This patch redesigns the interface between the generic memconsole driver
and its implementations to become more flexible than a flat memory
buffer with unchanging bounds. This allows memconsoles like coreboot's
to include lines that were added by runtime firmware after the driver
was initialized. Since the console log size is thus no longer static,
this means that the /sys/firmware/log file has to become unseekable.
Signed-off-by: NJulius Werner <jwerner@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch splits memconsole.c in 2 parts. One containing the
architecture-independent part and the other one containing the EBDA
specific part. This prepares the integration of coreboot support for the
memconsole.

The memconsole driver is now named as memconsole-x86-legacy.
Signed-off-by: NThierry Escande <thierry.escande@collabora.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The google memconsole driver is currently broken upstream, as it tries
to read memory that is described as reserved in /proc/iomem, by
dereferencing a pointer obtained through phys_to_virt(). This triggers
a kernel fault as such regions are unmapped after early boot.

The proper workaround is to use ioremap_cache() / iounmap() around such
accesses.

As some unrelated changes, I also converted some printks to use pr_info()
and added some missing __init annotations.

Tested: booted dbg build, verified I could read /sys/firmware/log
Signed-off-by: NMichel Lespinasse <walken@google.com>
Acked-by: NMike Waychison <mikew@google.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch introduces the 'memconsole' driver.

Our firmware gives us access to an in-memory log of the firmware's
output.   This gives us visibility in a data-center of headless machines
as to what the firmware is doing.

The memory console is found by the driver by finding a header block in
the EBDA.  The buffer is then copied out, and is exported to userland in
the file /sys/firmware/log.
Signed-off-by: NSan Mehat <san@google.com>
Signed-off-by: NMike Waychison <mikew@google.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>