[PATCH] printk: Fix alignment of buf causing crash on ARM EABI

On 06/05/2012 12:52 AM, Andrew Lunn wrote:

Commit 7ff9554bb578ba02166071d2d487b7fc7d860d62, printk: convert
byte-buffer to variable-length record buffer, causes systems using
EABI to crash very early in the boot cycle. The first entry in struct
log is a u64, which for EABI must be 8 byte aligned.

Make use of __alignof__() so the compiler to decide the alignment, but
allow it to be overridden using CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
for systems which can perform unaligned access and want to save
a few bytes of space.

Tested on Orion5x and Kirkwood.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>

Tested-by: Stephen Warren <redacted>
Acked-by: Stephen Warren <redacted>

Indeed, using alignof is a good idea.