Re: [PATCH v10 4/4] x86: vdso: Wire up getrandom() vDSO implementation
From: Eric Biggers <ebiggers@kernel.org>
Date: 2022-11-30 05:22:21
Also in:
linux-crypto, linux-patches, lkml
On Tue, Nov 29, 2022 at 10:06:39PM +0100, Jason A. Donenfeld wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/x86/entry/vdso/vgetrandom-chacha.S b/arch/x86/entry/vdso/vgetrandom-chacha.S new file mode 100644 index 000000000000..91fbb7ac7af4 --- /dev/null +++ b/arch/x86/entry/vdso/vgetrandom-chacha.S@@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include <linux/linkage.h> +#include <asm/frame.h> + +.section .rodata.cst16.CONSTANTS, "aM", @progbits, 16 +.align 16 +CONSTANTS: .octa 0x6b20657479622d323320646e61707865 +.text + +/* + * Very basic SSE2 implementation of ChaCha20. Produces a given positive number + * of blocks of output with a nonce of 0, taking an input key and 8-byte + * counter. Importantly does not spill to the stack. Its arguments are: + * + * rdi: output bytes + * rsi: 32-byte key input + * rdx: 8-byte counter input/output + * rcx: number of 64-byte blocks to write to output + */ +SYM_FUNC_START(__arch_chacha20_blocks_nostack)
How was this ChaCha20 implementation tested? It really ought to have some sort of test. Wouldn't this be a good candidate for a KUnit test? - Eric