Re: [Xen-devel] [PATCH v3 20/28] xen/arm32: head: Remove 1:1 mapping as soon as it is not used

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 22 Aug 2019, Julien Grall wrote:
> > >            */
> > > -        dsb
> > > +        lsr   r1, r9, #FIRST_SHIFT
> > > +        mov_w r0, LPAE_ENTRY_MASK
> > 
> > ldr?
> 
> What's wrong with the mov_w? Ok it is two instructions but... the constant
> will be stored in a literal and therefore induce a memory load (see patch #8).

I am just wondering why you would choose mov_w when you can just do a
single simple ldr.
 

> > 
> > > +        and  r1, r1, r0              /* r1 := first slot */
> > > +        cmp  r1, #XEN_FIRST_SLOT
> > 
> > NIT: align
> 
> align of?

This is just a code style thing. It doesn't show here but we usually
have 3 spaces between the command the the register, while here there are
only 2.

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