[Buildroot] "BR2_TARGET_ROOTFS_INITRAMFS" with U-Boot?

[Buildroot] "BR2_TARGET_ROOTFS_INITRAMFS" with U-Boot?

[Jens Maus]

Hi,

I am currently developing a buildroot-driven system (for RaspberryPi HW) which uses U-Boot together with BR2_TARGET_ROOTFS_CPIO and BR2_TARGET_ROOTFS_CPIO_UIMAGE in buildroot to generate a zImage and initrd file which I can then boot via

load mmc 0:1 ${kernel_addr_r} /zImage
load mmc 0:1 ${ramdisk_addr_r} /initrd
setenv bootargs ?root=/dev/ram0?
bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr}

in U-Boot. This works perfectly fine.

However, I am currently evaluating the possibilities to directly embed the initramfs into the kernel by switching to BR2_TARGET_ROOTFS_INITRAMFS. But I am not able to boot the generated zImage via

load mmc 0:1 ${kernel_addr_r} /zImage
setenv bootargs ??
bootz ${kernel_addr_r} - ${fdt_addr}

It simply hangs at ?Starting kernel?? 

Unfortunately I don?t have any idea why this kernel with the embedded initramfs doesn?t boot at all? It doesn?t even output any kernel information/debug on the console.

Any idea what might be wrong here or how I could debug the situation to get that zImage booted?

Best Regards,

Jens
-- 
Jens Maus, Dresden/Germany
http://jens-maus.de/

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[Buildroot] "BR2_TARGET_ROOTFS_INITRAMFS" with U-Boot?

[Baruch Siach]

Hi Jens,

On Fri, Mar 23, 2018 at 11:05:24AM +0100, Jens Maus wrote:
> I am currently developing a buildroot-driven system (for RaspberryPi HW) 
> which uses U-Boot together with BR2_TARGET_ROOTFS_CPIO and 
> BR2_TARGET_ROOTFS_CPIO_UIMAGE in buildroot to generate a zImage and initrd 
> file which I can then boot via
> 
> load mmc 0:1 ${kernel_addr_r} /zImage
> load mmc 0:1 ${ramdisk_addr_r} /initrd
> setenv bootargs ?root=/dev/ram0?
> bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr}
> 
> in U-Boot. This works perfectly fine.
> 
> However, I am currently evaluating the possibilities to directly embed the 
> initramfs into the kernel by switching to BR2_TARGET_ROOTFS_INITRAMFS. But I 
> am not able to boot the generated zImage via
> 
> load mmc 0:1 ${kernel_addr_r} /zImage
> setenv bootargs ??
> bootz ${kernel_addr_r} - ${fdt_addr}
> 
> It simply hangs at ?Starting kernel?? 
> 
> Unfortunately I don?t have any idea why this kernel with the embedded 
> initramfs doesn?t boot at all? It doesn?t even output any kernel 
> information/debug on the console.
> 
> Any idea what might be wrong here or how I could debug the situation to get 
> that zImage booted?

Your bigger kernel image, or its boot-time decompressed image, might be 
overwriting the DT. See section 4b in Documentation/arm/Booting of the kernel 
source.

baruch

-- 
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -

[Buildroot] "BR2_TARGET_ROOTFS_INITRAMFS" with U-Boot?

[Rafał Susz]

Hello Jens,

I made short test on my at91sam ARM9  based board. After simple
enabling  BR2_TARGET_ROOTFS_INITRAMFS
in buildroot  and changing bootargs to contain  root=/dev/ram0
I also observe stuck on "Starting linux kernel ..."  .

Make sure you have enabled RAMFS support in kernel. On my side it was not
selected causing the hang:

General Setup
  [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support


With it in I am able to boot up with ramfs.

best regards,
rafal


2018-03-23 11:39 GMT+01:00 Baruch Siach <baruch@tkos.co.il>:

