From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Fri, 17 Apr 2015 08:12:43 -0600 Subject: [U-Boot] [PATCH v6 00/15] Add PSCI support for Jetson TK1/Tegra124 + CNTFRQ fix In-Reply-To: <55311269.6070900@siemens.com> References: <20150414134636.GH16702@bill-the-cat> <552D1EDC.7060307@wwwdotorg.org> <552D2037.5050207@siemens.com> <1429021814.15516.72.camel@hellion.org.uk> <5530AC6B.7010707@siemens.com> <55311148.3090309@wwwdotorg.org> <55311269.6070900@siemens.com> Message-ID: <553114DB.3070909@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 04/17/2015 08:02 AM, Jan Kiszka wrote: > 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. I suspect the environment variable isn't working, and Linux is still being booted in non-secure mode. That would be a bug in U-Boot.