bzip2-compressed bzimage support?

bzip2-compressed bzimage support?

[Joey Korkames]

Does kexec-tools support bzip2-compressed bzImages? I'm trying the latest 
git master against this kernel....

http://packages.debian.org/sid/amd64/linux-image-2.6.32-trunk-amd64/download

...but am having no success. I'm assuming that it must be because the 
kernel-section is bzip2 compressed because gzip/lzma seems to be explicitly 
supported in the master branch's commits.

xen2:~# kexec --load --type=bzImage --initrd=/boot/debian/initrd.img-2.6.32-trunk-amd64 --command-line="root=/dev/mapper/mirror_dsksAB-OS_disk console=tty0" /boot/debian/vmlinuz-2.6.32-trunk-amd64
kexec_load failed: Function not implemented
entry       = 0x7fff5640 flags = 0
nr_segments = 4
segment[0].buf   = 0x1f77a30
segment[0].bufsz = 3874
segment[0].mem   = 0x3000
segment[0].memsz = 4000
segment[1].buf   = 0x7f28267dc810
segment[1].bufsz = 239800
segment[1].mem   = 0x1000000
segment[1].memsz = 23a000
segment[2].buf   = 0x7f2825f93010
segment[2].bufsz = 8456ab
segment[2].mem   = 0x7f7ae000
segment[2].memsz = 846000
segment[3].buf   = 0x1f6f910
segment[3].bufsz = 80e0
segment[3].mem   = 0x7fff5000
segment[3].memsz = a000

please CC me in to any replies, I am not subscribed to the list.

Thanks for reading
-joey

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Re: bzip2-compressed bzimage support?

[Florian Fainelli]

Hi Joey,

On Wednesday 20 January 2010 05:40:11 Joey Korkames wrote:
> Does kexec-tools support bzip2-compressed bzImages? I'm trying the latest
> git master against this kernel....
> 
> http://packages.debian.org/sid/amd64/linux-image-2.6.32-trunk-amd64/downloa
> d
> 
> ...but am having no success. I'm assuming that it must be because the
> kernel-section is bzip2 compressed because gzip/lzma seems to be explicitly
> supported in the master branch's commits.

a bzImage, whether it is compressed using bzip2, lzma, whatever remains a 
bzImage and as such can be used without knowing the compression used.

> 
> xen2:~# kexec --load --type=bzImage
>  --initrd=/boot/debian/initrd.img-2.6.32-trunk-amd64
>  --command-line="root=/dev/mapper/mirror_dsksAB-OS_disk console=tty0"
>  /boot/debian/vmlinuz-2.6.32-trunk-amd64 kexec_load failed: Function not
>  implemented

The "Function not implemented" error appears when the kernel you are running 
this command does not support the kexec system call, recompile with support 
for it and you should be fine.

> entry       = 0x7fff5640 flags = 0
> nr_segments = 4
> segment[0].buf   = 0x1f77a30
> segment[0].bufsz = 3874
> segment[0].mem   = 0x3000
> segment[0].memsz = 4000
> segment[1].buf   = 0x7f28267dc810
> segment[1].bufsz = 239800
> segment[1].mem   = 0x1000000
> segment[1].memsz = 23a000
> segment[2].buf   = 0x7f2825f93010
> segment[2].bufsz = 8456ab
> segment[2].mem   = 0x7f7ae000
> segment[2].memsz = 846000
> segment[3].buf   = 0x1f6f910
> segment[3].bufsz = 80e0
> segment[3].mem   = 0x7fff5000
> segment[3].memsz = a000
> 
> please CC me in to any replies, I am not subscribed to the list.
> 
> Thanks for reading
> -joey
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
> 

-- 
Regards, Florian

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Re: bzip2-compressed bzimage support?

[Joey Korkames]

Gotcha, kexec resuses the bzImage's decompression stub. Now I have another 
reason to dislike the Debian.org kernels. I didn't know the 
_destination_ kernel had to have the config option as well.

Thanks!
-joey


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Re: bzip2-compressed bzimage support?

[Joey Korkames]

Perhaps I spoke too soon:

xen2:~# grep -rn KEXEC /boot/debian/config-2.6.32-trunk-amd64 
378:CONFIG_KEXEC=y
380:# CONFIG_KEXEC_JUMP is not set

I figure that there should be an ELF hint indicating if a kernel is 
kexec-able so that kexec-tools can emit a specific (and useful) error 
message if given an unsuitable kernel. But this doesn't appear to be an 
unsuitable kernel based on the .config.

And just for good measure, it also appears to be a plain gzip bzImage.

xen2:~# grep -rn -E 'BZIP|GZIP|LZMA' /boot/debian/config-2.6.32-trunk-amd64 
68:CONFIG_HAVE_KERNEL_GZIP=y
69:CONFIG_HAVE_KERNEL_BZIP2=y
70:CONFIG_HAVE_KERNEL_LZMA=y
71:CONFIG_KERNEL_GZIP=y
72:# CONFIG_KERNEL_BZIP2 is not set
73:# CONFIG_KERNEL_LZMA is not set
125:CONFIG_RD_GZIP=y
126:CONFIG_RD_BZIP2=y
127:CONFIG_RD_LZMA=y
4682:CONFIG_DECOMPRESS_GZIP=y
4683:CONFIG_DECOMPRESS_BZIP2=y
4684:CONFIG_DECOMPRESS_LZMA=y

Now, if it doesn't matter how the bzImage is compressed, then what are the 
recent lzma commits to kexec-tools.git for?

Thanks for reading
Joey

Joey Korkames writes:

> Gotcha, kexec resuses the bzImage's decompression stub. Now I have another 
> reason to dislike the Debian.org kernels. I didn't know the 
> _destination_ kernel had to have the config option as well.
> 
> Thanks!
> -joey
> 

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Re: bzip2-compressed bzimage support?

[Eric W. Biederman]

Joey Korkames <joey@kidfixit.com> writes:

> Gotcha, kexec resuses the bzImage's decompression stub. Now I have another
> reason to dislike the Debian.org kernels. I didn't know the _destination_ kernel
> had to have the config option as well.

The _destination_ kernel doesn't need the config option.

Eric

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Re: bzip2-compressed bzimage support?

[Eric W. Biederman]

Joey Korkames <joey+lists@kidfixit.com> writes:


> Now, if it doesn't matter how the bzImage is compressed, then what are the
> recent lzma commits to kexec-tools.git for?

For arches other than x86 where the tradition is to put the decompressor
in the bootloader, instead of making the kernel a self extracting executable.

Eric

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