Re: [PATCH] x86,setup: add serial_console_port_base in boot_params

[ebiederm@xmission.com (Eric W. Biederman)]

Yinghai Lu <yinghai@kernel.org> writes:

> On 07/31/2010 07:42 PM, Eric W. Biederman wrote:
>> Yinghai Lu <yinghai@kernel.org> writes:
>> 
>>> On 07/31/2010 02:02 PM, H. Peter Anvin wrote:
>>>> On 07/31/2010 11:32 AM, Cyrill Gorcunov wrote:
>>>>>>
>>>>>> No, this is the internal part of the boot protocol, so it's not an issue.
>>>>>>
>>>>>
>>>>> Peter, I didn't mean any issue here, I meant that bootloaders don't know about
>>>>> this field yet and they will have to update own sources to pass port value
>>>>> at proper place of boot params. Or I miss something?
>>>>>
>>>>
>>>> Boot loaders that use the 16-bit entry point are unaffected.
>>>>
>>>> Boot loaders which use the 32-bit entry point but properly clears the
>>>> zero page simply will not have the feature.
>>>>
>>>> Boot loaders which use the 32-bit entry point but doesn't clear the zero
>>>> page are broken.
>>>>
>>> can you if this one is right for kexec path?
>> 
>> I am walking out the door, but this seems like nonsense to me.
>> 
>> Further I don't see why we would add something to the zero page
>> when we have a perfectly good way to pass this information via
>> the kernel command line.  strstr and strtoul are trivial little
>> functions so I don't see why anything would need to parse anything
>> other than console= or early_printk=.  The difference in code size
>> is negligible.
>> 
> so you prefer to check command line for console info in arch/x86/boot/compressed/misc.c again?
>
> that commandline is analyzed in arch/x86/boot/tty.c already.

Instead of changing 2 or 3 bootloaders, waiting years for the change
to propagate, and then trying to change users habits.

I definitely do.

Eric