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path: root/drivers/firmware/efivars.c
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Diffstat (limited to 'drivers/firmware/efivars.c')
-rw-r--r--drivers/firmware/efivars.c150
1 files changed, 104 insertions, 46 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index fe62aa39223..7acafb80fd4 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -103,6 +103,11 @@ MODULE_VERSION(EFIVARS_VERSION);
*/
#define GUID_LEN 36
+static bool efivars_pstore_disable =
+ IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
+
+module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
+
/*
* The maximum size of VariableName + Data = 1024
* Therefore, it's reasonable to save that much
@@ -165,6 +170,7 @@ efivar_create_sysfs_entry(struct efivars *efivars,
static void efivar_update_sysfs_entries(struct work_struct *);
static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
+static bool efivar_wq_enabled = true;
/* Return the number of unicode characters in data */
static unsigned long
@@ -1309,9 +1315,7 @@ static const struct inode_operations efivarfs_dir_inode_operations = {
.create = efivarfs_create,
};
-static struct pstore_info efi_pstore_info;
-
-#ifdef CONFIG_PSTORE
+#ifdef CONFIG_EFI_VARS_PSTORE
static int efi_pstore_open(struct pstore_info *psi)
{
@@ -1441,7 +1445,7 @@ static int efi_pstore_write(enum pstore_type_id type,
spin_unlock_irqrestore(&efivars->lock, flags);
- if (reason == KMSG_DUMP_OOPS)
+ if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled)
schedule_work(&efivar_work);
*id = part;
@@ -1514,38 +1518,6 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
return 0;
}
-#else
-static int efi_pstore_open(struct pstore_info *psi)
-{
- return 0;
-}
-
-static int efi_pstore_close(struct pstore_info *psi)
-{
- return 0;
-}
-
-static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
- struct timespec *timespec,
- char **buf, struct pstore_info *psi)
-{
- return -1;
-}
-
-static int efi_pstore_write(enum pstore_type_id type,
- enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, int count, size_t size,
- struct pstore_info *psi)
-{
- return 0;
-}
-
-static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
- struct timespec time, struct pstore_info *psi)
-{
- return 0;
-}
-#endif
static struct pstore_info efi_pstore_info = {
.owner = THIS_MODULE,
@@ -1557,6 +1529,24 @@ static struct pstore_info efi_pstore_info = {
.erase = efi_pstore_erase,
};
+static void efivar_pstore_register(struct efivars *efivars)
+{
+ efivars->efi_pstore_info = efi_pstore_info;
+ efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
+ if (efivars->efi_pstore_info.buf) {
+ efivars->efi_pstore_info.bufsize = 1024;
+ efivars->efi_pstore_info.data = efivars;
+ spin_lock_init(&efivars->efi_pstore_info.buf_lock);
+ pstore_register(&efivars->efi_pstore_info);
+ }
+}
+#else
+static void efivar_pstore_register(struct efivars *efivars)
+{
+ return;
+}
+#endif
+
static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t count)
@@ -1716,6 +1706,31 @@ static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
return found;
}
+/*
+ * Returns the size of variable_name, in bytes, including the
+ * terminating NULL character, or variable_name_size if no NULL
+ * character is found among the first variable_name_size bytes.
+ */
+static unsigned long var_name_strnsize(efi_char16_t *variable_name,
+ unsigned long variable_name_size)
+{
+ unsigned long len;
+ efi_char16_t c;
+
+ /*
+ * The variable name is, by definition, a NULL-terminated
+ * string, so make absolutely sure that variable_name_size is
+ * the value we expect it to be. If not, return the real size.
+ */
+ for (len = 2; len <= variable_name_size; len += sizeof(c)) {
+ c = variable_name[(len / sizeof(c)) - 1];
+ if (!c)
+ break;
+ }
+
+ return min(len, variable_name_size);
+}
+
static void efivar_update_sysfs_entries(struct work_struct *work)
{
struct efivars *efivars = &__efivars;
@@ -1756,10 +1771,13 @@ static void efivar_update_sysfs_entries(struct work_struct *work)
if (!found) {
kfree(variable_name);
break;
- } else
+ } else {
+ variable_name_size = var_name_strnsize(variable_name,
+ variable_name_size);
efivar_create_sysfs_entry(efivars,
variable_name_size,
variable_name, &vendor);
+ }
}
}
@@ -1958,6 +1976,35 @@ 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;
+
+ /*
+ * Disable the workqueue since the algorithm it uses for
+ * detecting new variables won't work with this buggy
+ * implementation of GetNextVariableName().
+ */
+ efivar_wq_enabled = false;
+
+ 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)
@@ -2006,6 +2053,24 @@ int register_efivars(struct efivars *efivars,
&vendor_guid);
switch (status) {
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,
@@ -2025,15 +2090,8 @@ int register_efivars(struct efivars *efivars,
if (error)
unregister_efivars(efivars);
- efivars->efi_pstore_info = efi_pstore_info;
-
- efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
- if (efivars->efi_pstore_info.buf) {
- efivars->efi_pstore_info.bufsize = 1024;
- efivars->efi_pstore_info.data = efivars;
- spin_lock_init(&efivars->efi_pstore_info.buf_lock);
- pstore_register(&efivars->efi_pstore_info);
- }
+ if (!efivars_pstore_disable)
+ efivar_pstore_register(efivars);
register_filesystem(&efivarfs_type);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-25 13:42:36 +0000