIG_EFI_VARIABLE_FILE_STORE
efi_status_t ret;
struct efi_var_file *buf;
loff_t len;
@@ -91,52 +82,6 @@ error:
out:
free(buf);
return ret;
-#else
- return EFI_SUCCESS;
-#endif
-}
-
-efi_status_t efi_var_restore(struct efi_var_file *buf, bool safe)
-{
- struct efi_var_entry *var, *last_var;
- u16 *data;
- efi_status_t ret;
-
- if (buf->reserved || buf->magic != EFI_VAR_FILE_MAGIC ||
- buf->crc32 != crc32(0, (u8 *)buf->var,
- buf->length - sizeof(struct efi_var_file))) {
- log_err("Invalid EFI variables file\n");
- return EFI_INVALID_PARAMETER;
- }
-
- last_var = (struct efi_var_entry *)((u8 *)buf + buf->length);
- for (var = buf->var; var < last_var;
- var = (struct efi_var_entry *)
- ALIGN((uintptr_t)data + var->length, 8)) {
-
- data = var->name + u16_strlen(var->name) + 1;
-
- /*
- * Secure boot related and volatile variables shall only be
- * restored from U-Boot's preseed.
- */
- if (!safe &&
- (efi_auth_var_get_type(var->name, &var->guid) !=
- EFI_AUTH_VAR_NONE ||
- !guidcmp(&var->guid, &shim_lock_guid) ||
- !(var->attr & EFI_VARIABLE_NON_VOLATILE)))
- continue;
- if (!var->length)
- continue;
- if (efi_var_mem_find(&var->guid, var->name, NULL))
- continue;
- ret = efi_var_mem_ins(var->name, &var->guid, var->attr,
- var->length, data, 0, NULL,
- var->time);
- if (ret != EFI_SUCCESS)
- log_err("Failed to set EFI variable %ls\n", var->name);
- }
- return EFI_SUCCESS;
}
/**
@@ -155,7 +100,6 @@ efi_status_t efi_var_restore(struct efi_var_file *buf, bool safe)
*/
efi_status_t efi_var_from_file(void)
{
-#ifdef CONFIG_EFI_VARIABLE_FILE_STORE
struct efi_var_file *buf;
loff_t len;
efi_status_t ret;
@@ -180,6 +124,5 @@ efi_status_t efi_var_from_file(void)
log_err("Invalid EFI variables file\n");
error:
free(buf);
-#endif
return EFI_SUCCESS;
}
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index f3533f4def3a..13db6eae882a 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -397,11 +397,15 @@ efi_status_t efi_set_variable_int(const u16 *variable_name,
ret = EFI_SUCCESS;
/*
- * Write non-volatile EFI variables to file
+ * Write non-volatile EFI variables
* TODO: check if a value change has occured to avoid superfluous writes
*/
- if (attributes & EFI_VARIABLE_NON_VOLATILE)
+ if (attributes & EFI_VARIABLE_NON_VOLATILE) {
+ if (IS_ENABLED(CONFIG_EFI_VARIABLE_NO_STORE))
+ return EFI_NOT_READY;
+
efi_var_to_file();
+ }
return EFI_SUCCESS;
}
@@ -594,9 +598,12 @@ efi_status_t efi_init_variables(void)
if (ret != EFI_SUCCESS)
return ret;
- ret = efi_var_from_file();
- if (ret != EFI_SUCCESS)
- return ret;
+ if (!IS_ENABLED(CONFIG_EFI_VARIABLE_NO_STORE)) {
+ ret = efi_var_from_file();
+ if (ret != EFI_SUCCESS)
+ return ret;
+ }
+
if (IS_ENABLED(CONFIG_EFI_VARIABLES_PRESEED)) {
ret = efi_var_restore((struct efi_var_file *)
__efi_var_file_begin, true);
--
2.43.0
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