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/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/*
* Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include <asm/hwcap.h>
#include <asm/neon.h>
asmlinkage void poly1305_init_arm(void *ctx, const u8 key[16]);
asmlinkage void poly1305_blocks_arm(void *ctx, const u8 *inp, const size_t len,
const u32 padbit);
asmlinkage void poly1305_emit_arm(void *ctx, u8 mac[16], const u32 nonce[4]);
asmlinkage void poly1305_blocks_neon(void *ctx, const u8 *inp, const size_t len,
const u32 padbit);
asmlinkage void poly1305_emit_neon(void *ctx, u8 mac[16], const u32 nonce[4]);
static bool poly1305_use_neon __ro_after_init;
static void __init poly1305_fpu_init(void)
{
#if defined(CONFIG_ZINC_ARCH_ARM64)
poly1305_use_neon = elf_hwcap & HWCAP_ASIMD;
#elif defined(CONFIG_ZINC_ARCH_ARM)
poly1305_use_neon = elf_hwcap & HWCAP_NEON;
#endif
}
#if defined(CONFIG_ZINC_ARCH_ARM64)
struct poly1305_arch_internal {
union {
u32 h[5];
struct {
u64 h0, h1, h2;
};
};
u64 is_base2_26;
u64 r[2];
};
#elif defined(CONFIG_ZINC_ARCH_ARM)
struct poly1305_arch_internal {
union {
u32 h[5];
struct {
u64 h0, h1;
u32 h2;
} __packed;
};
u32 r[4];
u32 is_base2_26;
};
#endif
/* The NEON code uses base 2^26, while the scalar code uses base 2^64 on 64-bit
* and base 2^32 on 32-bit. If we hit the unfortunate situation of using NEON
* and then having to go back to scalar -- because the user is silly and has
* called the update function from two separate contexts -- then we need to
* convert back to the original base before proceeding. The below function is
* written for 64-bit integers, and so we have to swap words at the end on
* big-endian 32-bit. It is possible to reason that the initial reduction below
* is sufficient given the implementation invariants. However, for an avoidance
* of doubt and because this is not performance critical, we do the full
* reduction anyway.
*/
static void convert_to_base2_64(void *ctx)
{
struct poly1305_arch_internal *state = ctx;
u32 cy;
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !state->is_base2_26)
return;
cy = state->h[0] >> 26; state->h[0] &= 0x3ffffff; state->h[1] += cy;
cy = state->h[1] >> 26; state->h[1] &= 0x3ffffff; state->h[2] += cy;
cy = state->h[2] >> 26; state->h[2] &= 0x3ffffff; state->h[3] += cy;
cy = state->h[3] >> 26; state->h[3] &= 0x3ffffff; state->h[4] += cy;
state->h0 = ((u64)state->h[2] << 52) | ((u64)state->h[1] << 26) | state->h[0];
state->h1 = ((u64)state->h[4] << 40) | ((u64)state->h[3] << 14) | (state->h[2] >> 12);
state->h2 = state->h[4] >> 24;
if (IS_ENABLED(CONFIG_ZINC_ARCH_ARM) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) {
state->h0 = rol64(state->h0, 32);
state->h1 = rol64(state->h1, 32);
}
#define ULT(a, b) ((a ^ ((a ^ b) | ((a - b) ^ b))) >> (sizeof(a) * 8 - 1))
cy = (state->h2 >> 2) + (state->h2 & ~3ULL);
state->h2 &= 3;
state->h0 += cy;
state->h1 += (cy = ULT(state->h0, cy));
state->h2 += ULT(state->h1, cy);
#undef ULT
state->is_base2_26 = 0;
}
static inline bool poly1305_init_arch(void *ctx,
const u8 key[POLY1305_KEY_SIZE])
{
poly1305_init_arm(ctx, key);
return true;
}
static inline bool poly1305_blocks_arch(void *ctx, const u8 *inp,
size_t len, const u32 padbit,
simd_context_t *simd_context)
{
/* SIMD disables preemption, so relax after processing each page. */
BUILD_BUG_ON(PAGE_SIZE < POLY1305_BLOCK_SIZE ||
PAGE_SIZE % POLY1305_BLOCK_SIZE);
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !poly1305_use_neon ||
!simd_use(simd_context)) {
convert_to_base2_64(ctx);
poly1305_blocks_arm(ctx, inp, len, padbit);
return true;
}
for (;;) {
const size_t bytes = min_t(size_t, len, PAGE_SIZE);
poly1305_blocks_neon(ctx, inp, bytes, padbit);
len -= bytes;
if (!len)
break;
inp += bytes;
simd_relax(simd_context);
}
return true;
}
static inline bool poly1305_emit_arch(void *ctx, u8 mac[POLY1305_MAC_SIZE],
const u32 nonce[4],
simd_context_t *simd_context)
{
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !poly1305_use_neon ||
!simd_use(simd_context)) {
convert_to_base2_64(ctx);
poly1305_emit_arm(ctx, mac, nonce);
} else
poly1305_emit_neon(ctx, mac, nonce);
return true;
}
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