Set the LMA of the riscv kernel to the OpenSBI jump target by default
This allows us to boot FreeBSD RISCV on QEMU using the -kernel command line
options. When using that option, QEMU maps the kernel ELF file to the
addresses specified in the LMAs in the program headers.
Since version 4.2 QEMU ships with OpenSBI fw_jump by default so this allows
booting FreeBSD using the following command line:
qemu-system-riscv64 -bios default -kernel /.../boot/kernel/kernel -nographic -M virt
Without this change the -kernel option cannot be used since the LMAs start
at address zero and QEMU already maps a ROM to these low physical addresses.
For targets that require a different kernel LMA the make variable
KERNEL_LMA can be overwritten in the config file. For example, adding
`makeoptions KERNEL_LMA=0xc0200000` will create an ELF file that will be
loaded at 0xc0200000.
Before:
There are 4 program headers, starting at offset 64