On Mon, 11 Jun 2012 08:13:08 +0200 Heiko Schocher <h...@denx.de> wrote:
> This merges support for the previously DENX-only kernel > feature of specifying an alternative, "external" buffer > for kernel printk messages and their associated metadata. > This patch is based on DENX-only kernel commit: > > commit 212f61c7fd3b952a81d1459dd32a86a32ddfd4ce > Author: Igor Lisitsin <i...@emcraft.com> > Date: Wed Apr 18 14:55:19 2007 +0400 > > Add support for external log buffer. > > Add support for external log buffer, for example passed by U-Boot, > which may already contain messages (from the boot loader and/or POST). > > Signed-off-by: Igor Lisitsin <i...@emcraft.com> > > see: > http://git.denx.de/?p=linux-denx.git;a=commit;h=212f61c7fd3b952a81d1459dd32a86a32ddfd4ce > > When this option is enabled, an architecture- or machine-specific log > buffer is used for all printk messages. This allows entities such as > boot loaders (e.g. U-Boot) to place printk-compatible messages into > this buffer and for the kernel to coalesce them with its normal > messages. This patch support this feature for arch/arm based > boards. Why was it done this way, rather than adding a hook to permit architectures to insert data into the head of the existing kernel buffer? The latter approach would be quite simple, wouldn't it? A single line added to printk.c which calls an arch function which locates the boot loader buffer and prints it, with printk. And this is more flexible - for example, there might be more than one external message stream which we wish to capture. _______________________________________________ Celinux-dev mailing list Celinux-dev@lists.celinuxforum.org https://lists.celinuxforum.org/mailman/listinfo/celinux-dev
