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371 lines
9.3 KiB
371 lines
9.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* INET An implementation of the TCP/IP protocol suite for the LINUX |
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* operating system. INET is implemented using the BSD Socket |
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* interface as the means of communication with the user level. |
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* |
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* IP/TCP/UDP checksumming routines |
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* |
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* Authors: Jorge Cwik, <[email protected]> |
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* Arnt Gulbrandsen, <[email protected]> |
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* Tom May, <[email protected]> |
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* Andreas Schwab, <[email protected]> |
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* Lots of code moved from tcp.c and ip.c; see those files |
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* for more names. |
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* |
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* 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek: |
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* Fixed some nasty bugs, causing some horrible crashes. |
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* A: At some points, the sum (%0) was used as |
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* length-counter instead of the length counter |
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* (%1). Thanks to Roman Hodek for pointing this out. |
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* B: GCC seems to mess up if one uses too many |
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* data-registers to hold input values and one tries to |
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* specify d0 and d1 as scratch registers. Letting gcc |
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* choose these registers itself solves the problem. |
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* |
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* 1998/8/31 Andreas Schwab: |
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* Zero out rest of buffer on exception in |
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* csum_partial_copy_from_user. |
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*/ |
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#include <linux/module.h> |
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#include <net/checksum.h> |
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/* |
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* computes a partial checksum, e.g. for TCP/UDP fragments |
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*/ |
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__wsum csum_partial(const void *buff, int len, __wsum sum) |
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{ |
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unsigned long tmp1, tmp2; |
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/* |
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* Experiments with ethernet and slip connections show that buff |
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* is aligned on either a 2-byte or 4-byte boundary. |
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*/ |
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__asm__("movel %2,%3\n\t" |
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"btst #1,%3\n\t" /* Check alignment */ |
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"jeq 2f\n\t" |
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"subql #2,%1\n\t" /* buff%4==2: treat first word */ |
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"jgt 1f\n\t" |
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"addql #2,%1\n\t" /* len was == 2, treat only rest */ |
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"jra 4f\n" |
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"1:\t" |
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"addw %2@+,%0\n\t" /* add first word to sum */ |
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"clrl %3\n\t" |
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"addxl %3,%0\n" /* add X bit */ |
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"2:\t" |
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/* unrolled loop for the main part: do 8 longs at once */ |
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"movel %1,%3\n\t" /* save len in tmp1 */ |
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"lsrl #5,%1\n\t" /* len/32 */ |
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"jeq 2f\n\t" /* not enough... */ |
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"subql #1,%1\n" |
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"1:\t" |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"dbra %1,1b\n\t" |
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"clrl %4\n\t" |
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"addxl %4,%0\n\t" /* add X bit */ |
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"clrw %1\n\t" |
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"subql #1,%1\n\t" |
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"jcc 1b\n" |
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"2:\t" |
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"movel %3,%1\n\t" /* restore len from tmp1 */ |
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"andw #0x1c,%3\n\t" /* number of rest longs */ |
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"jeq 4f\n\t" |
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"lsrw #2,%3\n\t" |
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"subqw #1,%3\n" |
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"3:\t" |
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/* loop for rest longs */ |
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"movel %2@+,%4\n\t" |
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"addxl %4,%0\n\t" |
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"dbra %3,3b\n\t" |
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"clrl %4\n\t" |
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"addxl %4,%0\n" /* add X bit */ |
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"4:\t" |
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/* now check for rest bytes that do not fit into longs */ |
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"andw #3,%1\n\t" |
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"jeq 7f\n\t" |
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"clrl %4\n\t" /* clear tmp2 for rest bytes */ |
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"subqw #2,%1\n\t" |
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"jlt 5f\n\t" |
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"movew %2@+,%4\n\t" /* have rest >= 2: get word */ |
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"swap %4\n\t" /* into bits 16..31 */ |
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"tstw %1\n\t" /* another byte? */ |
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"jeq 6f\n" |
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"5:\t" |
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"moveb %2@,%4\n\t" /* have odd rest: get byte */ |
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"lslw #8,%4\n\t" /* into bits 8..15; 16..31 untouched */ |
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"6:\t" |
