Re: [Qemu-devel] [PATCH 10/34] linux-user: Support for restarting system calls for Microblaze targets

[Peter Maydell]

On 4 March 2016 at 00:27, Edgar E. Iglesias <address@hidden> wrote:
> On Thu, Mar 03, 2016 at 08:15:13PM +0000, Peter Maydell wrote:
>> Hi Edgar -- I'm just looking back at these signal handling
>> race condition fix patches, and with this one I have a confusion
>> about the Microblaze Linux syscall code that I hope you can
>> clear up for me.
>>
>> Looking at the kernel entry.S code it looks to me like
>> the way syscalls work on microblaze is:

> Yes, that sounds right.

Thanks for the confirmation.

>> (For context, the original patch is this one:
>> http://patchwork.ozlabs.org/patch/514879/
>> and I now suspect my review comments at the time to be wrong.)
>
> I see. Functionally I think the patch is OK. It seems to have
> some whitespace fixes mixed with functional changes (nitpick).

It also fixes a bug in do_sigreturn -- you'll notice that
previously we were returning env->regs[10] and so would
corrupt the guest r3 with the guest r10 value. Switching to
using -TARGET_QEMU_ESIGRETURN avoids that.

> Either way:
>
> Reviewed-by: Edgar E. Iglesias <address@hidden>

(I'm going to add a brief comment about why not updating r14 is ok.)

Thanks
-- PMM