On Thu, 4 Feb 2021 13:37:43 +0530, Sandipan Das wrote:

The Power ISA says that the fixed-point load and update
instructions must neither use R0 for the base address (RA)
nor have the destination (RT) and the base address (RA) as
the same register. Similarly, for fixed-point stores and
floating-point loads and stores, the instruction is invalid
when R0 is used as the base address (RA).

[...]

Applied to powerpc/next.

[1/2] powerpc/sstep: Fix load-store and update emulation
      https://git.kernel.org/powerpc/c/bbda4b6c7d7c7f79da71f95c92a5d76be22c3efd
[2/2] powerpc/sstep: Fix darn emulation
      https://git.kernel.org/powerpc/c/22b89ba178dd0a66a26699ead014a3e73ff8e044

cheers