s390x: z17 target feature detection #1832
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folkertdev
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| /// These values are part of the platform-specific [asm/elf.h][kernel], and are a selection of the | ||
| /// fields found in the [Facility Indications]. | ||
| /// | ||
| /// [Facility Indications]: https://www.ibm.com/support/pages/sites/default/files/2021-05/SA22-7871-10.pdf#page=63 |
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Where did you get the information about the facility bits that will be added in z17? (It is not included in the documentation at this link.)
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I can confirm that the z17 facility bit values are correct. The new version of the Principles of Operation including z17 features will be released shortly after the general availability of the new machine (which is next week).
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| enable_if_set(133, Feature::guarded_storage); | ||
| enable_if_set(150, Feature::enhanced_sort); | ||
| enable_if_set(151, Feature::deflate_conversion); | ||
| // added in z17 |
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Do we need this comment? If so, should we add this information also for the vector-related facilities, and also specific machine information for pre-z17 machines?
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nah, this list doesn't really have structure to it, but it should be OK given the official docs.
| enable_if_set(151, Feature::deflate_conversion); | ||
| // added in z17 | ||
| enable_if_set(84, Feature::miscellaneous_extensions_4); | ||
| enable_if_set(86, Feature::message_security_assist_extension12); |
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We should really include all currently defined features here. What I see missing is the older variants of miscellaneous_extensions and messact_security_assist_extension. These all have defined facility bits.
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We can only add features here when they are also recognized by the compiler. I'll add them there, but that does not need to block this PR I think
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ah, I forgot that we did already add these to the compiler. Now they're in this PR too.
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tracking issue: rust-lang/rust#130869
I didn't add feature detection yet in #1826.
The implementation follows the information in rust-lang/rust#135413 (comment), in particular that
HWCAPis used to check for thevectorfeature because it needs kernel support, andstfleis used for the other features because they only need hardware support.cc @uweigand @taiki-e