ck_pr/aarch64: Specify output operands for ck_pr_md_store_* #215
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As in commit 2f9acab, we want to specify output operand widths so that MSAN compiler instrumentation correctly updates the shadow map. In particular, LLVM's implementation depends on having type information for output operands, even when that's not otherwise necessary. Without it, KMSAN in FreeBSD generates false positives on aarch64.
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Hello, is there any interest in taking this PR? It's useful when CK is used with code instrumented by MSAN and is low-risk otherwise. |
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Hi @markjdb, sorry about that, I just forgot, it is now merged, thank you! |
Thank you! Can I simply cherry-pick this into FreeBSD? |
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Yes, please do |
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@cognet I'm very sorry, I just realized that this commit doesn't exactly match the one I'm using in FreeBSD. It's not right. Could you please revert, and I'll submit the updated patch? I'm sorry again. |
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@markjdb done! |
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Thanks. I failed to adjust the indexes of the operands in the actual assembly. Now that there's an output operand, %0 becomes %1, %1 becomes %2. I'm running the test suite on an arm64 board now just to confirm that I didn't miss something else. |
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Oh of course, I wonder how I missed that |
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I resubmitted the corrected and properly tested patch in #216. |
This is required to enable KMSAN for aarch64 on FreeBSD. It will likely also be useful for userspace code which makes use of CK and is compiled with MSAN enabled.