kexec-tools: detect page_offset dynamically

ARM kernel can be compiled with CONFIG_VMSPLIT_1G, CONFIG_VMSPLIT_2G or
CONFIG_VMSPLIT_3G. This patch dynamically detects PAGE_OFFSET according
to _stext symbol from /proc/kallsyms.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
kexec-tools: add --page-offset option for ARM

When KALLSYMS is disabled or /proc is not mounted, this patch allows
--page-offset cmdline option for user to setup correct page_offset.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
kdump: pass acpi_rsdp to 2nd kernel if kernel does not export efi runtime maps

If kernel does not export efi runtime maps it means 1:1 mapping does not
work or user explictly boot with efi=old_map. In this case efi setup code
will failback to noefi boot, but for kdump case we still need pass extra
acpi_rsdp cmdline.

Thus adding a check in kdump path.

Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Simon Horman <horms@verge.net.au>