diff options
| -rw-r--r-- | drivers/firmware/efivars.c | 66 |
1 files changed, 63 insertions, 3 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index 9a1968e500f1..2cbb675a66cc 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -122,6 +122,9 @@ struct efivar_attribute { ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count); }; +static struct efivars __efivars; +static struct efivar_operations ops; + #define PSTORE_EFI_ATTRIBUTES \ (EFI_VARIABLE_NON_VOLATILE | \ EFI_VARIABLE_BOOTSERVICE_ACCESS | \ @@ -942,6 +945,28 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj, return count; } +static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor) +{ + struct efivar_entry *entry, *n; + struct efivars *efivars = &__efivars; + unsigned long strsize1, strsize2; + bool found = false; + + strsize1 = utf16_strsize(variable_name, 1024); + list_for_each_entry_safe(entry, n, &efivars->list, list) { + strsize2 = utf16_strsize(entry->var.VariableName, 1024); + if (strsize1 == strsize2 && + !memcmp(variable_name, &(entry->var.VariableName), + strsize2) && + !efi_guidcmp(entry->var.VendorGuid, + *vendor)) { + found = true; + break; + } + } + return found; +} + /* * Returns the size of variable_name, in bytes, including the * terminating NULL character, or variable_name_size if no NULL @@ -1154,6 +1179,28 @@ void unregister_efivars(struct efivars *efivars) } EXPORT_SYMBOL_GPL(unregister_efivars); +/* + * Print a warning when duplicate EFI variables are encountered and + * disable the sysfs workqueue since the firmware is buggy. + */ +static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid, + unsigned long len16) +{ + size_t i, len8 = len16 / sizeof(efi_char16_t); + char *s8; + + s8 = kzalloc(len8, GFP_KERNEL); + if (!s8) + return; + + for (i = 0; i < len8; i++) + s8[i] = s16[i]; + + printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", + s8, vendor_guid); + kfree(s8); +} + int register_efivars(struct efivars *efivars, const struct efivar_operations *ops, struct kobject *parent_kobj) @@ -1196,6 +1243,22 @@ int register_efivars(struct efivars *efivars, case EFI_SUCCESS: variable_name_size = var_name_strnsize(variable_name, variable_name_size); + + /* + * Some firmware implementations return the + * same variable name on multiple calls to + * get_next_variable(). Terminate the loop + * immediately as there is no guarantee that + * we'll ever see a different variable name, + * and may end up looping here forever. + */ + if (variable_is_present(variable_name, &vendor_guid)) { + dup_variable_bug(variable_name, &vendor_guid, + variable_name_size); + status = EFI_NOT_FOUND; + break; + } + efivar_create_sysfs_entry(efivars, variable_name_size, variable_name, @@ -1232,9 +1295,6 @@ out: } EXPORT_SYMBOL_GPL(register_efivars); -static struct efivars __efivars; -static struct efivar_operations ops; - /* * For now we register the efi subsystem with the firmware subsystem * and the vars subsystem with the efi subsystem. In the future, it |