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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Calculate a CRC T10-DIF with vpmsum acceleration
*
* Copyright 2017, Daniel Axtens, IBM Corporation.
* [based on crc32c-vpmsum_glue.c]
*/
#include <linux/crc-t10dif.h>
#include <crypto/internal/simd.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/cpufeature.h>
#include <asm/simd.h>
#include <asm/switch_to.h>
#define VMX_ALIGN 16
#define VMX_ALIGN_MASK (VMX_ALIGN-1)
#define VECTOR_BREAKPOINT 64
static DEFINE_STATIC_KEY_FALSE(have_vec_crypto);
u32 __crct10dif_vpmsum(u32 crc, unsigned char const *p, size_t len);
u16 crc_t10dif_arch(u16 crci, const u8 *p, size_t len)
{
unsigned int prealign;
unsigned int tail;
u32 crc = crci;
if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) ||
!static_branch_likely(&have_vec_crypto) || !crypto_simd_usable())
return crc_t10dif_generic(crc, p, len);
if ((unsigned long)p & VMX_ALIGN_MASK) {
prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
crc = crc_t10dif_generic(crc, p, prealign);
len -= prealign;
p += prealign;
}
if (len & ~VMX_ALIGN_MASK) {
crc <<= 16;
preempt_disable();
pagefault_disable();
enable_kernel_altivec();
crc = __crct10dif_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
disable_kernel_altivec();
pagefault_enable();
preempt_enable();
crc >>= 16;
}
tail = len & VMX_ALIGN_MASK;
if (tail) {
p += len & ~VMX_ALIGN_MASK;
crc = crc_t10dif_generic(crc, p, tail);
}
return crc & 0xffff;
}
EXPORT_SYMBOL(crc_t10dif_arch);
static int __init crc_t10dif_powerpc_init(void)
{
if (cpu_has_feature(CPU_FTR_ARCH_207S) &&
(cur_cpu_spec->cpu_user_features2 & PPC_FEATURE2_VEC_CRYPTO))
static_branch_enable(&have_vec_crypto);
return 0;
}
arch_initcall(crc_t10dif_powerpc_init);
static void __exit crc_t10dif_powerpc_exit(void)
{
}
module_exit(crc_t10dif_powerpc_exit);
bool crc_t10dif_is_optimized(void)
{
return static_key_enabled(&have_vec_crypto);
}
EXPORT_SYMBOL(crc_t10dif_is_optimized);
MODULE_AUTHOR("Daniel Axtens <dja@axtens.net>");
MODULE_DESCRIPTION("CRCT10DIF using vector polynomial multiply-sum instructions");
MODULE_LICENSE("GPL");
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