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"addl %4,%0\n\t" /* now add rest long to sum */ |
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"clrl %4\n\t" |
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"addxl %4,%0\n" /* add X bit */ |
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"7:\t" |
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: "=d" (sum), "=d" (len), "=a" (buff), |
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"=&d" (tmp1), "=&d" (tmp2) |
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: "0" (sum), "1" (len), "2" (buff) |
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); |
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return(sum); |
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} |
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EXPORT_SYMBOL(csum_partial); |
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/* |
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* copy from user space while checksumming, with exception handling. |
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*/ |
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__wsum |
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csum_and_copy_from_user(const void __user *src, void *dst, int len) |
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{ |
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/* |
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* GCC doesn't like more than 10 operands for the asm |
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* statements so we have to use tmp2 for the error |
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* code. |
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*/ |
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unsigned long tmp1, tmp2; |
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__wsum sum = ~0U; |
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__asm__("movel %2,%4\n\t" |
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"btst #1,%4\n\t" /* Check alignment */ |
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"jeq 2f\n\t" |
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"subql #2,%1\n\t" /* buff%4==2: treat first word */ |
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"jgt 1f\n\t" |
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"addql #2,%1\n\t" /* len was == 2, treat only rest */ |
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"jra 4f\n" |
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"1:\n" |
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"10:\t" |
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"movesw %2@+,%4\n\t" /* add first word to sum */ |
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"addw %4,%0\n\t" |
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"movew %4,%3@+\n\t" |
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"clrl %4\n\t" |
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"addxl %4,%0\n" /* add X bit */ |
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"2:\t" |
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/* unrolled loop for the main part: do 8 longs at once */ |
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"movel %1,%4\n\t" /* save len in tmp1 */ |
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"lsrl #5,%1\n\t" /* len/32 */ |
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"jeq 2f\n\t" /* not enough... */ |
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"subql #1,%1\n" |
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"1:\n" |
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"11:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"12:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"13:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"14:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"15:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"16:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"17:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"18:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"dbra %1,1b\n\t" |
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"clrl %5\n\t" |
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"addxl %5,%0\n\t" /* add X bit */ |
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"clrw %1\n\t" |
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"subql #1,%1\n\t" |
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"jcc 1b\n" |
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"2:\t" |
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"movel %4,%1\n\t" /* restore len from tmp1 */ |
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"andw #0x1c,%4\n\t" /* number of rest longs */ |
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"jeq 4f\n\t" |
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"lsrw #2,%4\n\t" |
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"subqw #1,%4\n" |
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"3:\n" |
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/* loop for rest longs */ |
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"19:\t" |
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"movesl %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"dbra %4,3b\n\t" |
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"clrl %5\n\t" |
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"addxl %5,%0\n" /* add X bit */ |
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"4:\t" |
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/* now check for rest bytes that do not fit into longs */ |
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"andw #3,%1\n\t" |
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"jeq 7f\n\t" |
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"clrl %5\n\t" /* clear tmp2 for rest bytes */ |
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"subqw #2,%1\n\t" |
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"jlt 5f\n\t" |
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"20:\t" |
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"movesw %2@+,%5\n\t" /* have rest >= 2: get word */ |
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"movew %5,%3@+\n\t" |
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"swap %5\n\t" /* into bits 16..31 */ |
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"tstw %1\n\t" /* another byte? */ |
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"jeq 6f\n" |
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"5:\n" |
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"21:\t" |
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"movesb %2@,%5\n\t" /* have odd rest: get byte */ |
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"moveb %5,%3@+\n\t" |
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"lslw #8,%5\n\t" /* into bits 8..15; 16..31 untouched */ |
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"6:\t" |
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"addl %5,%0\n\t" /* now add rest long to sum */ |
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"clrl %5\n\t" |
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"addxl %5,%0\n\t" /* add X bit */ |
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"7:\t" |
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".section .fixup,\"ax\"\n" |
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".even\n" |
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/* If any exception occurs, return 0 */ |
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"90:\t" |
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"clrl %0\n" |
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"jra 7b\n" |
