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path: root/drivers/firmware/efi/vars.c
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Diffstat (limited to 'drivers/firmware/efi/vars.c')
-rw-r--r--drivers/firmware/efi/vars.c142
1 files changed, 88 insertions, 54 deletions
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index d3b751383286..9336ffdf6e2c 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -37,6 +37,14 @@
/* Private pointer to registered efivars */
static struct efivars *__efivars;
+/*
+ * efivars_lock protects three things:
+ * 1) efivarfs_list and efivars_sysfs_list
+ * 2) ->ops calls
+ * 3) (un)registration of __efivars
+ */
+static DEFINE_SEMAPHORE(efivars_lock);
+
static bool efivar_wq_enabled = true;
DECLARE_WORK(efivar_work, NULL);
EXPORT_SYMBOL_GPL(efivar_work);
@@ -434,7 +442,10 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
return -ENOMEM;
}
- spin_lock_irq(&__efivars->lock);
+ if (down_interruptible(&efivars_lock)) {
+ err = -EINTR;
+ goto free;
+ }
/*
* Per EFI spec, the maximum storage allocated for both
@@ -450,7 +461,7 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
switch (status) {
case EFI_SUCCESS:
if (duplicates)
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
variable_name_size = var_name_strnsize(variable_name,
variable_name_size);
@@ -476,8 +487,12 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
status = EFI_NOT_FOUND;
}
- if (duplicates)
- spin_lock_irq(&__efivars->lock);
+ if (duplicates) {
+ if (down_interruptible(&efivars_lock)) {
+ err = -EINTR;
+ goto free;
+ }
+ }
break;
case EFI_NOT_FOUND:
@@ -491,8 +506,8 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
} while (status != EFI_NOT_FOUND);
- spin_unlock_irq(&__efivars->lock);
-
+ up(&efivars_lock);
+free:
kfree(variable_name);
return err;
@@ -503,24 +518,34 @@ EXPORT_SYMBOL_GPL(efivar_init);
* efivar_entry_add - add entry to variable list
* @entry: entry to add to list
* @head: list head
+ *
+ * Returns 0 on success, or a kernel error code on failure.
*/
-void efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
+int efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
{
- spin_lock_irq(&__efivars->lock);
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
list_add(&entry->list, head);
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
+
+ return 0;
}
EXPORT_SYMBOL_GPL(efivar_entry_add);
/**
* efivar_entry_remove - remove entry from variable list
* @entry: entry to remove from list
+ *
+ * Returns 0 on success, or a kernel error code on failure.
*/
-void efivar_entry_remove(struct efivar_entry *entry)
+int efivar_entry_remove(struct efivar_entry *entry)
{
- spin_lock_irq(&__efivars->lock);
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
list_del(&entry->list);
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
+
+ return 0;
}
EXPORT_SYMBOL_GPL(efivar_entry_remove);
@@ -537,10 +562,8 @@ EXPORT_SYMBOL_GPL(efivar_entry_remove);
*/
static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
{
- lockdep_assert_held(&__efivars->lock);
-
list_del(&entry->list);
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
}
/**
@@ -563,8 +586,6 @@ int __efivar_entry_delete(struct efivar_entry *entry)
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
- lockdep_assert_held(&__efivars->lock);
-
status = ops->set_variable(entry->var.VariableName,
&entry->var.VendorGuid,
0, 0, NULL);
@@ -581,20 +602,22 @@ EXPORT_SYMBOL_GPL(__efivar_entry_delete);
* variable list. It is the caller's responsibility to free @entry
* once we return.
*
- * Returns 0 on success, or a converted EFI status code if
- * set_variable() fails.
+ * Returns 0 on success, -EINTR if we can't grab the semaphore,
+ * converted EFI status code if set_variable() fails.
*/
int efivar_entry_delete(struct efivar_entry *entry)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
- spin_lock_irq(&__efivars->lock);
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
+
status = ops->set_variable(entry->var.VariableName,
&entry->var.VendorGuid,
0, 0, NULL);
if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
return efi_status_to_err(status);
}
@@ -620,9 +643,9 @@ EXPORT_SYMBOL_GPL(efivar_entry_delete);
* If @head is not NULL a lookup is performed to determine whether
* the entry is already on the list.
*
- * Returns 0 on success, -EEXIST if a lookup is performed and the entry
- * already exists on the list, or a converted EFI status code if
- * set_variable() fails.
+ * Returns 0 on success, -EINTR if we can't grab the semaphore,
+ * -EEXIST if a lookup is performed and the entry already exists on
+ * the list, or a converted EFI status code if set_variable() fails.
*/
int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
unsigned long size, void *data, struct list_head *head)
@@ -632,10 +655,10 @@ int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
efi_char16_t *name = entry->var.VariableName;
efi_guid_t vendor = entry->var.VendorGuid;
- spin_lock_irq(&__efivars->lock);
-
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
if (head && efivar_entry_find(name, vendor, head, false)) {
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
return -EEXIST;
}
@@ -644,7 +667,7 @@ int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
status = ops->set_variable(name, &vendor,
attributes, size, data);
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
return efi_status_to_err(status);
@@ -658,30 +681,29 @@ EXPORT_SYMBOL_GPL(efivar_entry_set);
* from crash/panic handlers.
*
* Crucially, this function will not block if it cannot acquire
- * __efivars->lock. Instead, it returns -EBUSY.
