/arch/powerpc/include/asm/checksum.h

  1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2#ifndef _ASM_POWERPC_CHECKSUM_H
  3#define _ASM_POWERPC_CHECKSUM_H
  4#ifdef __KERNEL__
  5
  6/*
  7 */
  8
  9#include <linux/bitops.h>
 10#include <linux/in6.h>
 11/*
 12 * Computes the checksum of a memory block at src, length len,
 13 * and adds in "sum" (32-bit), while copying the block to dst.
 14 * If an access exception occurs on src or dst, it stores -EFAULT
 15 * to *src_err or *dst_err respectively (if that pointer is not
 16 * NULL), and, for an error on src, zeroes the rest of dst.
 17 *
 18 * Like csum_partial, this must be called with even lengths,
 19 * except for the last fragment.
 20 */
 21extern __wsum csum_partial_copy_generic(const void *src, void *dst,
 22					      int len, __wsum sum,
 23					      int *src_err, int *dst_err);
 24
 25#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 26extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 27				      int len, __wsum sum, int *err_ptr);
 28#define HAVE_CSUM_COPY_USER
 29extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 30				    int len, __wsum sum, int *err_ptr);
 31
 32#define csum_partial_copy_nocheck(src, dst, len, sum)   \
 33        csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
 34
 35
 36/*
 37 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
 38 * 1's complement 16-bit checksum.
 39 */
 40static inline __sum16 csum_fold(__wsum sum)
 41{
 42	unsigned int tmp;
 43
 44	/* swap the two 16-bit halves of sum */
 45	__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
 46	/* if there is a carry from adding the two 16-bit halves,
 47	   it will carry from the lower half into the upper half,
 48	   giving us the correct sum in the upper half. */
 49	return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
 50}
 51
 52static inline u32 from64to32(u64 x)
 53{
 54	return (x + ror64(x, 32)) >> 32;
 55}
 56
 57static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
 58					__u8 proto, __wsum sum)
 59{
 60#ifdef __powerpc64__
 61	u64 s = (__force u32)sum;
 62
 63	s += (__force u32)saddr;
 64	s += (__force u32)daddr;
 65#ifdef __BIG_ENDIAN__
 66	s += proto + len;
 67#else
 68	s += (proto + len) << 8;
 69#endif
 70	return (__force __wsum) from64to32(s);
 71#else
 72    __asm__("\n\
 73	addc %0,%0,%1 \n\
 74	adde %0,%0,%2 \n\
 75	adde %0,%0,%3 \n\
 76	addze %0,%0 \n\
 77	"
 78	: "=r" (sum)
 79	: "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
 80	return sum;
 81#endif
 82}
 83
 84/*
 85 * computes the checksum of the TCP/UDP pseudo-header
 86 * returns a 16-bit checksum, already complemented
 87 */
 88static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
 89					__u8 proto, __wsum sum)
 90{
 91	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 92}
 93
 94#define HAVE_ARCH_CSUM_ADD
 95static inline __wsum csum_add(__wsum csum, __wsum addend)
 96{
 97#ifdef __powerpc64__
 98	u64 res = (__force u64)csum;
 99#endif
100	if (__builtin_constant_p(csum) && csum == 0)
101		return addend;
102	if (__builtin_constant_p(addend) && addend == 0)
103		return csum;
104
105#ifdef __powerpc64__
106	res += (__force u64)addend;
107	return (__force __wsum)((u32)res + (res >> 32));
108#else
109	asm("addc %0,%0,%1;"
110	    "addze %0,%0;"
111	    : "+r" (csum) : "r" (addend) : "xer");
112	return csum;
113#endif
114}
115
116/*
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.
120 */
121static inline __wsum ip_fast_csum_nofold(const void *iph, unsigned int ihl)
122{
123	const u32 *ptr = (const u32 *)iph + 1;
124#ifdef __powerpc64__
125	unsigned int i;
126	u64 s = *(const u32 *)iph;
127
128	for (i = 0; i < ihl - 1; i++, ptr++)
129		s += *ptr;
130	return (__force __wsum)from64to32(s);
131#else
132	__wsum sum, tmp;
133
134	asm("mtctr %3;"
135	    "addc %0,%4,%5;"
136	    "1: lwzu %1, 4(%2);"
137	    "adde %0,%0,%1;"
138	    "bdnz 1b;"
139	    "addze %0,%0;"
140	    : "=r" (sum), "=r" (tmp), "+b" (ptr)
141	    : "r" (ihl - 2), "r" (*(const u32 *)iph), "r" (*ptr)
142	    : "ctr", "xer", "memory");
143
144	return sum;
145#endif
146}
147
148static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
149{
150	return csum_fold(ip_fast_csum_nofold(iph, ihl));
151}
152
153/*
154 * computes the checksum of a memory block at buff, length len,
155 * and adds in "sum" (32-bit)
156 *
157 * returns a 32-bit number suitable for feeding into itself
158 * or csum_tcpudp_magic
159 *
160 * this function must be called with even lengths, except
161 * for the last fragment, which may be odd
162 *
163 * it's best to have buff aligned on a 32-bit boundary
164 */
165__wsum __csum_partial(const void *buff, int len, __wsum sum);
166
167static inline __wsum csum_partial(const void *buff, int len, __wsum sum)
168{
169	if (__builtin_constant_p(len) && len <= 16 && (len & 1) == 0) {
170		if (len == 2)
171			sum = csum_add(sum, (__force __wsum)*(const u16 *)buff);
172		if (len >= 4)
173			sum = csum_add(sum, (__force __wsum)*(const u32 *)buff);
174		if (len == 6)
175			sum = csum_add(sum, (__force __wsum)
176					    *(const u16 *)(buff + 4));
177		if (len >= 8)
178			sum = csum_add(sum, (__force __wsum)
179					    *(const u32 *)(buff + 4));
180		if (len == 10)
181			sum = csum_add(sum, (__force __wsum)
182					    *(const u16 *)(buff + 8));
183		if (len >= 12)
184			sum = csum_add(sum, (__force __wsum)
185					    *(const u32 *)(buff + 8));
186		if (len == 14)
187			sum = csum_add(sum, (__force __wsum)
188					    *(const u16 *)(buff + 12));
189		if (len >= 16)
190			sum = csum_add(sum, (__force __wsum)
191					    *(const u32 *)(buff + 12));
192	} else if (__builtin_constant_p(len) && (len & 3) == 0) {
193		sum = csum_add(sum, ip_fast_csum_nofold(buff, len >> 2));
194	} else {
195		sum = __csum_partial(buff, len, sum);
196	}
197	return sum;
198}
199
200/*
201 * this routine is used for miscellaneous IP-like checksums, mainly
202 * in icmp.c
203 */
204static inline __sum16 ip_compute_csum(const void *buff, int len)
205{
206	return csum_fold(csum_partial(buff, len, 0));
207}
208
209#define _HAVE_ARCH_IPV6_CSUM
210__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
211			const struct in6_addr *daddr,
212			__u32 len, __u8 proto, __wsum sum);
213
214#endif /* __KERNEL__ */
215#endif