1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Calculate a CRC T10-DIF with vpmsum acceleration 4 * 5 * Copyright 2017, Daniel Axtens, IBM Corporation. 6 * [based on crc32c-vpmsum_glue.c] 7 */ 8 9 #include <linux/crc-t10dif.h> 10 #include <crypto/internal/hash.h> 11 #include <crypto/internal/simd.h> 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/string.h> 15 #include <linux/kernel.h> 16 #include <linux/cpufeature.h> 17 #include <asm/simd.h> 18 #include <asm/switch_to.h> 19 20 #define VMX_ALIGN 16 21 #define VMX_ALIGN_MASK (VMX_ALIGN-1) 22 23 #define VECTOR_BREAKPOINT 64 24 25 u32 __crct10dif_vpmsum(u32 crc, unsigned char const *p, size_t len); 26 27 static u16 crct10dif_vpmsum(u16 crci, unsigned char const *p, size_t len) 28 { 29 unsigned int prealign; 30 unsigned int tail; 31 u32 crc = crci; 32 33 if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || !crypto_simd_usable()) 34 return crc_t10dif_generic(crc, p, len); 35 36 if ((unsigned long)p & VMX_ALIGN_MASK) { 37 prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK); 38 crc = crc_t10dif_generic(crc, p, prealign); 39 len -= prealign; 40 p += prealign; 41 } 42 43 if (len & ~VMX_ALIGN_MASK) { 44 crc <<= 16; 45 preempt_disable(); 46 pagefault_disable(); 47 enable_kernel_altivec(); 48 crc = __crct10dif_vpmsum(crc, p, len & ~VMX_ALIGN_MASK); 49 disable_kernel_altivec(); 50 pagefault_enable(); 51 preempt_enable(); 52 crc >>= 16; 53 } 54 55 tail = len & VMX_ALIGN_MASK; 56 if (tail) { 57 p += len & ~VMX_ALIGN_MASK; 58 crc = crc_t10dif_generic(crc, p, tail); 59 } 60 61 return crc & 0xffff; 62 } 63 64 static int crct10dif_vpmsum_init(struct shash_desc *desc) 65 { 66 u16 *crc = shash_desc_ctx(desc); 67 68 *crc = 0; 69 return 0; 70 } 71 72 static int crct10dif_vpmsum_update(struct shash_desc *desc, const u8 *data, 73 unsigned int length) 74 { 75 u16 *crc = shash_desc_ctx(desc); 76 77 *crc = crct10dif_vpmsum(*crc, data, length); 78 79 return 0; 80 } 81 82 83 static int crct10dif_vpmsum_final(struct shash_desc *desc, u8 *out) 84 { 85 u16 *crcp = shash_desc_ctx(desc); 86 87 *(u16 *)out = *crcp; 88 return 0; 89 } 90 91 static struct shash_alg alg = { 92 .init = crct10dif_vpmsum_init, 93 .update = crct10dif_vpmsum_update, 94 .final = crct10dif_vpmsum_final, 95 .descsize = CRC_T10DIF_DIGEST_SIZE, 96 .digestsize = CRC_T10DIF_DIGEST_SIZE, 97 .base = { 98 .cra_name = "crct10dif", 99 .cra_driver_name = "crct10dif-vpmsum", 100 .cra_priority = 200, 101 .cra_blocksize = CRC_T10DIF_BLOCK_SIZE, 102 .cra_module = THIS_MODULE, 103 } 104 }; 105 106 static int __init crct10dif_vpmsum_mod_init(void) 107 { 108 if (!cpu_has_feature(CPU_FTR_ARCH_207S)) 109 return -ENODEV; 110 111 return crypto_register_shash(&alg); 112 } 113 114 static void __exit crct10dif_vpmsum_mod_fini(void) 115 { 116 crypto_unregister_shash(&alg); 117 } 118 119 module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crct10dif_vpmsum_mod_init); 120 module_exit(crct10dif_vpmsum_mod_fini); 121 122 MODULE_AUTHOR("Daniel Axtens <dja@axtens.net>"); 123 MODULE_DESCRIPTION("CRCT10DIF using vector polynomial multiply-sum instructions"); 124 MODULE_LICENSE("GPL"); 125 MODULE_ALIAS_CRYPTO("crct10dif"); 126 MODULE_ALIAS_CRYPTO("crct10dif-vpmsum"); 127