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".previous\n" |
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".section __ex_table,\"a\"\n" |
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".long 10b,90b\n" |
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".long 11b,90b\n" |
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".long 12b,90b\n" |
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".long 13b,90b\n" |
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".long 14b,90b\n" |
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".long 15b,90b\n" |
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".long 16b,90b\n" |
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".long 17b,90b\n" |
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".long 18b,90b\n" |
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".long 19b,90b\n" |
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".long 20b,90b\n" |
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".long 21b,90b\n" |
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".previous" |
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: "=d" (sum), "=d" (len), "=a" (src), "=a" (dst), |
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"=&d" (tmp1), "=d" (tmp2) |
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: "0" (sum), "1" (len), "2" (src), "3" (dst) |
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); |
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return sum; |
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} |
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EXPORT_SYMBOL(csum_and_copy_from_user); |
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/* |
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* copy from kernel space while checksumming, otherwise like csum_partial |
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*/ |
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__wsum |
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csum_partial_copy_nocheck(const void *src, void *dst, int len) |
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{ |
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unsigned long tmp1, tmp2; |
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__wsum sum = 0; |
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__asm__("movel %2,%4\n\t" |
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"btst #1,%4\n\t" /* Check alignment */ |
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"jeq 2f\n\t" |
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"subql #2,%1\n\t" /* buff%4==2: treat first word */ |
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"jgt 1f\n\t" |
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"addql #2,%1\n\t" /* len was == 2, treat only rest */ |
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"jra 4f\n" |
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"1:\t" |
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"movew %2@+,%4\n\t" /* add first word to sum */ |
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"addw %4,%0\n\t" |
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"movew %4,%3@+\n\t" |
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"clrl %4\n\t" |
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"addxl %4,%0\n" /* add X bit */ |
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"2:\t" |
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/* unrolled loop for the main part: do 8 longs at once */ |
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"movel %1,%4\n\t" /* save len in tmp1 */ |
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"lsrl #5,%1\n\t" /* len/32 */ |
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"jeq 2f\n\t" /* not enough... */ |
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"subql #1,%1\n" |
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"1:\t" |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"dbra %1,1b\n\t" |
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"clrl %5\n\t" |
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"addxl %5,%0\n\t" /* add X bit */ |
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"clrw %1\n\t" |
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"subql #1,%1\n\t" |
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"jcc 1b\n" |
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"2:\t" |
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"movel %4,%1\n\t" /* restore len from tmp1 */ |
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"andw #0x1c,%4\n\t" /* number of rest longs */ |
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"jeq 4f\n\t" |
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"lsrw #2,%4\n\t" |
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"subqw #1,%4\n" |
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"3:\t" |
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/* loop for rest longs */ |
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"movel %2@+,%5\n\t" |
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"addxl %5,%0\n\t" |
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"movel %5,%3@+\n\t" |
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"dbra %4,3b\n\t" |
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"clrl %5\n\t" |
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"addxl %5,%0\n" /* add X bit */ |
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"4:\t" |
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/* now check for rest bytes that do not fit into longs */ |
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"andw #3,%1\n\t" |
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"jeq 7f\n\t" |
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"clrl %5\n\t" /* clear tmp2 for rest bytes */ |
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"subqw #2,%1\n\t" |
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"jlt 5f\n\t" |
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"movew %2@+,%5\n\t" /* have rest >= 2: get word */ |
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"movew %5,%3@+\n\t" |
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"swap %5\n\t" /* into bits 16..31 */ |
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"tstw %1\n\t" /* another byte? */ |
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"jeq 6f\n" |
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"5:\t" |
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"moveb %2@,%5\n\t" /* have odd rest: get byte */ |
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"moveb %5,%3@+\n\t" |
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"lslw #8,%5\n" /* into bits 8..15; 16..31 untouched */ |
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"6:\t" |
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"addl %5,%0\n\t" /* now add rest long to sum */ |
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"clrl %5\n\t" |
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"addxl %5,%0\n" /* add X bit */ |
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"7:\t" |
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: "=d" (sum), "=d" (len), "=a" (src), "=a" (dst), |
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"=&d" (tmp1), "=&d" (tmp2) |
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: "0" (sum), "1" (len), "2" (src), "3" (dst) |
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); |
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return(sum); |
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} |
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EXPORT_SYMBOL(csum_partial_copy_nocheck);
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