1 // SPDX-License-Identifier: GPL-2.0
3 * csum_partial_copy - do IP checksumming and copy
5 * (C) Copyright 1996 Linus Torvalds
6 * accelerated versions (and 21264 assembly versions ) contributed by
7 * Rick Gorton <rick.gorton@alpha-processor.com>
9 * Don't look at this too closely - you'll go mad. The things
10 * we do for performance..
13 #include <linux/types.h>
14 #include <linux/string.h>
15 #include <linux/uaccess.h>
19 __asm__ __volatile__("ldq_u %0,%1":"=r" (x):"m" (*(const unsigned long *)(y)))
22 __asm__ __volatile__("stq_u %1,%0":"=m" (*(unsigned long *)(y)):"r" (x))
24 #define extql(x,y,z) \
25 __asm__ __volatile__("extql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
27 #define extqh(x,y,z) \
28 __asm__ __volatile__("extqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
30 #define mskql(x,y,z) \
31 __asm__ __volatile__("mskql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
33 #define mskqh(x,y,z) \
34 __asm__ __volatile__("mskqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
36 #define insql(x,y,z) \
37 __asm__ __volatile__("insql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
39 #define insqh(x,y,z) \
40 __asm__ __volatile__("insqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
42 #define __get_word(insn,x,ptr) \
45 __asm__ __volatile__( \
46 "1: "#insn" %0,%2\n" \
49 : "=r"(x), "=r"(__guu_err) \
50 : "m"(__m(ptr)), "1"(0)); \
54 static inline unsigned short from64to16(unsigned long x)
56 /* Using extract instructions is a bit more efficient
57 than the original shift/bitmask version. */
66 tmp_v.ul = (unsigned long) in_v.ui[0] + (unsigned long) in_v.ui[1];
68 /* Since the bits of tmp_v.sh[3] are going to always be zero,
69 we don't have to bother to add that in. */
70 out_v.ul = (unsigned long) tmp_v.us[0] + (unsigned long) tmp_v.us[1]
71 + (unsigned long) tmp_v.us[2];
73 /* Similarly, out_v.us[2] is always zero for the final add. */
74 return out_v.us[0] + out_v.us[1];
80 * Ok. This isn't fun, but this is the EASY case.
82 static inline unsigned long
83 csum_partial_cfu_aligned(const unsigned long __user *src, unsigned long *dst,
86 unsigned long checksum = ~0U;
87 unsigned long carry = 0;
91 if (__get_word(ldq, word, src))
97 carry = checksum < word;
104 unsigned long word, tmp;
105 if (__get_word(ldq, word, src))
108 mskql(word, len, word);
110 mskqh(tmp, len, tmp);
111 carry = checksum < word;
119 * This is even less fun, but this is still reasonably
122 static inline unsigned long
123 csum_partial_cfu_dest_aligned(const unsigned long __user *src,
129 unsigned long word, carry;
130 unsigned long lastsrc = 7+len+(unsigned long)src;
131 unsigned long checksum = ~0U;
133 if (__get_word(ldq_u, first,src))
137 unsigned long second;
139 if (__get_word(ldq_u, second, src+1))
141 extql(first, soff, word);
144 extqh(second, soff, first);
151 carry = checksum < word;
157 unsigned long second;
158 if (__get_word(ldq_u, second, lastsrc))
161 extql(first, soff, word);
162 extqh(second, soff, first);
164 mskql(word, len, word);
166 mskqh(tmp, len, tmp);
167 carry = checksum < word;
175 * This is slightly less fun than the above..
