crypto/chacha20, crypto/poly1305: add MIPSLE assembly version

[stffabi]

Add assembly optimized versions for ChaCha20 and Poly1305 crypto algorithms for MIPSLE.

The algorithms have been ported from other ASM implementations, both of which are dual licensed under “GPL-2.0 OR MIT”

• https://github.com/torvalds/linux/blob/1b294a1f35616977caddaddf3e9d28e576a1adbc/arch/mips/crypto/chacha-core.S
• https://github.com/WireGuard/wireguard-monolithic-historical/blob/edad0d6e99e5133b1e8e865d727a25fff6399cb4/src/crypto/zinc/poly1305/poly1305-mips.S

The following are benchmarks done on a MT7688. It compares the base go implementation with the assembly version, once with a MIPS32r1 IS and once with MIPS32r2 IS.

goos: linux
goarch: mipsle
pkg: golang.org/x/crypto/chacha20
│ old.txt │ asm.txt │ asm-mips32r2.txt │
│ B/s │ B/s vs base │ B/s vs base │
ChaCha20/64 4.015Mi ± 1% 10.376Mi ± 1% +158.43% (p=0.000 n=10) 13.485Mi ± 2% +235.87% (p=0.000 n=10)
ChaCha20/256 4.473Mi ± 1% 12.846Mi ± 1% +187.21% (p=0.000 n=10) 18.859Mi ± 3% +321.64% (p=0.000 n=10)
ChaCha20/10x25 3.119Mi ± 1% 6.104Mi ± 2% +95.72% (p=0.000 n=10) 7.181Mi ± 3% +130.28% (p=0.000 n=10)
ChaCha20/4096 4.659Mi ± 4% 13.609Mi ± 4% +192.12% (p=0.000 n=10) 20.270Mi ± 5% +335.11% (p=0.000 n=10)
ChaCha20/100x40 4.020Mi ± 2% 9.918Mi ± 3% +146.74% (p=0.000 n=10) 13.433Mi ± 5% +234.16% (p=0.000 n=10)
ChaCha20/65536 4.301Mi ± 1% 9.727Mi ± 1% +126.16% (p=0.000 n=10) 12.393Mi ± 0% +188.14% (p=0.000 n=10)
ChaCha20/1000x65 4.187Mi ± 1% 10.076Mi ± 2% +140.66% (p=0.000 n=10) 13.032Mi ± 2% +211.28% (p=0.000 n=10)
geomean 4.082Mi 10.11Mi +147.56% 13.47Mi +229.90%

pkg: golang.org/x/crypto/internal/poly1305
│ old.txt │ asm.txt │ asm-mips32r2.txt │
│ B/s │ B/s vs base │ B/s vs base │
64 5.307Mi ± 0% 21.009Mi ± 0% +295.87% (p=0.000 n=10) 20.938Mi ± 0% +294.52% (p=0.000 n=10)
1K 6.566Mi ± 1% 66.676Mi ± 0% +915.47% (p=0.000 n=10) 66.042Mi ± 0% +905.81% (p=0.000 n=10)
2M 5.140Mi ± 1% 47.135Mi ± 0% +816.98% (p=0.000 n=10) 47.016Mi ± 0% +814.66% (p=0.000 n=10)
64Unaligned 5.322Mi ± 1% 21.024Mi ± 0% +295.07% (p=0.000 n=10) 20.871Mi ± 1% +292.20% (p=0.000 n=10)
1KUnaligned 6.561Mi ± 0% 66.614Mi ± 0% +915.26% (p=0.000 n=10) 66.333Mi ± 0% +910.97% (p=0.000 n=10)
2MUnaligned 5.140Mi ± 1% 47.197Mi ± 1% +818.18% (p=0.000 n=10) 47.126Mi ± 0% +816.79% (p=0.000 n=10)
Write64 6.599Mi ± 0% 57.268Mi ± 0% +767.77% (p=0.000 n=10) 57.368Mi ± 0% +769.29% (p=0.000 n=10)
Write1K 6.819Mi ± 0% 79.408Mi ± 0% +1064.55% (p=0.000 n=10) 79.246Mi ± 0% +1062.17% (p=0.000 n=10)
Write2M 5.140Mi ± 0% 47.169Mi ± 0% +817.63% (p=0.000 n=10) 47.116Mi ± 0% +816.60% (p=0.000 n=10)
Write64Unaligned 6.428Mi ± 3% 56.992Mi ± 1% +786.65% (p=0.000 n=10) 56.424Mi ± 1% +777.82% (p=0.000 n=10)
Write1KUnaligned 6.814Mi ± 2% 79.293Mi ± 0% +1063.68% (p=0.000 n=10) 79.513Mi ± 0% +1066.90% (p=0.000 n=10)
Write2MUnaligned 5.016Mi ± 2% 47.183Mi ± 1% +840.59% (p=0.000 n=10) 47.183Mi ± 0% +840.59% (p=0.000 n=10)
geomean 5.858Mi 49.17Mi +739.29% 49.02Mi +736.70%

