aws: Backport linear memory map change

[Philip Cox]

SRU Justification:

[Impact]

AWS discovered an issue of long EC2 instance launch times on the upcoming R8g instance types.

[Fix]

They have identified the following fixes that address this issue:

* https://<email address hidden><email address hidden>/
* https://<email address hidden><email address hidden>/

They would like this fixced in the jammy, and noble kernels.

For reference, here are the links to the above patches in 6.10-rc3:

* arm64: mm: Don't remap pgtables per-cont(pte|pmd) block
https://github.com/torvalds/linux/commit/5c63db59c5f89925add57642be4f789d0d671ccd
* arm64: mm: Batch dsb and isb when populating pgtables
https://github.com/torvalds/linux/commit/1fcb7cea8a5f7747e02230f816c2c80b060d9517

AWS has requested only the first two patches of the series of three patches be back ported.

[Test Plan]
I have tested this, as has AWS.

[Where problems could occur]
With the reordering of tlb invalidation and memory barriers, there is some risk, but this chance for regressions on this change is fairly small as the scope is fairly narrow.

[Other info]
SF# 00387444

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-aws/5.15.0-1065.71 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-aws' to 'verification-done-jammy-linux-aws'. If the problem still exists, change the tag 'verification-needed-jammy-linux-aws' to 'verification-failed-jammy-linux-aws'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-aws/6.8.0-1011.12 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-aws' to 'verification-done-noble-linux-aws'. If the problem still exists, change the tag 'verification-needed-noble-linux-aws' to 'verification-failed-noble-linux-aws'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!