License headers

This document defines the format of the copyright and license headers in OP-TEE source files. Such headers shall comply with the rules described here, which are compatible with the rules adopted by the Linux kernel community.

New source files

  • Rule 1.1 Shall contain exactly one SPDX license identifier, which can express a single or multiple licenses (refer to SPDX for syntax details).

  • Rule 1.2 The SPDX license identifier shall be added as a comment line. It shall be the first possible line in the file which can contain a comment. The comment style shall depend on the file type:

    • Rule 1.2.1 C source: // SPDX-License-Identifier: <expression>

    • Rule 1.2.2 C header: /* SPDX-License-Identifier: <expression> */

    • Rule 1.2.3 Assembly: /* SPDX-License-Identifier: <expression> */

    • Rule 1.2.4 Python, shell: # SPDX-License-Identifier: <expression>

  • Rule 1.3 Shall contain at least one copyright line

  • Rule 1.4 Shall not contain the mention ‘All rights reserved’

  • Rule 1.5 Shall not contain any license notice other than the SPDX license identifier

Note that files imported from external projects are not new files. The rules for pre-existing files (below) apply.

Pre-existing or imported files

  • Rule 2.1 SPDX license identifiers shall be added according to the license notice(s) in the file and the rules above (1.1 and 1.2*)

  • Rule 2.2 It is recommended that license notices be removed once the corresponding identifier has been added. Note however that this may only be done by the copyright holder(s) of the file.

  • Rule 2.3 Similar to 2.2, and subject to the same conditions, the text: “All rights reserved” shall be removed also.