Hi Corey,
If there are cases where an error is ambiguous then extending the errors is definitely
desirable. There are however a few things to consider
* If consistency is the only goal and the kernel is exporting enough information, then you
should consider writing wrappers / abstractions in user space
* Not all errors have an argument that they can refer to. For example, if you get
seL4_RevokeFirst when performing a page unmap because there are still other capabilities,
what argument do you attribute that to?
* Alternatively some errors could be related to multiple arguments. Consider getting
seL4_DeleteFirst when performing a CNode copy, do you consider it the fault of the index
(argument 0) or the bits to decode (argument 1) that the slot was not empty?
In both of those examples the error unambiguously indicates what went wrong, despite there
being no clear argument to attribute it to.
That said I would not be surprised if there are cases of ambiguity.
Adrian
On Fri 01-Jan-2016 10:02 PM, Corey Richardson wrote:
For consistency, it seems like it'd beneficial if:
seL4_RangeError
seL4_AlignmentError
seL4_DeleteFirst
seL4_FailedLookup
seL4_RevokeFirst
included an indication of which argument the error applies to. For some of
these errors, not every call has a unique argument which can cause the erorr.
This seems like a relatively straightforward change for me to get acquainted
with the full process of modifying and re-verifying the kernel. Are there
tradeoffs hidden here that would make this undesirable?
--
cmr
+16032392210
http://octayn.net/
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