x86: Pass memory range via E820 for kdump

command line size is restricted by kernel, sometimes memmap=exactmap has
too many memory ranges to pass to cmdline. And also memmap=exactmap and
kASLR doesn't work together.

A better approach, to pass the memory ranges for crash kernel to boot
into, is filling the memory ranges into E820.

boot_params only got 128 slots for E820 map to fit in, when the number of
memory map exceeds 128, use setup_data to pass the rest as extended E820
memory map.

kexec boot could also benefit from setup_data in case E820 memory map
exceeds 128.

Now this new approach becomes default instead of memmap=exactmap.
saved_max_pfn users can specify --pass-memmap-cmdline to use the
exactmap approach.

Signed-off-by: WANG Chao <chaowang@redhat.com>
Tested-by: Linn Crosetto <linn@hp.com>
Reviewed-by: Linn Crosetto <linn@hp.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

0 files changed, 0 insertions, 0 deletions