Re: Values generated by the ViryaOS uboot-script-gen do not work correctly on the Chromebook Snow

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 15 Nov 2023, Chuck Zmudzinski wrote:
> On 11/14/2023 6:43 PM, Mario Marietto wrote:
> > I hope that the informations below are correct :
> 
> I don't know that they are correct. I have not spent the necessary time to
> determine what the correct values for MEMORY_START and MEMORY_END are for
> the Chromebook we are using. I just presumed, probably incorrectly, that
> the entire 2 GB memory is safe, but obviously that is not the case with
> this Chromebook. Most likely, it requires a good understanding of the
> particular way booting is done on a Chromebook, which seems to be different
> from other devices.
> 
> I plan to eventually look into finding values for MEMORY_START and MEMORY_END
> sothe uboot-script-gen script computes usable values for loading Xen and dom0
> on this Chromebook in the script, but I might not get to that task 
> immediately.
> I plan to look at it within the next week or so.

A couple of suggestions. I noticed that the addresses you chose have a
higher alignment compared to the one chosen by Imagebuilder.
Imagebuilder uses 2MB:

offset=$((2*1024*1024))

I would think that a 2MB alignment should be sufficient, but you can
increase the alignment chosen by Imagebuilder simply by changing
"offset" at the top of uboot-script-gen. You seem to be used a 240MB
offset:

offset=$((240*1024*1024))

The other suggestion is about MEMORY_START and MEMORY_END. Looking at
the addresses you picked by hand, the following you should give you very
similar results:

MEMORY_START=0x33000000
MEMORY_END=0x80000000


> > - the imagebuilder config file :
> > 
> > MEMORY_START="0x0"
> > MEMORY_END="0x80000000"
> > LOAD_CMD="ext2load mmc 1:3"
> > BOOT_CMD="bootm"
> > DEVICE_TREE="exynos5250-snow.dtb"
> > XEN="xen-4.17-armhf"
> > XEN_CMD="console=dtuart dtuart=serial0 dom0_mem=1152M dom0_max_vcpus=2 
> > bootscrub=0 vwfi=native sched=null"
> > DOM0_KERNEL="zImage-6.6.0-xen-iommu-dma-on-xen"
> > DOM0_CMD="console=tty earlycon=xen earlyprintk=xen root=/dev/mmcblk1p4 rw 
> > rootwait clk_ignore_unused"
> > UBOOT_SOURCE="xen.source"
> > UBOOT_SCRIPT="xen.scr"
> > 
> > xen.source : (that does not work)
> > 
> > mmc dev 1
> > ext2load mmc 1:3 0xE00000 zImage-6.6.0-xen-iommu-dma-on-xen
> > ext2load mmc 1:3 0x1800000 xen-4.17-armhf.ub
> > ext2load mmc 1:3 0x1A00000 exynos5250-snow.dtb
> > fdt addr 0x1A00000
> > fdt resize 1024
> > fdt set /chosen \#address-cells <0x2>
> > fdt set /chosen \#size-cells <0x2>
> > fdt set /chosen xen,xen-bootargs "console=dtuart dtuart=serial0 
> > dom0_mem=1152M dom0_max_vcpus=2 bootscrub=0 vwfi=native sched=null"
> > fdt mknod /chosen dom0
> > fdt set /chosen/dom0 compatible  "xen,linux-zimage" "xen,multiboot-module" 
> > "multiboot,module"
> > fdt set /chosen/dom0 reg <0x0 0xE00000 0x0 0x87C200 >
> > fdt set /chosen xen,dom0-bootargs "console=tty earlycon=xen earlyprintk=xen 
> > root=/dev/mmcblk1p4 rw rootwait clk_ignore_unused"
> > setenv fdt_high 0xffffffffffffffff
> > bootm 0x1800000 - 0x1A00000
> > 
> > xen.source : (created by chuck and that works)
> > 
> > mmc dev 1
> > ext2load mmc 1:3 0x42000000 zImage-6.6.0-xen-iommu-dma-on-xen
> > ext2load mmc 1:3 0x51000000 xen-4.17-armhf-armmp-0x51004000.ub
> > ext2load mmc 1:3 0x5ffec000 exynos5250-snow.dtb
> > fdt addr 0x5ffec000
> > fdt resize 1024
> > fdt set /chosen \#address-cells <0x2>
> > fdt set /chosen \#size-cells <0x2>
> > fdt set /chosen xen,xen-bootargs "console=dtuart dtuart=serial0 
> > dom0_mem=1152M dom0_max_vcpus=2 bootscrub=0 vwfi=native sched=null"
> > fdt mknod /chosen dom0
> > fdt set /chosen/dom0 compatible  "xen,linux-zimage" "xen,multiboot-module" 
> > "multiboot,module"
> > fdt set /chosen/dom0 reg <0x0 0x42000000 0x0 0x87C200 >
> > fdt set /chosen xen,dom0-bootargs "console=tty1 root=/dev/mmcblk1p4 rw 
> > rootwait clk_ignore_unused --no-log"
> > bootm 0x51000000 - 0x5ffec000
> > 
> > all the values that you see in this conf. files have been calculated by 
> > chuck by hand,because the values generated by the imagebuilder are wrong. 
> > The only value that's well calculated by the imagebuilder is 0x87C200
> > 
> > - the size of all the binaries specified in the imagebuilder config file :
> > 
> > exynos5250-snow.dtb = 46.6 KiB (47,769 byte)
> > zImage-6.6.0-xen-iommu-dma-on-xen = 8.5 MiB (8,897,024 byte)
> > 
> > 
> > 
> > On Wed, Nov 15, 2023 at 12:17 AM Stefano Stabellini <sstabellini@xxxxxxxxxx 
> > <mailto:sstabellini@xxxxxxxxxx>> wrote:
> > 
> >     Hi Mario,
> > 
> >     I think we misunderstood each other :-)
> > 
> >     MEMORY_START-MEMORY_END is not supposed to be computed: it is supposed
> >     to come from the memory node in device tree tree (/memory) of the
> >     platform. The idea is that you should not have to do any computations,
> >     but only reuse the same address range specified there.
> > 
> >     Similarly in regards to "please post the size of all the binaries",
> >     this is just for debugging, so that I can see if there are any bugs with
> >     uboot-script-gen. I cannot debug the script unless I figure out what the
> >     problem is and the only way I can do that is with the binary sizes and
> >     redoing all the steps by hand.
> > 
> >     The expected outcome is that once we resolve the problem you should be
> >     able to use uboot-script-gen without any additional computation needed.
> > 
> >     Of course using static values is also OK.
> > 
> > 
> >     On Wed, 15 Nov 2023, Mario Marietto wrote:
> >     > ---> uboot-script-gen assumes that the memory range specified by 
> > MEMORY_START-MEMORY_END is valid and correct.
> >     >
> >     > Actually Chuck chose 0 as MEMORY_START and 0x800000 as MEMORY_END and 
> > these are stable values,they don't change. If you ask me to calculate
> >     > those values,it means that we need to compute these values. I imagine 
> > that to calculate these values is not easy.
> >     >
> >     > ---> To debug this kind of issues please post the size of all the 
> > binaries specified in the imagebuilder config file
> >     >
> >     > I imagine that I should also calculate those values. And again,I see 
> > a complication.
> >     >
> >     > I'm realizing that the method used by Chuck is easier because he uses 
> > stable values. In the end,there aren't any calculations to do and
> >     > since I'm looking for an easier method,not a more complicated one,I 
> > think that Chuck's method is good as is. 
> >     >
> >     > On Tue, Nov 14, 2023 at 11:51 PM Stefano Stabellini 
> > <sstabellini@xxxxxxxxxx <mailto:sstabellini@xxxxxxxxxx>> wrote:
> >     >       Hi Mario,
> >     >
> >     >       It is difficult to know how to change uboot-script-gen if we 
> > don't know
> >     >       why it is currently going wrong.
> >     >
> >     >       uboot-script-gen assumes that the memory range specified by
> >     >       MEMORY_START-MEMORY_END is valid and correct.
> >     >
> >     >       So if you specified a valid and correct memory range in your 
> > config file
> >     >       (0x41e00000-0x60000000) why is it failing?
> >     >
> >     >       The only thing uboot-script-gen does is choosing aligned 
