c18n: Save caller's stack pointer in trusted frame #2061
Merged
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Previously, the caller's stack pointer is only saved at the bottom of the caller's stack during domain transition. This means that the act of unwinding a trusted frame relies on external state, namely the value at the bottom of the caller's stack.
We now also save the caller's stack pointer in the trusted frame so that unwinding can be stateless, i.e., inspecting the content of the trusted frame alone is sufficient for restoring the stack pointer of the caller.