[U-Boot] [PATCH v7 1/2] armv8: Support loading 32-bit OS in AArch32 execution state

[Alison Wang]

> On 4 November 2016 at 02:26, Alison Wang <alison.wang at nxp.com> wrote:
> > York,
> >
> >
> >
> >                 No, he don’t have my 32-bit kernel image. I am not
> > sure he is using 32-bit kernel or 64-bit kernel.
> >
> >
> >
> > Ryan,
> >
> >
> >
> >                 I am not familiar with the boards you tested,
> 
> The FVP Foundation model is free to use from ARM.  The entire software
> stack I'm using is available via ARM's portal:
> 
> https://community.arm.com/groups/arm-development-platforms
> 
> 
> > so I have some
> > questions, please help to work with me to find the root cause.
> >
> >
> >
> > 1.       Are you loading 32-bit kernel or 64-bit kernel?
> >
> 
> I'm loading the "standard" 64-bit kernel.  I was using a kernel based
> off 4.8:
> 
> https://git.linaro.org/landing-teams/working/arm/kernel-
> release.git/log/?h=latest-armlt-20161001
> 
> > 2.       Is CONFIG_ARMV8_SWITCH_TO_EL1 defined on these boards?
> >
> 
> I guess it is for the FVP models, if I grep for it, it's in my
> configs' .h file:
> 
> include/configs/vexpress_aemv8a.h:15:#define CONFIG_ARMV8_SWITCH_TO_EL1
> 
> -------------------------------------------------------
> #ifdef CONFIG_TARGET_VEXPRESS64_BASE_FVP #ifndef CONFIG_SEMIHOSTING
> #error CONFIG_TARGET_VEXPRESS64_BASE_FVP requires CONFIG_SEMIHOSTING
> #endif #define CONFIG_ARMV8_SWITCH_TO_EL1 #endif
> -------------------------------------------------------
> 
> But it isn't in my Juno config.
> 
> 
> > 3.       Are you using some secure firmware on these boards? In
> detail, I
> > want to know which EL is running on these boards when calling
> > armv8_switch_to_el2 in arch/arm/lib/bootm.c. If it is already running
> > in EL2 when calling armv8_swith_to_el2, the attached patch with PSCI
> > enabled is needed.
> >
> 
> I'm using what ARM consider the "standard" boot flow.  I'm using ARM
> Trusted Firmware to boot u-boot which in turn boots an arm64 kernel.
> 
> I'd expect my setup to still work after you've added patches to allow
> an aarch32 kernel to be booted, but I guess you're changing the boot
> path for non-aarch32 kernels also.
[Alison Wang] Of course, although I add these patches to support aarch32
kernel, I should make sure aarch64 kernel work too.

If you are using ARM Trusted Firmware to boot u-boot, I want to know what
EL is running for your U-Boot. If it is running in EL2 or EL1, please add
the attached patch to test again.

Thanks.
> 
> Regards,
> Ryan.
> 
> >
> >
> >
> >
> > Best Regards,
> >
> > Alison Wang
> >
> >
> >
> > From: york sun
> > Sent: Friday, November 04, 2016 10:04 AM
> > To: ryan.harkin at linaro.org
> > Cc: Wang Huan <b18965 at freescale.com>; agraf at suse.de; Scott Wood
> > <scott.wood at nxp.com>; Stuart Yoder <stuart.yoder at nxp.com>; Leo Li
> > <leoyang.li at nxp.com>; fenghua at phytium.com.cn; monstr at monstr.eu;
> > thomas.ab at samsung.com; mk7.kang at samsung.com; u-boot at lists.denx.de;
> > Jason Jin <jason.jin at nxp.com>; Alison Wang <alison.wang at nxp.com>
> >
> >
> > Subject: Re: [PATCH v7 1/2] armv8: Support loading 32-bit OS in
> > AArch32 execution state
> >
> >
> >
> > Alison,
> >
> > Does Ryan have your 32-bit kernel image? I think kernel 32-bit
> doesn't
> > support spin table. Please work with Ryan if your PSCI patch is
> > required for the test.
> >
> > York
> >
> >
> >
> > -------- Original Message --------
> > From: Ryan Harkin <ryan.harkin at linaro.org>
> > Sent: Thursday, November 3, 2016 12:17 PM
> > To: york sun <york.sun at nxp.com>
> > Subject: Re: [PATCH v7 1/2] armv8: Support loading 32-bit OS in
> > AArch32 execution state
> > CC: Alison Wang <b18965 at freescale.com>,agraf at suse.de,Scott Wood
> > <scott.wood at nxp.com>,Stuart Yoder <stuart.yoder at nxp.com>,Leo Li
> >
> <leoyang.li at nxp.com>,fenghua at phytium.com.cn,monstr at monstr.eu,thomas.ab
> > @samsung.com,mk7.kang at samsung.com,u-boot at lists.denx.de,Jason
> > Jin <jason.jin at nxp.com>,Alison Wang <alison.wang at nxp.com>
> >
> > Hi York/Alison,
> >
> > Sorry for not having had time to look at this earlier.
> >
> >
> > On 26 October 2016 at 17:54, york sun <york.sun at nxp.com> wrote:
> >> On 10/07/2016 11:56 PM, Alison Wang wrote:
> >>> To support loading a 32-bit OS, the execution state will change
> from
> >>> AArch64 to AArch32 when jumping to kernel.
> >>>
> >>> The architecture information will be got through checking FIT image,
> >>> then U-Boot will load 32-bit OS or 64-bit OS automatically.
> >>>
> >>> Signed-off-by: Ebony Zhu <ebony.zhu at nxp.com>
> >>> Signed-off-by: Alison Wang <alison.wang at nxp.com>
> >>> Signed-off-by: Chenhui Zhao <chenhui.zhao at nxp.com>
> >>> ---
> >>> Changes in v7:
> >>> - Move the call for armv8_switch_to_el2_m into this patch.
> >>>
> >>
> >> Reviewers,
> >>
> >> May I have your comment please? I intend to merge this set when the
> >> merge window opens.
> >>
> >
> > I've just tested these two patches on ARM's FVP Foundation and AEMv8
> > models and ARM's Juno board.
> >
> > In all cases, with this patchset, the kernel fails to start.  I see a
> > continuous reboot, where the kernel starts then immediately resets:
> >
> > --------------------------------------------------
> > Starting kernel ...
> >
> > resetting ...
> > --------------------------------------------------
> >
> > So I wouldn't want to see these patches merged.
> >
> > Regards,
> > Ryan.
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