Re: [seL4] Try two for libsel4 not having a dependency on libc

Though I'm still opposed to this change overall, my two cents on the current state: - Should we just put the benchmarking code in libsel4bench [0]? I realise the former is for benchmarking the kernel and the latter is (arguably) for benchmarking userspace, but it seems to me a better home for it. - You've used `#pragma message` in one instance. I would prefer `#error` for consistency, though I'm aware `#pragma message` is more portable. Moreover, why are we emitting messages here in the first place? It's a perfectly valid (in fact the default) configuration to have the benchmarking syscalls disabled. [0]: https://github.com/seL4/libsel4bench On 03/07/15 10:19, Wink Saville wrote:

One other note, this isn't done. It still needs to be integrated with muslc (libc) and at a minimum seL4_Halt needs to be properly implemented. And I'm sure there will be plenty of other changes needed but I hope we're closer.

On Thu, Jul 2, 2015 at 5:11 PM Wink Saville mailto:wink@saville.com> wrote:

Here https://github.com/winksaville/sel4-min-sel4/tree/no-libc3 is try #3, I've pasted the commit message below as it tells the story, let me know what you think:

libsel4 with no libc dependency. The primary changes are introducing sel4_types.h and removing std* types plus porting assert and printf code from the kernel to libsel4. All of this means the code within libsel4 does not overload any typical libc entities. So now libsel4 uses types like seL4_Uint32 ... instead of uint32_t. And printf is now seL4_Printf and assert is seL4_Assert .... I'm also using sel4_ prefixes for various files as I felt it was more consistent with the names of the entities within the files. The only new library is libsel4_benchmark and since it consists of just sel4_benchmark.h we might want to move that back into libsel4. I would have liked to move out libsel4_assert, libsel4_printf and libsel4_putchar but since asserts are used by low level generated code I couldn't come up with a good way of doing that. Finally, the only file modified that effects kernel code is kernel/tools/bitfield_gen.py. It needed to be modified as it generates files for both kernel and user space. And for user space the generated code (types_gen.h) needed to use the new types and asserts. The changes should not change what is generated for the kernel and I did a comparison of kernel_final.{c|s} before and after my change and the only differences were time stamps

-- Wink

On Mon, Jun 29, 2015 at 7:07 PM Wink Saville mailto:wink@saville.com> wrote:

Will do.

On Mon, Jun 29, 2015, 7:05 PM Anna Lyons mailto:Anna.Lyons@nicta.com.au> wrote:

Hi,

> > Currently there is at least one known problem, I modified > bitfield_gen.py so types_gen.h has no asserts since at the moment the > kernel uses assert and userspace is libsel4_assert. We could either do > something like I've done and remove them or change the kernel to use > libsel4_assert or something else. >

The asserts are really important to avoid horrible bugs when using functions created by the bitfield generator, so if we go ahead with this let's make sure they survive in some form.

Cheers, Anna.

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