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, int len);
 22
 23#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 24extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
 25				      int len);
 26#define HAVE_CSUM_COPY_USER
 27extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 28				    int len);
 29
 30#define _HAVE_ARCH_CSUM_AND_COPY
 31#define csum_partial_copy_nocheck(src, dst, len)   \
 32        csum_partial_copy_generic((src), (dst), (len))
 33
 34
 35/*
 36 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
 37 * 1's complement 16-bit checksum.
 38 */
 39static inline __sum16 csum_fold(__wsum sum)
 40{
 41	u32 tmp = (__force u32)sum;
 42
 43	/*
 44	 * swap the two 16-bit halves of sum
 45	 * if there is a carry from adding the two 16-bit halves,
 46	 * it will carry from the lower half into the upper half,
 47	 * giving us the correct sum in the upper half.
 48	 */
 49	return (__force __sum16)(~(tmp + rol32(tmp, 16)) >> 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 __always_inline __wsum csum_add(__wsum csum, __wsum addend)
 96{
 97#ifdef __powerpc64__
 98	u64 res = (__force u64)csum;
 99
100	res += (__force u64)addend;
101	return (__force __wsum)((u32)res + (res >> 32));
102#else
103	if (__builtin_constant_p(csum) && csum == 0)
104		return addend;
105	if (__builtin_constant_p(addend) && addend == 0)
106		return csum;
107
108	asm("addc %0,%0,%1;"
109	    "addze %0,%0;"
110	    : "+r" (csum) : "r" (addend) : "xer");
111	return csum;
112#endif
113}
114
115#define HAVE_ARCH_CSUM_SHIFT
116static __always_inline __wsum csum_shift(__wsum sum, int offset)
117{
118	/* rotate sum to align it with a 16b boundary */
119	return (__force __wsum)rol32((__force u32)sum, (offset & 1) << 3);
120}
121
122/*
123 * This is a version of ip_compute_csum() optimized for IP headers,
124 * which always checksum on 4 octet boundaries.  ihl is the number
125 * of 32-bit words and is always >= 5.
126 */
127static inline __wsum ip_fast_csum_nofold(const void *iph, unsigned int ihl)
128{
129	const u32 *ptr = (const u32 *)iph + 1;
130#ifdef __powerpc64__
131	unsigned int i;
132	u64 s = *(const u32 *)iph;
133
134	for (i = 0; i < ihl - 1; i++, ptr++)
135		s += *ptr;
136	return (__force __wsum)from64to32(s);
137#else
138	__wsum sum, tmp;
139
140	asm("mtctr %3;"
141	    "addc %0,%4,%5;"
142	    "1: lwzu %1, 4(%2);"
143	    "adde %0,%0,%1;"
144	    "bdnz 1b;"
145	    "addze %0,%0;"
146	    : "=r" (sum), "=r" (tmp), "+b" (ptr)
147	    : "r" (ihl - 2), "r" (*(const u32 *)iph), "r" (*ptr)
148	    : "ctr", "xer", "memory");
149
150	return sum;
151#endif
152}
153
154static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
155{
156	return csum_fold(ip_fast_csum_nofold(iph, ihl));
157}
158
159/*
160 * computes the checksum of a memory block at buff, length len,
161 * and adds in "sum" (32-bit)
162 *
163 * returns a 32-bit number suitable for feeding into itself
164 * or csum_tcpudp_magic
165 *
166 * this function must be called with even lengths, except
167 * for the last fragment, which may be odd
168 *
169 * it's best to have buff aligned on a 32-bit boundary
170 */
171__wsum __csum_partial(const void *buff, int len, __wsum sum);
172
173static __always_inline __wsum csum_partial(const void *buff, int len, __wsum sum)
174{
175	if (__builtin_constant_p(len) && len <= 16 && (len & 1) == 0) {
176		if (len == 2)
177			sum = csum_add(sum, (__force __wsum)*(const u16 *)buff);
178		if (len >= 4)
179			sum = csum_add(sum, (__force __wsum)*(const u32 *)buff);
180		if (len == 6)
181			sum = csum_add(sum, (__force __wsum)
182					    *(const u16 *)(buff + 4));
183		if (len >= 8)
184			sum = csum_add(sum, (__force __wsum)
185					    *(const u32 *)(buff + 4));
186		if (len == 10)
187			sum = csum_add(sum, (__force __wsum)
188					    *(const u16 *)(buff + 8));
189		if (len >= 12)
190			sum = csum_add(sum, (__force __wsum)
191					    *(const u32 *)(buff + 8));
192		if (len == 14)
193			sum = csum_add(sum, (__force __wsum)
194					    *(const u16 *)(buff + 12));
195		if (len >= 16)
196			sum = csum_add(sum, (__force __wsum)
197					    *(const u32 *)(buff + 12));
198	} else if (__builtin_constant_p(len) && (len & 3) == 0) {
199		sum = csum_add(sum, ip_fast_csum_nofold(buff, len >> 2));
200	} else {
201		sum = __csum_partial(buff, len, sum);
202	}
203	return sum;
204}
205
206/*
207 * this routine is used for miscellaneous IP-like checksums, mainly
208 * in icmp.c
209 */
210static inline __sum16 ip_compute_csum(const void *buff, int len)
211{
212	return csum_fold(csum_partial(buff, len, 0));
213}
214
215#define _HAVE_ARCH_IPV6_CSUM
216__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
217			const struct in6_addr *daddr,
218			__u32 len, __u8 proto, __wsum sum);
219
220#endif /* __KERNEL__ */
221#endif