[Linux-Xtensa] fixup handlers in fast_syscall_xtensa (and fast_syscall_spill_registers)

Max Filippov jcmvbkbc at gmail.com
Wed Aug 6 23:47:58 UTC 2014


Hi Chris,

On Fri, Aug 1, 2014 at 5:53 AM, Max Filippov <jcmvbkbc at gmail.com> wrote:
> On Fri, Aug 1, 2014 at 5:23 AM, Chris Zankel <chris at zankel.net> wrote:
>> The other thing is that both system calls are somewhat deprecated, are they
>> not?
>
> They look like that. There's no more users of it in the kernel, and the mainline
> uClibc never used it. And I haven't been around long enough to know their
> origin.
>
>>> Seems to me that we need to treat exceptions raised in fast handlers like
>>> kernel exceptions, not like user. That will allow using pagefault handler
>>> level
>>> fixups and returning EINVAL from syscalls.
>>> What do you think is the best way to handle this situation?
>>
>> It's definitely broken, so would be good to fix it. The options are:
>>
>> a. deprecate it and remove the code; if removed later, change the comment
>
> My favourite option (:

So I've sent a proposed patch where I put these syscalls under CONFIG_*
symbols that will be disabled by default for new builds. So that people that
might be using them are still able to use them, with their existing issues,
and new kernels don't suffer from these issues and don't need complications
related to delivery of signals raised in double exceptions only needed for
these two syscalls.

-- 
Thanks.
-- Max


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