177 static inline unsigned long
178 csum_partial_cfu_src_aligned(const unsigned long __user *src,
182 unsigned long partial_dest)
184 unsigned long carry = 0;
186 unsigned long second_dest;
187 unsigned long checksum = ~0U;
189 mskql(partial_dest, doff, partial_dest);
191 if (__get_word(ldq, word, src))
194 insql(word, doff, second_dest);
196 stq_u(partial_dest | second_dest, dst);
199 insqh(word, doff, partial_dest);
200 carry = checksum < word;
206 if (__get_word(ldq, word, src))
208 mskql(word, len, word);
211 insql(word, doff, second_dest);
213 carry = checksum < word;
214 partial_dest |= second_dest;
216 stq_u(partial_dest, dst);
219 insqh(word, doff, partial_dest);
223 ldq_u(second_dest, dst);
224 mskqh(second_dest, doff, second_dest);
225 stq_u(partial_dest | second_dest, dst);
232 * This is so totally un-fun that it's frightening. Don't
233 * look at this too closely, you'll go blind.
235 static inline unsigned long
236 csum_partial_cfu_unaligned(const unsigned long __user * src,
238 unsigned long soff, unsigned long doff,
239 long len, unsigned long partial_dest)
241 unsigned long carry = 0;
243 unsigned long lastsrc;
244 unsigned long checksum = ~0U;
246 if (__get_word(ldq_u, first, src))
248 lastsrc = 7+len+(unsigned long)src;
249 mskql(partial_dest, doff, partial_dest);
251 unsigned long second, word;
252 unsigned long second_dest;
254 if (__get_word(ldq_u, second, src+1))
256 extql(first, soff, word);
259 extqh(second, soff, first);
263 insql(word, doff, second_dest);
265 stq_u(partial_dest | second_dest, dst);
266 carry = checksum < word;
267 insqh(word, doff, partial_dest);
273 unsigned long second, word;
274 unsigned long second_dest;
276 if (__get_word(ldq_u, second, lastsrc))
278 extql(first, soff, word);
279 extqh(second, soff, first);
282 mskql(word, len-doff, word);
284 insql(word, doff, second_dest);
285 carry = checksum < word;
286 stq_u(partial_dest | second_dest, dst);
288 ldq_u(second_dest, dst+1);
289 insqh(word, doff, partial_dest);
290 mskqh(second_dest, len, second_dest);
291 stq_u(partial_dest | second_dest, dst+1);
295 unsigned long second, word;
296 unsigned long second_dest;
298 if (__get_word(ldq_u, second, lastsrc))
300 extql(first, soff, word);
301 extqh(second, soff, first);
303 ldq_u(second_dest, dst);
304 mskql(word, len-doff, word);
306 mskqh(second_dest, len, second_dest);
307 carry = checksum < word;
308 insql(word, doff, word);
309 stq_u(partial_dest | word | second_dest, dst);
315 static __wsum __csum_and_copy(const void __user *src, void *dst, int len)
317 unsigned long soff = 7 & (unsigned long) src;
318 unsigned long doff = 7 & (unsigned long) dst;
319 unsigned long checksum;
323 checksum = csum_partial_cfu_aligned(
324 (const unsigned long __user *) src,
325 (unsigned long *) dst, len-8);
327 checksum = csum_partial_cfu_dest_aligned(
328 (const unsigned long __user *) src,
329 (unsigned long *) dst,
332 unsigned long partial_dest;
333 ldq_u(partial_dest, dst);
335 checksum = csum_partial_cfu_src_aligned(
336 (const unsigned long __user *) src,
337 (unsigned long *) dst,
338 doff, len-8, partial_dest);
340 checksum = csum_partial_cfu_unaligned(
341 (const unsigned long __user *) src,
342 (unsigned long *) dst,
343 soff, doff, len-8, partial_dest);
345 return (__force __wsum)from64to16 (checksum);
349 csum_and_copy_from_user(const void __user *src, void *dst, int len)
351 if (!access_ok(src, len))
353 return __csum_and_copy(src, dst, len);
355 EXPORT_SYMBOL(csum_and_copy_from_user);
358 csum_partial_copy_nocheck(const void *src, void *dst, int len)
360 return __csum_and_copy((__force const void __user *)src,
363 EXPORT_SYMBOL(csum_partial_copy_nocheck);