2b5bf115ae
Juniper's loader is that Juniper's loader maps all of the kernel and
preloaded modules at the right virtual address before jumping into the
kernel. FreeBSD's loader simply maps 16MB using the physical address
and expects the kernel to jump through hoops to relocate itself to
it's virtual address. The problem with the FreeBSD loader's approach is
that it typically maps too much or too little. There's no harm if it's
too much (other than wasting space), but if it's too little then the
kernel will simply not boot, because the first thing the kernel needs
is the bootinfo structure, which is never mapped in that case. The page
fault that early is fatal.
The changes constitute:
1. Do not remap the kernel in locore.S. We're mapped where we need to
be so we can pretty much call into C code after setting up the
stack.
2. With kernload and kernload_ap not set in locore.S, we need to set
them in pmap.c: kernload gets defined when we preserve the TLB1.
Here we also determine the size of the kernel mapped. kernload_ap
is set first thing in the pmap_bootstrap() method.
3. Fix tlb1_map_region() and its use to properly externd the mapped
kernel size to include low-level data structures.
Approved by: re (blanket)
Obtained from: Juniper Networks, Inc
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