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From: Blue Swirl <blauwirbel@gmail.com>
Date: Fri, 20 May 2011 19:03:53 +0300
Message-ID: <BANLkTin1nSNG42a8XEt78f3GYHh5xuv5OA@mail.gmail.com>
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Subject: Re: [Qemu-devel] [PATCH 2/2][SPARC] Fix TA0_Shutdown feature
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To: Julien Grall <julien.grall@gmail.com>
Cc: qemu-devel@nongnu.org, Fabien Chouteau <chouteau@adacore.com>

On Wed, May 18, 2011 at 4:17 PM, Julien Grall <julien.grall@gmail.com> wrote:
> On Tue, May 17, 2011 at 9:57 PM, Blue Swirl <blauwirbel@gmail.com> wrote:
>> On Tue, May 17, 2011 at 6:32 PM, Julien Grall <julien.grall@gmail.com> wrote:
>>> Fix TA0_SHUTDOWN feature
>>
>> But what would be the bug?
>
> We try to add RTEMS's support on leon platform for QEMU. RTEMS uses
> software trap 0 for various syscall.
> The current implementation of TA0_SHUTDOWN breaks the RTEMS boot.
>
>> No, this would actually be just opposite to how QEMU works.
>> Performance comes from doing more work at translation time in order to
>> save time during executing the generated code.
>
> I agree, this solution slows down the execution, but I didn't find
> another solution to fix this bug.

You should retain the feature check in translate.c but add a leon
specific helper in place of helper_shutdown, which can check for
psret.

It would be also possible to generate code for the psret check if the
helper overhead were an issue.