Re: [PATCH] 2.6.4-rc1 fix x86 early_printk and make it early

[Andi Kleen]

On 29 Feb 2004 22:24:12 -0700
ebiederm@xxxxxxxxxxxx (Eric W. Biederman) wrote:

>   o That is problematic with PAE support, because there is a moment
>     during paging_init() when the physical identity mappings do not
>     work. 

Just don't printk in that moment then.

>   o Using raw physical addresses is in bad form, and doesn't always work.

On x86-64 it's that __pa() doesn't always work very early.

>   o I can't possibly see how Andrew's Changelog that using __pa
>     is more friendly to the 4G/4G split is correct.  Unless someone
>     was hard coding a virtual address previously.

Yes, it shouldn't make any difference for 4/4.

> The second hunk in early_printk.c redefines VGABASE as __va(0xb8000).
> This is correct on both x86 and x86-64 so we don't need any more
> special cases.  

Please don't do that on x86-64. On x86-64 there are two ways to reach this
address and the previous one is available earlier.  Keep the current
address for x86-64 please.

-Andi
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