From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tony Lindgren <tony@atomide.com>
Subject: Re: [PATCH] arm: omap: RX-51: ARM errata 430973 workaround
Date: Wed, 6 Mar 2013 09:51:21 -0800
Message-ID: <20130306175120.GP11806@atomide.com>
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To: Pali =?utf-8?B?Um9ow6Fy?= <pali.rohar@gmail.com>
Cc: Nishanth Menon <nm@ti.com>, =?utf-8?B?0JjQstCw0LnQu9C+INCU0LjQvNC40YLRgNC+0LI=?= <freemangordon@abv.bg>, linux@arm.linux.org.uk, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org
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* Pali Roh=C3=A1r <pali.rohar@gmail.com> [130306 06:13]:
> On Monday 04 March 2013 19:58:06 Tony Lindgren wrote:
> > * Nishanth Menon <nm@ti.com> [130301 06:42]:
> > > On Fri, Mar 1, 2013 at 1:47 AM, =D0=98=D0=B2=D0=B0=D0=B9=D0=BB=D0=
=BE =D0=94=D0=B8=D0=BC=D0=B8=D1=82=D1=80=D0=BE=D0=B2=20
> <freemangordon@abv.bg> wrote:
> > > > They look similar, but they are not equivalent :). The
> > > > first major difference is here (code taken from
> > > > omap-smc.S)
> > > >=20
> > > >> ENTRY(omap_smc2)
> > > >>=20
> > > >>          stmfd   sp!, {r4-r12, lr}
> > > >>          mov     r3, r2
> > > >>          mov     r2, r1
> > > >>          mov     r1, #0x0        @ Process ID
> > > >>          mov     r6, #0xff
> > > >>          mov     r12, #0x00      @ Secure Service ID
> > > >=20
> > > > Always zero, while RX51 PPA expects a real value. I wonder
> > > > if it is a bug, but anyway I don't see the id parameter
> > > > (R0) used.
> > > >=20
> > > >>          mov     r7, #0
> > > >>          mcr     p15, 0, r7, c7, c5, 6
> > > >=20
> > > > According to ARM TRM, this is "Invalidate entire branch
> > > > predictor array"(IIUC). NFC why it is needed here, but
> > > > this will not work on RX-51 until IBE bit in ACR is set.
> > > >=20
> > > >>          dsb
> > > >>          dmb
> > > >>          smc     #0
> > > >=20
> > > > RX-51 needs smc #1 ;)
> > > >=20
> > > >>          ldmfd   sp!, {r4-r12, pc}
> > > >=20
> > > > The next major difference is that RX-51 expects parameter
> > > > count passed in R3[0] to be the count of the remaining
> > > > parameters +1, but omap_secure_dispatcher (in
> > > > omap-secure.c) is passing the exact count of the
> > > > remaining parameters.
> > > >=20
> > > > I guess all of the above problems can be
> > > > fixed/workarounded, but I wonder does it worth. Not to
> > > > say that I don't have BB around to test if the code still
> > > > works if I make changes to omap2-secure.c/omap-smc.S :)
> > >=20
> > > Yep, that was my point - instead of introducing new
> > > functions, extending the existing functions to handle new
> > > requirements is better solution, IMHO.
> >=20
> > I think there have been patches posted for ARM generic SMC
> > handling. Might be worth looking at those a bit and see if
> > this can be made generic. I think only the SMC call numbering
> > is different for various SoCs?
> >=20
> > Regards,
> >=20
> > Tony
>=20
> Hi Tony, where are patches for ARM generic SMC handling?

Sorry don't have the link available, but I recall seeing some patch
on linux-arm-kernel within past six months that added a generic
smc function.. Or maybe I was dreaming or something.

Regards,

Tony