1 #ifndef _ASM_POWERPC_CHECKSUM_H
2 #define _ASM_POWERPC_CHECKSUM_H
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #ifdef CONFIG_GENERIC_CSUM
13 #include <asm-generic/checksum.h>
16 * Computes the checksum of a memory block at src, length len,
17 * and adds in "sum" (32-bit), while copying the block to dst.
18 * If an access exception occurs on src or dst, it stores -EFAULT
19 * to *src_err or *dst_err respectively (if that pointer is not
20 * NULL), and, for an error on src, zeroes the rest of dst.
22 * Like csum_partial, this must be called with even lengths,
23 * except for the last fragment.
25 extern __wsum csum_partial_copy_generic(const void *src, void *dst,
27 int *src_err, int *dst_err);
29 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
30 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
31 int len, __wsum sum, int *err_ptr);
32 #define HAVE_CSUM_COPY_USER
33 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
34 int len, __wsum sum, int *err_ptr);
36 #define csum_partial_copy_nocheck(src, dst, len, sum) \
37 csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
41 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
42 * 1's complement 16-bit checksum.
44 static inline __sum16 csum_fold(__wsum sum)
48 /* swap the two 16-bit halves of sum */
49 __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
50 /* if there is a carry from adding the two 16-bit halves,
51 it will carry from the lower half into the upper half,
52 giving us the correct sum in the upper half. */
53 return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
56 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
62 unsigned long s = (__force u32)sum;
64 s += (__force u32)saddr;
65 s += (__force u32)daddr;
68 return (__force __wsum) s;
77 : "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
83 * computes the checksum of the TCP/UDP pseudo-header
84 * returns a 16-bit checksum, already complemented
86 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
91 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
94 #define HAVE_ARCH_CSUM_ADD
95 static inline __wsum csum_add(__wsum csum, __wsum addend)
98 u64 res = (__force u64)csum;
100 if (__builtin_constant_p(csum) && csum == 0)
102 if (__builtin_constant_p(addend) && addend == 0)
106 res += (__force u64)addend;
107 return (__force __wsum)((u32)res + (res >> 32));
111 : "+r" (csum) : "r" (addend) : "xer");
117 * This is a version of ip_compute_csum() optimized for IP headers,
118 * which always checksum on 4 octet boundaries. ihl is the number
119 * of 32-bit words and is always >= 5.
121 static inline __wsum ip_fast_csum_nofold(const void *iph, unsigned int ihl)
123 const u32 *ptr = (const u32 *)iph + 1;
126 u64 s = *(const u32 *)iph;
128 for (i = 0; i < ihl - 1; i++, ptr++)
131 return (__force __wsum)s;
141 : "=r" (sum), "=r" (tmp), "+b" (ptr)
142 : "r" (ihl - 2), "r" (*(const u32 *)iph), "r" (*ptr)
143 : "ctr", "xer", "memory");
149 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
151 return csum_fold(ip_fast_csum_nofold(iph, ihl));
155 * computes the checksum of a memory block at buff, length len,
156 * and adds in "sum" (32-bit)
158 * returns a 32-bit number suitable for feeding into itself
159 * or csum_tcpudp_magic
161 * this function must be called with even lengths, except
162 * for the last fragment, which may be odd
164 * it's best to have buff aligned on a 32-bit boundary
166 __wsum __csum_partial(const void *buff, int len, __wsum sum);
168 static inline __wsum csum_partial(const void *buff, int len, __wsum sum)
170 if (__builtin_constant_p(len) && len <= 16 && (len & 1) == 0) {
172 sum = csum_add(sum, (__force __wsum)*(const u16 *)buff);
174 sum = csum_add(sum, (__force __wsum)*(const u32 *)buff);
176 sum = csum_add(sum, (__force __wsum)
177 *(const u16 *)(buff + 4));
179 sum = csum_add(sum, (__force __wsum)
180 *(const u32 *)(buff + 4));
182 sum = csum_add(sum, (__force __wsum)
183 *(const u16 *)(buff + 8));
185 sum = csum_add(sum, (__force __wsum)
186 *(const u32 *)(buff + 8));
188 sum = csum_add(sum, (__force __wsum)
189 *(const u16 *)(buff + 12));
191 sum = csum_add(sum, (__force __wsum)
192 *(const u32 *)(buff + 12));
193 } else if (__builtin_constant_p(len) && (len & 3) == 0) {
194 sum = csum_add(sum, ip_fast_csum_nofold(buff, len >> 2));
196 sum = __csum_partial(buff, len, sum);
202 * this routine is used for miscellaneous IP-like checksums, mainly
205 static inline __sum16 ip_compute_csum(const void *buff, int len)
207 return csum_fold(csum_partial(buff, len, 0));
211 #endif /* __KERNEL__ */