cregit-Linux how code gets into the kernel

Release 4.14 arch/m68k/lib/checksum.c

Directory: arch/m68k/lib
/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              IP/TCP/UDP checksumming routines
 *
 * Authors:     Jorge Cwik, <jorge@laser.satlink.net>
 *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 *              Tom May, <ftom@netcom.com>
 *              Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de>
 *              Lots of code moved from tcp.c and ip.c; see those files
 *              for more names.
 *
 * 03/02/96     Jes Sorensen, Andreas Schwab, Roman Hodek:
 *              Fixed some nasty bugs, causing some horrible crashes.
 *              A: At some points, the sum (%0) was used as
 *              length-counter instead of the length counter
 *              (%1). Thanks to Roman Hodek for pointing this out.
 *              B: GCC seems to mess up if one uses too many
 *              data-registers to hold input values and one tries to
 *              specify d0 and d1 as scratch registers. Letting gcc
 *              choose these registers itself solves the problem.
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 * 1998/8/31    Andreas Schwab:
 *              Zero out rest of buffer on exception in
 *              csum_partial_copy_from_user.
 */

#include <linux/module.h>
#include <net/checksum.h>

/*
 * computes a partial checksum, e.g. for TCP/UDP fragments
 */


__wsum csum_partial(const void *buff, int len, __wsum sum) { unsigned long tmp1, tmp2; /* * Experiments with ethernet and slip connections show that buff * is aligned on either a 2-byte or 4-byte boundary. */ __asm__("movel %2,%3\n\t" "btst #1,%3\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\t" "addw %2@+,%0\n\t" /* add first word to sum */ "clrl %3\n\t" "addxl %3,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%3\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "dbra %1,1b\n\t" "clrl %4\n\t" "addxl %4,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %3,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%3\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%3\n\t" "subqw #1,%3\n" "3:\t" /* loop for rest longs */ "movel %2@+,%4\n\t" "addxl %4,%0\n\t" "dbra %3,3b\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %4\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "movew %2@+,%4\n\t" /* have rest >= 2: get word */ "swap %4\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\t" "moveb %2@,%4\n\t" /* have odd rest: get byte */ "lslw #8,%4\n\t" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %4,%0\n\t" /* now add rest long to sum */ "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "7:\t" : "=d" (sum), "=d" (len), "=a" (buff), "=&d" (tmp1), "=&d" (tmp2) : "0" (sum), "1" (len), "2" (buff) ); return(sum); }

Contributors

PersonTokensPropCommitsCommitProp
Greg Ungerer75100.00%1100.00%
Total75100.00%1100.00%

EXPORT_SYMBOL(csum_partial); /* * copy from user space while checksumming, with exception handling. */
__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *csum_err) { /* * GCC doesn't like more than 10 operands for the asm * statements so we have to use tmp2 for the error * code. */ unsigned long tmp1, tmp2; __asm__("movel %2,%4\n\t" "btst #1,%4\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\n" "10:\t" "movesw %2@+,%4\n\t" /* add first word to sum */ "addw %4,%0\n\t" "movew %4,%3@+\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%4\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\n" "11:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "12:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "13:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "14:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "15:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "16:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "17:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "18:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %1,1b\n\t" "clrl %5\n\t" "addxl %5,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %4,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%4\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%4\n\t" "subqw #1,%4\n" "3:\n" /* loop for rest longs */ "19:\t" "movesl %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %4,3b\n\t" "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %5\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "20:\t" "movesw %2@+,%5\n\t" /* have rest >= 2: get word */ "movew %5,%3@+\n\t" "swap %5\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\n" "21:\t" "movesb %2@,%5\n\t" /* have odd rest: get byte */ "moveb %5,%3@+\n\t" "lslw #8,%5\n\t" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %5,%0\n\t" /* now add rest long to sum */ "clrl %5\n\t" "addxl %5,%0\n\t" /* add X bit */ "7:\t" "clrl %5\n" /* no error - clear return value */ "8:\n" ".section .fixup,\"ax\"\n" ".even\n" /* If any exception occurs zero out the rest. Similarities with the code above are intentional :-) */ "90:\t" "clrw %3@+\n\t" "movel %1,%4\n\t" "lsrl #5,%1\n\t" "jeq 1f\n\t" "subql #1,%1\n" "91:\t" "clrl %3@+\n" "92:\t" "clrl %3@+\n" "93:\t" "clrl %3@+\n" "94:\t" "clrl %3@+\n" "95:\t" "clrl %3@+\n" "96:\t" "clrl %3@+\n" "97:\t" "clrl %3@+\n" "98:\t" "clrl %3@+\n\t" "dbra %1,91b\n\t" "clrw %1\n\t" "subql #1,%1\n\t" "jcc 91b\n" "1:\t" "movel %4,%1\n\t" "andw #0x1c,%4\n\t" "jeq 1f\n\t" "lsrw #2,%4\n\t" "subqw #1,%4\n" "99:\t" "clrl %3@+\n\t" "dbra %4,99b\n\t" "1:\t" "andw #3,%1\n\t" "jeq 9f\n" "100:\t" "clrw %3@+\n\t" "tstw %1\n\t" "jeq 9f\n" "101:\t" "clrb %3@+\n" "9:\t" #define STR(X) STR1(X) #define STR1(X) #X "moveq #-" STR(EFAULT) ",%5\n\t" "jra 8b\n" ".previous\n" ".section __ex_table,\"a\"\n" ".long 10b,90b\n" ".long 11b,91b\n" ".long 12b,92b\n" ".long 13b,93b\n" ".long 14b,94b\n" ".long 15b,95b\n" ".long 16b,96b\n" ".long 17b,97b\n" ".long 18b,98b\n" ".long 19b,99b\n" ".long 20b,100b\n" ".long 21b,101b\n" ".previous" : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst), "=&d" (tmp1), "=d" (tmp2) : "0" (sum), "1" (len), "2" (src), "3" (dst) ); *csum_err = tmp2; return(sum); }

