Re: [Minios-devel] [UNIKRAFT PATCHv4 15/43] uk/arch: Add necessary header files for Arm64

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 13/07/18 10:13, Wei Chen wrote:
> > > +#ifndef __UKARCH_LCPU_H__
> > > +#error Do not include this header directly
> > > +#endif
> > > +
> > > +struct __regs {
> > > +       /* Generic Purpose registers, from x0 ~ x29 */
> > > +       unsigned long x[30];
> > > +
> > > +       /* Link Register (x30) */
> > > +       unsigned long lr;
> > > +
> > > +       /* Exception Link Register */
> > > +       unsigned long elr_el1;
> > > +
> > > +       /* Processor State Register */
> > > +       unsigned long spsr_el1;
> > > +
> > > +       /* Exception Status Register */
> > > +       unsigned long esr_el1;
> > > +
> > > +       /* Stack Pointer */
> > > +       unsigned long sp;
> > > +};
> > > +
> > > +#define isb()   __asm__ __volatile("isb" ::: "memory")
> > What is this intended for?
> This is for instruction memory barrier.
Just to clarify, isb is not a memory barrier ;). It is an instruction 
synchronization barrier. Any instructions in program order after the isb 
will only be fetched from cache/memory once the instruction has 
completed. This is used to ensure the effect of modification such as TLB 
invalidation, system registers have been taken into account.
I am not aware of any equivalent on x86.

Cheers,

--
Julien Grall

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