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2     Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
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4     SPDX-License-Identifier: CC-BY-SA-4.0
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6
7# License
8
9The files in this repository are released under standard open source
10licenses, identified by [SPDX license tags][1]. Generally, kernel-level
11code is licensed under GPLv2 and user-level code under the 2-clause BSD
12license. See the individual file headers for details, or use one of the
13publicly available SPDX tools to generate a bill of materials. The
14directory `LICENSES` contains the text for all licenses that are
15mentioned by files in this repository.
16
17
18## GPL syscall note
19
20Note that, as in the [Linux syscall note for the GPL][2], the seL4
21kernel GPL license does *not* cover user-level code that uses kernel
22services by normal system calls - this is merely considered normal use
23of the kernel, and does *not* fall under the heading of "derived work".
24Syscall headers are provided under BSD.
25
26For a longer explanation of how the seL4 license does or does not affect
27your own code see also [this blog post][3].
28
29[1]: https://spdx.org
30[2]: https://spdx.org/licenses/Linux-syscall-note.html
31[3]: https://microkerneldude.wordpress.com/2019/12/09/what-does-sel4s-license-imply/
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