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Fix makecontext() on MIPS O32.
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Authored by jhb on Feb 2 2018, 10:51 PM.
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Details

Summary

The GP register can be clobbered by the callback, so save it in S1 while
invoking the callback function.

Test Plan
  • the various makecontext tests now pass on o32 instead of core dumping when trying to call ctx_done due to a trashed GP.

Diff Detail

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Build Status
Buildable 14751
Build 14872: arc lint + arc unit

Event Timeline

I take full blame, and acknowledge spending too much time in code with -G0, and thus being somewhat lazy about gp's treatment.

I'd say that because there are a bunch of different ABI semantics here, the comment could be modified to be more explicit about s1 being callee-saved in o32, while gp is callee-saved in n32 and n64, or something.

Thank you! It's good as-is, or with a comment which is more explicit about register saving responsibility.

This revision is now accepted and ready to land.Feb 3 2018, 1:11 AM
This revision was automatically updated to reflect the committed changes.