> > addresses
> >     >       within the MEMORY_START-MEMORY_END range. The addresses are 
> > supposed not
> >     >       to overlap (meaning the initrd will not overwrite part of the 
> > kernel
> >     >       when loaded). If the issue is a bug in uboot-script-gen, such 
> > as the
> >     >       generated addresses overlap or they are not aligned, then we 
> > can fix the
> >     >       alignment or overlap bug. To debug this kind of issues please 
> > post:
> >     >       - the imagebuilder config file
> >     >       - the generate boot.source script
> >     >       - the size of all the binaries specified in the imagebuilder 
> > config file
> >     >
> >     >       On the other hand if 0x41e00000-0x60000000 is not a safe memory 
> > range to
> >     >       use, then you need to specify a different memory range.
> >     >
> >     >       Cheers,
> >     >
> >     >       Stefano
> >     >
> >     >
> >     >
> >     >       On Mon, 13 Nov 2023, Mario Marietto wrote:
> >     >       > Hello.
> >     >       >
> >     >       > I'm trying to find an easier way to the problem that you can 
> > read here :
> >     >       >
> >     >       > 
> > https://github.com/mobile-virt/u-boot-chromebook-xe303c12/tree/chromebook/xen#starting-a-domu-guest
> >  
> > <https://github.com/mobile-virt/u-boot-chromebook-xe303c12/tree/chromebook/xen#starting-a-domu-guest>
> >     >       >
> >     >       > where Chuck says :
> >     >       >
> >     >       >  6. Create the u-boot shell commands that will be used to 
> > boot Xen and dom0.
> >     >       >
> >     >       > Create a file in /home/user (or any other directory) named 
> > bootxen.source with these contents :
> >     >       >
> >     >       >
> >     >       > mmc dev 1 && mmc rescan 1
> >     >       > ext2load mmc 1:3 0x42000000 zImage-6.1.61-stb-xen-cbe+
> >     >       > ext2load mmc 1:3 0x51000000 xen-4.17-armhf-armmp-0x51004000.ub
> >     >       > ext2load mmc 1:3 0x5ffec000 
> > exynos5250-snow-6.1.61-stb-xen-cbe+.dtb
> >     >       > fdt addr 0x5ffec000
> >     >       > fdt resize 1024
> >     >       > fdt set /chosen \#address-cells <0x2>
> >     >       > fdt set /chosen \#size-cells <0x2>
> >     >       > fdt set /chosen xen,xen-bootargs "console=dtuart 
> > dtuart=serial0 dom0_mem=1G dom0_max_vcpus=2 bootscrub=0 vwfi=native"
> >     >       > fdt mknod /chosen dom0
> >     >       > fdt set /chosen/dom0 compatible  "xen,linux-zimage" 
> > "xen,multiboot-module" "multiboot,module"
> >     >       > fdt set /chosen/dom0 reg <0x0 0x42000000 0x0 0x7D7200 >
> >     >       > fdt set /chosen xen,dom0-bootargs "console=tty1 
> > root=/dev/mmcblk1p4 rw rootwait clk_ignore_unused"
> >     >       > bootm 0x51000000 - 0x5ffec000
> >     >       >
> >     >       > The hex value 0x7D7200 is the size of the 
> > zImage-6.1.61-stb-xen-cbe+ file, and that value is computed from the
> >     >       uboot-script-gen script
> >     >       > available from here :
> >     >       >
> >     >       >
> >     >       > https://gitlab.com/ViryaOS/imagebuilder 
> > <https://gitlab.com/ViryaOS/imagebuilder>
> >     >       >
> >     >       >
> >     >       > This is the interesting point :
> >     >       >
> >     >       >
> >     >       > Please note that most of the other values in the script 
> > generated by the ViryaOS uboot-script-gen do not work correctly with
> >     >       the Chromebook
> >     >       > Snow, but the script does correctly calculate the size of the 
> > dom0 Linux kernel image.
> >     >       >
> >     >       >
> >     >       > Some time ago Stefano suggested to put the values below for 
> > MEMORY_START and MEMORY_END inside the xen-config file :
> >     >       >
> >     >       >
> >     >       > nano xen-config file :
> >     >       >
> >     >       >
> >     >       > MEMORY_START="0x41e00000"
> >     >       > MEMORY_END="0x60000000"
> >     >       > LOAD_CMD="ext2load mmc 1:3"
> >     >       > BOOT_CMD="bootm"
> >     >       > DEVICE_TREE="exynos5250-snow.dtb"
> >     >       > XEN="xen-4.17-armhf"
> >     >       > XEN_CMD="console=dtuart dtuart=serial0 dom0_mem=768M 
> > dom0_max_vcpus=2 bootscrub=0 vwfi=native sched=null"
> >     >       > DOM0_KERNEL="zImage-6.6.0-xen-dma-mapping"
> >     >       > DOM0_CMD="console=tty earlycon=xen earlyprintk=xen 
> > root=/dev/mmcblk1p4 rw rootwait clk_ignore_unused"
> >     >       > UBOOT_SOURCE="xen.source"
> >     >       >
> >     >       >
> >     >       > bash ./uboot-script-gen -c xen-config -d .
> >     >       >
> >     >       >
> >     >       > Image Name:    
> >     >       > Created:      Thu Nov  2 20:59:24 2023
> >     >       > Image Type:   ARM Linux Kernel Image (uncompressed)
> >     >       > Data Size:    884744 Bytes = 864.01 KiB = 0.84 MiB
> >     >       > Load Address: 42c00000
> >     >       > Entry Point:  42c00000
> >     >       >
> >     >       >
> >     >       > Generated uboot script xen.scr, to be loaded at address 
> > 0x42000000:
> >     >       > ext2load mmc 1:3 0x42000000 xen.scr; source 0x42000000
> >     >       >
> >     >       >
> >     >       > and I tried to boot Xen and Linux 6.6 as dom0 :
> >     >       >
> >     >       > SMDK5250 # mmc dev 1
> >     >       > SMDK5250 # ext2load mmc 1:3 0x42000000 xen.scr; source 
> > 0x42000000
> >     >       > but it did not work : it reboots on the verification screen.
> >     >       >
> >     >       > --
> >     >       > Mario.
> >     >       >
> >     >       >
> >     >
> >     >
> >     >
> >     > --
> >     > Mario.
> >     >
> >     > 
> > 
> > 
> > 
> > -- 
> > Mario.
>