poly1305.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2/*
 3 * Poly1305 authenticator algorithm, RFC7539.
 4 *
 5 * Copyright 2023- IBM Corp. All rights reserved.
 6 */
 7#include <asm/switch_to.h>
 8#include <linux/cpufeature.h>
 9#include <linux/jump_label.h>
10#include <linux/kernel.h>
11#include <linux/unaligned.h>
12
13asmlinkage void poly1305_p10le_4blocks(struct poly1305_block_state *state, const u8 *m, u32 mlen);
14asmlinkage void poly1305_64s(struct poly1305_block_state *state, const u8 *m, u32 mlen, int highbit);
15asmlinkage void poly1305_emit_64(const struct poly1305_state *state, const u32 nonce[4], u8 digest[POLY1305_DIGEST_SIZE]);
16
17static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_p10);
18
19static void vsx_begin(void)
20{
21	preempt_disable();
22	enable_kernel_vsx();
23}
24
25static void vsx_end(void)
26{
27	disable_kernel_vsx();
28	preempt_enable();
29}
30
31static void poly1305_block_init(struct poly1305_block_state *dctx,
32				const u8 raw_key[POLY1305_BLOCK_SIZE])
33{
34	if (!static_key_enabled(&have_p10))
35		return poly1305_block_init_generic(dctx, raw_key);
36
37	dctx->h = (struct poly1305_state){};
38	dctx->core_r.key.r64[0] = get_unaligned_le64(raw_key + 0);
39	dctx->core_r.key.r64[1] = get_unaligned_le64(raw_key + 8);
40}
41
42static void poly1305_blocks(struct poly1305_block_state *state, const u8 *src,
43			    unsigned int len, u32 padbit)
44{
45	if (!static_key_enabled(&have_p10))
46		return poly1305_blocks_generic(state, src, len, padbit);
47	vsx_begin();
48	if (len >= POLY1305_BLOCK_SIZE * 4) {
49		poly1305_p10le_4blocks(state, src, len);
50		src += len - (len % (POLY1305_BLOCK_SIZE * 4));
51		len %= POLY1305_BLOCK_SIZE * 4;
52	}
53	while (len >= POLY1305_BLOCK_SIZE) {
54		poly1305_64s(state, src, POLY1305_BLOCK_SIZE, padbit);
55		len -= POLY1305_BLOCK_SIZE;
56		src += POLY1305_BLOCK_SIZE;
57	}
58	vsx_end();
59}
60
61static void poly1305_emit(const struct poly1305_state *state,
62			  u8 digest[POLY1305_DIGEST_SIZE], const u32 nonce[4])
63{
64	if (!static_key_enabled(&have_p10))
65		return poly1305_emit_generic(state, digest, nonce);
66	poly1305_emit_64(state, nonce, digest);
67}
68
69#define poly1305_mod_init_arch poly1305_mod_init_arch
70static void poly1305_mod_init_arch(void)
71{
72	if (cpu_has_feature(CPU_FTR_ARCH_31))
73		static_branch_enable(&have_p10);
74}