Initialize dump_avail on RISC-V

[mhorne063_gmail.com]

Summary

The dump_avail[] array contains a set of physical memory ranges which are used to indicate valid physical addresses for kernel memory dumps.

Initialize this alongside phys_avail[] while bootstrapping pmap.

[markj]

sys/riscv/riscv/pmap.c

599 ↗

(On Diff #53798)

Is there a reason dump_avail[] can't just contain the same ranges as physmap[]?

[mhorne063_gmail.com]

sys/riscv/riscv/pmap.c

599 ↗

(On Diff #53798)

On x86 architectures where they actually test the memory, there could be small holes introduced to phys_avail[] and dump_avail[] that are not included in physmap[]. However, since we don't currently do this and would likely have to restructure this code anyway to support that feature, I don't see any issue with using physmap[] if it seems preferable to you.

[markj]

sys/riscv/riscv/pmap.c

599 ↗

(On Diff #53798)

Right, and here the only divergence between phys_avail[] and physmap[] is the physical memory occupied by the kernel image and preloaded files, so I think you might as well just have dump_avail[] be a copy of physmap[] for now.

[mhorne063_gmail.com]

Update to simply mirror physmap[].

[mhorne063_gmail.com]

sys/riscv/riscv/pmap.c

599 ↗

(On Diff #53798)

Thanks Mark, the patch is much cleaner now :)

[markj]

sys/riscv/riscv/pmap.c

636 ↗

(On Diff #54591)

I think the assignments to dump_avail[] should logically come after the start == end check.

[mhorne063_gmail.com]

Address markj's comment.