+ * efivars_lock. Instead, it returns -EBUSY.
*/
static int
efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor,
u32 attributes, unsigned long size, void *data)
{
const struct efivar_operations *ops = __efivars->ops;
- unsigned long flags;
efi_status_t status;
- if (!spin_trylock_irqsave(&__efivars->lock, flags))
+ if (down_trylock(&efivars_lock))
return -EBUSY;
status = check_var_size_nonblocking(attributes,
size + ucs2_strsize(name, 1024));
if (status != EFI_SUCCESS) {
- spin_unlock_irqrestore(&__efivars->lock, flags);
+ up(&efivars_lock);
return -ENOSPC;
}
status = ops->set_variable_nonblocking(name, &vendor, attributes,
size, data);
- spin_unlock_irqrestore(&__efivars->lock, flags);
+ up(&efivars_lock);
return efi_status_to_err(status);
}
@@ -706,7 +728,6 @@ int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes,
bool block, unsigned long size, void *data)
{
const struct efivar_operations *ops = __efivars->ops;
- unsigned long flags;
efi_status_t status;
if (!ops->query_variable_store)
@@ -727,21 +748,22 @@ int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes,
size, data);
if (!block) {
- if (!spin_trylock_irqsave(&__efivars->lock, flags))
+ if (down_trylock(&efivars_lock))
return -EBUSY;
} else {
- spin_lock_irqsave(&__efivars->lock, flags);
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
}
status = check_var_size(attributes, size + ucs2_strsize(name, 1024));
if (status != EFI_SUCCESS) {
- spin_unlock_irqrestore(&__efivars->lock, flags);
+ up(&efivars_lock);
return -ENOSPC;
}
status = ops->set_variable(name, &vendor, attributes, size, data);
- spin_unlock_irqrestore(&__efivars->lock, flags);
+ up(&efivars_lock);
return efi_status_to_err(status);
}
@@ -771,8 +793,6 @@ struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
int strsize1, strsize2;
bool found = false;
- lockdep_assert_held(&__efivars->lock);
-
list_for_each_entry_safe(entry, n, head, list) {
strsize1 = ucs2_strsize(name, 1024);
strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
@@ -814,10 +834,11 @@ int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
*size = 0;
- spin_lock_irq(&__efivars->lock);
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid, NULL, size, NULL);
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
if (status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
@@ -843,8 +864,6 @@ int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
- lockdep_assert_held(&__efivars->lock);
-
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid,
attributes, size, data);
@@ -866,11 +885,12 @@ int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
- spin_lock_irq(&__efivars->lock);
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid,
attributes, size, data);
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
return efi_status_to_err(status);
}
@@ -917,7 +937,8 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
* set_variable call, and removal of the variable from the efivars
* list (in the case of an authenticated delete).
*/
- spin_lock_irq(&__efivars->lock);
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
/*
* Ensure that the available space hasn't shrunk below the safe level
@@ -957,7 +978,7 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
if (status == EFI_NOT_FOUND)
efivar_entry_list_del_unlock(entry);
else
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
if (status && status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
@@ -965,7 +986,7 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
return 0;
out:
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
return err;
}
@@ -978,9 +999,9 @@ EXPORT_SYMBOL_GPL(efivar_entry_set_get_size);
* efivar_entry_iter_end() is called. This function is usually used in
* conjunction with __efivar_entry_iter() or efivar_entry_iter().
*/
-void efivar_entry_iter_begin(void)
+int efivar_entry_iter_begin(void)
{
- spin_lock_irq(&__efivars->lock);
+ return down_interruptible(&efivars_lock);
}
EXPORT_SYMBOL_GPL(efivar_entry_iter_begin);
@@ -991,7 +1012,7 @@ EXPORT_SYMBOL_GPL(efivar_entry_iter_begin);
*/
void efivar_entry_iter_end(void)
{
- spin_unlock_irq(&__efivars->lock);
+ up(&efivars_lock);
}
EXPORT_SYMBOL_GPL(efivar_entry_iter_end);
@@ -1067,7 +1088,9 @@ int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
{
int err = 0;
- efivar_entry_iter_begin();
+ err = efivar_entry_iter_begin();
+ if (err)
+ return err;
err = __efivar_entry_iter(func, head, data, NULL);
efivar_entry_iter_end();
@@ -1112,12 +1135,18 @@ int efivars_register(struct efivars *efivars,
const struct efivar_operations *ops,
struct kobject *kobject)
{
- spin_lock_init(&efivars->lock);
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
+
efivars->ops = ops;
efivars->kobject = kobject;
__efivars = efivars;
+ pr_info("Registered efivars operations\n");
+
+ up(&efivars_lock);
+
return 0;
}
EXPORT_SYMBOL_GPL(efivars_register);
@@ -1133,6 +1162,9 @@ int efivars_unregister(struct efivars *efivars)
{
int rv;
+ if (down_interruptible(&efivars_lock))
+ return -EINTR;
+
if (!__efivars) {
printk(KERN_ERR "efivars not registered\n");
rv = -EINVAL;
@@ -1144,10 +1176,12 @@ int efivars_unregister(struct efivars *efivars)
goto out;
}
+ pr_info("Unregistered efivars operations\n");
__efivars = NULL;
rv = 0;
out:
+ up(&efivars_lock);
return rv;
}
EXPORT_SYMBOL_GPL(efivars_unregister);