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Ensure that CONTEXT_XStateFeaturesMask is explicitly zeroed out on RtlCaptureContext #84012

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Merged
tannergooding merged 1 commit into from
Mar 28, 2023
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Ensure that CONTEXT_XStateFeaturesMask is explicitly zeroed out on RtlCaptureContext #84012

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1 change: 1 addition & 0 deletions src/coreclr/pal/src/arch/amd64/context2.S
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,7 @@ LEAF_END CONTEXT_CaptureContext, _TEXT

LEAF_ENTRY RtlCaptureContext, _TEXT
mov DWORD PTR [rdi + CONTEXT_ContextFlags], (CONTEXT_AMD64 | CONTEXT_FULL | CONTEXT_SEGMENTS)
mov QWORD PTR [rdi + CONTEXT_XStateFeaturesMask], 0
jmp C_FUNC(CONTEXT_CaptureContext)
LEAF_END RtlCaptureContext, _TEXT
Comment on lines 82 to 86
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@tannergooding tannergooding Mar 28, 2023

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Just something else to note...

It seems that CONTEXT_CaptureContext doesn't currently and, as far as I can tell, has never captured the YMM state. Is this expected? Should it be capturing that state as part of the thread suspend/restore logic here?

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@tannergooding tannergooding Mar 28, 2023

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Will address this question separately once I hear back from @janvorli

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@janvorli janvorli Mar 28, 2023

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@tannergooding the CONTEXT_CaptureContext is used only by the debugger code on Unix. It is not used for thread suspension. I am not sure if debugger stuff cares about the YMM registers or not.


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