arch/powerpc/crypto/crct10dif-vpmsum_glue.c

   1 /*
   2  * Calculate a CRC T10-DIF with vpmsum acceleration
   3  *
   4  * Copyright 2017, Daniel Axtens, IBM Corporation.
   5  * [based on crc32c-vpmsum_glue.c]
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/crc-t10dif.h>
  14 #include <crypto/internal/hash.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/string.h>
  18 #include <linux/kernel.h>
  19 #include <linux/cpufeature.h>
  20 #include <asm/switch_to.h>
  21
  22 #define VMX_ALIGN               16
  23 #define VMX_ALIGN_MASK          (VMX_ALIGN-1)
  24
  25 #define VECTOR_BREAKPOINT       64
  26
  27 u32 __crct10dif_vpmsum(u32 crc, unsigned char const *p, size_t len);
  28
  29 static u16 crct10dif_vpmsum(u16 crci, unsigned char const *p, size_t len)
  30 {
  31         unsigned int prealign;
  32         unsigned int tail;
  33         u32 crc = crci;
  34
  35         if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || in_interrupt())
  36                 return crc_t10dif_generic(crc, p, len);
  37
  38         if ((unsigned long)p & VMX_ALIGN_MASK) {
  39                 prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
  40                 crc = crc_t10dif_generic(crc, p, prealign);
  41                 len -= prealign;
  42                 p += prealign;
  43         }
  44
  45         if (len & ~VMX_ALIGN_MASK) {
  46                 crc <<= 16;
  47                 preempt_disable();
  48                 pagefault_disable();
  49                 enable_kernel_altivec();
  50                 crc = __crct10dif_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
  51                 disable_kernel_altivec();
  52                 pagefault_enable();
  53                 preempt_enable();
  54                 crc >>= 16;
  55         }
  56
  57         tail = len & VMX_ALIGN_MASK;
  58         if (tail) {
  59                 p += len & ~VMX_ALIGN_MASK;
  60                 crc = crc_t10dif_generic(crc, p, tail);
  61         }
  62
  63         return crc & 0xffff;
  64 }
  65
  66 static int crct10dif_vpmsum_init(struct shash_desc *desc)
  67 {
  68         u16 *crc = shash_desc_ctx(desc);
  69
  70         *crc = 0;
  71         return 0;
  72 }
  73
  74 static int crct10dif_vpmsum_update(struct shash_desc *desc, const u8 *data,
  75                             unsigned int length)
  76 {
  77         u16 *crc = shash_desc_ctx(desc);
  78
  79         *crc = crct10dif_vpmsum(*crc, data, length);
  80
  81         return 0;
  82 }
  83
  84
  85 static int crct10dif_vpmsum_final(struct shash_desc *desc, u8 *out)
  86 {
  87         u16 *crcp = shash_desc_ctx(desc);
  88
  89         *(u16 *)out = *crcp;
  90         return 0;
  91 }
  92
  93 static struct shash_alg alg = {
  94         .init           = crct10dif_vpmsum_init,
  95         .update         = crct10dif_vpmsum_update,
  96         .final          = crct10dif_vpmsum_final,
  97         .descsize       = CRC_T10DIF_DIGEST_SIZE,
  98         .digestsize     = CRC_T10DIF_DIGEST_SIZE,
  99         .base           = {
 100                 .cra_name               = "crct10dif",
 101                 .cra_driver_name        = "crct10dif-vpmsum",
 102                 .cra_priority           = 200,
 103                 .cra_blocksize          = CRC_T10DIF_BLOCK_SIZE,
 104                 .cra_module             = THIS_MODULE,
 105         }
 106 };
 107
 108 static int __init crct10dif_vpmsum_mod_init(void)
 109 {
 110         if (!cpu_has_feature(CPU_FTR_ARCH_207S))
 111                 return -ENODEV;
 112
 113         return crypto_register_shash(&alg);
 114 }
 115
 116 static void __exit crct10dif_vpmsum_mod_fini(void)
 117 {
 118         crypto_unregister_shash(&alg);
 119 }
 120
 121 module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crct10dif_vpmsum_mod_init);
 122 module_exit(crct10dif_vpmsum_mod_fini);
 123
 124 MODULE_AUTHOR("Daniel Axtens <dja@axtens.net>");
 125 MODULE_DESCRIPTION("CRCT10DIF using vector polynomial multiply-sum instructions");
 126 MODULE_LICENSE("GPL");
 127 MODULE_ALIAS_CRYPTO("crct10dif");
 128 MODULE_ALIAS_CRYPTO("crct10dif-vpmsum");