Re: [Minios-devel] [UNIKRAFT PATCH v4 6/9] plat/linuxu: Add linuxu (ARM) interrupts support

[Julien Grall <julien.grall@xxxxxxx>]

On 08/31/2018 07:38 AM, Florian Schmidt wrote:
> Hi Julien,
Hi Florian,

> On 08/30/2018 07:03 PM, Julien Grall wrote:
> > Hi,
> >
> > On 30/08/18 14:52, Florian Schmidt wrote:
> > > On 08/30/2018 03:10 PM, Sharan Santhanam wrote:
> > > > On 08/20/2018 01:21 PM, Florian Schmidt wrote:
> > > > In the sigrestorer.S[1] in glibc implmentation sets up Call frame 
> > > > information in front of the restorer function. Should we also not do 
> > > > this?
> > > > > +asm("__restorer:mov r7, #0x77\nsvc 0x0");
> > > > > +#else
> > > > > +#error "Unsupported architecture"
> > > > > +#endif
> > > > >   static void _irq_handle(int irq)
> > > > >   {
> > > > [1] 
> > > > https://code.woboq.org/userspace/glibc/sysdeps/unix/sysv/linux/arm/sigrestorer.S.html 
> > >
> > >
> > > I honestly don't know. Maybe one of our ARM experts can shed some 
> > > light on this? Why would it expect all registers to be on the stack?
> > I don't know the reasoning behind the CFI for this function. However, 
> > I don't think it is necessary to provide one for arm as you don't 
> > provide any for x86.
> Yes, that would have been my next question, why there's none for x86. :-)
AFAICT, libc is also providing CFI for x86 [2]. Actually the x86 one is 
more complex and provide a comment explaining why CFI is used here.
Cheers,

[2] 
https://code.woboq.org/userspace/glibc/sysdeps/unix/sysv/linux/x86_64/sigaction.c.html#_M/RESTORE
> Thanks for your input,
> Florian
--
Julien Grall

_______________________________________________
Minios-devel mailing list
Minios-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/minios-devel