Re: optee: os: toolchains would include linux target macros likes __linux__

[Randy Li]

On 2023/12/5 00:34, Jens Wiklander wrote:
> Hi Randy,
>
> On Mon, Dec 4, 2023 at 2:39 PM Randy Li <ayaka@xxxxxxxxxxx> wrote:
> > Hello
> >
> > I wonder why Optee OS would use a linux target toolchains but not a bare
> > metal target(none os)?
> I guess it started with that we didn't want to download both one Linux
> and one bare metal toolchain. We need both AArch32 and AArch64
> versions so it doubles up.
>
> > gcc-arm-10.3-2021.07-x86_64-aarch64-none-linux-gnu/bin/aarch64-none-linux-gnu-gcc
> > -dM -E - < /dev/null|grep linux
> > #define __linux 1
> > #define __gnu_linux__ 1
> > #define linux 1
> > #define __linux__ 1
> >
> > That makes hard to share a header files between Linux kernel and Optee.
> > We like to pass some structure in SHM, but optee don't have all those
> > Linux types likes <linux/types.h>.
> Surely you can define a .h file in a way that you can include it in
> both environments. We try to stick to ISO C.

Sometimes, we just need the macro functions like defined in 
<helper/bits.h> or <helper/align.h>

But in the Linux kernel environment, we don't have such header file.

Are there any safe environment macro that we could use to distinguish 
between Linux kernel and Optee TEE part(both OS and TA) ?

> > If optee didn't choose the toolchains for the Linux, we could easily
> > decide which part would use for Client Agent(Linux kernel) side or TEE
> > OS side.
> >
> > Why we don't use bare metal toolchains ?
> Feel free to do so.
>
> Cheers,
> Jens