1 #ifndef _ASM_POWERPC_CHECKSUM_H
2 #define _ASM_POWERPC_CHECKSUM_H
3 #ifdef __KERNEL__
4 
5 /*
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.
10  */
11 
12 /*
13  * This is a version of ip_compute_csum() optimized for IP headers,
14  * which always checksum on 4 octet boundaries.  ihl is the number
15  * of 32-bit words and is always >= 5.
16  */
17 #ifdef CONFIG_GENERIC_CSUM
18 #include <asm-generic/checksum.h>
19 #else
20 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
21 
22 /*
23  * computes the checksum of a memory block at buff, length len,
24  * and adds in "sum" (32-bit)
25  *
26  * returns a 32-bit number suitable for feeding into itself
27  * or csum_tcpudp_magic
28  *
29  * this function must be called with even lengths, except
30  * for the last fragment, which may be odd
31  *
32  * it's best to have buff aligned on a 32-bit boundary
33  */
34 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
35 
36 /*
37  * Computes the checksum of a memory block at src, length len,
38  * and adds in "sum" (32-bit), while copying the block to dst.
39  * If an access exception occurs on src or dst, it stores -EFAULT
40  * to *src_err or *dst_err respectively (if that pointer is not
41  * NULL), and, for an error on src, zeroes the rest of dst.
42  *
43  * Like csum_partial, this must be called with even lengths,
44  * except for the last fragment.
45  */
46 extern __wsum csum_partial_copy_generic(const void *src, void *dst,
47 					      int len, __wsum sum,
48 					      int *src_err, int *dst_err);
49 
50 #ifdef __powerpc64__
51 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
52 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
53 				      int len, __wsum sum, int *err_ptr);
54 #define HAVE_CSUM_COPY_USER
55 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
56 				    int len, __wsum sum, int *err_ptr);
57 #else
58 /*
59  * the same as csum_partial, but copies from src to dst while it
60  * checksums.
61  */
62 #define csum_partial_copy_from_user(src, dst, len, sum, errp)   \
63         csum_partial_copy_generic((__force const void *)(src), (dst), (len), (sum), (errp), NULL)
64 #endif
65 
66 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
67         csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
68 
69 
70 /*
71  * turns a 32-bit partial checksum (e.g. from csum_partial) into a
72  * 1's complement 16-bit checksum.
73  */
74 static inline __sum16 csum_fold(__wsum sum)
75 {
76 	unsigned int tmp;
77 
78 	/* swap the two 16-bit halves of sum */
79 	__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
80 	/* if there is a carry from adding the two 16-bit halves,
81 	   it will carry from the lower half into the upper half,
82 	   giving us the correct sum in the upper half. */
83 	return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
84 }
85 
86 /*
87  * this routine is used for miscellaneous IP-like checksums, mainly
88  * in icmp.c
89  */
90 static inline __sum16 ip_compute_csum(const void *buff, int len)
91 {
92 	return csum_fold(csum_partial(buff, len, 0));
93 }
94 
95 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
96                                      unsigned short len,
97                                      unsigned short proto,
98                                      __wsum sum)
99 {
100 #ifdef __powerpc64__
101 	unsigned long s = (__force u32)sum;
102 
103 	s += (__force u32)saddr;
104 	s += (__force u32)daddr;
105 	s += proto + len;
106 	s += (s >> 32);
107 	return (__force __wsum) s;
108 #else
109     __asm__("\n\
110 	addc %0,%0,%1 \n\
111 	adde %0,%0,%2 \n\
112 	adde %0,%0,%3 \n\
113 	addze %0,%0 \n\
114 	"
115 	: "=r" (sum)
116 	: "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
117 	return sum;
118 #endif
119 }
120 
121 /*
122  * computes the checksum of the TCP/UDP pseudo-header
123  * returns a 16-bit checksum, already complemented
124  */
125 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
126 					unsigned short len,
127 					unsigned short proto,
128 					__wsum sum)
129 {
130 	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
131 }
132 
133 #define HAVE_ARCH_CSUM_ADD
134 static inline __wsum csum_add(__wsum csum, __wsum addend)
135 {
136 #ifdef __powerpc64__
137 	u64 res = (__force u64)csum;
138 
139 	res += (__force u64)addend;
140 	return (__force __wsum)((u32)res + (res >> 32));
141 #else
142 	asm("addc %0,%0,%1;"
143 	    "addze %0,%0;"
144 	    : "+r" (csum) : "r" (addend));
145 	return csum;
146 #endif
147 }
148 
149 #endif
150 #endif /* __KERNEL__ */
151 #endif
152