Merge branch 'bpf-verifier-range-computation-improvements'

Cupertino Miranda says:

====================
bpf/verifier: range computation improvements

Hi everyone,

This is what I hope to be the last version. :)

Regards,
Cupertino

Changes from v1:
 - Reordered patches in the series.
 - Fix refactor to be acurate with original code.
 - Fixed other mentioned small problems.

Changes from v2:
 - Added a patch to replace mark_reg_unknowon for __mark_reg_unknown in
   the context of range computation.
 - Reverted implementation of refactor to v1 which used a simpler
   boolean return value in check function.
 - Further relaxed MUL to allow it to still compute a range when neither
   of its registers is a known value.
 - Simplified tests based on Eduards example.
 - Added messages in selftest commits.

Changes from v3:
 - Improved commit message of patch nr 1.
 - Coding style fixes.
 - Improve XOR and OR tests.
 - Made function calls to pass struct bpf_reg_state pointer instead.
 - Improved final code as a last patch.

Changes from v4:
 - Merged patch nr 7 in 2.

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Link: https://lore.kernel.org/r/20240506141849.185293-1-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>