RFR: 8361536: [s390x] Saving return_pc at wrong offset

[Martin Doerr]

On Wed, 9 Jul 2025 05:24:38 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

> Fixes the bug where return pc was stored at a wrong offset, which causes issue with java abi. 
> 
> Issue appeared in #26004, see the comment: https://github.com/openjdk/jdk/pull/26004#issuecomment-3017928879.

We're not really saving space. We just use less of the caller allocated stack space which is still as large as before.
But the change looks good and should make the stack walking code happy, because it can find the return_pc where it is expected, now.

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Marked as reviewed by mdoerr (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/26209#pullrequestreview-3001829975