Introduce the ast10x0 HACE peripheral#241
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The no_panics_test scans the compiled ELF and fails if any panic path is reachable. Two root causes remained in the SHA-2 / HMAC code linked into the hace_sha256 binary: - div_by_zero: chunks_exact(4).zip(..) in load_iv / digest_from_context. ChunksExact stores its chunk size as a runtime field, so Zip::new emits a len / chunk_size division the optimizer cannot prove non-zero. Replaced with index-stride loops over length-proven [u8; 4] arrays. - copy_from_slice len_mismatch_fail: the staging copies in HaceDigest::update and HaceHmacCtx::update copy between two range-sliced &[u8] of equal-by-construction length the optimizer cannot prove equal. Replaced with zip element-wise copies (no length assert, no division). Also hardened the AES IV copies (AesCipher::crypt, AesSkin CBC chaining) to use <[u8; AES_BLOCK]>::try_from array assignment instead of copy_from_slice, per the project no-panic patterns. no_panics_test now PASSES; nm shows no panic_is_possible, len_mismatch_fail, or div_by_zero symbols. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The HACE SHA-2/HMAC KAT test (hace_sha256_test) HardFaulted with an unaligned UsageFault (wild pointer 0x191818f6) at the sha256 stream-9000 case. Root cause: run_hace_sha2_kats builds a large single stack frame that overflowed the pigweed-default 2 KiB kernel bootstrap stack into adjacent .bss (INPUT_BUF); the first case that writes that 4 KiB buffer (stream-9000) clobbered the live frame and corrupted a saved pointer. The one-shot cases passed only because they never write INPUT_BUF. Two parts: - hmac.rs: move the large HMAC working buffers (key, ipad, opad, and the 1 KiB msg) off the stack into a single .ram_nc static (HmacNcBufs), so HaceHmacCtx is just a few scalars (~20 bytes). This removes the dominant per-op stack pressure from the back-to-back HMAC cases. Remaining copy_from_slice calls are also converted to zip-copies. - config.rs: raise KernelConfigInterface::KERNEL_STACK_SIZE_BYTES from the 2 KiB default to 16 KiB, giving the bootstrap/idle kernel stacks ample headroom for the crypto KAT workloads. The AST10x0 has 768 KiB SRAM so the extra RAM is negligible. hace_sha256_test and no_panics_test both pass. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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