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-rw-r--r--lib/crc32.c121
1 files changed, 44 insertions, 77 deletions
diff --git a/lib/crc32.c b/lib/crc32.c
index 49d1c9e3ce38..02e3b31b3a79 100644
--- a/lib/crc32.c
+++ b/lib/crc32.c
@@ -42,6 +42,48 @@ MODULE_AUTHOR("Matt Domsch <Matt_Domsch@dell.com>");
42MODULE_DESCRIPTION("Ethernet CRC32 calculations"); 42MODULE_DESCRIPTION("Ethernet CRC32 calculations");
43MODULE_LICENSE("GPL"); 43MODULE_LICENSE("GPL");
44 44
45#if CRC_LE_BITS == 8 || CRC_BE_BITS == 8
46
47static inline u32
48crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 *tab)
49{
50# ifdef __LITTLE_ENDIAN
51# define DO_CRC(x) crc = tab[(crc ^ (x)) & 255 ] ^ (crc >> 8)
52# else
53# define DO_CRC(x) crc = tab[((crc >> 24) ^ (x)) & 255] ^ (crc << 8)
54# endif
55 const u32 *b = (const u32 *)buf;
56 size_t rem_len;
57
58 /* Align it */
59 if (unlikely((long)b & 3 && len)) {
60 u8 *p = (u8 *)b;
61 do {
62 DO_CRC(*p++);
63 } while ((--len) && ((long)p)&3);
64 b = (u32 *)p;
65 }
66 rem_len = len & 3;
67 /* load data 32 bits wide, xor data 32 bits wide. */
68 len = len >> 2;
69 for (--b; len; --len) {
70 crc ^= *++b; /* use pre increment for speed */
71 DO_CRC(0);
72 DO_CRC(0);
73 DO_CRC(0);
74 DO_CRC(0);
75 }
76 len = rem_len;
77 /* And the last few bytes */
78 if (len) {
79 u8 *p = (u8 *)(b + 1) - 1;
80 do {
81 DO_CRC(*++p); /* use pre increment for speed */
82 } while (--len);
83 }
84 return crc;
85}
86#endif
45/** 87/**
46 * crc32_le() - Calculate bitwise little-endian Ethernet AUTODIN II CRC32 88 * crc32_le() - Calculate bitwise little-endian Ethernet AUTODIN II CRC32
47 * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for 89 * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for
@@ -72,48 +114,10 @@ u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len)
72u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len) 114u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len)
73{ 115{
74# if CRC_LE_BITS == 8 116# if CRC_LE_BITS == 8
75 const u32 *b =(u32 *)p;
76 const u32 *tab = crc32table_le; 117 const u32 *tab = crc32table_le;
77 118
78# ifdef __LITTLE_ENDIAN
79# define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8)
80# else
81# define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8)
82# endif
83
84 crc = __cpu_to_le32(crc); 119 crc = __cpu_to_le32(crc);
85 /* Align it */ 120 crc = crc32_body(crc, p, len, tab);
86 if(unlikely(((long)b)&3 && len)){
87 do {
88 u8 *p = (u8 *)b;
89 DO_CRC(*p++);
90 b = (void *)p;
91 } while ((--len) && ((long)b)&3 );
92 }
93 if(likely(len >= 4)){
94 /* load data 32 bits wide, xor data 32 bits wide. */
95 size_t save_len = len & 3;
96 len = len >> 2;
97 --b; /* use pre increment below(*++b) for speed */
98 do {
99 crc ^= *++b;
100 DO_CRC(0);
101 DO_CRC(0);
102 DO_CRC(0);
103 DO_CRC(0);
104 } while (--len);
105 b++; /* point to next byte(s) */
106 len = save_len;
107 }
108 /* And the last few bytes */
109 if(len){
110 do {
111 u8 *p = (u8 *)b;
112 DO_CRC(*p++);
113 b = (void *)p;
114 } while (--len);
115 }
116
117 return __le32_to_cpu(crc); 121 return __le32_to_cpu(crc);
118#undef ENDIAN_SHIFT 122#undef ENDIAN_SHIFT
119#undef DO_CRC 123#undef DO_CRC
@@ -170,47 +174,10 @@ u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len)
170u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) 174u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len)
171{ 175{
172# if CRC_BE_BITS == 8 176# if CRC_BE_BITS == 8
173 const u32 *b =(u32 *)p;
174 const u32 *tab = crc32table_be; 177 const u32 *tab = crc32table_be;
175 178
176# ifdef __LITTLE_ENDIAN
177# define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8)
178# else
179# define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8)
180# endif
181
182 crc = __cpu_to_be32(crc); 179 crc = __cpu_to_be32(crc);
183 /* Align it */ 180 crc = crc32_body(crc, p, len, tab);
184 if(unlikely(((long)b)&3 && len)){
185 do {
186 u8 *p = (u8 *)b;
187 DO_CRC(*p++);
188 b = (u32 *)p;
189 } while ((--len) && ((long)b)&3 );
190 }
191 if(likely(len >= 4)){
192 /* load data 32 bits wide, xor data 32 bits wide. */
193 size_t save_len = len & 3;
194 len = len >> 2;
195 --b; /* use pre increment below(*++b) for speed */
196 do {
197 crc ^= *++b;
198 DO_CRC(0);
199 DO_CRC(0);
200 DO_CRC(0);
201 DO_CRC(0);
202 } while (--len);
203 b++; /* point to next byte(s) */
204 len = save_len;
205 }
206 /* And the last few bytes */
207 if(len){
208 do {
209 u8 *p = (u8 *)b;
210 DO_CRC(*p++);
211 b = (void *)p;
212 } while (--len);
213 }
214 return __be32_to_cpu(crc); 181 return __be32_to_cpu(crc);
215#undef ENDIAN_SHIFT 182#undef ENDIAN_SHIFT
216#undef DO_CRC 183#undef DO_CRC