[coreboot] Solution to: filo build failure: get_multiboot_info is undefined

Stefan Reinauer stepan at coresystems.de
Tue Sep 29 01:21:47 CEST 2009

Myles Watson wrote:
> On Sat, Sep 26, 2009 at 11:22 AM, Peter Stuge <peter at stuge.se> wrote:
>> Peter Stuge wrote:
>>>         /* Get the information from the multiboot tables,
>>>          * if they exist */
>>>         get_multiboot_info(&lib_sysinfo);
>>> #endif
>>> Can anyone say why this wouldn't work properly?
> Shouldn't it be #if CONFIG_MULTIBOOT instead of #ifdef?
It should in coreboot, but not in libpayload or filo, afaict. We changed
the default behavior in coreboot explicitly because there was so much
code that assumed that behavior, and we didn't want to create an awful
lot of blind breakage or difference between Config.lb and Kconfig

>> --8<-- Config.in:
>> config MULTIBOOT
>>        bool "Multiboot header support"
>> -->8--
>> configs/defconfig:# CONFIG_MULTIBOOT is not set
>> Should a bool ever be unset?
Well, we're using Kconfig, and that's how Kconfig handles it... Maybe
that question is better answered by the Kconfig folks.

I think their idea was to have a positive for #if CONFIG_MULTIBOOT and
#ifdef CONFIG_MULTIBOOT if CONFIG_MULTIBOOT was true, and a negative for
both when it's false. Not many other ways to get that behavior

> My understanding is that CONFIG_MULTIBOOT = n when you see that
> message.  If it isn't defined at all it doesn't appear in the config
> file.
That's what I think too.


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