arch/m68k/include/asm/checksum.h

Source file repositories/reference/linux-study-clean/arch/m68k/include/asm/checksum.h

File Facts

System
Linux kernel
Corpus path
arch/m68k/include/asm/checksum.h
Extension
.h
Size
3497 bytes
Lines
151
Domain
Architecture Layer
Bucket
arch/m68k
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _M68K_CHECKSUM_H
#define _M68K_CHECKSUM_H

#include <linux/in6.h>

#ifdef CONFIG_GENERIC_CSUM
#include <asm-generic/checksum.h>
#else

/*
 * 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
 */
__wsum csum_partial(const void *buff, int len, __wsum sum);

/*
 * the same as csum_partial, but copies from src while it
 * checksums
 *
 * here even more important to align src and dst on a 32-bit (or even
 * better 64-bit) boundary
 */

#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
#define _HAVE_ARCH_CSUM_AND_COPY
extern __wsum csum_and_copy_from_user(const void __user *src,
						void *dst,
						int len);

extern __wsum csum_partial_copy_nocheck(const void *src,
					      void *dst, int len);

/*
 *	This is a version of ip_fast_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 = 0;
	unsigned long tmp;

	__asm__ ("subqw #1,%2\n"
		 "1:\t"
		 "movel %1@+,%3\n\t"
		 "addxl %3,%0\n\t"
		 "dbra  %2,1b\n\t"
		 "movel %0,%3\n\t"
		 "swap  %3\n\t"
		 "addxw %3,%0\n\t"
		 "clrw  %3\n\t"
		 "addxw %3,%0\n\t"
		 : "=d" (sum), "=&a" (iph), "=&d" (ihl), "=&d" (tmp)
		 : "0" (sum), "1" (iph), "2" (ihl)
		 : "memory");
	return (__force __sum16)~sum;
}

static inline __sum16 csum_fold(__wsum sum)
{
	unsigned int tmp = (__force u32)sum;

	__asm__("swap %1\n\t"
		"addw %1, %0\n\t"
		"clrw %1\n\t"
		"addxw %1, %0"
		: "=&d" (sum), "=&d" (tmp)
		: "0" (sum), "1" (tmp));

	return (__force __sum16)~sum;
}

static inline __wsum
csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
		  unsigned short proto, __wsum sum)
{
	__asm__ ("addl  %2,%0\n\t"
		 "addxl %3,%0\n\t"
		 "addxl %4,%0\n\t"
		 "clrl %1\n\t"
		 "addxl %1,%0"
		 : "=&d" (sum), "=d" (saddr)
		 : "g" (daddr), "1" (saddr), "d" (len + proto),

Annotation

Implementation Notes