Re: runtime check for omap-aes bus access permission (was: Re: 3.13-rc3 (commit 7ce93f3) breaks Nokia N900 DT boot)

["Pali Rohár" <pali.rohar@gmail.com>]

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On Tuesday 25 November 2014 22:08:17 Pali Rohár wrote:
> On Sunday 08 December 2013 00:22:06 Tony Lindgren wrote:
> > * Sebastian Reichel <sre@ring0.de> [131207 15:04]:
> > > On Sat, Dec 07, 2013 at 01:11:37PM -0800, Tony Lindgren
> 
> wrote:
> > > > > I asked Pali to send me his copy of the updated NOLO
> > > > > bootloader, so that I can test this. I just checked
> > > > > the omap documentation (I only have access to the
> > > > > public one) and crypto related stuff is not
> > > > > documented for the L3_PM_READ_PERMISSION register.
> > > > > There are a couple of reserved bits, which may be
> > > > > used for this, though.
> > > > > 
> > > > > I also CC'd Joel Fernandes, since he worked on the
> > > > > driver before and may have access to the
> > > > > documentation.
> > > > 
> > > > Looks like at least the 36xx public version referenced
> > > > here has them:
> > > > 
> > > > http://www.spinics.net/lists/linux-omap/msg21857.html
> > > > 
> > > > I'd assume the registers are the same for 34xx since we
> > > > don't have them defined separately in the kernel.
> > > 
> > > I can't find it in the omap36xx documentation either.
> > > Maybe I search at the wrong position. I tried to find
> > > something crypto related in
> > > 
> > > Table 9-89. L3_PM_READ_PERMISSION_i
> > 
> > Hmm maybe it's done based on the address in
> > L3_PM_ADDR_MATCH_k?
> > 
> > I guess the thing to do would be to compare the register
> > output between the two different firmware versions.
> > 
> > Regards,
> > 
> > Tony
> 
> Tony, if you can tell me how to read those registers I can
> provide output from both bootloaders (one that enable aes
> support in L3 firewall and one which not).
> 
> Also I can test other patches or provide other logs if you
> need something more...

CCing Nishanth Menon

Problem is that when L3 firewall is not configured by signed 
bootloader then loading omap aes driver cause kernel crash. We 
need some code which can check if omap aes is enabled or not at 
runtime in kernel...

More details with full email tread conversation is there:
http://thread.gmane.org/gmane.linux.ports.arm.omap/108397/

-- 
Pali Rohár
pali.rohar@gmail.com

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