Re: [RFC PATCH v1 04/25] unwind_user: Flexible FP/RA recovery rules

To enable support for SFrame V3 flexible FDEs with a subsequent patch,
add support for the following flexible frame pointer (FP) and return
address (RA) recovery rules:

  FP/RA = *(CFA + offset)
  FP/RA = register + offset
  FP/RA = *(register + offset)

Note that FP/RA recovery rules that use arbitrary register contents are
only valid when in the topmost frame, as their contents are otherwise
unknown.

This also enables unwinding of user space for architectures, such as
s390, that may save the frame pointer (FP) and/or return address (RA) in
other registers, for instance when in a leaf function.

Reviewed-by: Indu Bhagat <redacted>
Signed-off-by: Jens Remus <redacted>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260818144954.2320378-1-jremus@linux.ibm.com?part=4