[19:30] <freemangordon> Hi there. I am running Ubuntu 12.04 (armHF+thumb2)on Nokia N900 (Cortex-A8 r1p2) - the one with broken thumb2. AFAIK there are 2 erratas to be workarounded to have working thumb - 430973 and 657417. The first is workarounded in kernel (with a little help from u-boot) and the other - by linker. Can anyone tell me if something else is needed(I know it is #beagle, was pointed here by dm8tbr @ #maemo).  BTW Ubuntu runs just fine, no SIGILL crashes at all.
[19:51] <dm8tbr> freemangordon: aholler recently saw the thumb2 problem. don't know though if and which errata he had addressed.
[19:52] <freemangordon> dm8tbr, thanks, but I will wait for a couple of hours to see if I will get an answer. Will repeat my question if there is no. Don't want to be pushy, noone's on a hurry after all
[19:54] <dm8tbr> I don't remember who was involved in the discussion back then, but I think koen, mru and probably rcn-ee
[19:55] <aholler> dm8tbr: I just didn't know if it's a toolchain or hw-bug. I've only remembered that I couldn't use thumb2 to build a system.
[19:55] <mru> thumb2 on r1pX cortex-a8 is finicky
[19:55] <mru> there are multiple hardware bugs
[19:55] <dm8tbr> yes, and my recollection was that there was no way to work around all of them at the same time
[19:55] <dm8tbr> at least not reliably
[19:56] <koen> dm8tbr: does disabling t2 count as a workaround?
[19:56] <mru> something like that
[19:56] <freemangordon> mru, I know that, but I think i found the way to workaround all of them, just need someone more knowledgeable than me to confirm/not
[19:56] <dm8tbr> koen: freemangordon claims he's found a way
[19:56] <mru> and the secure monitor makes it hard/impossible to apply all the workarounds required
[19:56] <freemangordon> mru, there is an SCM call on n900 to play with ACR
[19:57] <freemangordon> SMC*
[19:57] <mru> right, n900 uses hs chips and might have its own secure monitor
[19:57] <freemangordon> mru: so I can set IBE bit which is non-accessible uotside the secure world
[19:57] <mru> so supposing you have write access to all the required registers, it's still hard to get it right
[19:58] <mru> and even if you do, there will be a performance hit
[19:58] <mru> just stick to arm code
[19:58] <mru> much simpler
[19:58] <freemangordon> mru: may give a short description on my findings before a definite conclusion. I am working on that for about 6 months or so.
[19:59] <mru> 6 months that could have been better spent imo
[19:59] <mru> if you need thumb2, get an r3 chip instead
[20:00] <mru> also, you don't actually need thumb2
[20:00] <freemangordon> mru: Nokia N900. No way to touch the HW
[20:00] <mru> so stick with arm code
[20:00] <freemangordon> and Ubuntu for OMAP3 if thumb2 comiled
[20:00] <freemangordon> *is
[20:00] <mru> so?
[20:00] <mru> nobody really runs that on beagle classic
[20:00] <denix> _av500_: indeed again!
[20:00] <mru> and xm doesn't have the bug
[20:00] <freemangordon> no option to run it on n900 without thumb workarounds
[20:01] <mru> then run something else
[20:01] <freemangordon> yeah
[20:03] <freemangordon> mru: ok, are you aware of anything beside erratas 430973 and 657417 which prevents thumb2 on thumb-broken omap cores. have in mind that we never hit 687067 as 430973 workaround does not use BTB invalidate by MVA instructions?