- 根目录:
- arch
- xtensa
- include
- asm
- checksum.h
/*
* include/asm-xtensa/checksum.h
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2005 Tensilica Inc.
*/
#ifndef _XTENSA_CHECKSUM_H
#define _XTENSA_CHECKSUM_H
#include <linux/in6.h>
#include <variant/core.h>
/*
* computes the checksum of a memory block at buff, length len,
* and adds in "sum" (32-bit)
*
* returns a 32-bit number suitable for feeding into itself
* or csum_tcpudp_magic
*
* this function must be called with even lengths, except
* for the last fragment, which may be odd
*
* it's best to have buff aligned on a 32-bit boundary
*/
asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
/*
* the same as csum_partial, but copies from src while it
* checksums, and handles user-space pointer exceptions correctly, when needed.
*
* here even more important to align src and dst on a 32-bit (or even
* better 64-bit) boundary
*/
asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len, __wsum sum,
int *src_err_ptr, int *dst_err_ptr);
/*
* Note: when you get a NULL pointer exception here this means someone
* passed in an incorrect kernel address to one of these functions.
*
* If you use these functions directly please don't forget the access_ok().
*/
static inline
__wsum csum_partial_copy_nocheck(const void *src, void *dst,
int len, __wsum sum)
{
return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
}
static inline
__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
int len, __wsum sum, int *err_ptr)
{
return csum_partial_copy_generic((__force const void *)src, dst,
len, sum, err_ptr, NULL);
}
/*
* Fold a partial checksum
*/
static __inline__ __sum16 csum_fold(__wsum sum)
{
unsigned int __dummy;
__asm__("extui %1, %0, 16, 16\n\t"
"extui %0 ,%0, 0, 16\n\t"
"add %0, %0, %1\n\t"
"slli %1, %0, 16\n\t"
"add %0, %0, %1\n\t"
"extui %0, %0, 16, 16\n\t"
"neg %0, %0\n\t"
"addi %0, %0, -1\n\t"
"extui %0, %0, 0, 16\n\t"
: "=r" (sum), "=&r" (__dummy)
: "0" (sum));
return (__force __sum16)sum;
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*/
static __inline__ __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
unsigned int sum, tmp, endaddr;
__asm__ __volatile__(
"sub %0, %0, %0\n\t"
#if XCHAL_HAVE_LOOPS
"loopgtz %2, 2f\n\t"
#else
"beqz %2, 2f\n\t"
"slli %4, %2, 2\n\t"
"add %4, %4, %1\n\t"
"0:\t"
#endif
"l32i %3, %1, 0\n\t"
"add %0, %0, %3\n\t"
"bgeu %0, %3, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"addi %1, %1, 4\n\t"
#if !XCHAL_HAVE_LOOPS
"blt %1, %4, 0b\n\t"
#endif
"2:\t"
/* Since the input registers which are loaded with iph and ihl
are modified, we must also specify them as outputs, or gcc
will assume they contain their original values. */
: "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (tmp), "=&r" (endaddr)
: "1" (iph), "2" (ihl)
: "memory");
return csum_fold(sum);
}
static __inline__ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
unsigned short len,
unsigned short proto,
__wsum sum)
{
#ifdef __XTENSA_EL__
unsigned long len_proto = (len + proto) << 8;
#elif defined(__XTENSA_EB__)
unsigned long len_proto = len + proto;
#else
# error processor byte order undefined!
#endif
__asm__("add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"add %0, %0, %2\n\t"
"bgeu %0, %2, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"add %0, %0, %3\n\t"
"bgeu %0, %3, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
: "=r" (sum), "=r" (len_proto)
: "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum));
return sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
unsigned short len,
unsigned short proto,
__wsum sum)
{
return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
}
/*
* this routine is used for miscellaneous IP-like checksums, mainly
* in icmp.c
*/
static __inline__ __sum16 ip_compute_csum(const void *buff, int len)
{
return csum_fold (csum_partial(buff, len, 0));
}
#define _HAVE_ARCH_IPV6_CSUM
static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__u32 len, unsigned short proto,
__wsum sum)
{
unsigned int __dummy;
__asm__("l32i %1, %2, 0\n\t"
"add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"l32i %1, %2, 4\n\t"
"add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"l32i %1, %2, 8\n\t"
"add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"l32i %1, %2, 12\n\t"
"add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"l32i %1, %3, 0\n\t"
"add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"l32i %1, %3, 4\n\t"
"add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"l32i %1, %3, 8\n\t"
"add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"l32i %1, %3, 12\n\t"
"add %0, %0, %1\n\t"
"bgeu %0, %1, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"add %0, %0, %4\n\t"
"bgeu %0, %4, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
"add %0, %0, %5\n\t"
"bgeu %0, %5, 1f\n\t"
"addi %0, %0, 1\n\t"
"1:\t"
: "=r" (sum), "=&r" (__dummy)
: "r" (saddr), "r" (daddr),
"r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
: "memory");
return csum_fold(sum);
}
/*
* Copy and checksum to user
*/
#define HAVE_CSUM_COPY_USER
static __inline__ __wsum csum_and_copy_to_user(const void *src, void __user *dst,
int len, __wsum sum, int *err_ptr)
{
if (access_ok(VERIFY_WRITE, dst, len))
return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
if (len)
*err_ptr = -EFAULT;
return (__force __wsum)-1; /* invalid checksum */
}
#endif