tree 5def2c91f78186e944c23ba1d1b3e0741382b180
parent d297366ba692faf1f0384811a6ff0b20c3470b1b
author H. Peter Anvin <hpa@zytor.com> 1242083536 -0700
committer H. Peter Anvin <hpa@zytor.com> 1242089105 -0700

x86: default CONFIG_PHYSICAL_START and CONFIG_PHYSICAL_ALIGN to 16 MB

Default CONFIG_PHYSICAL_START and CONFIG_PHYSICAL_ALIGN each to 16 MB,
so that both non-relocatable and relocatable kernels are loaded at
16 MB by a non-relocating bootloader.  This is somewhat hacky, but it
appears to be the only way to do this that does not break some some
set of existing bootloaders.

We want to avoid the bottom 16 MB because of large page breakup,
memory holes, and ZONE_DMA.  Embedded systems may need to reduce this,
or update their bootloaders to be aware of the new min_alignment field.

[ Impact: performance improvement, avoids problems on some systems ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>