runtime: start ARM atomic kernel helper traceback in caller
Like the VDSO, we cannot directly traceback from the Linux kernel ARM
atomic/barrier helpers. However, unlike the VDSO, this functions are
extremely simple. Neither of the functions we use, kuser_cmpxchg and
kuser_memory_barrier, touch SP or LR.
We can use this to our advantage to read LR and simply start tracebacks
in the caller.
Fixes #49182
Change-Id: I890edbeb7c128938000fe7baf6f913c02a956edd
Reviewed-on: https://go-review.googlesource.com/c/go/+/362977
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>