zstd: Disable intrinsics #17904
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zstd: Disable intrinsics #17904
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behlendorf
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Type: Architecture
robn
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Nov 6, 2025
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This looks much better. I'm just getting my hinky little rpi4 back on, and then I can at least say whether or not it "works" before/after. It doesn't have NEON though so its only half a test, but better than nothing. |
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Builds ok on 6.12.47 aarch64, and select parts of the test suite continue to run (most importantly, compression). So at least not worse I think. Good job!
mcmilk
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Nov 6, 2025
Disable the aarch64 NEON SIMD intrinsics for kernel builds. Safely using them in the kernel context requires saving/restoring the FPU registers which is not currently done. Additionally, remove the aarch64 optimized PREFETCH_L1 and PREFETCH_L2 instruction. Rely on the more portable compiler built ins. This lets us remove the problematic workaround in the aarch64_compat.h header which undefines the __aarch64__ macro. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
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Out of an abundance of caution I updated the patch to remove the aarch64 assembly for L1 and L2 prefetching. The generic |
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Status: Accepted
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Motivation and Context
#17852
Description
Disable the aarch64 NEON SIMD intrinsics for kernel builds. Safely using them in the kernel context requires saving/restoring the FPU registers which is not currently done.
This lets us remove the problematic workaround in the aarch64_compat.h header which undefines the aarch64 macro.
How Has This Been Tested?
Basic compilation will be tested by the CI, but unfortunately we don't yet have an aarch64 target. Help testing this on an aarch64 system would be appreciated.
Types of changes
Checklist:
Signed-off-by.