Re: early_printk accessing __log_buf

From: Mike Frysinger
Date: Wed Jul 18 2007 - 19:53:21 EST


On 7/18/07, Robin Getz <rgetz@xxxxxxxxxxxxxxxxxxxx> wrote:
On Wed 18 Jul 2007 18:16, Andrew Morton pondered:
> I'd suggest that any interface into here should be via function calls,
> not via direct access to printk internals: think up some nice
> copy_me_some_of_the_log_buffer() interface.

If so - I would still like to put it in:
- ifdef CONFIG_EARLY_PRINTK
- and define as __init

so that people don't use it when they shouldn't (when the kernel is up an
running).

Something simple like - early_copy_log_buff(void *dest, size_t n)

copies n bytes from log_buf to memory area dest. Returns number of bytes that
could not be copied. Can find out how many bytes are in the log_buff by
calling with zero size.

This is not destructive to existing interfaces (log_start and con_start are
not updated/used). This should ensure that if booting does work - that normal
messages come out the standard method.

Any other suggestions?

maybe something as cheesy as early_get_log_buf() ? that way you dont
have to do any buffer management, you can just operate read-only on
the string ...
-mike
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