Remove extra lines at the start of MAkefiles

• Add an mtree entry
• Check the headder type
• Use a brk instruction to stop execution as a syscall may drop the SVE context

• Zero the set in pmap_fini_asids
• Add a missing tlbi

This is not complete, but would be useful to get feedback on the approach

Remove userret from EXCP_MOE. Was missed in a rebase.

Fix the initial value of skip_userret

Is there a reason to not just read the ID register in the vmm code?

Set a variable to check if we need to skip userret

I see, the issue is the generated ifunc trampolines only have BTI landing pads when the note is in all object files.

The change is correct. I think it is more likely that rebuilding the kernel with a consistent toolchain is the fix for the BTI exception.

How does it fix the Branch Target exception? The kernel doesn't care about the note, it's just there to ensure all source files are built with BTI enabled.

Should the dma sync operations be BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD and BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE given virtio may read from & write to the buffer.

Where is the thunderbolt device defined? I don't see it in main.

Should the alignment for the rx & tx DMA tags be VTNET_ETHER_ALIGN?

In D54959#1259073, @jrtc27 wrote:

virtio_blk calls bus_dma_tag_set_iommu on PowerPC; would that not be needed for these new tags?

Do we want to zero the CPU for PPIs & IPIs? I expect that check should be before the handlers == 0 check as they may be sent to all CPUs.