On 2015-04-17 15:57, Stephen Warren wrote:
On 04/17/2015 12:47 AM, Jan Kiszka wrote:
On 2015-04-14 16:30, Ian Campbell wrote:
On Tue, 2015-04-14 at 16:12 +0200, Jan Kiszka wrote:
On 2015-04-14 16:06, Stephen Warren wrote:
On 04/14/2015 07:46 AM, Tom Rini wrote:
On Mon, Apr 13, 2015 at 06:48:05AM +0200, Jan Kiszka wrote:
> Changes in v6: > - rebased over master > - included Thierry's SMMU enabling patch > - moved activation patch at the end so that it can be held back > > This version can also be found at > https://github.com/siemens/u-boot/tree/jetson-tk1-v6.
So what level of coordination do we need on applying this series so that kernels (both old and new) can continue to function? And perhaps README updates or similar? Thanks!
Hopefully this series doesn't change anything by default, and simply allows people to turn on support for booting kernels in non-secure mode if they want to? If so, there shouldn't be any co-ordination required. If it changes the default behaviour, co-ordination is probably required, and that'd be a bad thing.
Sorry, forgot to mention: I can't flip the default behaviour to leave virtualization support off only for the TK1. That's a generic default.
Would enabling it in the compile but adding "bootm_boot_mode=sec" to the default environment (so it isn't used by default) be considered sufficiently backwards compatible?
This turned out to not work as expected: booting in secure mode seems to prevent that Linux can bring up CPUs 1-3. Not sure if this is to be expected or a bug, but I will now take a different route:
That was the whole point of the environment variable suggestion; the environment variable would default to off so nobody got new behaviour, but anyone who wanted to boot in secure mode could simply set the environment variable and get it. That way, nobody who doesn't want the feature needs to co-ordinate U-Boot and kernel updates. Why doesn't that work?
Because it breaks SMP on Linux, namely the boot of secondary cores. Don't ask me why, I didn't debug the details. But you can probably reproduce by specifying bootm_boot_mode=sec with current U-boot and recent upstream kernels.
Jan