Add detection for various aarch64 CPU features already supported by LLVM and Linux.
This commit adds feature detection for the following features:
- FEAT_CSSC
- FEAT_ECV
- FEAT_FAMINMAX
- FEAT_FLAGM2
- FEAT_FP8
- FEAT_FP8DOT2
- FEAT_FP8DOT4
- FEAT_FP8FMA
- FEAT_HBC
- FEAT_LSE128
- FEAT_LUT
- FEAT_MOPS
- FEAT_LRCPC3
- FEAT_SVE_B16B16
- FEAT_SVE2p1
- FEAT_WFxT
It also adds feature detection for FEAT_FPMR. It is somewhat of a
special case because FPMR only exists as a feature in LLVM 18, it has
been removed from the LLVM upstream. On that account the intention is
for it to be detectable at runtime through stdarch but not have a
corresponding compile-time Rust target feature.
Linux features: https://github.com/torvalds/linux/blob/master/arch/arm64/include/uapi/asm/hwcap.h
LLVM features: llvm-project/llvm/lib/Target/AArch64/AArch64.td
Expanded the cache size to 93 (we will need this in near future)
Fixed detection of VAES, GFNI and VPCLMULQDQ
Could not test with `cupid` because they do not support these yet
LLVM's `ssbs` and `mte` target_features represent two Arm features.
Linux's HWCAP also represents the same two features, so this is just a
documentation update.
LLVM's `ras` target_feature represents two Arm features - FEAT_RAS and FEAT_RASv1p1. There is no runtime detection for this, so this is a no-op in stdarch.
LLVM's `aes` feature covers both `FEAT_AES` and `FEAT_PMULL`, but Linux
exposes seperate feature bits. This patch makes the `aes` target_feature
correctly shortcut runtime `pmull` detection and also makes the `aes`
feature check for `pmull` at runtime to bring it in line with the
target_feature behaviour. In practice I think this makes the two runtime
features identical since the ID_AA64ISAR0_EL1 register does not allow
for PMULL without AES.
It hasn't been used since roughly 2018. The latest published version of
auxv has a less common license and doesn't specify any license in it's
Cargo.toml file.
Samsung Exynos 9810 has a bug that big and little cores have different
ISAs. And on older Android (pre-9), the kernel incorrectly reports
that features available only on some cores are available on all cores.
https://reviews.llvm.org/D114523