> Hi Jens,
>
> On Fri, Mar 23, 2018 at 11:05:24AM +0100, Jens Maus wrote:
> > I am currently developing a buildroot-driven system (for RaspberryPi HW)
> > which uses U-Boot together with BR2_TARGET_ROOTFS_CPIO and
> > BR2_TARGET_ROOTFS_CPIO_UIMAGE in buildroot to generate a zImage and
> initrd
> > file which I can then boot via
> >
> > load mmc 0:1 ${kernel_addr_r} /zImage
> > load mmc 0:1 ${ramdisk_addr_r} /initrd
> > setenv bootargs ?root=/dev/ram0?
> > bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr}
> >
> > in U-Boot. This works perfectly fine.
> >
> > However, I am currently evaluating the possibilities to directly embed
> the
> > initramfs into the kernel by switching to BR2_TARGET_ROOTFS_INITRAMFS.
> But I
> > am not able to boot the generated zImage via
> >
> > load mmc 0:1 ${kernel_addr_r} /zImage
> > setenv bootargs ??
> > bootz ${kernel_addr_r} - ${fdt_addr}
> >
> > It simply hangs at ?Starting kernel??
> >
> > Unfortunately I don?t have any idea why this kernel with the embedded
> > initramfs doesn?t boot at all? It doesn?t even output any kernel
> > information/debug on the console.
> >
> > Any idea what might be wrong here or how I could debug the situation to
> get
> > that zImage booted?
>
> Your bigger kernel image, or its boot-time decompressed image, might be
> overwriting the DT. See section 4b in Documentation/arm/Booting of the
> kernel
> source.
>
> baruch
>
> --
>      http://baruch.siach.name/blog/                  ~. .~   Tk Open
> Systems
> =}------------------------------------------------ooO--U--
> Ooo------------{=
>    - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot
>
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[Buildroot] "BR2_TARGET_ROOTFS_INITRAMFS" with U-Boot?

[Jens Maus]

Hi Rafal,

thanks for the hint. Of course, I do have initramfs support enabled in the kernel. The question really is which u-boot commands you were using to actually boot the kernel.

regards,
jens

> Am 23.03.2018 um 15:19 schrieb Rafa? Susz <rafal.susz@gmail.com>:
> 
> Hello Jens,
> 
> I made short test on my at91sam ARM9  based board. After simple enabling  BR2_TARGET_ROOTFS_INITRAMFS in buildroot  and changing bootargs to contain  root=/dev/ram0 
> I also observe stuck on "Starting linux kernel ..."  .
> 
> Make sure you have enabled RAMFS support in kernel. On my side it was not selected causing the hang:
> 
> General Setup
>   [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
> 
> 
> With it in I am able to boot up with ramfs.
> 
> best regards,
> rafal
> 
> 
> 2018-03-23 11:39 GMT+01:00 Baruch Siach <baruch@tkos.co.il>:
> Hi Jens,
> 
> On Fri, Mar 23, 2018 at 11:05:24AM +0100, Jens Maus wrote:
> > I am currently developing a buildroot-driven system (for RaspberryPi HW)
> > which uses U-Boot together with BR2_TARGET_ROOTFS_CPIO and
> > BR2_TARGET_ROOTFS_CPIO_UIMAGE in buildroot to generate a zImage and initrd
> > file which I can then boot via
> >
> > load mmc 0:1 ${kernel_addr_r} /zImage
> > load mmc 0:1 ${ramdisk_addr_r} /initrd
> > setenv bootargs ?root=/dev/ram0?
> > bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr}
> >
> > in U-Boot. This works perfectly fine.
> >
> > However, I am currently evaluating the possibilities to directly embed the
> > initramfs into the kernel by switching to BR2_TARGET_ROOTFS_INITRAMFS. But I
> > am not able to boot the generated zImage via
> >
> > load mmc 0:1 ${kernel_addr_r} /zImage
> > setenv bootargs ??
> > bootz ${kernel_addr_r} - ${fdt_addr}
> >
> > It simply hangs at ?Starting kernel??
> >
> > Unfortunately I don?t have any idea why this kernel with the embedded
> > initramfs doesn?t boot at all? It doesn?t even output any kernel
> > information/debug on the console.
> >
> > Any idea what might be wrong here or how I could debug the situation to get
> > that zImage booted?
> 
> Your bigger kernel image, or its boot-time decompressed image, might be
> overwriting the DT. See section 4b in Documentation/arm/Booting of the kernel
> source.
> 
> baruch
> 
> --
>      http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
> =}------------------------------------------------ooO--U--Ooo------------{=
>    - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot
> 

-- 
Jens Maus, Dresden/Germany
http://jens-maus.de/

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