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