Ok, added a github issue (34) with the commit.

Alex.

On 26.08.2016 01:20, Adrian Danis wrote:
> I cannot really see a nicer way to implement it, so I think it's fine if
> you want to put it up as a PR.
> 
> Adrian
> 
> On Fri 26-Aug-2016 7:15 AM, Alexander Boettcher wrote:
>> Hi Adrian,
>>
>> On 24.08.2016 01:35, Adrian Danis wrote:
>>> The position independent syscall code looks good. If you could perform a
>>> similar change to how OKL4 conditionally handles PIC then this would
>>> definitely be fine to go in.
>> ok. I adjusted the bindings depending on __pic__, which is set when
>> -fpic or -fPIC is used. Please have a look and give advices what should
>> be adjusted.
>>
>> Thanks,
>>
>> Alex.
>>
>> [0] https://github.com/alex-ab/genode/blob/sel4_syscall/sel4.patch
>>
>>> Adrian
>>>
>>> On Tue 23-Aug-2016 7:35 PM, Alexander Boettcher wrote:
>>>> Hello,
>>>>
>>>> we have now mainly all running with shared libraries on Genode/seL4, so
>>>> that we had to adjust the syscall bindings to be position independent
>>>> [0]. Now is the time to try to get in a form that it may get upstream.
>>>>
>>>> According to this post:
>>>>
>>>> On 29.10.2014 02:33, Adrian Danis wrote:
>>>>> Position independent code is a bit of a trickier issue. Presently we
>>>>> have no desire to use PIC, so copping a performance hit (incredibly
>>>>> small it may be) is undesirable. I think the best option here would be
>>>>> to make support of PIC at user level a build configuration option, and
>>>>> then make the stubs conditionally build in the additional ebx
>>>>> save/restore code. I do not know if attempting such conditional
>>>>> building
>>>>> will end up turning the assembly into an unreadable mess, but it would
>>>>> resolve the performance argument at least.
>>>>> The 'correct' way to do this with fitting into the current seL4 build
>>>>> system setup would be to add a configuration option to
>>>>> tools/common/Kconfig, use that variable to do the conditional
>>>>> compilation in syscalls.h and have tools/common/common.mk generate the
>>>>> -fPIC / -fno-PIC flags.
>>>>> If you can come up with a nice way of conditionally building both PIC
>>>>> and non-PIC versions of what is in syscalls.h then we would certainly
>>>>> accept it.
>>>> you would prefer to have, depending on some define, the syscall binding
>>>> adjusted.
>>>>
>>>> In OKL4 there were already such define magic, see beginning of [1] e.g.
>>>> There, depending on "__pic__", different L4_SAVE_REG/L4_RESTORE_REG
>>>> defines are prepared and later on used by the assembler parts. Is this
>>>> the way to go ? Thanks for any suggestions.
>>>>
>>>> Cheers,
>>>>
>>>> Alexander Boettcher.
>>>>
>>>> [0]
>>>> https://github.com/genodelabs/genode/blob/master/repos/base-sel4/patches/syscall.patch
>>>>
>>>>
>>>> [1]
>>>> https://github.com/genodelabs/genode/blob/master/repos/base-okl4/patches/syscall_pic.patch
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Devel mailing list
>>>> [email protected]
>>>> https://sel4.systems/lists/listinfo/devel
>>>
> 
> 


_______________________________________________
Devel mailing list
[email protected]
https://sel4.systems/lists/listinfo/devel

Reply via email to