Re: [Qemu-devel] [SeaBIOS] Boot failure with MS-Dos 6.22 (due to bad BIOS build?)

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2012-02-27 17:00, Peter Stuge wrote:
> Jan Kiszka wrote:
>>> Then I noticed, that if I rebuild the BIOS, from the exact same revision
>>> 1.6.3.1 revision that is committed in 'seabios' submodule in QEMU, then
>>> it works fine. So AFAICT, it is not the Seabios source code at fault,
>>> but rather the binary build we have commited to GIT. Should/can we rebuild
>>> the bios.bin in GIT ?
>>
>> Probably not without understanding what causes this strange
>> inconsistency. If Seabios builds without errors and then later on fails,
>> this is also a bug.
>>
>> Kevin, what information do you need to assess my tool chain?
> 
> In the coreboot project we have more than 10 years of experience from
> distribution toolchains consistently being too broken to build a
> working coreboot image. The same problems apply to SeaBIOS.
> 
> As you know, distribution toolchains are heavily patched, presumably
> to add some value to the distribution. The patches work fine when the
> toolchains should output userland binaries or the odd kernel. They
> fail frequently and in countless ways when used to produce bare metal
> binaries.
> 
> Within coreboot it is much less effort to build an i386-elf cross
> toolchain than to mess with the hundreds if not thousands of issues
> in the distribution toolchains. The same applies to SeaBIOS of
> course. The script we use in coreboot is here:
> 
> http://review.coreboot.org/gitweb?p=coreboot.git;a=tree;f=util/crossgcc
> 
> If you want to investigate and spend time on motivating distributions
> to unbreak their toolchains that's awesome, but be prepared to spend
> many weeks disassembling binaries and reverse engineering the toolchain.

Well, the Linux kernel can also be built with practically any distro out
there. Having a need for a separate toolchain for building x86 on x86 is
a bit overkill IMHO, at least for someone hacking on Seabios only
infrequently like /me.

Jan

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