arm: omap: RX-51: ARM errata 430973 workaround
Quoted 12 lines
-------- Оригинално писмо --------
От: Aaro Koskinen
Относно: Re: [PATCH] arm: omap: RX-51: ARM errata 430973 workaround До: Ивайло Димитров
Изпратено на: Събота, 2013, Март 2 01:51:39 EET
Quoted 8 lines
Quoted 1 line · Ивайло Димитров
Unfortunately it is necessary, on RX-51 PPA/NOLO leaves IBE bit unset.
You sure? I think you need to explain this more - the commit message in the original patch is empty/missing...
A.
Yes, I am sure, NOLO leaves IBE bit in ACR unset, I've verified that by reading/printing the contents of ACR from both u-boot and the kernel itself. With IBE bit unset, "mcr p15, 0, rX, c7, c5, 6" - flush BTAC/BTB instruction(which is needed to workaround errata 430973) is a noop.
Yes, I am sure, IBE but must be set by using a call to PPA, on RX-51 setting that bit from the kernel (as it is done in the "ARM errata: Stale prediction on replaced interworking branch" kernel patch, see http://kerneltrap.org/mailarchive/git-commits-head/2009/5/3/5622724) does not work, see the comment at the end: "Note that setting specific bits in the ACTLR register may not be available in non-secure mode.". This is exactly the case for RX-51. I've verified that too.
If you need anything else elaborated on, I'm fine, just ask :)
Regards,
Ivo