[PATCH 1/3] mbedtls: Introduce subset of compiler-rt from LLVM

[Jerome Forissier]

Hi Raymond,

On 6/20/25 21:08, Raymond Mao wrote:
> Hi Tom,
> 
> On Fri, 20 Jun 2025 at 15:00, Tom Rini <trini at konsulko.com> wrote:
>>
>> On Fri, Jun 20, 2025 at 02:00:09PM -0400, Raymond Mao wrote:
>>> Hi Tom,
>>>
>>> On Fri, 20 Jun 2025 at 13:20, Tom Rini <trini at konsulko.com> wrote:
>>>>
>>>> On Fri, Jun 20, 2025 at 08:10:08AM -0700, Raymond Mao wrote:
>>>>> Introduce the implementation of udivti3 and udivmodti4 from LLVM
>>>>> compiler-rt builtins for building MbedTLS bignum module via Clang.
>>>>>
>>>>> Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
>>>>> ---
>>>>>  lib/mbedtls/port/compiler-rt/LICENSE.TXT      | 311 ++++++++++++++++++
>>>>>  lib/mbedtls/port/compiler-rt/README.txt       |  11 +
>>>>>  .../compiler-rt/lib/builtins/int_endianness.h | 114 +++++++
>>>>>  .../port/compiler-rt/lib/builtins/int_lib.h   | 171 ++++++++++
>>>>>  .../port/compiler-rt/lib/builtins/int_types.h | 276 ++++++++++++++++
>>>>>  .../port/compiler-rt/lib/builtins/int_util.h  |  47 +++
>>>>>  .../compiler-rt/lib/builtins/udivmodti4.c     | 158 +++++++++
>>>>>  .../port/compiler-rt/lib/builtins/udivti3.c   |  23 ++
>>>>>  8 files changed, 1111 insertions(+)
>>>>>  create mode 100644 lib/mbedtls/port/compiler-rt/LICENSE.TXT
>>>>>  create mode 100644 lib/mbedtls/port/compiler-rt/README.txt
>>>>>  create mode 100644 lib/mbedtls/port/compiler-rt/lib/builtins/int_endianness.h
>>>>>  create mode 100644 lib/mbedtls/port/compiler-rt/lib/builtins/int_lib.h
>>>>>  create mode 100644 lib/mbedtls/port/compiler-rt/lib/builtins/int_types.h
>>>>>  create mode 100644 lib/mbedtls/port/compiler-rt/lib/builtins/int_util.h
>>>>>  create mode 100644 lib/mbedtls/port/compiler-rt/lib/builtins/udivmodti4.c
>>>>>  create mode 100644 lib/mbedtls/port/compiler-rt/lib/builtins/udivti3.c
>>>>>
>>>>> diff --git a/lib/mbedtls/port/compiler-rt/LICENSE.TXT b/lib/mbedtls/port/compiler-rt/LICENSE.TXT
>>>>> new file mode 100644
>>>>> index 00000000000..5a79a1b9d5c
>>>>> --- /dev/null
>>>>> +++ b/lib/mbedtls/port/compiler-rt/LICENSE.TXT
>>>>> @@ -0,0 +1,311 @@
>>>>> +==============================================================================
>>>>> +The LLVM Project is under the Apache License v2.0 with LLVM Exceptions:
>>>>> +==============================================================================
>>>>> +
>>>>> +                                 Apache License
>>>>> +                           Version 2.0, January 2004
>>>>> +                        http://www.apache.org/licenses/
>>>>
>>>> I don't know that this is compatible for us. Looking at
>>>> https://www.apache.org/licenses/GPL-compatibility.html it talks about
>>>> how you can use it with GPLv3 (which we are *NOT*) but not GPLv2.
>>>>
>>> My bad didn't realize Apache 2.0 is not compatible with GPLv2...
>>> I am not sure but it seems that this incompatibility does not even
>>> allow static linking into a GPLv2 project.
>>> Then, how to make it possible to use LLVM? Can we upgrade to GPLv2+?
>>
>> However the linux kernel people do it, we can do it too. And perhaps
>> that's part of what's motivating LLVM to be able to disable these
>> intrinsics that we don't actually need?
>>
> OP-TEE did the same thing, it is GPLv2 too.

No. optee_os is (mostly) BSD-2-Clause. Only the test suite (optee_test)
is GPLv2.

I too did not realize that Apache 2.0 was not compatible with GPLv2.
Otherwise I would not have suggested this option for U-Boot. Sorry about
that.

Regards,
-- 
Jerome

-- 
Jerome

> 
> Raymond
> 
> 
>> --
>> Tom