pkg: golang.org/x/crypto/chacha20poly1305
│ old.txt │ asm.txt │ asm-mips32r2.txt │
│ B/s │ B/s vs base │ B/s vs base │
Chacha20Poly1305/Open-64 1.230Mi ± 4% 3.042Mi ± 1% +147.29% (p=0.000 n=10) 3.548Mi ± 2% +188.37% (p=0.000 n=10)
Chacha20Poly1305/Seal-64 1.144Mi ± 1% 3.462Mi ± 1% +202.50% (p=0.000 n=10) 3.810Mi ± 1% +232.92% (p=0.000 n=10)
Chacha20Poly1305/Open-64-X 908.2Ki ± 1% 1718.8Ki ± 2% +89.25% (p=0.000 n=10) 1840.8Ki ± 2% +102.69% (p=0.000 n=10)
Chacha20Poly1305/Seal-64-X 839.8Ki ± 1% 1894.5Ki ± 2% +125.58% (p=0.000 n=10) 2006.8Ki ± 2% +138.95% (p=0.000 n=10)
Chacha20Poly1305/Open-1024 2.594Mi ± 3% 9.975Mi ± 1% +284.56% (p=0.000 n=10) 13.208Mi ± 3% +409.19% (p=0.000 n=10)
Chacha20Poly1305/Seal-1024 2.551Mi ± 1% 10.600Mi ± 2% +315.51% (p=0.000 n=10) 14.353Mi ± 3% +462.62% (p=0.000 n=10)
Chacha20Poly1305/Open-1024-X 2.470Mi ± 0% 8.569Mi ± 0% +246.91% (p=0.000 n=10) 10.705Mi ± 2% +333.40% (p=0.000 n=10)
Chacha20Poly1305/Seal-1024-X 2.413Mi ± 1% 9.036Mi ± 1% +274.51% (p=0.000 n=10) 11.330Mi ± 1% +369.57% (p=0.000 n=10)
Chacha20Poly1305/Open-1350 2.594Mi ± 3% 9.899Mi ± 2% +281.62% (p=0.000 n=10) 13.237Mi ± 2% +410.29% (p=0.000 n=10)
Chacha20Poly1305/Seal-1350 2.556Mi ± 1% 10.471Mi ± 1% +309.70% (p=0.000 n=10) 13.452Mi ± 1% +426.31% (p=0.000 n=10)
Chacha20Poly1305/Open-1350-X 2.503Mi ± 2% 8.817Mi ± 1% +252.19% (p=0.000 n=10) 11.382Mi ± 1% +354.67% (p=0.000 n=10)
Chacha20Poly1305/Seal-1350-X 2.460Mi ± 0% 9.093Mi ± 1% +269.57% (p=0.000 n=10) 11.873Mi ± 2% +382.56% (p=0.000 n=10)
Chacha20Poly1305/Open-2048 2.694Mi ± 2% 11.024Mi ± 2% +309.20% (p=0.000 n=10) 14.963Mi ± 1% +455.40% (p=0.000 n=10)
Chacha20Poly1305/Seal-2048 2.699Mi ± 0% 11.477Mi ± 2% +325.27% (p=0.000 n=10) 15.240Mi ± 1% +464.66% (p=0.000 n=10)
Chacha20Poly1305/Open-2048-X 2.637Mi ± 1% 10.056Mi ± 1% +281.37% (p=0.000 n=10) 13.375Mi ± 1% +407.23% (p=0.000 n=10)
Chacha20Poly1305/Seal-2048-X 2.627Mi ± 1% 10.328Mi ± 2% +293.10% (p=0.000 n=10) 13.819Mi ± 2% +425.95% (p=0.000 n=10)
Chacha20Poly1305/Open-4096 2.732Mi ± 5% 11.225Mi ± 4% +310.82% (p=0.000 n=10) 16.041Mi ± 4% +487.09% (p=0.000 n=10)
Chacha20Poly1305/Seal-4096 2.704Mi ± 2% 10.839Mi ± 7% +300.88% (p=0.000 n=10) 15.693Mi ± 7% +480.42% (p=0.000 n=10)
Chacha20Poly1305/Open-4096-X 2.670Mi ± 1% 10.381Mi ± 4% +288.75% (p=0.000 n=10) 15.035Mi ± 4% +463.04% (p=0.000 n=10)
Chacha20Poly1305/Seal-4096-X 2.680Mi ± 1% 10.867Mi ± 5% +305.52% (p=0.000 n=10) 15.421Mi ± 7% +475.44% (p=0.000 n=10)
Chacha20Poly1305/Open-8192 2.708Mi ± 2% 11.053Mi ± 3% +308.10% (p=0.000 n=10) 15.926Mi ± 5% +488.03% (p=0.000 n=10)
Chacha20Poly1305/Seal-8192 2.632Mi ± 4% 10.896Mi ± 6% +313.95% (p=0.000 n=10) 16.031Mi ± 5% +509.06% (p=0.000 n=10)
Chacha20Poly1305/Open-8192-X 2.666Mi ± 4% 10.948Mi ± 4% +310.73% (p=0.000 n=10) 15.855Mi ± 3% +494.81% (p=0.000 n=10)
Chacha20Poly1305/Seal-8192-X 2.637Mi ± 2% 10.805Mi ± 2% +309.76% (p=0.000 n=10) 14.725Mi ± 6% +458.41% (p=0.000 n=10)
Chacha20Poly1305/Open-16384 2.499Mi ± 4% 10.405Mi ± 13% +316.41% (p=0.000 n=10) 13.628Mi ± 7% +445.42% (p=0.000 n=10)
Chacha20Poly1305/Seal-16384 2.484Mi ± 4% 9.069Mi ± 4% +265.07% (p=0.000 n=10) 12.131Mi ± 3% +388.29% (p=0.000 n=10)
Chacha20Poly1305/Open-16384-X 2.389Mi ± 7% 10.028Mi ± 5% +319.76% (p=0.000 n=10) 14.472Mi ± 3% +505.79% (p=0.000 n=10)
Chacha20Poly1305/Seal-16384-X 2.475Mi ± 4% 9.084Mi ± 2% +267.05% (p=0.000 n=10) 12.212Mi ± 6% +393.45% (p=0.000 n=10)
geomean 2.259Mi 8.271Mi +266.21% 10.90Mi +382.79%

Fixes golang/go#39139

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