An EFI variable is nothing but a wrapper of a corresponding u-boot
environment variable (See efi_variable.c), but under the current
implementation, NON_VOLATILE attribute is not honored while u-boot
environment variables can be saved/restored in storage.
With this patch, the expected semantics will be mimicked by deleting
all the EFI variables *without* NON_VOLATILE attribute when loading
them from storage at boot time.
Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
---
env/env.c | 4 +++
include/efi_loader.h | 1 +
lib/efi_loader/efi_variable.c | 64 +++++++++++++++++++++++++++++++++--
3 files changed, 66 insertions(+), 3 deletions(-)
diff --git a/env/env.c b/env/env.c
index afed0f3c95c3..c507a4ac5f78 100644
--- a/env/env.c
+++ b/env/env.c
@@ -5,6 +5,7 @@
*/
#include <common.h>
+#include <efi_loader.h>
#include <environment.h>
DECLARE_GLOBAL_DATA_PTR;
@@ -195,6 +196,9 @@ int env_load(void)
if (ret) {
debug("Failed (%d)\n", ret);
} else {
+#ifdef CONFIG_EFI_LOADER
+ efi_purge_volatile_variables();
+#endif
printf("OK\n");
return 0;
}
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 9f7a4068efa6..9cad1dcd62bb 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -533,6 +533,7 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t
*variable_name_size,
efi_status_t EFIAPI efi_set_variable(u16 *variable_name, efi_guid_t *vendor,
u32 attributes, efi_uintn_t data_size,
void *data);
+int efi_purge_volatile_variables(void);
/*
* See section 3.1.3 in the v2.7 UEFI spec for more details on
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 19d9cb865f25..ad8cd36fa1e1 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -8,6 +8,8 @@
#include <malloc.h>
#include <charset.h>
#include <efi_loader.h>
+#include <environment.h>
+#include <search.h>
#define READ_ONLY BIT(31)
@@ -142,6 +144,8 @@ static const char *parse_attr(const char *str, u32 *attrp)
if ((s = prefix(str, "ro"))) {
attr |= READ_ONLY;
+ } else if ((s = prefix(str, "nv"))) {
+ attr |= EFI_VARIABLE_NON_VOLATILE;
} else if ((s = prefix(str, "boot"))) {
attr |= EFI_VARIABLE_BOOTSERVICE_ACCESS;
} else if ((s = prefix(str, "run"))) {
@@ -293,7 +297,7 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
efi_guid_t *vendor,
}
}
- val = malloc(2 * data_size + strlen("{ro,run,boot}(blob)") + 1);
+ val = malloc(2 * data_size + strlen("{ro,run,boot,nv}(blob)") + 1);
if (!val) {
ret = EFI_OUT_OF_RESOURCES;
goto out;
@@ -302,12 +306,16 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
efi_guid_t *vendor,
s = val;
/* store attributes: */
- attributes &= (EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS);
+ attributes &= (EFI_VARIABLE_NON_VOLATILE |
+ 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)
+ if (attr == EFI_VARIABLE_NON_VOLATILE)
+ s += sprintf(s, "nv");
+ else if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS)
s += sprintf(s, "boot");
else if (attr == EFI_VARIABLE_RUNTIME_ACCESS)
s += sprintf(s, "run");
@@ -334,3 +342,53 @@ out:
return EFI_EXIT(ret);
}
+
+/*
+ * Purge all the variables which are not marked non volatile.
+ * This function is assumed to be called only once at boot time.
+ */
+int efi_purge_volatile_variables(void)
+{
+ char regex[256];
+ char * const regexlist[] = {regex};
+ char *list = NULL, *name, *value;
+ int len, ret = 0;
+ u32 attr;
+
+ snprintf(regex, 256, "efi_.*-.*-.*-.*-.*_.*");
+
+ len = hexport_r(&env_htab, '\n', H_MATCH_REGEX | H_MATCH_KEY,
+ &list, 0, 1, regexlist);
+
+ if (len < 0)
+ return -1;
+ else if (!len)
+ return 0;
+
+ name = list;
+ while (*name) {
+ /* variable name */
+ value = strchr(name, '=');
+ if (!value)
+ break;
+ *value = '\0';
+ value++;
+
+ parse_attr(value, &attr);
+ if (!(attr & EFI_VARIABLE_NON_VOLATILE)) {
+ if (env_set(name, NULL)) {
+ printf("cannot purge efi variable: %s\n", name);
+ ret = -1;
+ }
+ }
+
+ name = strchr(value, '\n');
+ if (!name)
+ break;
+ name++;
+ }
+
+ free(list);
+
+ return ret;
+}
--
2.19.1
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