Contributors

PersonTokensPropCommitsCommitProp
Greg Ungerer108100.00%1100.00%
Total108100.00%1100.00%

EXPORT_SYMBOL(csum_partial_copy_from_user); /* * copy from kernel space while checksumming, otherwise like csum_partial */
__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum) { unsigned long tmp1, tmp2; __asm__("movel %2,%4\n\t" "btst #1,%4\n\t" /* Check alignment */ "jeq 2f\n\t" "subql #2,%1\n\t" /* buff%4==2: treat first word */ "jgt 1f\n\t" "addql #2,%1\n\t" /* len was == 2, treat only rest */ "jra 4f\n" "1:\t" "movew %2@+,%4\n\t" /* add first word to sum */ "addw %4,%0\n\t" "movew %4,%3@+\n\t" "clrl %4\n\t" "addxl %4,%0\n" /* add X bit */ "2:\t" /* unrolled loop for the main part: do 8 longs at once */ "movel %1,%4\n\t" /* save len in tmp1 */ "lsrl #5,%1\n\t" /* len/32 */ "jeq 2f\n\t" /* not enough... */ "subql #1,%1\n" "1:\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %1,1b\n\t" "clrl %5\n\t" "addxl %5,%0\n\t" /* add X bit */ "clrw %1\n\t" "subql #1,%1\n\t" "jcc 1b\n" "2:\t" "movel %4,%1\n\t" /* restore len from tmp1 */ "andw #0x1c,%4\n\t" /* number of rest longs */ "jeq 4f\n\t" "lsrw #2,%4\n\t" "subqw #1,%4\n" "3:\t" /* loop for rest longs */ "movel %2@+,%5\n\t" "addxl %5,%0\n\t" "movel %5,%3@+\n\t" "dbra %4,3b\n\t" "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "4:\t" /* now check for rest bytes that do not fit into longs */ "andw #3,%1\n\t" "jeq 7f\n\t" "clrl %5\n\t" /* clear tmp2 for rest bytes */ "subqw #2,%1\n\t" "jlt 5f\n\t" "movew %2@+,%5\n\t" /* have rest >= 2: get word */ "movew %5,%3@+\n\t" "swap %5\n\t" /* into bits 16..31 */ "tstw %1\n\t" /* another byte? */ "jeq 6f\n" "5:\t" "moveb %2@,%5\n\t" /* have odd rest: get byte */ "moveb %5,%3@+\n\t" "lslw #8,%5\n" /* into bits 8..15; 16..31 untouched */ "6:\t" "addl %5,%0\n\t" /* now add rest long to sum */ "clrl %5\n\t" "addxl %5,%0\n" /* add X bit */ "7:\t" : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst), "=&d" (tmp1), "=&d" (tmp2) : "0" (sum), "1" (len), "2" (src), "3" (dst) ); return(sum); }

Contributors

PersonTokensPropCommitsCommitProp
Greg Ungerer78100.00%1100.00%
Total78100.00%1100.00%

EXPORT_SYMBOL(csum_partial_copy_nocheck);

Overall Contributors

PersonTokensPropCommitsCommitProp
Greg Ungerer286100.00%1100.00%
Total286100.00%1100.00%
Directory: arch/m68k/lib
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.