Move utf16 functions to kernel core and rename

We want to be able to use the utf16 functions that are currently present
in the EFI variables code in platform-specific code as well. Move them to
the kernel core, and in the process rename them to accurately describe what
they do - they don't handle UTF16, only UCS2.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

6 files changed, 89 insertions, 62 deletions

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 42c759a4d047..3e532002e4d1 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -39,6 +39,7 @@ config FIRMWARE_MEMMAP
 config EFI_VARS
         tristate "EFI Variable Support via sysfs"
         depends on EFI
+        select UCS2_STRING
         default n
         help
           If you say Y here, you are able to get EFI (Extensible Firmware
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index bf15d81d74e1..182ce9471175 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -80,6 +80,7 @@
 #include <linux/slab.h>
 #include <linux/pstore.h>
 #include <linux/ctype.h>
+#include <linux/ucs2_string.h>
 
 #include <linux/fs.h>
 #include <linux/ramfs.h>
@@ -172,51 +173,6 @@ 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
-utf16_strnlen(efi_char16_t *s, size_t maxlength)
-{
-        unsigned long length = 0;
-
-        while (*s++ != 0 && length < maxlength)
-                length++;
-        return length;
-}
-
-static inline unsigned long
-utf16_strlen(efi_char16_t *s)
-{
-        return utf16_strnlen(s, ~0UL);
-}
-
-/*
- * Return the number of bytes is the length of this string
- * Note: this is NOT the same as the number of unicode characters
- */
-static inline unsigned long
-utf16_strsize(efi_char16_t *data, unsigned long maxlength)
-{
-        return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
-}
-
-static inline int
-utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
-{
-        while (1) {
-                if (len == 0)
-                        return 0;
-                if (*a < *b)
-                        return -1;
-                if (*a > *b)
-                        return 1;
-                if (*a == 0) /* implies *b == 0 */
-                        return 0;
-                a++;
-                b++;
-                len--;
-        }
-}
-
 static bool
 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
                      unsigned long len)
@@ -268,7 +224,7 @@ validate_load_option(struct efi_variable *var, int match, u8 *buffer,
         u16 filepathlength;
         int i, desclength = 0, namelen;
 
-        namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
+        namelen = ucs2_strnlen(var->VariableName, sizeof(var->VariableName));
 
         /* Either "Boot" or "Driver" followed by four digits of hex */
         for (i = match; i < match+4; i++) {
@@ -291,7 +247,7 @@ validate_load_option(struct efi_variable *var, int match, u8 *buffer,
          * There's no stored length for the description, so it has to be
          * found by hand
          */
-        desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
+        desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 
         /* Each boot entry must have a descriptor */
         if (!desclength)
@@ -581,7 +537,7 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
         spin_lock_irq(&efivars->lock);
 
         status = check_var_size_locked(efivars, new_var->Attributes,
-               new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
+               new_var->DataSize + ucs2_strsize(new_var->VariableName, 1024));
 
         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
                 status = efivars->ops->set_variable(new_var->VariableName,
@@ -759,7 +715,7 @@ static ssize_t efivarfs_file_write(struct file *file,
          * QueryVariableInfo() isn't supported by the firmware.
          */
 
-        varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
+        varsize = datasize + ucs2_strsize(var->var.VariableName, 1024);
         status = check_var_size(efivars, attributes, varsize);
 
         if (status != EFI_SUCCESS) {
@@ -1211,7 +1167,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
 
                 inode = NULL;
 
-                len = utf16_strlen(entry->var.VariableName);
+                len = ucs2_strlen(entry->var.VariableName);
 
                 /* name, plus '-', plus GUID, plus NUL*/
                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
@@ -1469,8 +1425,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
 
                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
                         continue;
-                if (utf16_strncmp(entry->var.VariableName, efi_name,
-                                  utf16_strlen(efi_name))) {
+                if (ucs2_strncmp(entry->var.VariableName, efi_name,
+                                  ucs2_strlen(efi_name))) {
                         /*
                          * Check if an old format,
                          * which doesn't support holding
@@ -1482,8 +1438,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
                         for (i = 0; i < DUMP_NAME_LEN; i++)
                                 efi_name_old[i] = name_old[i];
 
-                        if (utf16_strncmp(entry->var.VariableName, efi_name_old,
-                                          utf16_strlen(efi_name_old)))
+                        if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
+                                          ucs2_strlen(efi_name_old)))
                                 continue;
                 }
 
