[PATCH v3] ARM: L2 : Errata 588369: Clean & Invalidate do not invalidate clean lines

[Shilimkar, Santosh]

> -----Original Message-----
> From: Russell King - ARM Linux [mailto:linux at arm.linux.org.uk]
> Sent: Monday, January 11, 2010 8:54 PM
> To: Shilimkar, Santosh
> Cc: Catalin Marinas; linux-arm-kernel at lists.infradead.org; linux-omap at vger.kernel.org;
> tony at atomide.com; Woodruff, Richard
> Subject: Re: [PATCH v3] ARM: L2 : Errata 588369: Clean & Invalidate do not invalidate clean lines
> 
> On Mon, Jan 11, 2010 at 08:48:37PM +0530, Shilimkar, Santosh wrote:
> > Thanks for cooments !!
> > > -----Original Message-----
> > > From: Catalin Marinas [mailto:catalin.marinas at arm.com]
> > > Sent: Monday, January 11, 2010 8:07 PM
> > > To: Shilimkar, Santosh
> > > Cc: linux at arm.linux.org.uk; linux-arm-kernel at lists.infradead.org; linux-omap at vger.kernel.org;
> > > tony at atomide.com; Woodruff, Richard
> > > Subject: Re: [PATCH v3] ARM: L2 : Errata 588369: Clean & Invalidate do not invalidate clean lines
> > >
> > > Does your secure monitor corrupt r4-r8? Maybe you could add a comment
> > > with a few words on this API.
> >
> > Yes they are corrupted. I will add some comments on the API.
> >
> > > Do you need to specify "r12" as well? What about "cc", are they
> > > preserved by the secure monitor?
> >
> > r12 and reset of the registers are preserved. Lr needs to be saved but
> > because of function call, the compiler saves/restores it.
> 
> That's not guaranteed; the compiler can re-use lr for its own purposes
> within a function.  You need to add lr to the list of clobbered registers.
Ok will add that.
> > I didn't get your this comment "What about "cc", are they preserved
> > by the secure monitor ?  Do you mean rest of the register. If yes then
> > the secure monitor don't tamper those registers.
> 
> No - Catalin means are the NZCV flags changed by the secure monitor, or
> are they preserved?  If they're preserved, you don't need a "cc" clobber.
> If they're not preserved, you do.
I will double check this but IIRC the flags are preserved.

Regards,
Santosh