On 3/22/2023 1:14 PM, tip-bot2 for Chang S. Bae wrote:
The following commit has been merged into the x86/fpu branch of tip: x86/arch_prctl: Add AMX feature numbers as ABI constants Each distinct XSAVE feature has a number assigned to it. Among other things, the number determines the ordering of features in the XSAVE buffer and is also used to generate XSAVE bitmasks like the value for XCR0. AMX state is dynamically enabled by the architecture-specific prctl(). This prctl() takes one XSAVE feature number as an argument. However, the feature numbers are not defined in any readily available userspace headers. The means that each userspace app trying to use dynamic feature prctl()s will likely end up defining their own constants for each feature. Since these feature numbers are a part of the uabi, expose them in the prctl() uabi header. Save everyone the trouble of looking them up and defining their own. [ dhansen: expand changelog a bit ]
Sorry, it looks like I was not diligent enough to explain what those numbers are and that they are now part of the ABI.
Thank you for the write-up. Chang
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