Re: 2.6.19-git13: uts banner changes break SLES9 (at least)

Re: 2.6.19-git13: uts banner changes break SLES9 (at least)

[Paul Mackerras]

Linus Torvalds writes:

> On Mon, 11 Dec 2006, Olaf Hering wrote:
> > 
> > arch/powerpc/boot/wrapper:156:    version=`${CROSS}strings "$kernel" | grep '^Linux version [-0-9.]' | \
> 
> This is also obviously broken (and really sad), but actually ends up being 
> better than what get_kernel_version apparently does, by at least adding 
> the requirement that the string "Linux version" be slightly more correct.
> 
> However, it's also TOTALLY BROKEN. 

It's the minimum effort for the barely acceptable outcome. :)

The wrapper script, although it currently lives in arch/powerpc/boot,
is designed and intended to be standalone, so that people can use it
outside the kernel tree, and possibly even without having the kernel
source easily to hand.  Therefore I didn't want to use any kernel
header files.

Apparently the only reason "mkimage" wants to know the kernel version
is to put it as a comment in the image, which can be displayed to the
user when booting with u-boot (the bootloader used on some embedded
platforms).  So it's not critical if the grep fails, and it's slightly
more useful to do the grep than it would be to not even try to provide
any version string to mkimage.

If there is a reliable way to get the version string, great, I'll use
that.

Paul.

Re: 2.6.19-git13: uts banner changes break SLES9 (at least)

[David Miller]

From: Paul Mackerras <paulus@samba.org>
Date: Tue, 12 Dec 2006 09:04:41 +1100

> If there is a reliable way to get the version string, great, I'll use
> that.

FWIW, on sparc and sparc64 we have this information block for
the boot loader.

The first two instructions at the entry point simply branch
over the boot loader information block header.

The information block starts with a known magic string "HdrS" which
does not match any valid Sparc instruction.  Any tool can search for
it starting at the symbol "_start" in the kernel image.

Inside this information block we stick a 32-bit word which contains
LINUX_VERSION_CODE.

That only gives you the version, not the whole version string, but you
could put the whole string in such a location when adding such a
facility to powerpc if you wanted to.

Re: 2.6.19-git13: uts banner changes break SLES9 (at least)

[Gerd Hoffmann]

  Hi,

> That only gives you the version, not the whole version string, but you
> could put the whole string in such a location when adding such a
> facility to powerpc if you wanted to.

Hmm, as we have those fancy ELFNOTE macros now, can't we just the
version string into one?

cheers,

  Gerd

-- 
Gerd Hoffmann <kraxel@suse.de>