Move PLTs to the beginning of amd64 kmods.

[markj]

Summary

As with .text, the idea is to ensure that executable sections are
segregated from the rest. For some reason, firmware modules end up with
a 16-byte PLT. This wasn't the case before LLVM 11 I believe.

[kib]

Can you show output from readelf -a for that files ? It is very strange to see plt in the result of incremental linking.

[markj]

In D26444#588245, @kib wrote:

Can you show output from readelf -a for that files ? It is very strange to see plt in the result of incremental linking.

Sure: https://reviews.freebsd.org/P424

This was linked with the patch applied.

[kib]

Hm, I see the same .plt section on stable/12 with clang 10.0.1 as well.

There are two PLT32 relocs, but creating plt for them is not the duty of ld -r. Anyway.

[markj]

In D26444#588281, @kib wrote:

Hm, I see the same .plt section on stable/12 with clang 10.0.1 as well.

Huh, I don't remember seeing this. Maybe I last checked when llvm was at version 9.

There are two PLT32 relocs, but creating plt for them is not the duty of ld -r. Anyway.

Indeed. In regular modules there are many PLT32 relocs but no .plt, and I don't see any differences in cc/ld flags.