On 20.09.16 10:45, Thomas Abraham wrote: > On Tue, Sep 20, 2016 at 12:03 PM, Alexander Graf <ag...@suse.de> wrote: >> >> >> On 20.09.16 08:25, Thomas Abraham wrote: >>> On Tue, Sep 20, 2016 at 11:35 AM, Alexander Graf <ag...@suse.de> wrote: >>>> >>>> >>>> Am 20.09.2016 um 07:51 schrieb Thomas Abraham <ta.oma...@gmail.com>: >>>> >>>> Hi Alison, >>>> >>>> >>>> On Mon, Sep 19, 2016 at 7:38 PM, Alexander Graf <ag...@suse.de> wrote: >>>> >>>> >>>> >>>> On 09.09.16 10:48, Alison Wang wrote: >>>> >>>> This patch is to use the the generic lowlevel_init instead of the >>>> >>>> specific one. >>>> >>>> >>>> Signed-off-by: Alison Wang <alison.w...@nxp.com> >>>> >>>> >>>> If I had to guess, I'd think they only had their own version because the >>>> >>>> old one required a GIC. >>>> >>>> >>>> I apologize for the delay. >>>> >>>> The reason for using a custom version was to avoid enabling >>>> ARMV8_MULTIENTRY config option since the Exynos7 code was ready for >>>> it. >>>> >>>> >>>> Either way, since Samsung doesn't reply, I'm fine potentially breaking >>>> >>>> their boards if that means that we can make progress for actively >>>> >>>> maintained ones: >>>> >>>> >>>> Reviewed-by: Alexander Graf <ag...@suse.de> >>>> >>>> >>>> This patch without the ARMV8_MULTIENTRY and ARMV8_SWITCH_TO_EL1 config >>>> options does not switch the boot CPU from EL3 to EL1. So it would be >>>> preferable to not merge this patch until ARMV8_MULTIENTRY is enabled >>>> for Exynos7. >>>> >>>> >>>> Why do you want to switch it to EL1 in the first place? Linux is very happy >>>> to live in EL2 - which is what we call it in by default. >>> >>> Okay, there is no particular requirement to be in EL1 for Exynos7. EL2 >>> would also be fine. But Exynos7 support in u-boot is not yet ready for >>> enabling ARMV8_MULTIENTRY config option. Is there anything be blocked >>> due to Exynos7 using a custom lowlevel_init function? >> >> Yes, we're changing the semantics of armv8_switch_to_el2 and >> armv8_switch_to_el1: >> >> http://lists.denx.de/pipermail/u-boot/2016-September/266217.html >> >> which is a prerequisite for AArch32 kernel boot on AArch64 systems. > > Okay. > >> >> How quickly do you think you could make Exynos7 work with MULTIENTRY? >> > > Exynos7420 uses CPU 0 of Cluster 1 as boot CPU (master CPU). The macro > 'branch_if_master' requires all affinity values to be zero for a CPU > to be identified as a master CPU. And so the boot CPU is incorrectly > detected as a slave CPU. I have tested with the following temporary > workaround to enable ARMV8_MULTIENTRY on Exynos7420. If it looks fine, > this can be merged along with Alison's patch.
That certainly works for me. Is there a particular reason why you want to do the EL1 switch? I would strongly prefer if we could just enter OSs in EL2 always. Alex _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
