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// SPDX-License-Identifier: GPL-2.0-only
/*
* Accelerated CRC32(C) using ARM CRC, NEON and Crypto Extensions instructions
*
* Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
*/
#include <linux/cpufeature.h>
#include <linux/crc32.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <crypto/internal/simd.h>
#include <asm/hwcap.h>
#include <asm/neon.h>
#include <asm/simd.h>
static DEFINE_STATIC_KEY_FALSE(have_crc32);
static DEFINE_STATIC_KEY_FALSE(have_pmull);
#define PMULL_MIN_LEN 64 /* min size of buffer for pmull functions */
asmlinkage u32 crc32_pmull_le(const u8 buf[], u32 len, u32 init_crc);
asmlinkage u32 crc32_armv8_le(u32 init_crc, const u8 buf[], u32 len);
asmlinkage u32 crc32c_pmull_le(const u8 buf[], u32 len, u32 init_crc);
asmlinkage u32 crc32c_armv8_le(u32 init_crc, const u8 buf[], u32 len);
static u32 crc32_le_scalar(u32 crc, const u8 *p, size_t len)
{
if (static_branch_likely(&have_crc32))
return crc32_armv8_le(crc, p, len);
return crc32_le_base(crc, p, len);
}
u32 crc32_le_arch(u32 crc, const u8 *p, size_t len)
{
if (len >= PMULL_MIN_LEN + 15 &&
static_branch_likely(&have_pmull) && crypto_simd_usable()) {
size_t n = -(uintptr_t)p & 15;
/* align p to 16-byte boundary */
if (n) {
crc = crc32_le_scalar(crc, p, n);
p += n;
len -= n;
}
n = round_down(len, 16);
kernel_neon_begin();
crc = crc32_pmull_le(p, n, crc);
kernel_neon_end();
p += n;
len -= n;
}
return crc32_le_scalar(crc, p, len);
}
EXPORT_SYMBOL(crc32_le_arch);
static u32 crc32c_le_scalar(u32 crc, const u8 *p, size_t len)
{
if (static_branch_likely(&have_crc32))
return crc32c_armv8_le(crc, p, len);
return crc32c_le_base(crc, p, len);
}
u32 crc32c_le_arch(u32 crc, const u8 *p, size_t len)
{
if (len >= PMULL_MIN_LEN + 15 &&
static_branch_likely(&have_pmull) && crypto_simd_usable()) {
size_t n = -(uintptr_t)p & 15;
/* align p to 16-byte boundary */
if (n) {
crc = crc32c_le_scalar(crc, p, n);
p += n;
len -= n;
}
n = round_down(len, 16);
kernel_neon_begin();
crc = crc32c_pmull_le(p, n, crc);
kernel_neon_end();
p += n;
len -= n;
}
return crc32c_le_scalar(crc, p, len);
}
EXPORT_SYMBOL(crc32c_le_arch);
u32 crc32_be_arch(u32 crc, const u8 *p, size_t len)
{
return crc32_be_base(crc, p, len);
}
EXPORT_SYMBOL(crc32_be_arch);
static int __init crc32_arm_init(void)
{
if (elf_hwcap2 & HWCAP2_CRC32)
static_branch_enable(&have_crc32);
if (elf_hwcap2 & HWCAP2_PMULL)
static_branch_enable(&have_pmull);
return 0;
}
arch_initcall(crc32_arm_init);
static void __exit crc32_arm_exit(void)
{
}
module_exit(crc32_arm_exit);
u32 crc32_optimizations(void)
{
if (elf_hwcap2 & (HWCAP2_CRC32 | HWCAP2_PMULL))
return CRC32_LE_OPTIMIZATION | CRC32C_OPTIMIZATION;
return 0;
}
EXPORT_SYMBOL(crc32_optimizations);
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_DESCRIPTION("Accelerated CRC32(C) using ARM CRC, NEON and Crypto Extensions");
MODULE_LICENSE("GPL v2");
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