Support same log buffer or tracing buffer in both bootloader and kernel

; Summary: Support same log buffer or tracing buffer in both bootloader and 
; Proposer: Tim Bird - Sony Network Entertainment

== Description ==
It would be nice to share log buffer or trace buffers between the bootloader 
and the kernel,
so that either log messages or trace events (respectively) could be coalesced 
from both sources in a
unified view.

This work might be related to work involving using fixed memory locations for 
buffers.  This is done implicitly by Android's RAM-console feature, and by 
Alternatively, if performance is not an issue, the kernel could copy messages
from the bootloader log buffer into the kernel log buffer at startup.

It appears that U-boot uses a log-buffer format similar to the Linux kernel.

Note that this is useful for on-box analysis (using 'dmesg' locally, and 
getting both
bootloader and kernel messages).  It  is obvious that someone with a serial 
can see both sets of text messages coalesced, and could use a tool like to get timing information for the text messages.
(Although, due to delays in setting up the kernel console device, the timings
are inaccurate for a portion of the bootup.)

Handling trace events in a coalesced fashion is a whole other issue.

== Related work ==
* In 2009 there was a proposal to add an "alternative log buffer" for printk 
** See
* Does u-boot support any tracing code similar to ftrace?

== Scope ==

== Contractor Candidates ==
No one so far.

== Comments ==

[[Category:Project proposals 2012]]

Celinux-dev mailing list

Reply via email to