On Thu, Oct 27, 2016 at 12:08 PM, <[email protected]> wrote:
> Now here's the problem. We want message register two. But on ARM, the
> first 4 message registers are done actually in register (not the IPC
> buffer). When we called seL4_CallWithMRs, it gave returned us message
> register 2 in the variable we passed to it, but we have then thrown it
> away, thus forever losing the error information.
>
I can see the more complex generated functions (that use more than the
number of available real registers) are comfy using SetMR before and GetMR
after *WithMRs calls. I'm assuming a SetMR is safe after the *WithMRs call?
Correct me if I've misunderstood something in there, but it seems about
right.
Naively, would the following be appropriate to generate:
LIBSEL4_INLINE long
seL4_ARM_Page_Map(seL4_ARM_Page service, seL4_ARM_PageDirectory pd,
seL4_Word vaddr, seL4_CapRights rights, seL4_ARM_VM
Attributes attr)
{
...
/* Perform the call, passing in-register arguments directly. */
output_tag = seL4_CallWithMRs(service, tag,
&mr0, &mr1, &mr2, seL4_Null);
/* Unmarshal real register results into the IPC buffer. */
seL4_SetMR(0, mr0);
seL4_SetMR(1, mr1);
seL4_SetMR(2, mr2);
// 4th register isn't relevant for this function, but would be elsewhere
return seL4_MessageInfo_get_label(output_tag);
}
At the moment, the generator only spews unmarshalling code if there are
output parameters. I can hang an else on that to generate the SetMR calls.
As for adding more tests, people are always encouraged to do that :)
>
Cool, I'll add some. :-)
Thanks,
Jeff
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