@@ -1561,8 +1517,8 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
          * Does this variable already exist?
          */
         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
-                strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
-                strsize2 = utf16_strsize(new_var->VariableName, 1024);
+                strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024);
+                strsize2 = ucs2_strsize(new_var->VariableName, 1024);
                 if (strsize1 == strsize2 &&
                         !memcmp(&(search_efivar->var.VariableName),
                                 new_var->VariableName, strsize1) &&
@@ -1578,7 +1534,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
         }
 
         status = check_var_size_locked(efivars, new_var->Attributes,
-               new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
+               new_var->DataSize + ucs2_strsize(new_var->VariableName, 1024));
 
         if (status && status != EFI_UNSUPPORTED) {
                 spin_unlock_irq(&efivars->lock);
@@ -1602,7 +1558,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 
         /* Create the entry in sysfs.  Locking is not required here */
         status = efivar_create_sysfs_entry(efivars,
-                                           utf16_strsize(new_var->VariableName,
+                                           ucs2_strsize(new_var->VariableName,
                                                          1024),
                                            new_var->VariableName,
                                            &new_var->VendorGuid);
@@ -1632,8 +1588,8 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
          * Does this variable already exist?
          */
         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
-                strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
-                strsize2 = utf16_strsize(del_var->VariableName, 1024);
+                strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024);
+                strsize2 = ucs2_strsize(del_var->VariableName, 1024);
                 if (strsize1 == strsize2 &&
                         !memcmp(&(search_efivar->var.VariableName),
                                 del_var->VariableName, strsize1) &&
@@ -1679,9 +1635,9 @@ static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
         unsigned long strsize1, strsize2;
         bool found = false;
 
-        strsize1 = utf16_strsize(variable_name, 1024);
+        strsize1 = ucs2_strsize(variable_name, 1024);
         list_for_each_entry_safe(entry, n, &efivars->list, list) {
-                strsize2 = utf16_strsize(entry->var.VariableName, 1024);
+                strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
                 if (strsize1 == strsize2 &&
                         !memcmp(variable_name, &(entry->var.VariableName),
                                 strsize2) &&
diff --git a/include/linux/ucs2_string.h b/include/linux/ucs2_string.h
new file mode 100644
index 000000000000..cbb20afdbc01
--- /dev/null
+++ b/include/linux/ucs2_string.h
@@ -0,0 +1,14 @@
+#ifndef _LINUX_UCS2_STRING_H_
+#define _LINUX_UCS2_STRING_H_
+
+#include <linux/types.h>        /* for size_t */
+#include <linux/stddef.h>       /* for NULL */
+
+typedef u16 ucs2_char_t;
+
+unsigned long ucs2_strnlen(const ucs2_char_t *s, size_t maxlength);
+unsigned long ucs2_strlen(const ucs2_char_t *s);
+unsigned long ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength);
+int ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len);
+
+#endif /* _LINUX_UCS2_STRING_H_ */
diff --git a/lib/Kconfig b/lib/Kconfig
index 3958dc4389f9..fe01d418b09a 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -404,4 +404,7 @@ config OID_REGISTRY
         help
           Enable fast lookup object identifier registry.
 
+config UCS2_STRING
+        tristate
+
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index d7946ff75b2e..6e2cc561f761 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -174,3 +174,5 @@ quiet_cmd_build_OID_registry = GEN     $@
       cmd_build_OID_registry = perl $(srctree)/$(src)/build_OID_registry $< $@
 
 clean-files     += oid_registry_data.c
+
+obj-$(CONFIG_UCS2_STRING) += ucs2_string.o
diff --git a/lib/ucs2_string.c b/lib/ucs2_string.c
new file mode 100644
index 000000000000..6f500ef2301d
--- /dev/null
+++ b/lib/ucs2_string.c
@@ -0,0 +1,51 @@
+#include <linux/ucs2_string.h>
+#include <linux/module.h>
+
+/* Return the number of unicode characters in data */
+unsigned long
+ucs2_strnlen(const ucs2_char_t *s, size_t maxlength)
+{
+        unsigned long length = 0;
+
+        while (*s++ != 0 && length < maxlength)
+                length++;
+        return length;
+}
+EXPORT_SYMBOL(ucs2_strnlen);
+
+unsigned long
+ucs2_strlen(const ucs2_char_t *s)
+{
+        return ucs2_strnlen(s, ~0UL);
+}
+EXPORT_SYMBOL(ucs2_strlen);
+
+/*
+ * Return the number of bytes is the length of this string
+ * Note: this is NOT the same as the number of unicode characters
+ */
+unsigned long
+ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength)
+{
+        return ucs2_strnlen(data, maxlength/sizeof(ucs2_char_t)) * sizeof(ucs2_char_t);
+}
+EXPORT_SYMBOL(ucs2_strsize);
+
+int
+ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)
+{
+        while (1) {
+                if (len == 0)
+                        return 0;
+                if (*a < *b)
+                        return -1;
+                if (*a > *b)
+                        return 1;
+                if (*a == 0) /* implies *b == 0 */
+                        return 0;
+                a++;
+                b++;
+                len--;
+        }
+}
+EXPORT_SYMBOL(ucs2_strncmp);